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Introduction

Multi-purpose shipttCapricorntt

Open container ship"Nedlloyd Europa"

Car & Passenger Ferry"Pride of Hull"

Chemical tanker and aproduct tanker

Anchor Handling TirgSupplier (AHTS)

Fishing vessel @urocutter)"2575"

l lntroduction

This chapter shows some 3-dimen-sional views of ships. All visibleparts and spaces are numbered andnamed.

This is meant as an introduction todifferent types of ships and can beused as a reference for the followingchapters. It can also be used as anindication of the size of a compart-ment compared to the whole ship.

2 Multi-purpose ship "Capricorn"

1. Rudder2. Propeller

3. Main engine with gearbox andshaft generator

4. CO2 bottles in CO2 room5. Man overboard boat (MOB)

6. Free fall lifeboat

7. Crane for MOB, lifeboat,liferaft and provisions.

8. Funnel with all exhaust pipes

9. Rear mast with navigationlights

10. Cross trees with radarscanners11. Topdeck with magnetic

compass and search light12. Accommodation13. Hatch cradle14. Heavy fuel oil tank15. Bulk cargo16. Vertical bulkhead or pontoon

17. Heavy cargo, steel coils18. Project cargo19. Horizontal decks or hatchcovers

20. General cargo, rolls of paper

21. Shear strake22. Hold fan23. Fixed bulkhead24. Container pedestal

25. Tanktop, max. load 15 t/m226. Containers,5 rows, 3 bays21. Vertical bulkhead or pontoon

28. Hatch coaming29. Wing tank (ballasr)

30. Bulk cargo

31. Gangway

32. Stacked hatches

33. Top light, range light

34. Breakwater

35. Anchor winch36. Collision bulkhead37. Deeptank

38. Bow thruster in nozzle39. Forepeak tank in bulbous stem40. Port side41. Starboard side

Ship Knowledge, a modern encyclopedia IO

Principal Dimensions

Length o.a.Length b.p.p.Breadth mouldedDepth to maindeckDesign Draught

in holdon hatches

Containersin holdon hatches

1 1 8 . 5 5 m1 1 1 . 8 5 m

15.20 m8.45 m6.30 m

Corresponding deadweight 6600 tons( excl. grain bulkheads/tweendeck)

Capacities

Containers (14 ton homogeneous, v.c.g. 457o) inaccordance with ISO standard atmean draught of appr. 6.30 mtr.

174TEU96 TEU

I'74TEU242TEU

-)

Tonnage Regulation (London 1969) 4900 GTGrain capacity (excl. bulkheads) 328500 cbft

Speed

At a draught of 6.30 m service speed will be 14 knots, at ashaft power of 3321 kW.(main engine = 3840 kW / 150 kW for PTO / 907o MCR)

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Sltip Knowledge, er modent encvclopedict I l

3 Open container ship "Nedlloyd Europa"

l .

2.aJ .

4.

5 .

6.'7

8 .9.10 .l l .t 2 .1 3 .14 .1 5 .16 .1 7 ,1 8 .t9.

20.2 t .22.

Rudder

Propeller

Stem

Container with a length of 40feet (FEU) on a 40' stack

Container with a length of 20feet (TEU) on a 20' stackAccommodation ladderPilot or bunker door

Container guide railRow no 11

Row no 04

Tier no 08Wing tank (water ballast)Service gallery

Fixed stackMovable stackBay no l5

Bay no 06Tier no 86

Cells, hold I and 2, forcontainers with dangerousgoods (explosives)

Container supportBreakwater

Bulbous bow

PrincipalIMO noNameGross Tonnage

Net Tonnage

Deadwt Tonnage

Year when BuiltEngine

Ship Builder

Speed

Yard Number

Dimensions

Depth

Vessel TypeCall SignContainersFlag

In Service

Dimensions8915691Nedlloyd Europa485081925450620t99l41615 hp SulzerMitsubishi H.I.Nagasaki Japan23.5 knots1 1 8 4266.30-32.24-23.2512.50Container ShipPGDF3604 teuNeth.t997

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Ship Knou'ledge, a moclent enc\clopeclict 12

Ship Knowledge, a modern encyclopedia

4 Car & Passenger Ferry "Pride of Hull"

1. Becker rudder2. Controllable pitch propeller

3. Sternfibe4. Ballast tank

5. Aft engine room with gearbox

6. Seawater inlet chest

7. Forward engine room with I of the 4 main engines8. Stern ramp

9. Mooring gear

10.CO2 - battery space11. Harbour control room for loading officer12.Maindeck for trailers and double stacked containers13. Gangway14.Outside decks15.Lifeboat hanging in davits16.Deck 11

17.Funnel

lS.Exhaust pipes

19.Panorama lounge

20.Officer and crew mess2l.Passenger cabins22.Fast-rescue boat23 .Div er accommodation24.Upper trailer deck25.Ramp to lower hold26. Stabili zer, retli actable27. Shops and restaurants

28.Helicopter deck29.Entertainment spaces and bars30.Fan room3l.Heeling tank

32.Void

33.Ro-ro cargo

34. Web frame

35.Car deck

36. Marine evacuation system37. Cinema

38.Satellite dome for internet

39.Satellite dome for communication (Inmarsat)

40.Radar mast41.Officer cabins42.Wheelhouse43.Car deck fan room44.Forecastle

45.Anchor

46.Bulbous bow47.Bow thrusters

Ship Knowledge, a modern encyclopedia I4

Principal Dimensions:

Delivered: Nov.2001

Contract Price: 128million USD

Classification:Lloyd's Register +100A1,Roll-on Roll-off Cargo andPassenger Ship+LMC, UMS, SLM.

Dimensions:Length o.a. 215.10 mLength b.p. 203.70 mBeam mld. 31.50 mDraught design 6.05 mDepth

to maindeck 9.40 m

Tonnage:GT 59,925NT 26,868tDW design 8,800tDW scantling 10,350

Passengers:Total capacity 1360- cabins 546

Car I Tbailer Deck:Cars 1380Lane 3355 m.

Access:Stern ramp (l x w)12.5x18 m

Machinery:Main engines (4):Output, Kw each 9450Output, BHP ttl 51394Rpm 500

Aux engines (2):kWeach 4050Rpm 720

Propellers (2):Diameter 4.9 mRpm 720

Bowthrusters (2):kWeach 2000

Speed / Consumption:Trial speed 23.8 knotsService speed 22.0 knotsFuel consump. l30.8t.l24hrFuel quality 380 cSt

Thnk Capacities:Heavy Rret oit 1000 m3Lub oil 50 m3Fresh water 400 m3Ballast water 3500 m3

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16Ship Knowledge, a modern encyclopedia

5 Chemical tanker and a product tanker

Balanced rudder with

conventional propeller

Auxiliary unit

Lifeboat in gravity davits

Hydraulic prime mover

Cargo control room

Tank heating / tankwash room

Cofferdam, empty space

between two tanks

Vent pipes with pressure-

vacuum valves

Hydraulic high pressure oil-and

return lines for anchor and

Double bottom tank

TanktopLongitudinal vertically

corrugated bulkhead

Transverse horizontally

corrugated bulkhead

17. Cargo pump

18. Catwalk19. Railing

20. Deck longitudinals

21. Deck transverses

22. Cargo heater

23. Forecastle deck with anchor-

and mooring gear

24. Bow thruster25. Bulbous bow

1 3 .t4.1 5 .

16.

moonng gear.

10. Hose crane11. Manifold

12. Wing tank in double hull

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Ship Knowledge, a modern encyclopedia I 7

6. Anchor Handling Tirg Supplier (AHTS)

1 .2.3 .4.5 .6.7.8.

9.10.1 1 .t2.1 3 .t4.

Stern roll for anchor handling

Stoppers for anchor handling

Steering engine

Starboard ducted propeller

Stern tube

Transverse thruster

CofferdamTanks for dry bulk cargo e.g.

cement

Mud tanks

Propeller shaft(Reduction) Gear box

Main engine

Fire pump

Life rafts

15. MOB-boat with crane

16. Storage reel for steel wires

for anchor handling

17. Anchor handling winch

18. Bridge with controls for deck

gear and ship's steering

Fire fighting monitor

Radar antennas

Antenna for communication

system / satellite antenna

Watertight bulkhead

Anchor windlass, below deck

Azimuth thruster

Bow thruster

19.20.2 r .

22.23.24.25.

hvo 3D itnages o.l'a platlrtrm supply ves,sel,

Ship Knowledge, a modern encyclopedia t8

@


8.

7 Fishing vessel (Eurocutter) "2575"

1. Rudder2. Jet nozzle

3. Propeller

4. Engine room

5. Engine room bulkhead

6. Main engine

7. Fuel tanks, two wing tanks and

a center tank

Starboard bracket pole, used

when fishing is done with nets

and otter boards. The derrick

will not be used in that case

Mast aftRevolving drum for nets

FunnelMessroom, dayroomBridge with navigational

equipment and control panels

for main engine, drum for nets

and fish winch

Cabin for four

Railing

Capping

Scupper hole

Wooden workdeck

Hatch on fish tank

Drop chuteFish tank, with an insulationlayer of about 20 cm all

around

22. Bilge keel

23. Shear strake

24. Double bottom

25. Bow thruster installation

26. Name of the ship and fishery(registration) number

27. Fish winch

28. Conveyor belt and fish cleaning

table

29. Guide pulleys for fish line

30. Forecastle deck

3I. Fish wire blocks

32. Fish wire

33. Fish derrick

34. Mast

35. Radar antenna on mast

Principal Dimension:

Dimensions:Length: 23.99 mBreadth: 6.20 mDepth: 2.70 m

Gross lbnnage: 102 GT

Delivered: 2000

Main Engine: 300 hp

9.10.1 1 .12.1 3 .

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1. Principal Dimensions

1.L General

Measurement T[eatyAll aspects concerning the measurements of seagoing vessels are aranged inthe certificate of registry act of 1982. Part of the certificate of registry act is theInternational treaty on the measurement of ships, as set up by the IMO-conference in 1969. The treaty applies to seagoing vessels with a minimumlength of 24 metres and came into force in July1994.

PerpendicularLine perpendicular to another line orplane (for instance the water line). Ona ship there are:Fore Perpendicular (FPB or FP)This line crosses the intersection ofthe water line and the front of thestem.Aft Perpendicular (APR or AP)This line usually aligns with thecenterline of the rudder stock (the

imaginary line around which therudder rotates).Load LineThe water line of a ship lying in thewater. There are different load linesfor different situations. such as:Light water lineThe water line of a ship carrying onlyher regular inventory.

Deep water lineThe water line of maximum loaddraught in seawater.Water lineThe load line at the summer mark ascalculated in the design of the ship bythe ship builder.Construction water line (CWL)The water line used to determine thedimensions of the various compo-nents from which the vessel isconstructed.

Deck lineExtended line from the topside of thefixed deck covering at the ship's side.

Moulded dimensionsDistance between two points,measured on inside plating (oroutside framing).

Base LineTop of the keel.

Plimsoll MarkThe Plimsoll mark or Freeboard markconsists of a circle with diameter ofone foot, which through a horizontalline is drawn with as upper edge thecentre of the circle. This levelindicates the minimum freeboardinsalt water summer conditions.Beside the circle is a number ofhorizontal lines indicating the mini-mum freeboard as above. Summerfreeboard: S. Other conditions:Tropical: T, Winter: W, Fresh (water):F, Tropical Fresh: TF, and for smallships, less than 100 m: Winter NorthAtlantic: WNA. All connected by avertical line. For easy checking of theposition of the Mark, above the marka reference line is drawn: the Deckline. Normally at the level of theweather deck, but in case the weatherdeck is not the freeboard deck (e.g.Ro-Ro), at the level of that deck.When the distance is impracticallylarge, or the connection deckshellplate is rounded off (tankers,bulkcarriers), the reference line ispositioned at a lower level. The Markand the Deckline are to be markedpermanently on port and starboard-side, midlength.

The draught marks, Plimsoll Lineand Plimsoll Mark are permanentmarks. Usually this means thatthey are carved into the hull.

Ship Ktowledge, a modern encyclopedia 24

Explanation of the picture at theright:

S = Summer (for waterwith a density of1.U25 tlm3)

W = Winter (ditto)T = Tropics (ditto)WNA = Winter North

Atlantic (ditto)TF = Tropical Fresh waterF = Fresh water

Air Draught

When a ship carries a deck cargo oftimber, and certain demands are met,this ship is allowed to have moredraught (less freeboard). This isbecause of the reserve buoyancycaused by the deck cargo. To indicatethis, the ship has a special Plimsoll'smark for when it is carrying a deckcargo of timber, the so-called timbermark.

1.2 Dimensions

Length between perpendiculars (Lpp)Distance between the Fore and the AftPerpendicular.Length over all (Loa)The horizontal distance from stem tostern.Length on the water line (Lwl)Horizontal distance between themoulded sides of stem and stern whenthe ship is on her summer mark.

Breadth (B)The greatest moulded breadth,measured from side to side outsidethe frames, but inside the shellplating.Breadth over allThe maximum breadth of the ship asmeasured from the outer hull onstarboard to the outer hull on port side.

Draught at the stem (Tfwd)Vertical distance between the waterline and the underside of the keel, asmeasured on the fore perpendicular.Draught at the stern (Ta)

The vertical distance between thewater line and the underside of thekeel as measured from the aftperpendicular.

T[imThe difference between the draught atthe stem and the draught at the stern.

-

I'lintsoll ntark

I'lint.soll line

I)ruught marks

I)eckline

tr reeboard

Draught(r)

Depth(D)

i


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TrTft T L T,

I

Loa

25

Down and trimmed by the head.If the draft is larger at the stem, thanat the stern.Dqwn and trimmed by the stern.If the draft is larger at the stern, thanat the stem.On an even keel, in proper trim.The draft of the stern equals the draftof the stem.

DepthThe vertical distance between thebase line and the upper continuousdeck. The depth is measured at halfLpp at the side of the ship.

FreeboardThe distance between the water lineand the top of the deck at the side (at

the deck line). The term surlmerfreeboard means the distance fromthe top of the S-line of the Plimsoll'smark and the topside of the deck line.

Air draughtThe vertical distance between thewater line and the highest point ofthe ship. The air draught is measuredfrom the summer mark. If the shiphas less draught one can ballast untilit reaches the summer draught and soobtain its minimum air draught.

SheerThis is the upward rise of a ship'sdeck from amidships towards thebow and stern. The sheer gives thevessel extra reserve buoyancy at thestem and the stern.

CamberGives the athwart-ships curvature ofthe weather deck. The curyaturehelps ensure sufficient drainage.

Rise of floorUnique to some types of vessels liketugboats and fishing boats. This isthe upward rise of the lower edges ofthe floors from the keel towards thebilges.

Thrn of bilgeGives the turn of bilge of the ship.

L.3 Proportions

The ratios of some of the dimensionsdiscussed above can be used toobtain information on resistance,stability and manoeuvrability of theship. Some widely used relations are:

UBThe ratio of length and breadth candiffer quite dramatically dependingon the type of vessel. Commonvalues:Passenger ships 6-8Freighters 5-7Tirg boats 3-5

A larger LIB value is favourable forspeed, but unfavourable formanoeuvrability.

LIDThe length/depth-ratio. The custo-mary values for L/D varies between10 and 15. This relation plays a rolein the determination of the freeboardand tHe longitudinal strength.

B/T (T = Draught)The breadth/draught-ratio, variesbetween 2.3 and4.5. A larger breadthin relation to the draught (a largerB/T-value) gives a greater initialstability.

Ri6a ot botom

Ship Knowledge, a madem encyclopedia

Nett Tonnage (NT)

26

B I )Thc breadth / depth-ratio; varies'rc'tr\

€€n 1.3 and 2. If this valuebecomes larger, it wil l have anunt-avourable effect on the stability,because the deck will be floodedri hen the vessel has an inclination)and on the strength.

1.4 Volumes and weights

GeneralThe dimensions of a ship can beerpressed by using termsm which,lescribe the characteristics of the:hip. Each term has a specificabbreviation. The type of shipdetermines the term to be used. Forinstance, the size of a containervessel is expressed in the number ofcontainers it can transport; a roll-onroll-off carrier's size is given by thetotal deck-areain square metres and apassenger ship in the number ofpeople it can carry. At the IMO-conference in 1969 the new units"Gross Tonnage" and "Nett

Tonnage" were introduced, toestablish a world-wide standard incalculating the size of a ship. In manycountries the Gross Tonnage is usedto determine port dues and pilotage,or to determine the number of peoplein the crew.

Register tonTo determine the volume of a spacethe register ton is used. One registerton equals 100 cft, or 2.83 m3.

Gross TonnageThe gross tonnage is calculated usinga formula that takes into account theship's volume in cubic metre belowthe main deck and the enclosedspaces above the main deck.

This volume is then multiplied by aconstant, which results in a dimen-sionless number (this means novalues of T or m3 should be placedafter the number). All distances usedin the calculation are mouldeddimensions.

In order to minimize the dailyexpenses of a ship, the ship ownerwill keep the GT as low as possible.One way of doing this is by keepingthe depth small, so more cargo


(mostly containers) can be placed ondeck. It is typical for small containerships to use this strategy. As aconsequence of this, dangeroussituations can occur because the lossof reserve buoyancy can result in aloss of stability and more "water ondeck".

Nett TonnageThe Nett Tonnage is also adimensionless number that describesthe volume of the cargo space. TheNT can be calculated from the GT bysubtracting the volume of spaceoccupied by:- crew- navigation equipment- propulsion equipment- workshops

The NT may not be less than307o ofthe GT.

Displacement (in m3)The displacement equals the volumeof the part of the ship below thewater line including the shell plating,propeller and rudder.

Underwater body (in m3)The underwater body of a ship equalsthe displacement minus the contri-bution of the shell, propeller andrudder. Or: the calculated volume ofthe part of the hull which is sub-merged in the water, on the outside ofthe frames without extensions.

An e.rample o.f'u .tltip n'itlt o ,smull depth

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Displacement A (in t)The displacement is the weight of the volume of water displaced by the ship.

One could also say: the displacement equals the total mass of the ship.

Displacement (t) = waterdisplacement (m) * density of water (t/m)

Light displacement (in t)This is the weight of the hull including the regular inventory. The regularinventory includes: anchors, life-saving appliances, lubricating oil, paint, etc.

Dead weight (in t)This is the weight a ship can load until the maximum allowable submersion isreached. This is a constant, which is unique for every ship.

Dead weight (t) = maximum weight A(t) - light displacement (t)

Dead weight (t) = maximum weight A(t) - actual weight A(t)

Cargo, carrying or dead weight capacity (in t)This is the total weight of cargo a ship can carry. The cargo capacity (in t) isnot a fixed number, it depends on the ship's maximum allowable submersion,which will include the capacity (in t) of fuel, provisions and drinking water. Fora long voyage there has to be room for extra fuel, which reduces the cargocapacity. If, on the other hand, the ship refuels (bunkers) halfway, the cargocapacity is larger upon departure. The choices for the amount of fuel on boardand the location for refuelling depend on many factors, but in the end themaster has final responsibility for the choices made.

Cargo capacity (t) = dead weight (t) - ballast, fuel, provisions (t).Tlte. corgo cupat:itt, Iargell, deterntines

the arnount of morrc1, a ,ship generates.

2. Form coefficients

Form coefficients give clues about the characteristics ofthe vessel's shape from the water line down into thewater. This makes it possible to get an impression of theshape of the underwater body of a ship without extensiveuse of any data. However, the form coefficients do notcontain any information on the dimensions of the ship,they are non-dimensional numbers.

2.1 Waterplane-coefficient Cw.

The waterplane-coefficient gives the ratio of the area ofthe water line A and the rectangular plane spanned byLpp and Bmld. A large waterplane-coefficient incombination with a small block-coefficient (or coef-ficient of fineness) is favourable for the stability in bothathwart and fore and aft direction.

Aw

Ship disc'harging bulk cargl


Waterplane-coefficient (Cw) =Lpp * Bmld

28

2.2 Midship section coefficient, Cm.

The midship-coefficient gives the ratio of the area of the midship section (Am)

and the area spanned by Bmld and T.

AmMidship-coefficient (Cm) =

Bmld x T

2.3 Block coefficient, coefficient of fineness, Cb.

The block coefficient gives the ratio of the volume of the underwater body and

rhe rectangular beam spanned by Lpp, Bmld and T. A vessel with a small blockcoefficient is referred to as 'slim'. In general, fast ships have a small block

coefficient.Customary values for the block coefficient of several types of vessels:

TankerFreighterContainer vesselReeferFrigate

0.80-0.900.70-0.800.60-0.750.55-0.700.50-0.55

A ship v,ith a smoll bbc'k-coffic'ient ancl

o large midship ,recticnt coe'fJicient

A ship with a large block-coe.fficient aml

a large midship secticn cutd prismatic

c'oqfficient.

VBlock coefficient (Cb) =

Graplilcal representotion of the bktck cofficient.

LppxBmldxT

V2.4 Prismatic coefficient, Cp.

The prismatic coefficient gives theratio of the volume of the underwaterbody and the block formed by thearea of the midship section (Am) andLpp. The Cp is important for theresistance and hence for thenecessary power of propulsion (if theCp decreases, the necessarypropulsion power also becomessmaller).

The maximum value of all thesecoefficients is reached in case of arectangular beam, and equals 1. Theminimal value is theoreticallv 0.

Prismatic coefficient(Cp) =Lpp x Am

Graplit:ul represetztcrtion of the prismatic c'officient.

Ship Knowledge, a modern encyclopedia 29

3. Lines and offsets (Lines plan)

When the principal dimensions,displacement and line-coefficientsare known, one has an impressiveamount of design information, butnot yet a clear image of the exactgeometrical shape of the ship. Thiscan be obtained bv the use of a linesplan.

The shape of a ship can vary inheight, length and breadth of theship's hull. In order to represent thiscomplex shape on paper, cross-sections of the hull are combinedwith three sets of parallel planes,

each one perpendicular to the others.

Water lines.Horizontal cross-sections of the hull are called water lines. One of these is the

water lines/design draught. This is the water line used in the design of the ship

when it is hypothetically loaded. When the water lines are projected and drawn

into one particular view, the result is called a water line model.

The waterlines

Ordinates.Evenly spaced vertical cross-sections in athwart direction are called ordinates.

Usually the ship is divided into 20 ordinates, from the cenfie of the rudder

stock (ordinate 0) to the intersection of the water line and the mould-side of the

stem (ordinate 20). The boundaries of these distances are numbered I to 20,

called the ordinate numbers. A projection of all ordinates into one view is

called a body plan.

The orclinates

ButtocksVertical cross-sections in fore and aft direction are called buttock lines. These

cross-sections are parallel to the plane of symmetry of the ship. When thebuttocks are projected and drawn into one particular view, the result is called a

sheer plan.

Buttock lines

DiagonalsThe diagonals are cross-sections offore and aft planes that intersect withthe water lines and verticals at acertain angle. On the longitudinalplan they show up as straight lines.The curvature of the watet (nes andbuttocks are compared to each otherand modified until they areconsistent. When this procedure isexecuted, the results can be checkedusing the diagonals. The mostcommon diagonal is called the bilgediagonal.

Ship Knowledge, a rnodem encyclopedia

The diagonals

30

\. - *jrr s the lines plans are being-:'r ' rr ith the aid of computer-:,' jr.lnlr that have the possibility to.':--.t,)rrn the shape of the vessel--: :retically when modifications in.-6 .11p's design require this. When-,: .inc'splan is ready, the programs- ;'. h€ used to calculate, among,:-.cr thin-qs. the volume and stabilityI ;1g .,hip.

r.. .hon'n in the lines plan below,-. i:: rhe water lines and the buttocksis Jrau'n in one half of the ship. In'-..: b.td1' plan, the frames aft of the-:::J.hips are drawn on the left side-::..i the fore frames are drawn on the-::rt. The linesplan is drawn on the:..rJc of the skin plating.

l:.' lines plans shown here are of.:'..els that have underwater bodies

that differ quite dramatically. Thereader can tell from these plans that aship will be slimmer with smallercoefficients, when the water lines,ordinates and buttocks are more

closely spaced. For instance, arectangular forecastle has only onewater line. one ordinate and onebuttock. the coefficients are 1.

Lenglh ov.r rll :219,3:16 [mlLength over c/ul :212,@0 lmlMoulded bre rdth :32.221O [mlDrall :122Q lmlDisgl.emeni :59279 [tlCb ; 0,691 [-lCp :0,707 [ lCm : 0.878 [.1LCB :.0,3213 [$ LpplXb : 1O2.5Al [mlKMtfensr€Ee :14.490lml

'i-=-.*--_=1+

I'lte line.c plan o.f'a contoiner vessel w'ith a lengtlt over all of'203.5 meter,\

Ship Knowledge, a modern encyclopedia 3I

Tug boat? 500

5 0 0 0

2 s to

Lpp = 35.ooo m

Cb = 0.565

Volume = 896 m3

Bmld = 10.080 m

Cm = 0.908

LCB = 2.90 Vo

Tmld = 4.500 m

Yacht

Lpp = 23.500 mCb = 0.157

Volume = 92 m3Bmld = 6.250 m

Cm = 0.305LCB = -3.16 Vo

Tmld = 4.000 mcp = 0.515

KM = 6.06 m

5 0 0 0

2 . 5 0 0

0 0 0 0

5 . 0 0 0

2 . 5 0 0

0 . 0 0 0

1,lflfl1: {Lp,+ . d X X

8:5885 . 0 0 0 I " 0 . 0 0 0 l - 5 . 0 0 0 2 0 . 0 0 0

Coast guard ship with a somewhat exceptional underwater-shape.

1 l

1 i_ : * _ i * * - - - *

Lpp = 73.200 mCb = 0.637

Volume = 4196 rrfBmld = 18.000 m

Cm = 0.933LCB = -0.75 Vo

Tmld = 5.000 mcp = 0.683

3 O O 0 2 5 . 0 0 0


KM - 8.67 m

Ecor cargo ship, multi-purpose.

Lpp = 134.ooo mCb = 0.710Volume = 18644 m3Bmld = 28.000 mCm = 0.992LCB = -2.24 VoTmId = 7.000 mcp = 0.715KM = 14.46 m

f ngole

tfp = 96.ooo mCb = 0.452\folume = 1620 m3Bmld = 11.500 mCm = 0.752l-CB = -2.30 VoTmld - 3.250 mcp = 0.601KM = 6.17 m

rbbreviations used in the drawings:

= length between perpen-diculars

= breadth moulded= draught moulded= block coefficient or

coefficient of fineness

Cm = midship sectioncoefficient

Cp - prismatic coefficientVolume = volume of the under-

water body, as measuredon the water lines, to theoutside of the frames (m3).

Frigate

5 . 0 0 0

2 . 5 0 0

0 . 0 0 0

- point of application of theresultant of all upwardforces; longitudinal centreof buoyancy (m).

= Height of meta-centreabove the keel (m).

r. .Pp

r lmld

f n l d

r-b

LCB

.::: Knowledge, a modern encyclopedia

KM

33

4. Drawings

Of the many drawings, only the mostimportant ones are mentioned here.In general, the following demandsare made:

The general arrangement plan, safetyplan, docking plan and capacity planhave to be submitted to the ShippingInspectorate for approval.

The general arrangement plan,midship section drawing, shellexpansion and construction plan (or

sheer plan or working drawing) haveto be submitted to the classificationbureau for approval.

4.1. General arrangement plan

The general plan roughly depicts thedivision and arrangement of the ship.The following views are displayed:

- a (SB) side-view of the ship.- the plan views of the most

important decks.- sometimes cross-sections, or a

front and back view are included.

The views and cross-sectionsmentioned above, display amongother things:- the division into the different

compartments (for example: tanks,engine room, holds)

- location of bulkheads.- location and arrangement of the

superstructures.- parts of the equipment (for

example: winches, loading gear,bow thruster, lifeboat).

Next to these, some basic data areincluded in the drawing like:principal dimensions, volumes of theholds, tonnage, dead weight, enginepower, speed and class.

Fig: General arrangement plan of amulti-purpose vessel that carriesmainly paper, timber products andcontainers.

PEOPI'ECK

H - H r t r + | 1 - H

TDEEOA

i rI Il l

r l C

OTFICERSDECK


An example ofa general arrange,nent plun

34

Frarre 126

UTPfrIilS

h f i E f dtr!ilbtl|mndCthlilr ntd#d

ffir.,r,.lhdil (rir qnr)Irddf,tt (hd qmlrilqa

t.$ttdd rlhhfttrdtIDGd

ICE&l t rHr /S t

lGSnl@J0 rr'S,EE n7.711 nrtr00 n92,1.tf{t T.{s cram ilI

716 i$2ilnl

A n tJli nJY, nt

r f t c c

Niestenn Sunder bv

mrodirmueffi


HIGH CUBIC CONTAINER 5OOO

35

4.2 Midship section

This cross-section shows one or moreathwart cross-sections of the ship. Incase of a freighter it is always across-section of the hold closest tothe midship. Some of the data showsincludes:

- principal dimensions- engine power and speed- data on classification- equipment numbers- maximum longitudinal

bending moment.

Veb Frorre

Fnone Sooclno 700 nm

Veb evenv Znd flaBe

Prlncloqt dlnenslons t

Lenoht b,o.o.Lpnoth nute 101,85 n

Dpoth rrtd. 7,7Deslon drouoht 5,8

Enolne outoutlfox dlsotocenent lce 7441

C.p, propetter

Classlflcatlon r Llovds + l00AlStrenothenlno for heovv conooesContolner conoops In hotds ond on uoperdeck hotchcovers

Pt. Ht, steet

Botlost drouoht In lce condltlonBolla<t denortunp r aft r 4,251 n

frd r 3,107 nBalla<t ar^r-lval r oft t 4.118 Fl

frd r 3,115 rrl

Tonktoo toool r 15 t/n?Stacklood contoJners hotd t ?0 ft - 75 ton

r 4 0 f t - 9 0 t o n

Stocktood contolners on hotches t ?0 ft - 30 ton

idd3

Upen Veb

ddflgi$

(tlne tood)Hotch Lood

r 4 0 f t - 4 0 t o n

2 Anchors ??95 ko P00L TV44 nn Stud Choln U3 495 nMar. [ono. bendlnnnorrent r 166000 kN.rn

(hooolno)

,

Here part oJ'the midship section oJ'the same multi-purpose ship is sltown.


r+l!-

t--1;l , - \ l

{!Jr-l- tlorto i

Tonktop

36

1'- v

\ai:\

r- -._ rc \._\- \.-\-\

-/ -t- / -/

' . !! c.rpansion of u container-feeder.

{J Shell Expansion

ln order to get an idea about thecomposition of the different plates ofrhe shell plating and their particulars,tor example hull openings), a shellerpansion is drawn. This drawingcan be made in two forms. In oner ersion the true athwart-length of therhell is shown; therefore the length:hown in fore and aft direction is notrhe real length of the shell. Thisresults in what seems a somewhatdistorted image of the ship. The otherrersion (shown below) shows a 3D-like view of the ship.

{.4 Other plans

Construction planThis drawing depicts the fore and aftcross-section midships (CL) and theplan views of the most importantdecks. Sometimes the drawing alsoincludes the watertight and otherimportant bulkheads. It indicates


their locations and the dimensions ofthe structural members (including theplate thickness).

Safety planThe safety plan is a generalilrangement plan on which all thesafety devices (for example lifeboats,life rafts, escape routes, fireextinguishers) are shown.

Docking planThe docking plan is a simplifiedversion of the general plan. Itindicates where the ship should besupported by the keel blocks in caseof docking. Furthermore the bottomand other tank plugs are shown withthe type of liquid with which tanksmay be filled.

Capacity planThis is also a simplified version ofthe general plan. All tanks and holdsare indicated with their volumes andcentre of gravity respectively.

Together with the stability and 'light

weight' particulars, this forms thebasis from which stabilitycalculations can be performed.Normally this drawing goes togetherwith the deadweight scale, whichgives information about therelationship between draught and forexample displacement in fresh andsalt water.

5. Important data onvarious ships

Ship owners have an interest inpromoting their ships as much aspossible, especially the types ofcargo their ships can transport. Or toput it in another way: how they canearn money. The table on the nextpage contains data of a number ofships which differ very much in thetype of cargo they can carry. Theabbreviations and other informationare explained, unless they havealready been explained in the text.

t- -/*l- /- J : 2 7J

J l fT l - l r \ l

ffi \\\\\\- \

t / / / / , ' /

r,r iii!1:84

37

CLASS S.TYPE LLOYD'S + 100 Al + LMC UMS LA NAV1 (1

strengthened for heavy cargoes (2)

Ice Class Finnish/Swedish 1 A

PRINCIPAL DIMENSIONS (3)Leneth over all 168.14 m

Breadth moulded 25.20125.30 m

He eht n hold as SID 14.30 m

He eht n lower hold as TWD 3 height 3.30, 7.00 or 10.25 m

He eht n tween deck as TWD 3 heights 9.90, 6.20 or 2.95 m

Desisn draft 10.00 m

Max summer draft 10.65 m

GT abt 16,800 (4

NT abt 6,900

DEADWEIGHT all told design draft abt 18,900/18,275 mt (excl/incl TWD) (5max summer draft abt 21,150120,525 mt (excl/incl TWD)

CAPACITY srain = bale hold 0 14,000 cbft 400 m3 (6

hold I 179,000 cbft 5,050 m3

hold2l3 662,000 cbft 18,750 m3

total 855,000 cbft 24,200 m3if tween deck installed 63.000 cbft/1.780 m3 less in holds

FLOOR SPACE tank too total1,625 (no 0: 50 m2, no 1: 340 m2, no 2/3: 1.235 m2\ (7

tween deck total 1,840 m2 (no l:425 m2, no 2/3: I,415 m2)

weather deck total 2,800 m2 (no 0: 50 m2, no l; 425 m2, no 2:685 m2, no 3: 650 m2)

AIR CHANGE (basis emDtv holds) abt20 x per hour (8)

CONTAINER INTAKE (eJHold units 478 TEUDeck units 632TEUTotal units 1.110 TEUMax size height up to 9'6", width up to 2,500 mm

limited quantity alternative dimensions such as length 45 ft

Power available for reefer connect. up to 800/900 kW

SIDEPORTS 5 side shifters. each 16t SWL. 500t canacitv ner hour ( l0

IIATCHES weather deck no 0: 6.50 x 7.50 mno 1:25.60 x 17.80/15.20 m (11)

no 2: 38.40 x 17.80 m no 3: 25.60 x 20.40 msteel, end folding type

tween deck no 1: 25.60 x 17.80/15.20110.10 m no 2: 38.40 x 17.80 munder crossbeam: 4.20 x 17.80 m no 3: 25.60 x 20.40 m

consisting of l8 steel pontoons;

I of 6.37 x 17.72 m 2 of 6.37 x 10.02 mI of 6.37 x 15.12 m 5 of 6.37 x 17.72 m2 of 3.17 x 17.72 m 4 of 6.37 x20.32 m2 of 1.50 x20.32 m I of 4.20 x 17.72 m

B ulkheads/compartments removable pontoons up to 14 compartments at TEU interval

MAXIMUM LOAD ( 1 2Weather deck hatch covers 7.75 tlm2 weatherload, 2.00 t/m2 payload

Tween deck hatch covers hold 1: J.5 tlm2, hold 2: 5,5 tlm2, hold 3: 5.0 t/m2

Tank ton 20.0 tlm2

DECK CRANES combinable (13Tons/reach 3 of 120 mt SWL/14n and 50 mt SWL/30mPosition 2 x PS (aft and mid) and 1 x SB (forward)

MAIN ENGINE waftsila 16,400 HP/12,060 kw Bowthruster 1,155 HP/850 kW (14

Soeed ballast abt 20.0 knotsdesisn draft abt 19.6 knots

max laden abt 19.2 knots

Fuel consumption per dav abt 45 mt IFO 380 cSt

no MDO at sea, except for maneuvering

BUNKER CAPACITY (1s)lntermediate Fuel Oil 1,700 m3

Marine Diesel Oil 180 m3

BALLAST CAPACITY J,200 m3 ( 16

Ship Knowledge, a modern encyclopedia -t8

5.1 General cargo ship

F-xplanation on the previous diagram

Lloyd's+ l 0 0 A l*LMC

UMSLA\AV1

Dead weight all told =

Capacity

Cbft

\laximum load

\lain engine

\ IDO

= name of the classification society (1)= built according to and under supervision of the Rules of this class.= Lloyd's Machinery Class. All machinery has been built in accordance with the

specifications of this classification.= Unmanned Machinery Space. The engineroom does not have to be manned permanently.= Lift Appliance. The cargo gear has been approved as classed.= Permission for a single bridge watch control, although SOLAS-rules only permit this in

favourable circumstances.The vessel has been reinforced to carry heavy cargoes.1\ = Finnish/Swedishlce-class.

Height in hold as SID = Height in hold as single decker ( no tween deck)

Height in lower deck as TWD = Height in lower hold as a tweendecker

Height in tween deck as TWD = Height in the tweendeck as a tweendecker.

(2 )

(3)

Ii all the tween decks are installed in the hold, the capacity of the hold decreases by 63000 ft3 or 1780 m3.

Floor Space = Deck area of the tank top, tween deck and weather deck overall and per hold.

Container intake = The number of containers with a length of 20'that ean be loaded.

Maximum heieht and breadth.( 1 0 )(11)

= Minimum strength of the hatches (also according to class) as determined by the ( 12)

Deck cranes (combinable) =

loadline convention. The criteria are based on the maximum height of a

water column on the hatch, which is 1.8 metres.The deck cranes can be combined (in twins). (13)

All three cranes can lift up to 120 tons if they are extended 14 metres. If they

are extended 30 metres, they can lift up to 50 tons.Position of the cranes: 2 on port side, one on starboard (fore).

( 4 )Dead weight at design draught. Approximately 18900118275 metric tons (5)(excluding/including tween decks).

= Grain = bale. Because the hold is box shaped, the total m3 of bulk cargo equals (6)

the total m3 of general cargo.= cubic feet.

(7)( 8 )(e)

= 45mt IFO 380cST - 45 tons intermediate fuel oil 380 centistoke (Centistoke ( 14)is a measurement for the viscosity).

= marine diesel oil(1s)

, t

!

. f L- 4't

'?!|lrrrn3c

t t a l

I

Sltip Knowledge, a modern encyclopedia 39

5.2 Refrigerated vessel

Flag:Call sign:Lloyds No: (1)

Built:DWT: (2)

panamaH.3.8.Y.9r67801200012.902 mt

GTA.IT:Loa:Beam: (3)

Summer draught:Holds/FIatches/

Compartments: (4)

Ventilation/Air changes: (5)

Different temps: (6)

Cranes:Pallet cranes:Container capacity: (7)

Reefer plugs: (8)

Speed banana laden: (9)

Aux: (11)Tank capacity: (12)

Additional Features:

|.382t6.408155 m24m10,1 m

4t4n5Vertical / 908/2 per hold2 x 4 0 t2 x 8 t294 TEU plus 60 FEUor 207 FEU185abt.2l.5 knots

abt. 6 MT IFO 380 RMG 35r.800 MT rFo 380 RMG 35I5O MT MDO DMABowthruster

Consumption (reefer plant): (10) abt. 49 MT IFO 380 RMG 35

(1)

(2)(3)(4)

(s)(6)

(7)(8)(e)

(10)

(11)(r2)

Explanation on the specifications of the "Comoros Stream"

Lloyd's number is also the IMO-registration number of the ship, even after a change of ownership, thisnumber stays with the vessel.Dead weightBreadthThe number of holds, hatches and compartments. Most holds have three tween decks resulting in a holdwhich is divided into 4 compartments.The ventilation is vertical. The entire hold capacity can be replenished 90 times per hour.Number of isolated compartments where the temperature can be adjusted separately of the othercompartments; two per hold.The vessel can transport 294TEUs + 60 FEUs or 207 FEUs.Ship can supply 185 containers with electricity.If the vessel is fully laden with bananas, the maximum speed is 21.5 knots.The daily fuel consumption ( including the refrigerating plant) is approximately 49 tons of Intermediate FuelOil 380 (old notation) or Residual Machine G35, the viscosity is 35 cst (at 100'C). G gives the quality ofthe viscosity.The daily fuel consumption of the auxiliaries is 6 tons.Capacity of the fuel tanks is 1800 tons RMG and 180 tons DMA (Distillate Marine Fuels, A is gas oil).

Opened hold of the "Comoros Steam"


Hold of a reefer

40

53 Coastal trade liner

Flag:Buil t :T)'pe:D.w.T.: (1)

D.W.C.C Summer: (2)

GT / NT:L.O.A. :B .O .A . :Draught laden: (3)

Air draught: (4)

Classification: (5)

Trading area:

Container intake (total):

Cubic capacity GR / BA:Movable bulkhead:Tanktop strength:Hatch strength:

Dutch1998 | t999boxed shape / sid2964 mt2800 mt2056 I tt6888.95 m12.50 m04.34 m09.30 mB.V. 1 3l3Ecargo-ship deepsea - BRGunrestricted watersincl. river Rhine108 teus151.000 cbft215 mtlm2I mtlm2

Ventilation:

Dimensions of holds (m)

length/breadth/depthHold 1:

Dimensions (m) of hatchesHatch 1:

Tank capacityFuel:Ballast:Fresh water

Engine equipmentMain engine:Output:Consumption:

electrical, 6 airchangesplh

62,40x10,24x6,75

62,40 x 10,24

217 cbm1307 cbm24 cbm

Wartsila 8L201320 bhpAbt. 10.5 knots onabt. 5.500litres MGO

Explanation on the specifications of the 6'Hansa Bremen"

r l ) D e a d w e i g h tr2) Dead weight Cargo Capacity at Summer draught.r3) Maximum draughtr-1) Air draught at summer draught, if the (loaded) vessel is notr5 ) Bureau Veritas, the ship satisfies the rules and requirements

at summer draught,of the classification

additional ballast may be used.bureau for this type of ship.

5.4 Ferrv

Length o.a.:Length b.p.:Breadth moulded:Depth maindeck:Depth upperdeck:Design draught:Total power at MCR: (1)

Trial speed at design draught:Passenger capacity:No of passenger cabins:Dead weight:Trailer lane length: (2)

Car lane length: (3)

172.90 m160.58 m25.70 m9.40 m15.10 m6.35 m44,480 kW28 kts1.6001604.500 T1.780 m450 m

Explanation on the specifications of the "Blue Star 2"

(1) Power of the main engine. MCR = Maximum Continuous Rating.(2) Maximum total trailer length available.(3) Maximum total car length available.

Ship Knowledge, a modern encyclopedia 4I

5.5 Bitumen tanker

Explanation on the specifications of the "Corel Actinia"

Present flag:Port of registry:Ship type:

IMO number:Dead weight (summer draft):Cargo tank volume:Main engine:

Aux. engines:

DutchRotterdamLPG (1) Carrier S.P. (2) 9.3 bar-48C 2PG (3)90319853566 tons3200 m3Deutz SBV 9M 6281690 kW at900 r.p.m.Deutz/IrlWM TBD (4\ 234V9

(1 )(2)(3)(4)

Liquid Petroleum GasSafety PressureClassification NotationTurbo Gasoil

3x331 kWType of fuel: MDOTotal cabins: 10Required minimum crew: l0

Imo Type II, Marpol - Annex I & IIBuilt:Dwt m. tons:GT:NT:Speed:L.o.a.Breadth:Draft:Cargo cap.98.5 Vo:Type steel: (2)Ice class:Exterior heating of cargo tanks up to2 sloptanks cap.206 cbm total (3)

After lengthening Anthony Veder's gas

carrier "Coral Actinia" with 24.05 m

enough space was provided to install a

second cargo tank, increasing cargo

capacity with 1000 m3 to 3200 m3.

5.6 Chemical tanker

(1 )20006430 mt4670167915.5 knots118.00 m17.00 m6.45 m6871 cbmduplex stainless steel1 A

8 0 ' c

Explanation on the specifications of the "Dutch Aquamarine"

(1) Marpol requirements, Annex l: oil products, Annex ll: liquid chemicals.(2) The tanks are constructed of duplex stainless steel.(3) Sloptanks are tanks that collect the tank washing water.


Ship Knowledge, a modem encyclopedia 43

1. History of modern shipping

1.1 The development of regular service liners during the 19thand the first half of the 20th centurv.

The period from 1800 until the Second World ; ,"* the rise of the regularservice liners. This was the result of the transport of cargo and passengersbetween Europe and the colonies in the East and the West, and the increasingnumber of emigrants leaving for Nonh America.

C las,s ic pa s se nge r ship

Shipbuilding changed slowly butsteadily to facilitate the new demandsusing new technologies.The main developments were:- Wood as main construction material

was replaced by iron and later bysteel.

- Sailing ships were replaced bysteam ships and later by motorships

- New types of ships like tankers andreefers were developed.

- A gradual improvement in speed,size and safety.

In general, the big and versatile tradevessels of this period were still in useeven as late as the 1970s.Transportation of passengers, generalcargo, oil, refrigerated cargo, heavyboxed parcels, animals and bulk withone and the same ship was very

Tlte Cottica, an old J'reighter / passenger

ship

common. Even today's "multi

purpose" ships do not achieve thislevel of versatility.

1.2 After World War ll.

After some initial hesitation, theperiod after the Second World Warshowed a continuous increase inworld trade and thus in sea trade. Thisincrease in global commerce, onlyinterrupted by short periods ofrelapse, lasts even to this day. In thebeginning this resulted in more andmore ships, subsequently theybecame faster and bigger. A lot ofsmaller ships were then taken out ofservice. The modernization ofshipbuilding and navigation led to theloss of many jobs in the sector. Afterthe 7970's more and more universalships were replaced by specializedvessels that can cafiy only one typeof cargo. This process had alreadystarted on a much smaller scale since1900. These new vessels are:

-Oil tankers-Bitumen tankers-Chemical tankers-Container ships-Heavy-cargo ships-Cattle ships-Reefers

Bitwnen tanker A traditional ntulti-purpose ship,


Passenger liners have been supersededalmost entirely by aeroplanes,

because of the large distancesinvolved. However. after 1990 thenumber of passenger ships thatspecialize in luxury cruises haveincreased enormously.

2 Classification of shipsin types.

In this overview types of vessels arecategorized. It is by no means acomplete overview. Some vessels can

be placed in more than one category.

2.1 Ships for the transport ofcargo and passengers

Bale and unit cargo:Container vesselsHeavy-cargo vesselsMultipurpose vesselsCattle ships

Refrigeratedcargo:LPG/LNG carriersConventional refrigerated shipsFishing vessels

Bulk cargo:Crude carriersProduct tankersChemical tankersBulk carriers

Roll-on/Roll-off:RoRo freightersCar and passenger ferriesRecreation:Cruise shipsSailing/motor yachts

2.2 Other ships.

Fishing vessels:

Trawlers

Other types of fishing vessels

Vessels providing services for shipping:

Seagoing tugs

Harbour tugsIcebreakersPilot vesselsCoast guard vesselsResearch vessels

Salvage:TugsShear legsDiving vesselsBarges

Construction and infrastructure:DredgersCable layersShear legs

Navy:Aircraft carriersCruisersDestroyersFrigatesSubmarinesMine sweepers

Offshore:Seismic survey vesselsDrilling rigs / Jack-upsDrilling shipsSemi-submersible drilling unitsFloating (Production) Storage andOffloading vesselsShuttle tankersSupply vesselsConstruction vessels

3 Brief discussion onseveral types of ships.

The discussion of the vessels belowincludes a general description, dimen-sions and other characteristics. Forinstance, important features for acontainer vessel are the maximumnumber of containers it can carry andthe deadweight. For a passenger liner,the deadweight is not important, butthe number of passengers is. A tugboat has to possess a high bollardpull, whereas that is not important fora dredger.

A navj, sultply vessel. Compa.rable to a

cargo slip / tunker

\ tnultipurpose support vessel (v,ith

irt'rn't' L'rone and A1ft"urne).for the

,,.ft\lnre irdustrl,.


A modem cndse ,sltip

A I;PSO tcutker

47

3.L Multipurpose ships.

Multipurpose means that thesevessels can transport many types ofcargo. These ships use hatchcoversas bulkheads as well as tweendecks inthe hold. These hatchcovers can beplaced at varying heights andpositions. Usually the headledges andhatch coamings are of the same dimen-sions as the holds, which makesloading and discharging easier. Theholds are sealed with hatches using avariety of systems. Cargo like woodor containers can be carried on top ofthe hatches. Often the bulwark isheightened to support the containers.

Possible cargo- containers- general cargo- dry bulk cargo like grain- wood- cars r- heavy items (project cargo)

Characteristics- dead weight (t)- hold capacity (m3, ft3)- number of containers and their

dimensions- maximum deck load (t/m2)- maximum wheelload (t)- lifting capacity of cargo gear

Multipurpose vessels can be sub-divided into:- ships with cargo gear (up to I20

tons lifting capacity per crane)- ships without cargo gear- coastal trade liners

A multipurpose vessel can also beequipped with one or more ramps onthe side of the ship. Loading anddischarging can then commencethrough these ramps by forklifts. Thisis faster and less dependent on theweather.

a. Ships with cargo gear.Multipurpose ships with cargo gearare heavier than comparable vesselswithout cargo gear. As a result theircarrying capacity is less. Somevessels can not pass under a bridgebecause of the height of the cranes.The advantage of such a ship is thatshe can work in ports and industrialzones where no cranes are available.


Multi-pu rpose,ship " Schi ltppe rsgrcLcht"

v,ith its ov;tt cetgo gectr antl loctdfug ramps

b. Ships without cargo gear.Ships without cargo gear aredependent on the presence of loadinggear in the ports and are thereforelimited in their employability.

c. Coastal trade linersIn order to navigate from the sea intothe inland waterways, coastal tradeliners have a small draught; usuallynot more then 3.60 metres, a small airdraught of approximately 6.5 metresand, compared to other ships of thesame size, a large ballast tankcapacity. Like inland vessels, coastaltrade liners (also called sea-riverships) often have a hydraulically

Multipurpose ship, tto corgo gear witl'r

hatclt cradle

Locr - 89.25 rn Breadth - 13.10 nt

G'l'- 2780 DWT"- 3791 t

adjustable wheelhouse. When theship has to pass under a bridge, thewheelhouse can be lowered. Mastsmust also be able to be lowered.

Coastal trttde liner

Loa - 106 m lJreadtlt - 11.40 m

D e p t h - 5 . 6 m M a x T - 3 . 5 n r

GT'- 2077 DWT - 2580 rons;

Max TEUs - 182

Additional characteri stics.- draught when loaded- vertical clearance when loaded- draught when not loaded- vertical clearance when not loaded.- ballast tank capacity

3.2 Container ships

Since the 1960s the transport ofcontainers has continued to grow. Thespecific advantage of the use ofcontainers is that the cargo can betransported directly from customer tocustomer, and not just from port toport. The transport by water is just alink in the chain of transport.Container vessels have grown from acapacity of 1500 TEU (1966) toapproximately 8000 TEU (2002).

The sizes of containers vary. The

ISO-standards distinguish theTEU and the FIEU, which may

differ in height.

TEy = twenty feet equivalentunit. The nominal length of these

containers is:

20'= 20 * 0.305 = 6.10 metres.

The actual length is 1.5'(38mm)shorter, leaving some spacebetween the containers.FEU = forty feet equivalent unit.The nominal length of these

containers is :

40' = 40 * 0.305 = 12.20 metres.

Possible Cargo- containers

Characteristics- Maximum amount of TEUs or FEUs- Amount of TEUs or FEUs below the

weather deck along with theirheights.

- Number of container tiers.- Presence of cargo gear- Open or closed ship.

There are two main types of containervessels:a. Big intercontinental container

vessels up to 8,400 TEU (1999)b. Container feeders, starting at 200

TEU,

48

rr. t Intercontinental) container shipsr- trptsins. vessels are divided into

-L'nerations (see the table below). The'.rs container ships can only go to the.trsest ports because of the ship's size

.,nd the transfer capacity of the port.

[-erge container vessels usually do not;rur e their own loading gear. After. 991 ships without hatches were' . 'Lr i l t . a lso cal led cel lu lar vessels.l]c'cnuse there are no hatches it means:hat water can pour into the holdstropical rains, seawater). Therefore

.pecial provisions have to be maderrrr the bilge pumping systems.

\dvantages of cellular vessels:- nrore efficient cargo handling,

ii.hich reduces the lay time andharbour fees.

- guide rails, to keep thecontainers in position instead oflashings.

- no hatch covers to be carried- hi-eh freeboard and strong

construction due to the suide rails

Disadvantages:- the high freeboard has an adverse

effect on the GT measurement of thevessel

- the price is high because of theamount of steel used and theintricate engineering

.\nalogous to big tankers and bulkcarriers, container vessels can also beclassified on the basis of the passagethat is just suitable.

Ncdl l r ty t l i \nrct ' ic t r , on () l )an cel l r iot 'cr t t t t t t i t r t ' t ' .s l t ip L = 266 t t t ( t r ( . \ ,

I l = -12 tn(tt '( ',\. -j.568 1 l '. '{ t

These designations are:

- Panamax ships. Ships with a widthless than 32.25 metres. Theyhave the maximum width withwhich they can still pass the locksin the Panama Canal.

- Post panamax ships. These ships aretoo large to pass through the PanamaCanal. Since 1988 container vesselswith widths exceeding 32.5 metreshave been constructed.

- Suezmax ships have a draught ofless 19 metres, which allows them to

use the Suez Canal. The Suez Canalis currently being deepened.

b. Container feedersContainer feeders are small ormedium-sized ships starting at 200TEU that specialize rn transportingcargo from small ports to large portsand vice versa, or for use in serviceswhich are not profitable for the largercontainer vessels. The feeders may beequipped with cargo gear. Often,multi purpose ships are employed ascontainer feeders.

C.- r t t t 1 o i tt t' t' f'a t' Ll a r

Generation period area of navigation containers vessels

I before 1966 local services near

the coast, USA

Australia

P r e - I S O . L * b * h =35'*lJ'*24*

Predominantlymodified ships, with

own cargo gear.

2 after 1966 Short international

services, USA,

Europe, Australia,

Japan, etc..

ISO-standard.L= 20'or 40'. B=8'. H= 8' or

8'6"Container vessels of

700-1500 TEU

3 after I97l Long international

and intercontinental

services

High cubecontainers. H=9'and

9'6".

High speed container

vessels bigger than

2000 TEU.

4 after 1984 Around the globe,

also China. India and

African countries.

Deviations from

ISO-standard. E.g.

t_45'�

Container vessels

bigger than 3000

TEU

Slip Knowledge, a modern encyclopedia 49

3.3 Heavy-cargo ships

Heavy-cargo ships can be dividedinto:- semi-submersible heavy-lift ships- conventional heavy-lift ships- dock-ships (semi-submersible)

Their construction and stabilityallows them to carry extremely largeand heavy objects. The semi-submersible ships can lower theirmain deck below the waterline inorder to lift large floating objects likedrilling rigs (float on / float off).

Semi-subnter,sible ,rhip looding a drilLing

rr g.

Semi-submersible ship with the ktwer hulL

of a.floating ptoduction tutit (,semi-sult).

The conventional vessels are oftenfitted with loading gear, which doesnot necessarily mean that the vesselsare able to lift heavy objects, butwhen there is no heavy cargo, thevessels can function as multipurposevessels.Possible Cargo- Heavy or bulky objects- Complete parts of factories- Drilling rigs- Multipurpose / general cargo


Characteristics- Canying capacity- Maximum deck load- Dimensions of holds and decks- Lifting capacity per crane and

maximum height above deck.

Heav,v cargo vesscl,s, ctLso suitrtble as

nt ult i lturltos e,s h ip s

3.4 Refrigerated ships (rcefers)

Modern refrigerated ships arecarrying cargo more and more incontainers instead of on trays.Refrigerated containers have a builtin refrigerating system, which can beplugged in to the ship's electricitygrid. Air is used to get rid of theexcess heat and therefore theventilation of the containers is veryimportant. Refrigerated containerscan also be transported by a regularcontainer vessel.

Ref'rigercrted slip "Sarfia Lucie", tvith

cargo gear.

When fruit is carried, not just thetemperature is being controlled, butalso the composition of the air in thecontainers in order to control theripening process of the fruit. Anincreasing number of reefers aretaking on general cargo as return

cargo, for instance cars and trucks.Compared to multipurpose vessels,reefers have:- smaller coamings- more tweendecks- loading gear with a limited lifting

capacity of about 40 tons.

Possible cargo- Fruit, vegetables (cooled, chilled)- Meat, fish (frozen)- General cargo- Containers on deck and sometimes

in the holds

Characteristics- Canying capacity- Tonnage- Temperature range- Cooling and freezing capacity at

different temperatures- Range of atmospheric control in the

holds / airchanges per hour- High sailing speed

3.5 Thnkers

- Gas tankersGas tankers are ships that are used tocarry liquefied gas. In general, thereare two kinds of liquefied gases:- Liquefied Petroleum Gas (LPG)- Liquefied Natural Gas (LNG)LPG largely consists of propane andbutane with freezing points of -42"C

and -0.5"C at atmospheric pressurerespectively. LNG is a mixture ofmethane and ethane. Under normalatmospheric pressure the former has afreezing point of -161"C and the latterfreezes at -88"C. Other similarliquefied gases can also be trans-ported by these gas tankers. LPG andsimilar compounds can be kept liquidat moderate pressures and tempe-ratures, but often higher pressuresand lower temperatures are needed tokeep the gases in their liquid state.The tanks have to be well insulatedbecause of the followins two reasons:

- Heat leaking into the tanks canvaporize part of the liquid. If, as aresult of this, the fluid level dropsand the free liquid surface increases,this can lead to sloshing of theliquid against the inside of the tank,which will damage the tank wall.

50

i l)(l rar*er

- At the low temperatures inside thetank the steel loses its toughness andstrength. Therefore it is very impor-tant that the liquid does not comeinto contact with the steel. This isexactly the reason why the tankwalls are not strong enough to resiststrong sloshing of the liquid.

Gas tankers are often steam turbineships, the boil-off of the cargo can beused as fuel for the boilers. ftoil-off is

-sas evaporated from the cargo inorder to maintain a low temperature)

Possible cargo- LNG- LPG- Similar liquefied gases.

Characteristics- Tank capacity (m3)- Minimum allowed tank wall

temperature- Maximum ullage in the tanks- Time needed for loadine and dis-

charging

- Crude oil tankersCrude oil tankers are used to carry thecrude oil from a loading port near anoil field or from the end of a pipeline

to a refinery. In general, these vesselsare very large. The carrying capacityof these crude oil tankers has risen toas much as 500.000 tons. In contrastto product tankers, crude oil tankershave a limited number of tanks,usually approximately 15 tanks plus

two slop tanks.


Nortlt West Shearrvoter, LNC -tanker

The large crude oil tankers aresubdivided into the following classes:- Ultra Large Crude Carrier (ULCC)

>300,000 dwt- Very Large Crude Carrier (VLCC)

200,000 - 300,000 dwt- Suez max (old max Suez draught)

ca. 120,000 - 160,000 dwt- AFRA max, ca. 70,000 -

100,000 dwt

The large draught of the largertankers restricts the sailing routes andlimits the number of ports that can becalled for loading or discharge ofcargo.

Cntdc oil uutker.

GRT': I5(t.106 - LOA: 32&n

IJreatlth: 57m - f : 20.20nt (wa.r, 2 l.(;)

Deadweiglt (surnrner): 29 1,6 I 3 tons

Crude oil tankers receive theircargoes through pipes from shorefacilities or from a single mooringbuoy, via a hose or via a flexiblepipeline urm mounted on the jetty.

The hose or hoses is/are temporarilyconnected to transverse pipes ondeck, at mid length, the so-calledmanifold. The oil is pumped on boardby shore pumps. From the transverselines, the oil goes to droplines,vertically down into the ship, to the

bottom lines. Three or four

longitudinal pipelines with branchesto each tank. At the end of eachbranch a valve is installed. Thebottom lines are in aft directionconnected to the pumps in the pumproom, a vertical space between thecargo tanks and the engine room. To

discharge cargo, the ship's pumps in

the pump room draw the oil from the

cargo tanks, and press it upwards tothe decklines, from aft to the mani-fold midships. Via a hose the oil ispumped ashore to the receivingfacility where the cargo ends up in a

shore tank. Needless to say thatnumerous valves isolate pumps,

tanks, and the separate pipelines fromeach other. Loading and dischargingtakes some 24 to 36 hours per

operation.

Apart from the cargo pipeline systemthere are various other cargo relatedpipeline systems on deck and in thetanks:

- Inert gas system to fill up the emptyspace created while dischargingwith inert gas. (a gas with nooxygen) in order to preventexplosions. Oil will not burn as longas the percentage of oxygen staysbelow 57o.Inert gas is also used toslow down corrosion of ballast tankswhen they are not treated with paint.This still occurs on some oldertankers. During the loading inert gas

is discharged into the atmosphere.- Tank wash system used to remove

deposits from the inside tank wallbefore repairs, docking or reloading.

I

a*, ,_ rfill|lhrr -

r r . l t l l I t t - :

NO S I {OXING " '

P rodut:t'lhnke r C lo s e - t t1t

5T

- A system for the temperature controlof sloptanks. Usually crude is notheated during the voyage.

- The ballast system is completelyseparated from the cargo system.

When a large ship like a crude-oiltanker is damaged by collision orgrounding, vast amounts of oil canleak into the ocean. Therefore,regulations now require that suchvessels have a double hull.

Possible cargo- Crude oil

Characteristics- Carrying capacity (tons)- Tank volume (m3)- Discharging speed (m,/h)- Maximum laden draught (m)

- Product tankers"Product" refers to the products ofrefineries and the petrochemicalindustries instead of crude-oil.Product tankers have a large numberof tanks with a total carrying capacityof approximately 50,000 tons. Thepiping systems on a product tankerare different from the systems incrude oil tankers. Normally everytank has its own filling and dischargeline to the manifold and its own cargopump.

Possible cargo- Oil products like gasoline, kerosene,

naphtha, diesel oil, lubricating oil,bitumen

- Vegetable oil- Wine- Drinking waterCharacteristics- Carrying capacity (t)- Total volume and volume per Ank (m)- State of tank wall surfaces

3.5 Chemical tankers

There are very strict requirementsand regulations for chemical tankersbecause of the toxicity andflammability of the typical chemicalcargo. All cargo tanks are separatedfrom:- the shell by a ballast tank- the engine room bulkhead by a

cofferdam- the forepeak bulkhead by a

cofferdam.


Procluct Tanker in Panatna Canttl

This ensures that in case of leakagefrom one of the tanks, the crew andenvironment are not subjected todanger.To prevent mixing of incompatiblecargoes, a cofferdam separates tankswith different contents. A cofferdamis a small empty space fitted with asounding apparatus, a bilge connec-tion and ventilation.The size of chemical tankers variesbetween 2500 and 23,000 GT. Thenumber of tanks in transversedirection varies between 3 for tankersup to 6000 tons and 6 for largertankers.

Possible cargo- Acids- Bases- Alcohol- Edible oils- Chlorinated alkanes- Amines- Monomers- Petrochemical products

Characteristics- Canying capacity- Number of tanks- Tank coating / Stainless steel

Clrcrnical 'lhnker

3.6 Bulk carriers

Bulk carriers are ships especiallydesigned to carry loose cargo in bulk.There are three types of bulk carriers:a. Handy size, 30,000 tons

dead weight, often with own cargogear. Cargo: precious ore, sand,scrap, clay, grain and forest products

b. Panamax, 80,000 tons deadweight, no cargo gear.Cargo: grain and ore

c. Capesize, 160,000 tons dead weight,no cargo gear. Cargo: coal, ore.

Bulk carriers are usually dischargedby grabs or by suction pipes. Pouringthe cargo through a shooter or via aconveyor belt does the loading. Bulkcarriers have large upper and lowerballast tanks to give the empty vesselenough draught and a better beha-viour whilst in transit.

52

.4n ore carrier being discharged by a lighter.

Ships transporting ore have a specialdesign. Ore is very heavy, (stowage

factor is approximately 0.5 ms/t) andthus ships only need small holds to beloaded completely. To prevent a toolarge stability the holds must not besituated too low or too close to thesides of the ship. Some bulkcarrierscan also function as a tanker. Thiscombination carrier is called an OreBulk Oil (OBO) carrier.

Possible cargo- Coal- Ore- grain and other agricultural products- fertiliser- cement- light minerals

Characteristics- Carrying capacity (t)- Cargo volume (m3)

3.7 Roll on Roll off

- Ro-Ro carriersTo facilitate the ffansport of mobilecargo, Ro-Ro vessels have continuousdecks, spanning the entire length ofthe ship. As a result of this the vesselloses its stability rapidly if waterenters the decks after a collision or aburst side door. In connection withthis, the safety regulations for thesevessels have been sharpened in thelast few years (2003) by therequirement of division doors.

The tweendecks of these ships areoften adjustable in height. Loadingand discharging proceeds via the

Ship Knowledge, a modem encyclopedia

ramps in the side or stern which alsofunction as a driveway. Because theramps may not be deformed toomuch, RoRos are equipped with anantiheeling system which automaticallydistributes water between two op-posing ballast tanks. To prevent thecaJgo from moving in bad weather,the vehicles are fastened using alashing system. During loading anddischarging additional ventilation isrequired to get rid of the exhaustfumes.

- Ro-Ro car and passenger ferriesAlmost all ferries transport bothpassengers and vehicles, whether theyare navigating inland waterways orthe oceans and seas. The vesselsusually shuttle between two ports on avery tight schedule. The passengersdrive their own cars on board via aramp, which is either part of the ship,placed on the quay, or a combinationof these two. Ferries have the sametype of decks as the Ro-Ro catriers,and therefore they face the sameproblems when water floods thedecks.

Smnll Ro-Ro freighte r with vehicles in the

holds and on the main deck

Possible cargo- Trucks- passengers- cars- trains- trailers (with containers)

Characteristics- number of cars or ffucks- lane length- height between decks- number of passengers- carrying capacity

3.8 Cruise ships

Except in some archipelagos areas, asthe Philippines and Indonesia, thetraditional passenger liners havedisappeared. International and inter-continental transport of passengers isnow almost completely done byaircraft. The modern cruise ships areused for making luxurious holidaytrips to distant countries and ports. Onboard there is a whole range offacilities for relaxation likeswimming pools, cinemas, bars,casinos, theafres etc.

Possible cargo- passengers

Characteristics- maximum number of passengers- number of cabins according to size,

luxury and location on the ship.

Without exception, these vessels areequipped with very good airconditioners. Stability fins limit therolling to 2", ultimately 4". Evenmodern curise ships with sails haveno noticeable list when sailing. Thenumber of persons on board can be ashigh as 4000; the crew is half or twothird that number.

Ro-Ro carrier

53

Navigating tltrouglt unknov,n territrtries on a lu.ll.;,trv ship

3.9 Cattle ships Characteristics

Cattle ships transport livestock suchas sheep from Australia to the FarEast. and cows from NorthwestEurope to the Mediterranean. Theholds are set up as stables. The siloswith fodder are located at the main orlower deck. Sheep are often fedautomatically, while cows are fedsemi-automatically: the feed ismechanically moved from the silo tothe deck where it is then distributed tothe animals by mean of wheel-barows. A network of conveyor beltsand lifts dumps the manureoverboard. A proper air conditioningis required: at least 45 air changes perhour are necessary. To achieve a lowstability cattle ships are very slenderships. This prevents the animals frombreaking their legs when the shipexperiences rolling. The slendershape of the fore ship also preventstoo much pitching.

Possible cargo- Livestock like cows, sheep, goats,

camels. horses etc.

- total deck area (m2)- stable system- floor system- manure system

3.10 Yachts

Yachts can be distinguished as motoryachts and sailing yachts with anauxiliary motor. These vessels arepurchased by and used for:- private individuals for use in leisure

time; these yachts have a length of10 to 20 metres.

- Wealthy persons who use the yachtas their (temporary) domicile,either for leisure or forrepresentative purposes ;

- Companies which use the yachts forrepresentative purposes; theseyachts have a length ofapproximately 15 metres or more.

- Private individuals or companieswho buy the yacht for races.

- Large yachts used in chartering; thelength of these yachts starts atapproximately 15 metres.

The building of large luxurious motorand sailing yachts is very similar tothe building of commercial ships, butwith more emphasis on the finish andappearance.

Large yachts with a length of 25metres and over are also called Mega-yachts.

Possible cargo- none or some passengers

Characteristics- dimensions- total sail area and nature of the

rigging- motor power- number of cabins and number of

berths- luxury- seaworthiness

3.1l, Fishing vessels

- T[awlersTrawlers are fishing vessels whichdrag their nets through the water. Inpelagic fishery, the nets are sus-pended between the water surfaceand the seabed. In bottom fishery thenet is dragged over the seabed, which

Seaworthy sailing ),ac:ht, length I5 metres

Cattle Sltip Motor yucht, length l9 ntetres


requires additional power, especiallyif the nets are equipped withdisturbing chains to churn up the seatloor. The construction and equip-ment of these fishing vessels stronglydepend on the fishing method and thespecies of fish aimed at. The mostimportant types of trawlers are thecutter and the stern trawler.

Possible cargo- cooled fish (in crushed ice)- frozen fish or shell-fishCharacteristics- engine power- volume of fish holds- transport temperature- freezing capacity- method of fish processing- method of refrigerating and freezing- the fish winch and net drum- possible fishing methods

T'ruv,Ler en-?,agetl in lrot,'l .f islting. Speed

vltilst .fishing is ttppntximcficly -J knots,

v'liLst not .fishing. the speecl cut be l2

krutts. Tlrc lertgth o.f' tlrc nets c'cut be

berw'een 60 and 80 metres and tlte Iilrcs

t'an be 300 to 600 m.etrcs.

Re.fri ge ratecl t rau, le r

- Other fishing vesselsNon-trawling vessels can range froma simple craft deploying a net tofishing vessels which can lay out netswhich are several kilometres inlength, waiting for the fish to swiminto the net. Typical examples are:seiners, tuna clippers, crab boats, etc.

Possible cargo- Frozen fish, or crustaceans- Cooled fish (in crushed ice)

Characteristics- nature of the vessel- fishing methods applied- engine power- refrigerating capacity- volume of fish holds- methods of processing and storing fish

3.L2 Tlrgs

- Seagoing tugsA common characteristic of alltugboats is their low aft deck. Thisguarantees that the towing line hassome freedom of movement. Thepoint of application of the force in thetowing line must be located close tothe midships in such a way that theforce has no influence on themanoeuvrability.

The towing winch is of greatimportance because it has to be ableto transfer the total force of thepropeller to the towing line.

Seagoing tugs are used for:- salvage- towing- anchor handling in the offshore

industry- environmental service- ships with engine trouble

Partly completed ships, floatingwrecks, docks, drilling rigs and otherlarge floating objects that have to berelocated can be towed by tugboats.Ever since the introduction of semi-submersible heavy lift caniers, longdistance towing is used less often as amethod of transport. Coastal statesoften use seagoing tugs to avert animminent environmental disaster.

- Escort tugsEscort tugs are used to escort (large)

ships along dangerous passages. Theyhave been developed after a numberof serious (tanker) accidents in recentyears. Escort tugs operate in confinedcoastal waters and are small sturdyseagoing tugs that can push or pull alarge ship away from a danger zonewhen the own propulsion is notsufficient. Escort tuss need to be

highly manoeuvrable and thereforeoften have azimuthing thrusters.

- Harbour tugsHarbour tugs are used in ports, inlandwaterways and coastal areas for:- assisting and towing vessels in

and out of ports- assisting seagoing tugs when these

are towing a bulky object- salvaging, or assisting in salvage in

ports or coastal areas.- fighting fires and environmental

disasters.- Keeping ports free of ice

Characteristics- Power installed- bollard pull: this is the towing force

at zero velocity- salvage pump capacity- fire fighting equipment- means of fighting pollution

Escort Tug

7"1rc "'lb"uelbutk" l.s as,sis'rlng u VLCC


i / - - ' - - 3@ r

7'1rc stune c0rg0 l,r'.t,sc1 in ice

3.13 lcebreakers

Icebreakers are similar to tugboats;they ate often fully equipped fortowing and salvaging.Their main function is to cut achannel through an ice-sheet at sea, ina port, a river or other inland water-ways. Obviously these ships have tobe able to resist floating ice. The foreship is especially reinforced and thematerial used must have a very highimpact value. The shell must be freeof protrusions because floating icewill rip these off immediately.

There is hardly a paint strong enoughto resist the forces involved inicebreaking. For the same reason the

wear resistance of the steel in theshell and the propeller is subject tohigh requirements. Ice is usuallybroken by sailing the sloping bow onthe ice, until the weight of the fore-ship breaks the ice. Some icebreakershave nuclear propulsion.

Characteristics- engine power- bollard pull- shape of the fore-ship, this is impor-

tant for the method of icebreaking.- total mass of the ship, this is

important for the ability to penetratethe ice.

l t t t c t l l t

breultlt

= 167 tneler .

=-l I tnetc.t:

3.14 Dredgers

- Ttailing hopper suction dredgerTrailing hopper suction dredgers areused to maintain or deepen channelsand fairways and for construction ofartificial islands. These vessels areusually equipped with two adjustablesuction pipes, which drag over thebottom to dredge. Dredging pumps inthe holds or in the suction pipes pumpa mixture of water and material fromthe sea floor into the holds. Till now(2003) they are able to dredge to adepth of 155 m. The holds are calledhoppers. The solid material precipi-

tates in the hopper; the excess waterflows overboard. In order to dredge inadverse weather, the suction pipes aresuspended from special cranes, whichoperate with heave compensation.This ensures that the suction nozzlesstay in contact with the seabed.When the vessel is at its (plimsoll)

mark, it will navigate to the dis-charging site. The discharging can bedone with pressure, using the dred-ging pumps and the pressure lines atthe bow. When the vessel navigatestowards the direct vicinity of thedumping location, the dischargingcan also be done using the spraynozzle,located on the fore end. Thisis called rainbowing. In both casesthe solid precipitate is mixed withwater so that pumps can be used.When the ship reaches the exactdumping location, the cargo isdischarged through the bottom flaps.The load is then dumpedinstantaneously. To facilitate this wayof discharging, some small hoppersuction dredsers are constructed as

"+

56

(lurso yessel w'itlt it'e breukcr stern

T'rai lin,q lroppe r suctiort dredgc t

TrtLi I c r ltoppc rsuc'ti on dretl g,e r,

Iloitrbou;irtg

Ship Knov,ledge, a modern encyclopedia

r. 'urrving t'tt ltut' i l .\, =30000 tort

: .,. rr hinged port and starboard halves,.,, hich separate when the load is.:r.char-qed. These vessels are called.nlit rail suction dredgers

Possible cargo- . i . i Id

- gravel- :tr'&turr or clayish soil- rport) mud

C'haracteristics- pump capacity

Jepth range- hold volume (the largest is 13,000 m3)- carrying capacity

' i t ru i l dre( lger

- Cutter suction dredgersFor tougher types of soils, the kindrhat cannot be simply sucked up,.utter suction dredgers are used.These vessels rake the seabed with arotating cutter and are often used inthe development of new ports andnew waterways. Cutter suctiondredgers can be equipped with theirr)wn means of propulsion, but this isnot always the case. Spud poles areused to temporarily fix the vessels.The dredgers then move in a swingingmotion to deepen the bottom. Theloosened soils are washed awaythrough a dredging pump and atloating discharge pipeline to the soildestination. The soil can also bepumped into a barge that can

(.. trttcr sur'l ion tlretlgar, mov'ittg urututttl u

'l)ud p0le

Slip Knowledge, a modern encyclopedia

1*, < r f

A coble slti lt

transport the material over largerdistances. Cutter suction dredgers arenever equipped with a hopper.

Characteristics- torque and cutter power- pump power- presence of propulsion- presence of transverse propellers- length and maximum depth of

suction head

3.15 Cable laying ships.

a. Cable laying shipsCable laying ships are vessels, whichcan lay one or more cables on the seafloor. If the distance exceeds thelength of one cable, multiple cableshave to be joined together on board ofthe ship. These vessels are fullyequipped for this task. The ships alsohave the ability to repair brokencables. Crucial in the cable layingprocess is that the positions of thecables on the sea floor correspond totheir positions on the map.Furthermore, during the joining of thecables, the vessel must be able tokeep its position. For these reasons,cable ships are always equipped withmultiple adjustable, and often alsoazimuthing, propellers in com-

bination with DP and DT (dynamrcpositioning and tracking).

Possible cargo- new cables- old cables- repair equipment

Characteristics- carrying capacity (t)- engine power- details of DP/DT installation

3.L6 Navy vessels

- Aircraft carriersAircraft carriers are medium-size tolarge vessels suitable for aircraft andhelicopters to land on and take offfrom.

FF+FE@

A cablc ,s 'h i1t

57

- CTOL (Conventional Take Off andLanding) Aircraft carriers usuallyneed catapults, driven by steampower to allow the aircraft to takeoff and an angled deck with brake-cables to recover the landing aircraft.

An airc'ru.fi carrier

- STOVL (Short take-off and verticallanding) aircraft carriers are smallerthan CTOLs. They use a sort of ski-jump for greater lift during take-offand do not have the auxiliaries thatCTOLs have.

- CruisersCruisers mostly have a displacementof more than 10,000 tons and aresufficiently armed to operate on theirown. Tasks are surveillance,blocking, protection of convoys andsupporting large fleets

- DestroyerA destroyer is smaller than a cruiserbut is also fitted to operateindependently. These are multi-functional warships designed to fightsubmarines and surface vessels and toescort convoys.

-Frigates

Frigates are very versatile warships.They are suitable for air defence,anti-submarine warfare and surfacewarfare. They have a wide array ofsensors, communication devices andlarge numbers of sonars. There areseveral different weapon systems onboard which are controlled from thecommand room and can follow and


attack a target fully automatically.Frigates are often equipped with ahelicopter landing platform. Theships have a length of about 130metres and a crew of 150. The vesselsare lightweight, highly manoeuvrableships with a large propulsion power(gas turbines) divided over twoengine rooms. At a speed of 30 knotsthey can come to a complete stopwithin 1.5 ship-lengths.

F ri gatc

- CorvettesCorvettes have a displacement of 700to 2000 tons and are well armed.They are best equipped to act inregional operations and are seldomused for long-range operations.

- SubmarinesSubmarines are hard to detect andtherefore very popular in the naviesworldwide.Types are:- Ballistic Missile Nuclear Submarine

(SSBN), large submarines (120-170metres) armed with ballisticmissiles. These vessels are part ofthe strategic nuclear deterrenceforce of the superpowers. They canstay below the surface for months ifnecessary.

Subrnarine

- Nuclear-powered Attack Sub-marine. (SSN) Large submarinesbetween 70 and 150 metres armedwith:

- torpedoes, against surface vesselsand submarines

- underwater-to-surface missiles(USM) against surface vessels

-cruise missiles against land-basedtargets

- General purpose Diesel-ElectricSubmarines (SSK-SSC)Small to medium submarines armedwith torpedoes and USMs. Thepropulsion is provided by propellersgetting their power from largebatteries (accumulators). In order torecharge the batteries with theirdiesel generators, SSKs/SSCs haveto snorkel (submarine at periscopedepth) at regular intervals.

- Fast Attack Craft (FAC)FACs have a displacement of lessthan 700 tons, a speed of 25 knots ormore and are designed for fast hit-andrun tactics within a range of 100miles from the coast.

- Offshore Patrol Vessel (OPV)Ships with a displacement of approx.700 tons that can patrol the waters ofthe Exclusive Economic Zone (EEZ)

for an extended period of time.Usually an OPV is lightly armed andequipped with a helicopter deckwhich enhances their patrollingcapabilities.

- Mine Counter Measure Vessels(MCMv)

An MCMV is any vessel that isdesigned to locate and destroy mines.

The main types are:- Mine hunters (MHS). These vessels

are equipped with several types ofmine detecting sonars. They usuallyhave a Remotely Operated Vehicle(ROV) for investigation of a sonar

Cruiser

Con,elte

58

contact and the delivery of a mineJestruction charge.

- Fleet minesweeper (MSF). Thisrl pe of vessel is capable of towingmeans to sweep anchored as well asbottom mines with acoustic,ma-snetic or pressure ignition.

- Amphibious ships.Vessels designed to deliver anamphibious force to a coastaloperation area. Embarked landingcraft or helicopters will be used fordisembarkation of the force. Thereare many types of Amphibious ships.

- Landing craft.Landing craft are smaller thanamphibious craft, designed to sailtowards a beach and allow vehicles.troops and equipment to leave theship via a ramp at the bow of the ship.They can not operate in roughconditions and are usually transportedto the area of operation in anamphibious ship.

Support vessels.Ships like:

- Intelligence collection ships (AGI). Aship designed to gather informationon other ships and coastal installa-tions in other countries.- Replenishment Oiler (AOR). Thisship can carry water, stores, fuel andammunition and can supply these

-qoods at sea.- Hydrographic survey ship (AGS). Avessel used to survey the bottom ofthe sea to make charts for navigation.- Oceanic Research Ship (AGOR). Thisvessel gathers information about thephysical and biological qualities ofthe sea.- Rescue and Salvage Ship (ARS).

Comparable to a seagoing tug, withthe equipment for fire fighting.


Two hydrographic sunet, ship,v

4. The'l\{aridmd' Offshore

4.1 Introduction

As our world continues to expand inpopulation and the use of energyconsuming applications is evergrowing and growing, this makes usmore than ever dependent on"energy". As a consequence, nowa-days oil and gas are still our mostimportant source of energy.

Within the world of oil and gas,Crude oil is called "Petroleum".

Petroleum is a combination of theGreek word PETRA and the Latinword OLEUM, "Petroleum", literallymeans "ROCK OIL". Crude oilactually comes from rocks (the oil isentrapped within rock formations andthe different layers of rocks). Most ofthe oil and gas is found within the so-called Sandstone and Limestonelayers. According to scientists, oiland gas come from the remains ofplants and (minuscule) animals thatlived and died in the sea, millions ofyears ago. As time passed, largeamounts of sediment covered theorganic material. The increasingweight of these overlaying sedimentsresulted in tremendous pressure andheat on the organic material buriedbelow and transformed this organicmaterial during millions of years intooil and gas. Parallel to this process thesurrounding organic material trans-formed into sedimentary rock e.g.sand- and limestone.

4.2 The early developments

In the early years of 1800 whale oilwas used for illumination andlubricating purposes. Around the year1850 this oil became very scarce andexpensive as whales in the USAwaters had nearly been hunted toextinction. As a consequence peoplewere anxious to find alternatives.Around these times an oil well nearTitusville, Pennsylvania was foundwhere oil spontaneously came to thesurface of the land. It literally leakedout of the rocks which inspired a mannamed Colonel Drake to recover this"rock oil" and sell it as an inexpen-sive substitute for whale oil. Properrecovery of the oil by simplycollecting from trenches did not workout well. This finally - after someyears of trial and error - resulted in1859 in the early technique of drillingto collect the oil from its point oforigin, initially at a depth of 27metres.In L897, this was followed byextensive successful drilling on thebeach and extended to approximately90 metres in the ocean on thecoastline of South Carolina, the firststeps to offshore activities!

Exactly 50 years later on the 4th ofNovember 1947 the first real offshoreoil was found out of sight of land inthe Gulf of Mexico, 9 seamilesoffshore in a water depth of as little as6 metres. From then on over the last50 years progress has been revolu-tionary. Offshore oil and gas develop-ments are now taking place in over 40countries, hundreds of kilometresfrom the shore in ever-increasingwaterdepths.

4.3 Definition of 66Offshore"

The word "Offshore" in the Oil andGas Industry refers to industrialactivities in open sea, starting fromthe search (exploration) of oil and gasto production (exploitation) andtransporting them to the shore.

The Offshore is part of an industrythat actually designs, builds andoperates the offshore structures toallow the execution of offshoreactivities.

' , l i t te l tunter

59

{.{ Stages of Offshore activities

Thc' rable below briefly highlights the main activities of Offshore and of the vessels / units in use to facilitate the

rr l i labil i ty of "Oil & Gas".

Item Activity VesseUunit in operationa searching for oil seismic surveying seismic survey vesselsb finding it exploration 1. Jack-up drilling rigs, see note I

2. Drilling vessels (ship shape) see note I

3. Semi-submersible drillins unitsc building the production facilities construction and installation of the

production platform/unit

1. Crane vessels

2. Offshore barges

3. Heavv lift carrierd developing the field driling and completing the

production wells and

interconnecting the production

wells with the production facility

1. Jack-up drilling rigs

2. Semi-submersible drilling units

3. Pipelaying barges or pipelaying

vesselse getting the hydrocarbons to the

surface and processing at the

surface

production

depressurization and separationin oil, gas and water fractions

l. Fixed platforms

2. Tension leg platforms

3. FPSOs (Floating Production

Storage and Offloading Vessel)

4. FSOs (Floating Storage and

Offloading Vessel)

5. Production jack-ups or semi-subs

6. Subsea installations

7. Others, see note 2f bringing'the product'to the shore transportatlon 1. Shuttle tankers

2. Pipelines, laid at the seabed bypipelaying vessels, see note 3

g Support Supply and servicesMaintenance and repair

Watch keeping

1. Suppliers, crewboats, anchor

handlers

2. Diving and Multipurpose supportvessels

3. Standby and chase vessels

Notes:1. The type of vessel / unit to be used

depends on the water depth.Due to the limited length of the legsof the jack-up drilling rigs, theserigs are limited in their drillingoperations to a maximum of I20 to150 metres water depth; however ingeneral preferred for use by clientsbecause of their stable workplatform. Within and above theoperational limitations of the jack-

ups the semi-submersible drillingrigs may be used.Depending on the distance to theshore base and the expected seastate conditions, the ship shapeddrilling vessel is a good alternative.

2.The technique to get the hydro-carbons to the surface is rapidlyexpanding over the last years,

Ship Knotrledge, a modern encyclopedia

resulting in all kinds of differenttypes of production facilities such as:

- SALM (Self Anchoring LegMooring system)

- SALS (Self Anchoring LegSystem)

- Spar (A very large spar buoy withproduction and storage facility)

- SPM (Single Point MooringSystem)

- Satellite Platform (Unmanned)

3.The technique of laying pipes onthe seabed in extended water depthhas drastically improved and as aconsequence more and more really"high-tech" pipe-laying unitsemerge and are successfullyoperating. To allow the instal-lation of pipelines in open sea thefollowing pipelaying vessels areapplied:

- S-lay pipelaying vessels (shallowand deep water)

- J-lay pipelaying vessels (deepwater).

- Reel-lay pipelaying vessels (smalldiameter)

Technical aspectsAll technical aspects as for ordinaryships in the designing andengineering process are applicablesuch as strength, stability, hydro-dynamical behaviour, freeboard, safetyetc., additionally augmented by thespecific technical requirementswithin the offshore application.Certification aspectsBased on the applicable specifictasks, Classification Societies andNational Authorities have imposedadditional Rules, Regulations andRequirements as a basis for certi-fication and safe working conditions.See also chapter 6.

{.5 Brief description of offshoreunits. (See table on the left)

a. Seismic Survey vesselI ir.. purpose of a Seismic Survey, . ' .re I is to produce detailed:tl'rrrnration for oil companies as a

-.r.is for actual production drilling.

firi: information is the result of the,'r.rluated reflected sound waves in::r.' sea floor. To obtain these results.rrLrrd waves are init iated by the. r'.:e I by means of air guns, the:.r'tlections are collected by a number,t' detectors within long cables (so

..rl led streamers) towed by the vessel.

\r i ! l /1/( ' . l / /r l ' (?,\ ' l 'A,\ ' , \ 'C I I I l ()pe l ' ( l t lOn

b.l Jack-upsThe Jack-up dril l ing rig (oftenshortened to "Jack-up" or "Drilling

rig" is used for exploration drilling inapprox. 10 metres to max. 150 metreswater depth. The Jack-up barge is atriangulary or a rectangularly shapedbarge that is towed to the worklocation. At the location the bargeraises its deck alongside the legs withthe lower ends of the legs resting onthe seabed.Jack-up barges are mainly used forexploration drilling (usually 3 legged)and as a work barge for constructionwork (typically 4-legged). Longdistance transport of Jack-ups is bytowing with a tug (wet tow) or byheavy lift transport ship. (See photosection 3.3 of this chapter)

Ship Knowledge, a modent encyclopedia

Jur:k-up t'ig itt u .jucked up po,t'itiort.

1. Drilling denick2. A-frame3. Crown block4. Monkey board5. Drill floor6. Jacking gear &jack houses

7 . L e g8. Deck crane9. Accommodation10. Helideck11. Deck incl. tanks & workspaces12. Cantilever, supporting the denick.

I

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b.2 I ) r i l l ing sh i l r

A sh ip-sha; rec l dr i l l ing sh ip is Lrsec l f i r r '

ch' i l l in-g erplorat ion ancl proch-rct iott

wel ls i r t nrec l iL t t r to c leep watc l ' ( f r t t t t t

l -50 to 30(X) nretres r 'vater clcpth).

A n ' roc lern c l r i l l sh ip car t obta in ar t

a \er i igc speec l o l ' l - l knots i t t t rar ts i t

u i t h a h i ch c l r i l l i ng ec lL r i l ' l l en t s to rage

c r .Lp r . r c i t r . The r essc l i s i c l ca l f o r

t l r i l l i ng eonsccL t t i r c wc ' l l s i n c l i f f b ren t

1 r . 1 1 ' { : r , l ' t l l t ' \ \ r r 1 ' l q l .' l - t ,

n l r in t r . r in 1- ros i t ion c l l t r i t tg

1 r1 . rg1 ' ; 11 i1 r11 : t l t c sh ips a t ' e e i t he r

l l r r r r ) t ' c t l i n an ancho r l l a t t en tn . . l r r r r r r r t i e p o s i l i r r t t i t t s

. ic |cnc l ino on the wi l ter c lepth .

I ) r ' i l l i ng c l c r r i c k

Dcck( 'o lLrnrns

[ ] l i s t c r s( ' r 'oss b t 'acc

[ ) i l cona l b race

\neho r racks

\ne ho r u i r t chesi ( )n e ( ) r 'ner ec lgcs)

l - i l e . b o a t s t a t i o n

\ l O . B . B o a t

I )ce k e r - i .ures

I j l r r t l l c t '

\ l \ , , n \ ( ' t t ( ; . t r l r l i t l t t i t l

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c l r i l l i nganchor 'or rc ly

( D P ) .

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Dr i l l i ng c l e r r i c k

Dr i l l f loor '

R iser anc l p ipe s to fagc

Supply hanc l l ing l roarc l c rane

Accor.r.rn.roclat ion / hel icleck /

l i fcboat str. i t iorrs

b.3 Serni-subrnersible dri l l ing unit

A senr i -s r - rbmcrs ib le c l r i l l in -s r - tn i t is

lusec l 1or c l r i l l rng thc cxp lorat ion anc l

proc luct ion wel ls in 150 - 2 . -5(X) r t t

water clepth.

Anchorecl turi ts cutt () l let ' i - t tc i t t t tLtx.

l -5(X) nr wi l tc r c lepth . Dynanr ica l ly

pos i t i onec l vcssc l s can ope ra te

inclelrenclent o1' rvatet ' clcpth (Lrp tt t

arounc l the year 2(XX) ch ' i l l ing wi ts

per furn iec l in nr . tx .2 .3(X) n t w i i ter

clepth ).An impor tant ac lvantage of the sent i -

sLrbr rers ib lc type in cot lpat ' ison wi th

the sh ip-shapcc l type dr i l l ing vesse l is

the bet ter nrot ion behav iour o1 ' the

Lrn i t in harsh env i ro t . t t t te t t ts which can

give an cxtenc lec l work ing winc low

A dynarnical ly posi t ioned (D.P.)

vessel uses its propellers, rudders.

tunnel thrusters and/or azimuthing

thrusters to stay on position. A

control system cont inuously

determines the required thrLrst

vector basecl on information fl 'om

a position ref-erence system" l ike

radio or hydro-acoustic beacons

or (D) GPS.

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t.l I f.2 Crane vesselsThese are semi-submersible barges orr e ssels, equipped with one or twoheavy-duty offshore cranes. The,;.rrgest crane vessels are the Semi-Subrnersible Crane Vessels (SSCV).

The maximum hoisting capacity isr()dav (2003) 7,000 tonnes per crane.The vessels are used for transpor-rution and installation of largernodules (weighing up to 12,000rrrrres) of fixed offshore platforms.

The base of the platform (called

racket) is either launched from ahar,ee or lifted onto the sea-bed by thejrane vessel prior to installation of thetopside modules. After installation ofrhe jacket it is firmly connected to the.eabed by steel piles, that are driven.krrvn by large hydraulic hammers.uspended from the offshore cranes.

\lore recently the crane vessels are:Llso used for the removal of offshoreplatforms when the oil/gas reservoirs.rre depleted. Some crane vessels alsohave pipelaying facilities.

I

t

1'�

Dual pur l tos( .sent i - . tu l ;ntct" ,s ib l ( . ( run(

rc,rsci .l 'or ltt ' tn'.t ' I i.f i itr g/irt.tt trl lrrl i rrt ttrtt l

( . | - lur 1 1t i 1tc lur i t t .q

1. J-lay tower

2. 3,000 tonnes crane

3. 4,000 tonnes crane

4. Crane A-frame

5. J ib6. Storage barge

7. Supply vessel / tugboat

8. Accommodation / helideck llife-

boat stations

9. Pipe storage rack

Module:On top of a jacket, various itemsare to be fitted and interconnected.These parts are pre-fabricated asfar as practicable, and as squarelyas possible, so that, when placedon top of the jacket, and afterfixing them permanently to thestructure of the jacket, onlyconnections between these itemshave to be made. These pre-fabricated structures, often box-shaped are called MODULES.The weight of each module islimited by the weight the availableoffshore crane unit can handle.

4#j'

eig�

( i ' trttt, t 'c.s,seI irt.sto||itt,q fi.rad 1tIutfrtrnts

Ship Knowledge, a ntodent encyclopedia 63

Jacket structure on its final locationlaunching & installation

e.l Fixed Production Platforms.Fixed Production Platforms arepref abricated onshore, transported onbarges to their f inal productionlocations at sea and subsequentlythey are installed and completed tofacilitate the actual oil / gas produc-tion. The platfbrm can be subdividedinto the following main components:

- steel jacket or concrete substructure- deck- modules- drilling derrick- helideck- flareboom

Most platforms stand in water depthsvarying from approx. 20 m to 150 m.The highest jacket ever built was fora water depth of 412 m.

' l l . l ' ( )n l r t< r t t io t t t ' r t t tnccl t ' t l I ( ) l l t r

t t i lva l l ( r l , Sr l l r ,g i t ,s o i l t r t t l tc / r ' t t t l t r t t ' t r t ' i l . t '

rrtttot'c(l :Jttrt t lc ttutl;t ' t 's. \1/trtt 't ' dcpt lt -i 5t t

I i l( lr(s

ready fo,

[ ' i r t : 'd pft tql111 t i1117 1tl t t l fo t 'nt

e.2 Tension Leg Platform (TLP)The Tension Leg Platform is used fordrilling and production purposes. Theunit resembles a semi submersibledrilling unit and is attached to the seafloor with tensioned steel cables. Thebuoyancy of the platform appliestension to the cables. The advantageof the TLP is the economical aspect incomparison with the fixed platforms,specifically for deeper water. In casethe production in a particular fieldgoes down, this platform can be re-used in other locations.

e.3 FPSO (Floating ProductionStorage and Offloading vessel)

An FPSO is a floating unit, which isinstalled on or in close vicinity of anoil or gas field for receiving,treatment, storage and offloading ofoil and/or gas to a shuttle tanker. It isconnected directly with the oil/gasreservoir below.

l. internal turret (riser connections offlowlines comins from the seabed

2. flare boom3. topsides4. accommodation / helideck /

lifeboat stations5. offloading hose6. shuttle tanker

ShiJt Knowledge, et modent encyclopeclia

1'l '.t{) v it lr s' lrtrtt lr, tutrl irt ' ltt, lr irtd

64

\,rtc'r an FSO (Floa-

, . : r g Storage and, r i t loading vessel)

,,: in principle the. . :nr€ funct ion wi th:r. exception of the:r!'atrnent" (no pro-

- ; - ' : \ instal lat ion on'',,trrd) and is connec--'.i to a production

: . rc i l i t v .

t. l . Shuttle tankers.:: the absence of a pipeline from the': ' ..rduction facil i ty to the shore,'rrninal a shuttle tanker is needed to.,ke over the oil cargo from the FPSO:' FSO on location for transportation

' ' rhe shore terminal.

l':r..rto of shuttle tanker:Bow loading station incl. temporaryrnooring affangement to FPSO

- Cargo lines: Helideck-. \ccommodation' Tanks below deck.

t.1 Pipelaying barges / semisubs /vesselsi ,,r the installation of subsea oil and

.-r . p ipel ines anchor moored or

.:r narnically positioned flat bottom'.rr '{eS. semi-submersibles or ship-.:rriped vessels are used. Many of:rc\e pipelaying barges have a heavy-

.:.rr\ crane for installation work. Pipes

..:',' supplied to the pipelaying vessel-r pipe-supply carriers. Cranes on the'rpelaying vessel unload the carrier.,rrtl hoist the joints into temporary:'rpe-storage racks. On the main deck.: ut)ffiplete pipe joining and coating.,wtor'! is provided. After welding the'rpe joints, non-destructive testing\DT) is executed prior to transpor-.:rg the joined pipes horizontally over:rr' firing line to the pipe stinger (used. 'hallow and deep water, max 1600

r.,. The stinger extends out-board'. c'r the stern of the pipelaying barge

..:rJ functions as an articulated

. Kttow'ledge, a modern encyclopedia

Sr'lranrtrtit. ' t, icv of't lrc l)ro(:e.\ ',\ urul slrtrugc ort bourtl an I; 'PS0 *'i l l t rLu extenrul lurrcl

Slutttle ktnlicr in drt' rlock

\-lur lt ipcltL.r'rng rc,r,ir ' l witlt (rune ltur,ge alongsidc

65

S-1a1, pipeLuying vessel ttn DP with pipe supplier nlottg,side S-lcr1t ltipelaying t"essel on DP v"orking neor o Juck-up platfonn

outrigger that allows for the lowering

of the pipe line onto the seabed. Thisprocess is controlled by means of pipe

tensioners (varying in capacity from

40 - 250 tons.) For deep water (over

1000 m water depth) installation of

subsea pipelines al-Iay tower is used.

This J-lay tower is uPended and

allows welding, coating, NDT and

lowering in a vertical manner. The

shape of the pipe when lowered onto

the seabed resembles a hockey stick(hence the designation J-laY).

g.la Platform Supply Vessel (PSV)

Used for the supply of fuel, drilling

mud, fresh water, (drilling) equiP-ment and pipes to or from offshoreplatforms or other vessels (e.g. supply

of pipes to pipelaying vessels).

During supply operations often DP is

used to stay on position (oY-stick

controlled). Other functions besidessupply are fire fighting and towing of

floating units. For towing operationsPSVs have a high bollard pull. Often

a PSV can also perform anchor

handling operations, see description

of AHTS below. Suppliers are

characterised by a superstructure and

deckhouse at the foreship and a long

flat aft deck. They have no heli-deck

and no cranes. The offshore platform

or vessel uses its own cranes to lift

cargo from the PSV deck.The difference with an AHT is that a

PSV has a long aft deck and below-

deck storage tanks.

g.Lb Crew boatUsed for crew changes in benign

waters. In other areas (e.g. North Sea)

helicopters are used.


Cotnbined lleel-l-ay uncl J-Ltrl' pipel(D'inq ves,sel

1. J-lay tower / Reeling ramp

2. Storage reels for flexibles / rigid

reeled pipe line

3. Piperack for rigid pipe sections

4. Board crane 400 ton capacity

5. Accommodation / helideck /

lifeboat station

P lotlorm S up plv Ve s,s e I

66

Pkuftirm Supply Vessel

g.Lc Anchor Handling ftg (AHT)

An anchor handling tug is used to setand retrieve anchors of mooredoffshore units and for towing theseunits. The AHT often looks similar to

a PSV but has a shorter aft deck and

an open stern with a stern roll to be

able to pull anchors on the deck. If the

anchor handler can also function as a

supplier it is called an AnchorHandling Tug Supplier (AHTS).(see illustration chapter 1, section 9)

g.2a Diving Support Vessel (DSV)

Diving support vessels are used to

support divers doing inspection,construction or repair work on subseastructures. To facilitate the divingoperations DSVs have diving bell(s)and decompression chambers for the

divers. A moonpool is used to lowerdivers or subsea tools.

Such a subsea tool is the RemotelyOperated Vehicle (ROV), a self-propelled underwater robot forinspection or construction and repairwork. Usually the ROV is connectedby an umbilical to the support vessel.

DSVs are anchor moored ordynamically positioned. Whenworking with divers, very strictrequirements to the anchor mooringor DP system apply, as a drift-off ofthe DSV could bring the divers in

danger. Therefore DSVs have tocomply with the highest DP standards(DP class 3).

g.2b Multipurpose Support Vessel (MSV)

A multipurpose support vessel issomewhat similar to a diving supportvessel, but has no facilities for divers.Without diving operations, the DPrequirements are less stringent. MSVs

can be used for a large variety of taskslike:-survey work (e.g. seabed, pipeline,

subsea structure);-(subsea) construction, installationand maintenance or repair work;

-ffenching of cables or pipelines;-installation of flexibles;-well intervention and workoverservices.

MSVs typically have a relativelylarge accommodation, a heli-deck, aflat work-deck aft, (heave-

compensated) crane(s) and/or an A-frame aft and moonpool(s) forcontrolled lowering of ROVs or otherequipment. The vessel can be ship-

shaped or of the semi-submersibletype. Often an MSV also has facilitiesfor divers and can work as a DSV.

g.3 Standby vessels and chase vesselsStandby vessels stay in the neigh-

bourhood of platforms or offshoreoperations to perform rescue opera-tions in case of emergencies. Chasevessels are used to chase ships awayfrom- platforms, offshore operationsor seismic survey vessels and forsupply operations. Of course these

tasks can be combined in one shiP.

Often converted fishing vessels are

used for this.

Chase Vessel


r t t t r

l /

1 Preliminary work

1.1 The application for specffication

1.2 The preliminary sketch

1.3 The tender

1.4 The estimate of construction

) Design and construction

Design department

Specialist knowledge

Planning

The production

The logistics

Delivery

Sea trials

Period of guarantee

ct2.1' r )

2.32.4) <

3.13.2

1 Preliminary work

Prior to the actual construction of the ship, the shipping company, financer andfuture owners have already completed a trajectory of negotiations andconsiderations. Unlike a car, a cargo ship is not ready for delivery in a widerange of models, but it has to be constructed following the demands of theshipping company. However, it is becoming increasingly popular to classifyships into categories where their designs are then standardised. This makesmass-production possible.

- The price of construction is exactly - the desired carrying capacity andknown tonnage

- The almost complete absence of the - desired speed and top speeddesign-period shortens the delivery - types of cargo the ship must be ableperiod to transport

- Because the costs of designing the - Layout of the holds with fixed orship are spread over multiple ships, movable bulkheads and tween-the overall costs are lower. decks

- System of hatches or an open holdThe disadvantages of a standardised - Necessity, strength and kind ofship are: cargo gear

The advantages of a standardised shipare:- the clients know what they can

expect- the design has already proven itself

and, ifnecessary, it has beenimproved.

- the design may not be entirelysuitable for the demands of theshipping company

- the involvement of the shippingcompany is limited to only details

In spite of the disadvantages,shipyards have introduced good andversatile standardised ships in recentyears. Some shipping companies arenow ordering whole series of thesewith sometimes only a few modifi-cations to the design. However, eachmodification will cost extra.

Pontoon hatches used as tween dec'k in a

ntulti prtrpose ship

1.1 The application forspecification

The shipping company first makes upan application for specification. Thisis a list of demands which the shiphas to fulfil. It specifies:

- Preferred suppliers of the engines,auxiliaries, navigation equipment,cargo gear etc.

Part of rhe nnrrro')ro,, equiptnent

- Number of crew and passengers todetermine the number of cabins

- Luxury and dimensions of thecabins and general accommodation

- Range to determine the size of thefuel tanks and storage compart-ments

- Limitations to the size of the ship inrespect to the routes it will navigate(bridges, locks, waterdepth etc.)and composition of the crew

- Special demands like reinforcementagainst ice or ramps in the side ofthe ship


0.O.0 C&rsl/fcrdollr, mF tN cnlft/fcrfrcg

The rosselirdt.ding lts hull, machinery ard squiprnontto be built urderlhe specisl

ern€y of tJo,ydg Rcdltff of Sfmhg end b be cla$cd and rageilrcd as +100 A1

+WC, UMS, ll /S, PCWBT, SCit, l-A, }.|AV l, lcedars 1A'Sbengthened brhesw

cJgocC Tfiter ded( Cargoec. Cmtdner orrgocs il! hold end m tpperdedC,

!frln$terrd ior regular discharlp by grab.

The v?$d to be legetr d un&r$. frag of tre l{e&alandg.

The iollowirg maddme Rrdes and Regulntione, thot€ ooming into eftoct as of the dalc of

cmrUon d the confrrct to be cmdfied u,i0t, lrdlding ndos and teei&tons ltniltl et

the <tay of ercculion of thc snfiect comirp into forca anel being applitzbb to tha w!!d

bc'tbc ecttaldefilory:

- Ruleg and rrgulelion of Clelclficattcn Sodsty

- Inbmgtbnal corfvwrtion for the satcty d lif€ at rea, 1992 and lablt amendnenb

- fnbmetionelcmronfpn on bad [nos, 19€8

Regdssom ftr ttc Meaersment of Ve$d (loncbt, 1969)

- Comnntion on tha Intamation l Reguldiona lor fpventirq co$ieions 8t see, 1972

- Cqnpn0on on the Intsna0onal Regrdttilont fur p"t€ntng polhl0om d rs 1973,

1978 (Annex l, fV, V) md ldegt emendmerfi

Actr d ffimafionelTclcoommrrica0on and Rrdb Conbonce (Gfi,tr)SS Atca lll)

- Suez Canal naviOdon rule

Paname Canal nantgdon rub

- USCG rules forfonrgn @ ehip viaiting US hsbqr (+ USDPH)

l|atimc rubs dfio Ncthabnds (NSl), irxfu(lhg NSI Noise Rc$.dttions

Regulalione ol Unatbnded Mecfilnery Spacc by NSI

Rtdc of Aurfrr$en Wrtorridc Worlrcr's Federdion (AWWF), Aurffian Nwigdon

and FilotRule

- Ref54 of Solss 19El forUte caniage of dangcour goods DHI (Parfnl application)

- St lrwtrn€ Scarly md Grut t dcs mquiurcntr

Yednum!.r 871

One t,vltic'ctl page as takenfrctm tlrc "spec'ffic:atiot1,t" indicating the applicable

Classification and the diJferent National Authorities.

offer consists of an estimate of thecosts and a preliminary sketch, which,in turn, consists of an outlinespecification and a generalarrangement plan. The outlinespecification is a brief technicaldescription and the generalarrangement plan is a side view of theship, which depicts the arrangementof all spaces in the vessel. A list ofdeviations often accompanies theoutline specification. This shows howthe preliminary sketch differs fromthe application for specification andgives the reasons for the deviations.On the basis of the offers, a shippingcompany will continue negotiationswith2 or 3 shipyards.

A preliminary sketch is made in theproject department of the shipyard.This requires a lot of calculations,especially if the design is entirelynew. The demands on computerprogramming and personnel are quiteheavy and if the shipyard is too smallto carry out such an amount ofcalculating work they will co-operatewith other shipyards, or subcontractthe work. A computer-programme isused in the following (first in thepreliminary sketch and later on in thefinal design):

- the design of the lines plan and theshape of the superstructures,maximum deckload etc.

- hydrostatic calculations, both for theloaded ship and for all kinds ofemergencies like leakage, runningaground, docking and how well allof these calculations satisfy thedemands laid down by the law.These calculations also give thestability and the longitudinalstrength.

- Hydrodynamic calculations, fromwhich the resistance curves arederived. The ship's behaviour at seaand its manoeuvrability at differentconditions of loading.

- The necessary size of thepropeller(s)

- Checking whether the outlinespecification satisfies all the legalrequirements, see fig.

- If freight contracts have alreadybeen made, the ultimate completiondate

- Required ceffication and regisftation

The shipping company then submitsthis list of demands to severalshipyards. The shipyards will then letthe shipping companies know if theyare interested in the assignment. Thiswill depend on:

- the technical capability of theshipyard

- the amount of material andmanpower in the available time

- does the shipyard want to build sucha type of ship?

- expected price level- expected competition


After the exploratory talks theshipping company sets a time periodin which the shipyards can submit anoffer without engagement. Thismeans that the shipping companydoes not have to pay for the offer andthat the shipyards do not know whichone will get the assignment.

Sometimes the shipping companyalready has a preference for aparticular shipyard, and then theoffers are used to compare thedifferent prices.

L.2 The preliminary sketch

The offer without engagement is theresponse of the shipyard to theapplication for specification. This

71

Poopdeck

A general arrangement plon.for a oil/gas/c:ltenical tanker


Profile

Ivlaindeck

Tweendeck

Tanktop

OfficersdeckBoatdeck

72

Forecastledeck

- e - = . � H

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PRINCIPAL PARTICULARS

Length o.a. 139.95 MLerrgth p.p. 134.70 MRule lenght Bur.Ver. 132.31MBreadthmoulded 21.00 MDepth moulded 10.60 MDraft summer freeboard CA. 8.06 MDesiga Draft 6.90 MDeadweight (6.90nt) appr. 11700 tonDeadweight (8.06 mt) appr. 14800 tonDraft scantling 8.10 MTotalengiaeoutput 5400kWService speed 14 KnGross tonnage approx. 8550 GT

CAPACITIES

Cargotanks 100% appr. 16000m3 -

Slobtank appr. 380 m3Washwater/ballasttank appr; 247 m3Ballast water appr. 6014 m3Potable water "itin. 99 m3HFO appr, 725m3Gasoil appr. 114 m3

CLASS: BUREAUVERITASCLASS I

+ OILTANKER/CHEMCALTANKERIMO tr, Umesticted Navigation( association with a list of defined chemical ca€oes, sailing under French flag)

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1.3 The tender

After having studied all the offers, theshipping company will make adefinitive choice for a particulardesign. This leads to a preliminaryestimate of construction or preli-minary building plan, a document thatmay be as large as 200 pages. Thepreliminary building plan is then sentto two or three shipyards for an offer.This procedure is called a tender, andparticipating in it is called "to

tender". Sometimes the EU demandsan "open tender" in which othershipyards, if they are from the EU,can partake.

It can sometimes take months for theshipyards to calculate an accurateprice from the tender, but they still donot receive any money; there are stillno obligations. Finally the order willbe granted to one of the shipyards. Inthis choice, not just the price is takeninto consideration, but also otherfactors like the reputation of theshipyard (working within budget andtime) and if the shipyard hasconstructed a vessel for the shippingcompany before.

1.4 The estimate of construction

After this preparation, often lasting ayear, the parties involved sign thefinal building contract. The buildingcontract establishes all the legalpositions and commercial conditionsbetween the shipyard, the shippingcompany and often also the financier.Now that the building contract hasbeen signed, all the parties haveobligations that start with the downpayment and end with the delivery oncompletion and the final payment.

Within the contract there will be aprovision to allow for adjustment ofthe price should any changes be madeto the original design at some stageduring the building contract. For anyalterations or components of whichthe price is unknown the price will beestimated and included with any otherestimates. The payment wil l besettled at a later date in accordancewith the provisions made within thecontract. Part of the building contractis the estimate of construction. which


describes the ship in detail and has afully elaborated general arrangementplan. The shipyard assigns a yardnumber to the future ship, which isstated on all the drawings anddocumentation. At this point the clockstarts to tick for the time ofconstruction.

2. Design and construction

The building time, as agreed in thecontract, comprises the design phaseand the building phase. The buildingtime varies between 6 and 24 months.A building group is formed by theshipping company and the shipyardwho both appoint people, who are ,each person in his or her own field ofexpertise, responsible for the entirebuilding process until the delivery.

2.1 The design department(engineering)

The design department is often calledthe drawing office, even thoughnowadays there is not a singledrawing table to be found. The ship isworked out in detail in constructiondrawings (or sheer plan or workingplan) and floor plans. The schemes ofall the mechanical, hydraulic,pneumatic, and electrical systems aredetailed and the accommodation isdrawn in.

Certain essential drawings have to besubmitted to the classification societywhere the ship is to be registered. Andeven though people from the shippingcompany are in the building group,some drawings still need approvalfrom the management of the shippingcompany. Furthermore, the whole ofthe design has to live up to (legal)demands of the classification bureau,who regularly send their inspectors tothe shipyard to assure compliancewith initially approved drawings.There are shipyards that have a smalldesign department. They will contractthe design out to an independentmarine engineering office, or theywill co-operate with other shipyards.The working out of all the details to acomplete and approved set ofdrawings takes tens of thousands oreven hundreds of thousands of hours.This is costly; as a rule of thumb up to

I}Vo of the total building price isestimated.

In many countries there exists a goodco-operation between the variousshipyards, and standardisation has led

A t'ro,ss-set' l ion tttt (r .\( 'reen

to a better match of products andcomputer-programme. This makes itincreasingly easy for shipyards tobuild parts for each other.

2.2 Specialist knowledge

For certain difficult areas of design,specialist research and engineeringfirms are approached. These firmswill produce work for:

- the optimisation of the shape of theship

- calculations on noise and vibrations- the optimisation of the propellers,

ducts and rudders

Research on the shape is done both bycomputer calculations and results ofmodel testing in one of the modeltanks. The resistance curves forexample are obtained by measuringthe required propulsion power atdifferent draughts and speed. Inaddition to this, research is done onthe influence of swell on the speed,the necessary propulsion power,navigability, the rolling and pitchingbehaviour and manoeuvrability. In thecase of very large ships, research isdone on the extreme forces andmoments of inertia that arise in theship in case of heavy swell.

The optimisation of the ship's shape isa very laborious task wheremeasuring and calculating go hand inhand.

74

t t c t 'r t be.fore optiru iscrtiott

, t t isal iner dur ing sat tkceping und mattoet t r i t t lq lc ,st , \ ' ( t t M,\RIN

Wtve-ptrtte rn trl ie r oltt i ttt isutitttr

2.3 Planning

The planning department makes thedrawings of the design departmentready for production puposes; theright drawings at the right workplace.Furthermore, all the steel parts aregiven a code.

With the aid of a computer-programme, a draughtsman ordraughtswoman nests the steel plates.This means that the steel platespresent at the shipyard(s) are chosenin such a way that, after cutting intoshape, there is a minimal amount ofwaste. The computer also controls thecutting torch, a plasma cutter in awater-bath. Because of this the excessheat is drained quickly. As a resultminimal distortions will occur andthere is a good control of the exactdimensions of the plates. The cuttingmachine can also engrave the codenumber of a part into the steel.

In the figure above the wave patternsof a ship at a certain velocity beforeand after optimisation are depicted.The optimisation procedure hasreduced the wave resistance becausethe ship makes fewer waves afteroptimisation. The bulb stem hasalready reduced this resistancebecause the wave produced by thebulb stem counteracts the bow wave.However, this is only one effect that


is accounted for in the optimisationprocess, there are many other effectsthat can further minimize waveresistance.

A plote L'Lrttcr

75

Englne room caslng

Rudder eection

-o Bdtompanel @

G

66l

6 r ( o

Sleedng engine


{ o a B o t t o m p a n e l o )

.15 Bottompanel e

6

cD Bottom panel'o

@

Amidship secton, iEformed by two side panels

and a bottorn parEl.


Panel,s and sec'tion.s of'a ,sltilt

77

2.4 The production

A ship is constructed in variousstages, which can sometimes overlap:

- pre-treatment- building by panel- building by section- building of hull and deckhouse- painting- launching- fitting out and subsequently

completion- trials at the shipyard- sea trial

.\utomation of the steel constructionhas led to more efficiency. Further-more, the designers will design thesections in such a way that as much* elding as possible can be done byrr elding robots. Building by sectionenables parts of the double bottom,the foreship and the aft ship to bewelded whilst lying upside down inthe workplace. This way of weldingproduces a uniform quality of thervelds within less production time.Because access to the differentsections is much more restricted whenthey are joined together, the sectionsare completed as far as possible priorto the joining. This means that pipingsystems, tanks, filters and other smallauxiliaries are all placed in the sectionbefore the joining of all the sections.

The building of a ship used to beginwith the placing of the keel followedby the keelplate. The rest of theconstruction was then connected to

this. Nowadays, laying the keelmeans that the first bottom segment isplaced in the assembly hall.Subsequently, the other sections ofthe ship are then built to or on this. Atthis stage, the production is wellunderway.

Modern shipyards do the actualbuilding in large indoor assemblyhalls where they use pre-painted steelplates. After welding the plates, thejoints are immediately painted.

Several factors determine where theship will be finished. The finishing iseither done in the assembly hall or atthe fitting out dock. In some cases thedeckhouse can not physically fit intothe assembly shop. And if thelaunching of the vessel is going to bean end-launch, the vessel should havethe minimal amount of weight onboard. The launching is always anexciting moment because at themoment the ship is launched, there isno way of stopping it.

Viev' in an u,tsenbh, shop

Anotlrcr v'iev' in utt us,;entblv sltoD

tirrt bottrnn segtnetrt is pluc:ed.

\itip Knowledge, a modern encyclopedia 78

.{C---' X

: , l t ' - l t t t t t t t : l t

ln end-launches, the ship acquires sornuch speed that it takes a lot of effortitr Stop the vessel in the water. In side-ilunches, the ship can bounce back.tgainst the wharf, especially whenrhe water level is high. The ship doesr'rctt gain much speed, but insteadproduces very high waves. After thelaunch, the final touches like masts,hatches, sometimes the engines,I'unnel, ventilation shafts, cranes etc.rre added to the ship at the fitting outJock. Finally, the cabins and other:p&ceS are furnished and theinventory is brought on board.

\\'hen the ships electrical wiring isready, it is connected to the shore.upply to get a voltage. After this allrhe engines, generators and auxi-liaries are brought on line and the.hip can then begin to functionindependent from the shore. Uponcompletion of the vessel in the.hipyard all the final testing will beconducted at the shipyard with ther-rception of items which can only be

')tip Knowledge, a modern encyclopedia

tested during sea trials in open sea.Final testing at the shipyard is relatedto electrical systems, engines, gene-rators, pumps, technical equipment,life-saving equipment and a lightweight / stability test. Final testing inopen sea is mainly related to finaltesting of machinery under workingconditions, fuel consumption, vessel'sspeed, rudder tests and anchortests.

In principle all these tests will beconducted in the presence of theowner's representative(s), classifica-tion surveyor(s) and - if applicable -

National Authority representative(s).

Next is the first, technical, sea trial,which can sometimes take up to 2days. This is the first time that theship leaves the shore and iscompletely self-reliant. The ship as awhole and all of its parts areextensively tested and all the resultsare carefully recorded. The classi-fication society and the Shippinginspectorate are also present to see ifall the legal demands are met.

In general, these trials are usuallysuccessful, but there are always smallimperfections which can be amendedduring or after the trial. How the shipexactly behaves in open sea willbecome clear when the ship is in use;however, the speed and fuelconsumption of the empty ship can bemeasured during sea trials.

2.5 The logistics

More and more shipyards advertiseshorter delivery periods, and moreand more shipping companiesstipulate that. In order to facilitatethis trend, lots of shipyards contractother shipyards to build parts of theship. It is also common that the hullof the ship is constructed in cheapercountries and that the hull is fitted outand completed locally. But evenwithout these measures, all the semi-finished parts must be ready for thenext phase of construction tocommence. Besides, all thepurchased parts must be ready intime, but not too early because of thecosts for storage and the loss ofinterest. Keeping the constructionprocess manageable requires that a

Tlre nraitt eng,itrc (70 ton,s ) is brctught on

hoa rrl

lnstulltrt ion r1f a complcte det'khott,se,

u,hile the ,ship is ut the.l ' i tt ing out dock.

proper overall planning of the projectin terms of technicalities, logisticsand finance should be available anytime of the day. Such a managementsystem integrates and controls datafrom the preparation, design, pur-chase, stocks, production, admini-stration and project management.

79

3 Delivery

3.1 Sea trials

The Shipping Company andCertifying Authorities will finallyaccept the ship subject to positiveresults of sea-trial tests and the issueof the relevant certificates. Duringthis short voyage the protocol ofconsignment is signed, the shipyard'sflag will be exchanged by the flag ofthe shipping company and thefinancier pays the last installment.Because there is a l2-month period ofguarantee on the ship, the shippingcompany usually requires a bankguarantee from the shipyard. This iscalled upon when the shipyard can

not, or refuses to comply with theguarantee. It is normal that in the firstmonth of a ship's life a guaranteeengineer from the shipyard is onboard.

3.2 Period of guarantee

The guarantee conditions are anintegral part of the building contract,because, just like any other product,the ship has a period of guarantee. Ingeneral, this period is 12 months afterthe delivery of the vessel. Theshipyard almost always adopts theguarantee conditions and periods ofthe companies supplying the differentship components. If the ship needsrepairing within the period ofguarantee, the vessel's location andthe urgency of the repair jobs

determines who will repair the vesseland where it will be done.

If the ship cannot be repaired at or bythe shipyard, for instance, becausethe ship is in another country theshipping company is allowed to havethe ship be repaired by a third party,but only if the costs of repairing theship are not more than the price the

shipyard would ask. This conditionprotects the shipyards against exces-sive bills if there is a deal between theshipping company and the repairyard.

Repairs of components and equip-ment are almost exclusively done bylocal service-dealers, especially whenthe parts are of a well-known brake.This is always done in consultationwith the shipyard or the supplier. Thecrew is prohibited to do repairsduring the period of guarantee unlessthe repairs ure absolutely necessary.If this is the case, the shipyard has tobe contacted for consultation first.

Sometimes suppliers have twoperiods of guarantee for their product.The first period covers some monthsafter delivery from the factory thesecond period covers some monthsafter the product is put into operation.The reason for this is, that theresometimes is a long period betweenthe delivery to the shipyard and themoment the component is put intooperation.

Sea trial test of a container shin


Ship Knowledge, a modern encyclopedia 8l

Forces on a shin

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F orces on a ship

General

Longitudinal strength

l.l Shearing forces

2.2 Explaining bending moments

1.3 Longitudinal reinforcements

l.-l The loading programme

Torsion of the hull

Local stress

1.1 Panting stresses

1.2 Pitching loads

J.3 Diagonal loads

J.{ Vibration loads.1.5 Docking loads

Ship in waves

Stiffening

6.1 Purpose of stiffeners

6.2 Longitudinal framing system

and transverse framing

system

3.

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1 General

There are many forces acting on a ship. How they act is largely determined bythe purpose the ship was built for. Forces on a tugboat will be different fromthe forces acting on a container ship. The types of forces that occur in wavesare the same for every ship but the magnitudes and points of action depend onthe shape of the ship below the waterline.

The pattern of forces on a ship is verycomplicated and largely depends onthe following parameters:

- the weight of the empty ship- the weight of the cargo, fuel,

ballast, provisions, etc.- ice- hydrostatic* pressure on the hull

applied by the water- hydrodynamic* forces resulting

from the movement of the ship inthe waves

- vibrations caused by engines,propeller, pitching

- incident forces caused by docking,collisions

These and other forces cause the shipto be deflected. When the force stopsacting, the ship will regain its originalshape. Every ship is different andsome have more or less of thisflexibility. If, however, the forcesexceed a certain limit, the defor-mation can be permanent.

2 Longitudinal strength

2.L Shearing forces

When a ship is in calm water, the totalupward force will equal the totalweight of the ship. Locally thisequil ibrium will not be realisedbecause the ship is not a rectangularhomogeneous object. The local

*Static and dynamicThe concepts static and dynamic are widely used in this and otherchapters. Static means that the work done on an object is absorbedimmediately. Dynamic means that the work done on an object is absorbedgradually.

Examples of static:- A swing with a child is slowly pushed forwards from rest. This is a

static movement because the force exerted on the swing is absorbedinstantaneously.

- A crane on a ship is loading a ship with cargo. As the cargo runner isstiffened, the ship lists slowly. This is a static movement because theship absorbs the force that lifts the weight instantaneously.

Examples of dynamic- The same swing is pushed forwards suddenly. The weight of the swing

cannot absorb this sudden burst of force and gets out of control. This isa dynamic motion.

- The same crane has lifted the weight several metres. The weightsuddenly snaps and falls on the quay.This causes the ship to listviolently to the other side. The ship is unable to absorb the suddenchange in weight and, as a result, acquires a dynamic motion.

A ,shi1t tt,ith lrcal in utr uttsttthle .s'ituution.


:-'r'e nce\ between upward pressure

.. ihc' local weight give rise to; . , r ing forces that lead to.--rtLrdinal tensions. The shearing'-: i. the force that wants to shift- .rthrr art-ship) plane from one part.:rc 'hip to another. The submerged..: rrf the ship clearly shows the::rrence in volume between the:,i.hips. the fore- and the aft ship;.. i. the reason for the difference in

upward pressure. In the drawing onthe right a part of the aft ship isdepicted along with the shearing forcenear a bulkhead. The shearing force atthe bulkhead is 400-200=200 tons.The downward force causes ahogging moment of 400t x 6m. Theupward force causes a saggingmoment of 200t x 3m. The bendingmoment at the bulkhead is: 2400tm-600tm = l800tm hogging.

The longitudinal forces occurbecause:a. the weights in the ship are not

homogeneous in the fore and aftdirection

b. the upward pressure differsbecause of the shape of theunderwater body

400t

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\ltip Knowledge, a modern encyclopedia

-tt -f

s i r i l i z i r

85

The ship is panially in a trough. In this case the foreship will experience a large

sagging moment while the aft ship expeiences a large hogging moment.

22 Explaining bending moments

Below is an explanation of howbending moments and shearing forcesare continuously changing. As anexample a rectangular vessel is usedwhich is divided into three compart-ments (A, B and C). In figures 1, 2and 3 both outer comparfinents arefilled with cargo. In figures 4 and 5the inner comparhrent (B) is filledwith cargo. In figures 2 and 5 thevessel is on a wavetop and in figures3 and 6 the.vessel is in a trough. Theupward pressures keep changingbecause the wave pattern is alsochanging. The downward forceshowever stay the same. The up anddownward forces per comparfinentare depicted as vectors.

fig 3

trough

f ig2

wavetop

f ts1

calm water

Container feeder in heavy weathen Thc ship is panially on a wavetop; hogging

load curve

Ship Krnwledge, a modzm encyclopedia 86

sheering force curve

t

;;

called summing. The sum of the areasabove the baseline has to equal thesum of the areas below the baseline.

The shearing forces are expressed intons.

The bending moment is determinedby summing the shearing forces goingfrom left to righr

The bending moment is expressed intonmetre (tm). If the shearing forcecurve changes from rising to fallingor vice versa, the bending momentwill bend at the bending point from"hollow" to "round" or vice versa.When the shearing force curvecrosses the baseline, the bendingmoment line will change from risingto falling or vice versa. The ship will

fig s

. :I

; l

T

The mean resultant per compartmentis given as a vector on the line below.

The load curYe gives the differenceof the up- and downward forces permetre at each point on the baseline.The sum of the areas above thebaseline and the areas below thebaseline should be equal.The shearing force curve gives a sumof the shearing forces on the right partproduced by the left side, going fromlcft to right. If the direction of theforce is changing (from upward todownward or vice versa), the shearingforce curve will change from rising tofalling or vice versa. The shearingforce curve has an exfreme value atthe points where the direction of theforce is changing. Converting theload curve to a shear force curve is

take the shape of the bending momentline if this has only one extreme(maximum) value.The sinration in figures I and 2 iscalled a hogging condition and thesituation in figures 3, 4, 5 and 6 iscalled a sagging condition. Aroundthe half height of the vessel there is a"neutral zone". Here there are hardlyany tension or compression sffesses.However, especially at the ends of thevessel, heavy horizontal shearingstress can occur.

fig 6

trough

fig +

calm water

toaO curve i

wavetop


2.3 Longitudinal reinforcements

The preceding shows that the biggeststresses occur in the outer fibres: inthe shear strake, bilge strake, upperstrake of the side bulkhead andbottom strakes. This is were thethickest plating is applied. Thepictures above show a view thatclearly emphasizes the difference inplate thickness between the upperstrake of the side bulkhead and theside bulkhead just below it. In thisship (container feeder) the upperstrake of the side bulkhead is about2.5 times as thick as the continuousside bulkhead. The place where theplate thickness changes (from 22 mmto 9 mm) is called the taper.

2.4 The loading programme

When the ship's officer has enteredthe weight of all the items on the shipinto the loading programme, thecomputer can calculate the stability,shearing forces and bending mo-ments. The program compares thepresent situation with the requi-rements and regulations of theclassification bureau and the properauthorities. The following pagescontain a number of examples ofloading situations as the computer onboard depicts these. The situationshave been greatly exaggerated forclarity. Of the total loadingprogramme, only a few (shortened)pages are shown.

Situation IOnly the holds in the fore and the aftship are loaded, resulting in a greathogging moment. The graph showsthat the bending moment reaches thelimit for seagoing condition. There-fore, this is a dangerous situation.During (un)loading in port thisbending moment is still allowable.The difference between maximumallowable bending moments at sealevel and in the harbour comes fromthe additional bending moments duethe waves at sea.Situation 2The cargo is distributed equally overthe whole ship, resulting in modestshear forces and bending moments.Because part of the cargo is placed onthe main deck, the initial stability(GMO) is negative. This means thatthe centre of gravity (G) is above themetacentre (M) when the ship has nolist. When the ship starts listing Mwill move upwards due to thewidening of the waterline till itreaches G. In case of an increasingdifference between G and M the shipwill eventually capsize.Situation 3Only the holds in the midship sectionare loaded. Because of this the shipexperiences a large sagging moment.The maximum bending momentexceeds the acceptable bendingmoment for seagoing condition atVzL (frame 108) by 27o.In port this isstill permissible. See also the table"strength summary" and the graph ofbending moments.

Explanation of the above pictures:

1. Upper strake side bulkhead(22 mm)

2. Main deck or gangway (14 mm)

3. Longitudinal or side bulkhead(9 mm)

4. Deck beam (HP-profile)

5. Deck beam (flat bar)

6. Longitudinal frame (HP-profile)

7. Web frame with plate stiffeners

around manhole.

8. Inner side of the shell with

stringer.

9. Stringers on the side bulkhead.


Minimum pressure

Pnessure distribution for a hogging condition

llaximum stress M

Global stress level (equivalent stress) for a hogging condition

Two computer simulations which show the tension and compressive stresses in hogging condition.

fig Knowledge, a modern encyclopedia

Minimum stress

89

SEATMDE B,V.

Voy.10{ I{OGGING ft'omTRht brRnL Sctrv. 1.(P6 C OECK

l ll l

t ll l .

t tr. DA DECK

B DECK

lmton m.- Llghtwclght

2C-,28 2A 18 I

l-l - Dcedloed

l lIJi t o z 0 107

78 7A

SHEAR FORCE

o o o o oX X X X X

0338 3A

055B 6A

065B 6A

0448 4A

1000 t

xAox(

O O

XX x

o o o

x x xo o o

X X

o oLimit, Harbourx xLimit, Seagoing-f5g[Ugl

o o o ox x x

X

BENDING MON,|ENTooLimit, Harbour>o<Limit, SeagoingrACtggl


5" 100 15" 20" 25" 30"

Stpar Forca and B€ndlry Motrcnt Reqdb

Dl&ncee Buoyancy Lbtfirebht Compartneils BraakBuk - BaytfromAp. fromOX Wght Mdmeni Wglrt

-trfiomant Wglrt Moment Wglil ltlomont Wglt Moment

m m -t

tm t h t tn t tn t tn

GM sdidConedionGM lluidGM rcq.FbelRdlp.

1.37 m0.08 m1.29 m0.15 m-1.1 "SB15.0 sec.

KMTLCBLCFlmmersionTrimMom

9.37 m1.94 m2.92 m

21 Ucm138 frn/cm

Str€ngthSF BM

t t m

€ . 8 0 1 7 2 . 8 5 1 0 0 07.800 61.450 -53 €403 401

u.625 U.625 -1912 {6886 179851.200 18.050 4038 -1422fi 291474.n0 -5.050 1335 -163783 389190.025 -20.n5 -9304 -138955 dt8',,

110.860 41.610 -11017 47478 5396133.900 €4.650 -117U 4%n 5$41.f6.501 ..-.:77.257 ":11910 €9430 6089

0 0 026598 n0 1n27g7gt3 507 28(El

125681) 721 *F85132885 14rJ0 38081'1?,.453 1739 34379 9091t287 2n 16923 1g2g742U 2669 Afiz 184663392 2A9/- 4208 1826

'EADWEIGHT SUMMARY

20CONTAINERS,|{ICOilTANERS

CONTAIIIEiRSBREAIGI'IJ(

00

2U909900

0 00 0

10774 - 462,n895 82n$t5 82n8*5 89312914 1(X6

-11287 1W2

0 0 00 617 fi12

19448 1139 298€,21W 908 469821W €33 5131915618 -1flA 369624tn .968

&E7 €4f f i 7 0

858418615

STREI{GTTI SI'MMARY

Frame Fromno. AP39 26.00051 34.02557 38.60061 12.01075 51.2008'r 55.400s2 6:!.100108 71.W120 &1.100125 8E.2{X)130 90.025142 98.100150 rGl.850160 110.800171 118./m0188 130.300

Maximun :Poei[on (m):Baya:

ShoarForc€s Bending Moment%dpofinbs. %of Permiss.

t Seag. Hatb. fn Seag. Hatb.11S 47 41 19978 29 25tt39 4 39 29g,'2 45 381076 12 38 U?53 53 /ti|io37 40 35 3784{1 59 4796E 37 32 46982 80 60€93 27 23 50,,g2 90 6518i] 7 6 53'��A2 I 72

€33 25 22 51319 90 69€02 37 32 4247 83 59

-19041 & 35 41151 78 56-1176 4 38 3052 71 50-18:!9 03 54 25€2.8 53 38-1411 52 45 18904 48 324E8 36 31 85E4 6 18-527 19 18 330,1 11 E€ , 2 2 2 3 5 9 2 2

-10i!9 q! il 53956 7298.10 98.1 98.1 65./tg 65.5 65.5

2C 2C 2C AAF4B 5A-48 5Ar4B

oREWAITDSTORES 1{Xt 3.0SHEAVYFUEI- 89.f €3.40DTESEL OtL 107 38.03Fre$IWATER 2Q. 65.01WATERAAU ST 1296 2.47MtscELltNEot s 91 54.54oEAIX'VE|G||T *22 112DEADLOAO O OLlGffTvrGl@rT 6089 10.41DtsPtAcEt ENT 11910 3.31DWffiSE:R1/E 1128|

TCG vCG S.Cor.(pcs.)m m m0 0 ( 0 )

4.A2 17.08 ( 62)

4.22 17.08 ( 62)0.00 8.12 ( 6)

0.00 13.E1 0.q)4.00 2.61 0.07-0.(n 0.s6 0.010.02 8.98 0.00{.03 1.25 0.000.15 5.92 0.00

-0.05 7.71 0.080 0 0.00

0.00 8.26 0.004.03 8.00 0.0E

Wei$t LCGt m0 0

1302 4.52

13fi2 4.521826 €.17

FIYDROSTANCS & STAHLITYIhaught AP 7.55 mthaught M. 7.00 mDnaught FP 6.45 mTrim 1.10 mAir Draqght 28.99 m

- Prom.Ratio 82 %

Ship Knowledge, a rnodern encyclopedia

(Values aborc for fim=O)

91

Situation 2

0338 3A

055B 5A

r-1ili tt lJ (

frt lt l5C

066 8 6

0778 7A

044B 4A cr 28 2A

1000 t

oX x

oX

oX

bx(

2

o oX

o o oX X X

o o

x

011 B 1

o oLimit, Harbourx xLimit, Seagoingrfistr13l

o o o ox x xX

SHEAR FORCE

o o o o oX X X X X

lOflN tm BENDING MOII,IENTooLimit, HarbourxxLimit Seagoirg-fi6ft1pl


Shear Force and Bending Moment Results

Distancee Brcyancy Llghtweigtrt Comparfnents BreakBulk Baysfrom Ap. fiom OX Wght Moment Wght Moment Wght Moment Wgtrt Moment Wgtrt Moment

m m t t m t t m t f n t t m t t m

$trengthSF BM

t t m

- 3 . 6 0 1 7 2 . 8 5 1 0 0 07.800 61.450 470 -31165 401

u.625 34.625 -3747 -182130 179851,200 18.050 8737 -2A0/,27 291474.300 -5.050 -10983 -288729 389190.025 ';0.775 -1U02 -258328 4788

110.860 41,610 -15406 -198358 5396133.900 €4.650 -16197 -158411 5934146.501 -n,251 -16340 -14W28 6089

0 026598 22097873 361

125683 613132885 1333122453 16i11102487 17427420/- 174763392 1752

0 014265 020887 U2nuT 263331553 4103278/-1 519725332 5n325023 585324s,E1 5853

0 00 0

31981 44281197 88290039 154075390 203760624 239058719 2ffi56719 zffi

0 0 00 150 /EE

194r',8 -28r'. -209831066 306 {5433n9 -117 -10812774 251 31816152 -105 18823840 -17 913640 { -27

STRE}.IGTH SUMMARY

Frame Frornno. AP39 28.00051 34.62557 38.60061 42.O'�t075 51.20081 55.400s2 63.100108 74.3{10120 83.100125 E8.200130 90.025112 98.1001s{, 103.85t

'160 110.860171 118.400t88 130.300

Ma,dmum :Posaton (m) :B€ys:

ShearForcee Bendingiloment% of p€rntss. % of Perniss.

t Seag. Ha6. tn Soeg. Harb.- 2 1 8 9 8 7 0 7 1 1-284 12 10 -2098 4 3- 1 6 0 7 6 - 3 0 6 0 s 4

32 '�t '�l -3289 6 ,t3{r8 12 10 {54 2 1

- 0 0 0 - 3 / . 2 1 0- 3 9 2 1 - s f l , 1 1

- 1 1 7 5 4 - 1 0 8 1 3 21 2 7 5 4 - ' 1 0 8 7 3 2' t 9 5 8 7 - 5 8 1 1 12 5 1 1 0 8 3 1 8 1 01 3 9 6 5 2 3 5 8 5 3€ 3 2 2 2 5 5 9 7 5

- 1 0 5 1 3 1 W 2 6 4- 1 ' � t 4 4 4 1 1 0 3 4 3- 3 3 1 1 1 8 1 1 1

306 12 10 -32U 7 551.20 34.6 51.2 41.58 103.8 103.8

5C 7A€B 5C 88*il.2G.2B2c..2A

DEADNA'EIGHT SIilIIARY

20'OOilTAINERS40'@NTAINERS

coinArNERSBREAXAULX

CREWAND STORESHEAVY FUELDIESEL OILFRESH WATERWATERAAUASTrilscElut{EorrsD€ADI'I'EIGHTD€ADLOADLIG}ITWEIG}ITDISPI-ACEI'ENTT}WRESERI/E

LCG TCG vCG S.Co.r.(pct)m m m m0 0 0 ( 0 )

1.38 4.23 17.11 ( 120)

1.38 4.23 17.11 ( 126)988 O.t2 10.31 ( 15)

-36.38 0.00 15.90 0.0021.85 0.(n 0.88 0.028.27 0.00 0.21 0.0065.01 0.(n 8.98 0.002.17 .O.03 1.25 0.00

5.l.5tt 0.15 5.92 0.008.30 4.06 10 80 0.u2

0 0 0 0 . 0 010.41 0.00 8.28 0.009.08 .0.fi| 9.88 0.02

Welgfitt0

ffi

2W5853

1 31391 1

2U21290

9110251

06089

163407gt9

HYDROSTATICS & STABILIWDraught AP 11.07 mDraught M. 8.64 mDnaught FP 6.20 mTrim 4.87 mAir Draught 25.85 mPropp.Ratio 149 %

GM sdidConectionGM fluidGM req.Hee!Rollp.

f m0.02 mI m0.15 m10.6 "PS

4O.'l sec.

KMTLCBLCFlmmersionTrimMom

9.72 m2.71 m6.88 m

24 Ucnt192 tn/cnt

Ship Knowledge, a modenr encyclopedia

(Values abov€ for bim=O)

93

Situation 3

--Cglgg

- TrilC- Lbhtmlfi

Dcrfted, l

t lL l i] f @ , 0 1 ) l07

78 7A

S}IEAR FORCE

o o o o o

X X X X X

066 8 6 2B2A 18 1

- Brcymqr

.o otimit" HarbourxxLimit, Seagoirg-Actual

o o o o g g g

tf x x x

1m0t

X

o ox

o o o

x x xo ox x

l(xnotn BEMxr{G nc,HEhn

Ship Knowledge, a modem encyclnpedia 94

GZ, M

10" 150 20" 25" 30"

SlEr Force and Berding Moment Resullg

Di$ancee Buoyancy Ligtrtrireight Conparlmenta BrekBulk Baysftun Ap. fiorn OX Wgtrt Moment Wglrl Moment Wgtrt Moment Wght Moment Wght Moment

m m t t m l t m t t m t t m t t m

0 028598 22097t73 305

132885 1'�t25122453 152'�1102487 16847420/- 168963392 1689

0 014265 018602 023786 380018810 651915013 750014704 7500u7a 7500

)EADWEIGHT SUMIIARY

20'CONTA]NERS40'CONTAINERS

CONTAINERSBREAKBULK

CREW AND STORESHEA\^/ FUELDIESEL OILFRESHWATERWATER EALLASTMISCELIINEOUSDEADWEIGHTDEADLOAT)LIGHTWEIGHTDISPLACEMENTDW RESERVE

0 00 00 0

21874 658-13967 1155-37139 1260€7139 1260-37139 1260

Weight

01260

12607500

82481 1

2021129.

9110419

00089

165376858

0 0 00 476 22170 -558 12621

2713 -290 43362-3322 1466 -33716-5704 685 -51E6€704 15 -5-5704 4 -12

StrarqthSF BM

t t m

VCG S.Con.(pce,)m m0 ( 0 )

17.57 ( 0O)

17.577.57

16.613.220.248.981.255.q28.01

08.288.11

mRadmRadmRadmRedmRadmRad

[email protected]

34.62574.W90.025

110.860133.900146.501

72.85'�1 0 0 061.450 -144 -9411 40134.625 -2661 -123187 1798-5,050 -9763 -2,'3138 3891

-20.n5 -12518 -188139 478€41.610 -15155 -108:164 5396€4.650 -16387 47ft7 s934-77.251 -16538 €5252 6089

STREilGTH SUMMARY

Frame Fromno. AP39 26.00051 34.62s57 38.80061 12.01075 51.200El 55.4q)q2 8i1.100108 74.3q)120 83.100125 86.2@130 90.025142 98.100150 103.E50160 110.8@171 118.4(n188 130.300

Maximum :Po*lion (m):Bays:

Sfi€ar Fotcsg% of penniss.

t Se€g. Hatb.$2 18 10

-558 24 20-900 12 35

-1351 57 47-2292 86 74-21Ei' 84 74-1377 56 49

-2g[J 11 10715 2S 25

1084 12 361& 57 491e/.'t 09 561174 47 39885 27 23301 12 102 7 1 1

-2202 86 7451.20 51.2 51.2

5C 5C 5C

B€nding Momenl% ot permiss.

tn Seag. Ha6.130.19 19 17QA21 19 '16

9506 15 125494 9 7

-11053 T3 15-2802 45 8-34if30 80 49-,,33F,2 I 63414f/. 98 603&t41 92 56-9t718 81 49-19802 51 32-11609 44 24-51E6 20 12-15,.7 6 4

- 7 7 1 0

43634 I 6376.61 76.6 76.6

48{A 48!44 48!44

GM sdidConectionGM fluidGM req.HeelRdlp.

.0.53 425-4.95 0.00

-16.95 0.00-7.18 0.008,27 0.0065.01 0.O2-1.61 -0,03i l"v 0.15-2.69 4.03

0 010.41 0.d)213 4.O2

LCG TCGm m0 0

,f.53 -O.25

( 80)( 8 )

0.000.0r0.000.q)0 0 0000o.020.(X)0.q)0.02

FM)ROSTATICS & STABILIWDraught AP 8.74Draught M. 9.07Draught FP 9.41Trim -0.66Air Draught 27.62Propp.Ratio 103

mmmmm%

Floodangle, Thf 51.2Deck Subm. 21.0cbWindForce

KMT 9.87 mLCB 2.99 mLCF 7.36 mfmmersion 25 UcmTrimMom 206 !n/cm(Values above for tim=0)

Actuar iH-GM lluid 1 74 Min 0 15 mGZ 30 1 075 Min 0 200 m@ m e x 1 1 6 2 mGZ max at 38.8' Min 25"

1.76 m0.02 m1.74 m0.15 m-0.7 "sB12.3 soc.

Heel5"10"15 '20"25"30'40"50"60"70"Gontainer COG

GZ0 . 1 50 3 10.490.700.931 . 0 81 1 61 .060 8 20.49

50

mmmmmmmmmm%

0.590.051 Um^Z

Wind Lever hr1 0.056 mCargo WindArea 252 m^2TotalWindfuea A 1610 m^2 Ar€s 40+30 0 199 Min 0 030

Area 30Ar€a 40

Ar€aAAr€a B

O 275 Min 0 0550 474 Min. 0.090

0 0970.598

ArEB/A 6 .143 M in 10Stab.RarEp 512" Min ooWind l-leol ThO 1 8" Max 16'


3 Torsion of the hull

Torsion occurs when there is anasymmetry in the mass-distributionover the horizontal plane. Forexample, if there is a weight of 100tons on the starboard side of the fore-ship which is compensated by anequivalent weight on the port side ofthe aft ship, there will be torsion (ortorque). If both weights are 10 metresfrom the centreline, the torsion willbe 100t x 10m = 1000tm. In adverseweather, especially when the wavescome in at an angle, the torsion canincrease as a consequence of theasymmetric distribution of the up-ward pressure exerted by the water onthe submerged part of the hull.Torsion causes a ship to be subject toextra stresses and deformations. Thiscan result in hatches leaking or badlysealing. Especially "open ships", i.e.ships with large deck openings, tendto be torsionally weak and aresensitive to this. A good example arecontainer ships and modern box holdgeneral cargo ships.

H euvi b, pitching .fishing bocLt.

4 Local stresses

4.1 Panting stresses

These occur mostly in the fore-shipduring pitching. The constantlychanging water pressure increases thestress in the skin and the frames.Panting stress is not a result ofhydrostatic pressure, but more aresult of hydrodynamic pressure. Toreduce the panting stress effect,panting beams in transverse directionand stringers against the ship's shellare added to the forepeak and aft peakstructure.

4.2 Pitching loads

Pitching loads occurs in the flatbottom of the foreship as a result of(heavy) pitching of the ship. Thepitching stresses are reduced byincreasing the bottom-plating thick-ness, by the addition of extra sidekeelsons and closer spacing of theframes and floors on every frame.

4.3 Diagonal loads

These. occur when the ship itsasymmetrically laden and duringrolling of the ship in waves. Theeffect of the diagonal loads is reducedby the addition of frame brackets,deck beam brackets, cross frames andtransverse bulkheads.

Dirtgonal loacls clue trt rollirtg in v't^,es

4.4 Vibration loads

These can be caused by:- vibrations of the engine- forces on the aft ship caused by

the rotations of the propeller.

4.5 Docking loads

These result from vertical upwardforces where the keel blocks areplaced and vertical downward forcesbetween the keel blocks and the sideblocks.

Forces ctn tlte .foreship if the ship is on u

,Neve top (Le.fi) ancl in a trough(right).

ljr-:fi$.:

\

Duntage cuused 121: pantirtg ,struin. Entire .forepettk tank tont c{f.

Ship sil.c 100.000 t. dead v:eight


5 Ship in waves

fbF< t-rgures. made by computerrirujtron. show exaggeratedly howr c-rll container ship in heavy wavesr+r-. t distOrted.

. i i l(/r 's top, hogging Waves coming in from starboard at an angle, torsion

;,::: Kno*'ledge, a modern encyclopedia

Wcwes c'oming in.frctm portsicle at an angle, forsiort

97

6 Stiffening

6.1 Purpose of stiffeners

To prevent the planes (plate fields) ofa ship from distorting under influenceof the shearing loads, bendingmoments and local loads, they haveto be stiffened. Examples of planesare the shell, decks, bulkheads andtank top. Compared to the dimensionsof the ship, the plating is not verythick (about l0 - 20 mm). Once thestiffeners are in place, they alsocontribute to the reinforcement of theplane by reducing the tensions in itand by preventing local buckling.This enables the stiffened planes to bethinner than the planes, which are notstrengthened.

An example of this are the frames onthe inside of the skin, most of whichare of the type "Holland Profile"(HP).The drawings show the impor-tance of stiffenine.

C-ontltressing .fort'es on u ltlulc resttlt irt

plute brckling.

Itue.tt lt lulc.

Fr t r t 'es or t n l t lu l r ,v ' i r l t ut t HP-. f inntc t t t '

ntgle bur ut tlte lt luct: of' lsctulirtg. ' l '1rc

ltlut' itrg rtf 'on I{P-.| 't 'r.tttrt, or atrglc bur

itt.s'tt 'utl o.f 'u singla .stt ' i1t u,i l l rctlut c l lrc

risli rl ltcndittg.

If all the frames run parallel (in eitherathwart or fore and aft direction) it ispossible that the frames can bendperpendicular to the frame direction.To prevent this, a stiffening is placedperpendicular to the frame direction.Such a stiffening is called a stringerfor transverse frames and a webframefor longitudinal frames. Bulkheadsare also constructed using thissystem. In the case of decks, deckbeams and deck eirders form thestiffening.

Prtrulle I . l ' t ' ttnte,\ ()tt a plrtlt ' .rtrb,jcctt 'd lrt

bet t t l in .q tn0t t rct t t

' l 'hc,srut t t ' s i l t t r t t io t t ot t l r t tov ' +r i l l t r t

,st t ' i ttecr lt luccd pt' rytt,rtrl iculrt r to l ltc

f't'r t trtt' d i re t' t i o r t

Similar stiffenings have differentnames for different planes.

II

Illtrt'es ott t.r stifJe

ircs c.rl rtt lorcc.

'.s st ott .f

,q reqLu

C'otttltre.

IJt tc l t l i r t r

Angle profile

Planes: Stiffening: Support:

shell (vertical) frames stringers (horizontal)

web frames

bulkheads horizontal stiffeningvertical stiffening

stringers(horizontal)web girders

decks deck frames deck girders

flat bottom bottom frames (fore

and aft)bottom frames

(transverse)

floors

keelsons

tank top upper frames (fore

and aft)

upper frames(transverse)

floors

keelsons


Frames

Ice frames

Web frames

Deck frames

Deck beams

Centre keelson

Side keelson

Cross-section of a container ship near the engine roan. (transverse frames)


I

t .

6.2 Longitudinal framingsystem and transverseframing system.

We have seen in this chapter thatlongitudinal loads are present on allships and that they play a larger roleif the ship is longer and/or narower.This is why ships with a length ofmore than 70 metres are usuallyconstructed according to a longi-tudinal stiffening system. This meansthat the frames and the deck beamsrun in the fore and aft direction. Shipshorter than 70 metres (for examplefishing boats and tugboats) are

usually built according to a transversestiffening system.

Lloyd's Register does not require acalculation for longitudinal strengthif the ship is shorter than 65m.

On the next pages we see twodifferent kinds of ships. First a double-hull tanker built with the longitudinalframing system, secondly a tug boatbuilt with transverse frames.

20

I22

I

Two drau,ings' oJ'a modertL tlouble-htill tanker built usittg tlrc longitr,tditrul svstent


Ptating

ShellLongitudinal bulkhead(of the inner hull)

Transverse bulkhead

Longitudinal bulkhead

Lower hopper

Tanktop

Bottom

8. Side longitudinals

9. Bottom frame /

Longitudinal10. Inner bottom

longitudinal

11. Bulkhead stiffener

12. Stiffener with brackets

13 Tie beam or cross-tie14. Stringer15. Stringer deck16. Watertight floor17. Full floor18. Watertight side keelson19. Web frame

22

Holds

20. Wing ballast tank21. Double bottom22. Cargo tark

Stiffenings on the plating Plate-stiffeners

l .2.

3.4.5.6.7.

20

I

Ship Knowledge, a modern encyclopedia I0t

1 Wheelhouse front windows2 Wheelhouse rear windows3 Portside funnel4 Starboardside funnel5 Mast6 Deckhouse top (location for

raft | rescueboat)7 Foredeck8 Forward bitts9 Forward bulwark with

fairlead10 Location bow fender11 Side bollard forward12 Bilge keel13 Towing bitt14 Sideshell transverse frame15 Deck bracket16 Bilge bracket

17 Transverse full floor18 Stringer19 Stern fender20 Sternroller, for

anchor handling2l Bulwark toprail, gunwale22 Thruster nozzle23 Pbop deck, working deck.24 Rubbing bar25 Deck beam26 Transverse bulkhead27 Location towing winch28 Steering-gear room29 Side bollard aft30 Longitudinalbulkhead

(Tailshaft tunnel)3l Bilge plating


'r\,

l i{ 4'-' -l i -

! i

Bender Shipbuilding & Repair Co., Inc.

.Sltip Knowledge, a modern encyclopedia

:--*-j

- F '

: ! * - - . ; ' u ' :

',ff

* * ^ - .; - ? - *

J J- - - t - - r

L. IMO

Within the United Nations, maritime affairs are taken care of by theInternational Maritime Organization, in abbreviation, IMO. The mainobjective, from the first conference in 1948 up to its entry into force in 1958,is improvement of safety at sea.

Seafaring has, through history,always been one of the mostdangerous occupations. Even todaythat is still true. Many countries hadunilateral regulations on safety. Assea trade is of international nature.the rules and regulations had better tobe set up internationally, instead of byindividual countries, to make thembetter overall. To improve thissubject, in 1948 the basis was laid forIMO.

Safety of ships and navigation wasthe first issue, but also from thebeginning Marine Pollution, particu-larly from oil carried in tankers, wasof great importance.

and conventions have been adopted.After adoption, individual govern-ments must ratify the protocols orconventions. Depending on thenumber of governments and thetonnage governed by them, aconvention comes into force, after acertain time.Then its followed by the implemen-tation, when the new regulationbecomes law under the responsibilityof the flagstate. This processsometimes takes years.

As mentioned above, the mainConventions are SOLAS (Safety ofLife at Sea) and MARPOL (MarinePollution). SOLAS goes back as far

,

. q ' - 1 t t - .

' ,1- ,":tPt "'#,.

Desigtted, upltrovecl crncl survetvd to tt;itlt,stcuil tlrc rouglte,st ,seu,s.

The governing body is the Assembly,with Committees for the differentobjectives. Safety is dealt with by theMSC. the Marine Safetv Committee.

MEPC, the Marine EnvironmentProtection Committee deals withpollution problems.

The above has resulted in two majorissues: SOLAS and MARPOL.The former deals with the Safety ofLife at Sea, SOLAS, and the latterwith Marine Pollution, or Marpol.Through the years many protocols

as 1914, but due to World War I nevercame into force. A number of safetyconventions have been implementedsince; the last one SOLAS 1974, withamendments, is now valid.MARPOL started only in 1954,dealing with oil pollution. NowMARPOL 73178 with variousamendments is valid.

The above Conventions resulted inworldwide recognised certificateswhich ships have to carry, after beingsurveyed to ensure that they meet therequirements. A variety of compul-

rq

,: fy:W

Ship Knowledge, a modern encyclopedia r06

sory equipment has to be type-approved by Flagstate(s) and/orClassification Society.

2. Certificates

The following certificates are in use:

For SOLAS:

1. Cargo ship Safety ConstructionCertificate

2. Cargo ship Safety EquipmentCertificate

3. Cargo ship Safety RadioCertificate

4. Cargo ship Safety Certificate,combining 1,2 and3.

In SOLAS the ship's construction isalso regulated, with regards tostrength, maximum size of floodablecompartments, intact and damagestability.

Rules and regulations and certificatesare more stringent for passenger shipsthan for cargo ships.

The Loadline Certificate, evidence ofmeeting freeboard requirements,already existed. This was started inthe United Kingdom by a member ofparliament, Mr Plimsoll, after whichcertificates have been issued by theClassification Societies since 1876,when the freeboard mark becamecompulsory.

Sun'ey tu verifi, loctd lines on side r$'

.sl t ip.


For bulk carriers a special certificatehas been created in connection withthe transport of Solid Bulk Cargoes.These cargoes have been categonzedA, B and C, depending on theirhazards. For each of these cargoesthere are special requirements.

For MARPOL:

The International Oil PollutionPrevention Certificate (IOPP), for oiltankers of 400 GT and above and forother cargo ships above 400 GT.commonly called Annex I.Tankers originally simply pumpedtheir tank washings overboard,causing enornous pollution in the seaand on the beaches. Now this outflowis restricted to max 30 litres pernautical mile, and only when they arenot in restricted waters.

As said before, it started with oilpollution. Later other pollutants werealso taken into consideration :

Annex ll deals with Noxious Liquidsand Chemicals.The relevant regulations are found inthe BCH Code, Code for theconstruction and equipment of shipscarrying dangerous chemicals in bulk.This Code classifies ships andcargoes. Cargoes are classified inaccordance with their threat to sealife, people etc. Ships are divided in othree categories, depending on theirability to cope with the hazard of thevarious cargoes.

Annex III deals with harmfulsubstances in packed form,

Annex IV sewage,Annex V garbage,Annex VI air-pollution andAnnex VII ballast water.

3. CLASSIFICATION

Ships are built in accordance withRules and regulations of aClassification Society. The societyapproves the relevant drawings, andcheeks the actual construction.Classification is controlling strengthand quality of materials andworkmanship in connection with theship, when built "under Class". TheClassification Society issues a

$vvvrslteT't chec'k links and ,shuckle,s of ut

anc:hor chain.

In a nranufacturer's u,orkshop a local

,turt"e))o r revi ev's the .fit-up and

ulignment of intermediute ancl thrust

shufts.

certificate upon completion ofconstruction: the Cenificate of Class,for Hull and Machinery. At the sametime a trading certificate is issuedwith a validity of 5 years which has tobe endorsed every year, on comple-tion of the Annual Survey. To carryout the different surveys, the ClassSocieties each maintain a worldwidenetwork of surveyors, centralized bytheir main offices.

The main Societies are grouped underIACS, the International AssociationOf Classification Societies.

The main members are (in alphabeticorder):- American Bureau of Shipping

(ABS)- Bureau Veritas (BV)- Det Norske Veritas (DNV)- Germanischer Lloyd (GL).- Lloyd's Register (LR)- Nippon Kaiji Kyokai (NKK)

The Certificate of Class is the basisfor underwriters to insure a ship.

107

In general, the Classification Societylooks after the technical condition ofthe ship, and the Flagstate after thepeople on board, and their behaviourin connection with safety, environ-ment and communication. Manyflagstates delegate their tasks to theClassification Society. Therefore, onmany ships, apart from the classcertificate, the statutory certificatesare issued by the ClassificationSociety.Before any Certificate can be issued,a ship must be registered in a certaincountry, the Flagstate. This meansthat the flagstate accepts a ship ascarrying their flag and belonging totheir'fleet'. Against a certain fee, andtaxation on the earnings, theauthorities allow the shipowner tosail under their jurisdiction. The townwhere the ship has been registeredhas to be marked on the stern. Asproof of the registration the Flagstate

In,spectittg a lntch on o lil'e boat Jbrutmpliance witlt the latest reSpilutiort,s.

issues the International TonnageCertificate, or the ClassificationSociety issues this certificate on theirbehalf. This certificate is worldwideaccepted as giving the official detailsof the ship: main dimensions andcontents of the various spaces, in

I n i t i a l( spe c: ia l )

I s t . a n n r r a l

panicular the spaces in connectionwith cargo: cargo holds, tanks, etc.,all in accordance with regulations setout in the Tonnage Convention.

Harbour dues are in most ports basedon the gross tonnage, and thecertificate is the official paper withthe correct figures of tonnage.Producing this certificate involves alot of calculation of contents ofspaces, measuring from drawings ormeasuring on board.

The Flagstate is also responsible forthe Minimum Safe ManningCertificate, stating the minimumnumber of crew, and the requiredtraining for them, who have to be onboard when the ship is underway.

Apart from the International TonnageCertificate, the Suez Canal and thePanama Canal have their own way ofestablishing 'tonnage' to base theirfees on. Therefore, special tonnagecertificates are issued for Suez Canaland Panama Canal.

The Classification Societies are, since1968. associated in IACS. Since 1970they are consultative to IMO,contributing their expert technicalknowledge.

A relatively new issue of IMO is theInternational Safety Management(ISM). Since July 2002 all ships musthave an ISM certificate. In july 2000,passenger ships, tankers and bulk-carriers already needed to have abovecertificate. This certificate. for bothship and office, is a statement thatOwners/l\4anagers and the ship's staffare committing themselves tomaintain the vessel as required, and

to fulfil obligations connected withsafety and pollution.

Since 1999 all compulsorycertificates have been harmonized toa validity of 5 years, in phase with theClassification Special Survey cycle.Before, the Safety EquipmentCertificate had a validity of 2 years,the Radio Certificate I year, andIOPP Certificate 5 years. Thisresulted in certificates with differentexpiration dates, creating the hazardof an expired certificate goingunnoticed. The Safety Constructionand Loadline Certificates werealready in phase with theClassification cycle.

4. ISM-code (InternationalSafety lManagement)

4.1 Introduction

Most regulations in shipping concerntechnical aspects of the ship and therequired training of the crew. TheISM-code is a list of regulations forthe organisation of the ship, sobasically it concerns the manage-ment-system.

The management-system comprises of:- the organisation on board the ship- the organisation on shore; the

organisation of the shippingcompany

- the communication between shoreand ship

The importance of good managementfor safety in general is illustrated bythe fact that SjVo of all accidents inshipping are the result of humanEITOTS.

S p e c i a l

2rrcl :r tr rrui. l l jJ r 'd t r r rnt ra l

Cl a s s ificcrti on S pec i a I S urvey C)'c le


lnter rrrecl iat e:

II

( : ] n r o n t . h s e i t h e l s i c l c )

Inax i ) 1r0al 's

t t t t .h tr t t .h

.,1t.h arr.rrui:LI

108

[:rtr Cltt,s.s and ISM, ship:; htu,e to drt,-doc'k

4.2 Objectives

The objectives of the ISM-code are:- to satisfy all relevant national and

international laws like SOLAS,MARPOL, ISM, Class andLabour laws

- creating a permanent awareness ofsafe behaviour by the personnelon board and ashore

- ensuring a readiness to acteffectively in emergencies

- guaranteeing safety at sea- preventing accidents and damage

to environment

The ISM-code is a standard safety ofconsisting of 13 elements, eachdescribing a business operation that isrelevant to safety and environment.The elements can be considered asparagraphs of the ISM-code. Theycan deal with:- maintenance (planned

maintenance)- office personnel and crew

4.3 How ISM works

a. The shipping companiesEvery shipping company mustpossess a "Document of Compliance"or "DOC". This document states thatthe shipping company is seen fit toexploit the ship in accordance withthe demands of the ISM-code. One ofthe demands is that the shippingcompanies must develop, execute andmaintain a safety management system(sMS).

ttt'0 tm1e,r ut.flve \)e(Lr,\

The Flagstate issues the DOC, butonly after an official bureau ofclassification has approved the safetymanagement system. The DOCremains valid for a period of fiveyears, provided that the annualsurveys by the bureau of classifi-cation yield good results.

b. The shipsThe ships can get a safetymanagement certificate (SMC) if theDOC has been issued to the shippingcompany. The SMC also remainsvalid for a five year period. Duringthis period there should be aninspection somewhere between thesecond and third years.

4.4 The audits

The SMS is inspected by means of anaudit. An audit is a prescribed surveyto check whether the organisations onshore and on the ship are able tosuccessfully execute the regulationsand have reached certain goals.Audits can be distinguished intointernal audits and external audits.The ISO-organisation (see below)grants one certificate to the entireorganisation, contrary to the ISMwhich has separate certificates for theorganisation on and off shore.

a. Internal auditsInternal audits are performed by theshipping company and can comprisematters like:- the overlap between the way of

working on board and the SMSregulations applied

- checking if the measures taken forsafety and the environment are inaccordance with the SMS

- testing the SMS for efficiency andtake measures if necessarv

All relevant personnel must beinformed of the results of these auditsand the measures taken. The manage-ment must correct all shortcomings.Internal audits are usually performedannually.

b. External auditsExternal audits are performed by thebureau of classification undersupervision of the Flagstate. If theorganisation lives up to the standardsset, the shore organisation receivesthe DOC and the ship the SMC.

5. International organisationfor standardisation (ISO),Quality managementsystems.

ISO has drawn up the ISO 9000standard. This standard sets demandsfor matters that an organisationshould have or do in such a way thatthe customer can be confident that theproduct meets the standards of goodquality.

A company will voluntarily use theISO-standards, possibly underpressure of the free market. Thecompany will draw up a qualitymanagement system (QMS) that canbe certified by a bureau ofclassification.

The ISO-9000 standard is a generalstandard aligned to the ISM-code.This means that every companydraws up and executes its own QMSbased on the demands.


6. Marine pollutions(MARPOL)

in 1973 IMO adopted the Interna-tional Convention for the Preventionof Pollution from Ships, (IOPP)modified again in 1978. MEPC, theMarine Environment ProtectionCommittee, does the daily work andhas given clarification. The actualregulations to prevent pollution byenvironment unfriendly substancesate given in "Annexes". All theregulations are guided by the size ofthe ship. Bigger ships must meetmore and more stringent require-ments.

The following applies to ships. Forplatforms and other stationary equip-ment at sea, other regulations apply,also specified under Marpol.

6.1 Annex I

This regulation is against pollution byoil. It concerns the oil generated bythe engine room for all ships, and forcargo residue of oiltankers. Enginerooms generate waste oils, mostlymixed with water. This mixture iscollected in the engineroom bilgewells, from where it is pumped to abilge holding tank. When the ship isunderway at sea, at least 50 milesfrom the nearest land. and not in arestricted area, oily mixtures with anoil content of max 15 ppm areallowed to be pumped overboard. Tofulfil this requirement, ships have tobe provided with a bilge-waterseparator, combined with an oilcontent meter with a 15 ppm alarm.When the oilcontent is found to bemore than 15 ppm, the alarm soundsand the overboard valve is automa-tically closed. The dirty water is thenpumped to the sludge tank.

Moreover extensive and accuraterecord is to be carried out of allhandling of oils in connection withthe engine room. The equipmentitself must be type-approved.

Oiltankers have apart from theengine-room generated oils, anotherproblem. When an oil cargo is dis-charged, there is always residue, andoften the tanks must be cleaned to


In port, oiL arul sLutlge (lre to be pumpetl

oshore kt r t racepl ion. foci l i t . t , t ' iu the

.sI ttrukt nl d i,st' I tu rge ct nt r t t,t ' I i ort.

prepare them for a next cargo.Washing is done with rotating waterjets in the tanks, generating an oilywater mixture which is pumped to theso-called slop tank. There it settlesinto oil and water. The water can bepumped out, under control of the OilDischarge Monitor which measuresthe oil content. Again max 15 ppm,underway, 50 miles from shore, not inrestricted areas and not more than30 litres of oil per nautical mile, andthe oil pumped overboard maximisedto l/15000 part of the cargo (for newships l/30.000). The surplus oil is tobe retained in the sloptank. Either tobe pumped ashore later, or when thenext cargo is suitable, usually onlypossible with crude, to be mixed withthat next cargo.

Crude tankers during discharge washtheir tanks with cargo, to prevent theaccumulation of sediment. The cargooil is pumped through the rotating jetswith high pressure, and the sedimentsare kept mixed with the cargo andpumped ashore with the cargo. This iscalled Crude Oil Washing (COW).A problem connected with highpressure washing and COW is thatstatic electricity is generated. CrudeOil Washing is therefore only allowedat an atmosphere with reduced oxy-gen, below the level that explosionscan occur. COW is compulsorythrough Marpol legislation, and InertGas is a consequence, but legislatedvia SOLAS.

Snruil bilgt'ptrttt lt

Ililge water separutor vtith l5 pptn oil

content meter / uLarnt

Bi lgc l t t t t t t l t

t I0

Contrary to some years ago, alltankers now need their cargo andballastwater to be kept in completelyseparate tanks. These are calledSegregated Ballast Tanks (SBT).

Before, the tankers had to clean atleast two tanks which had beenloaded with oil, to a condition thatthey could be filled with ballast water,sufficiently clean to be pumped out inthe loading port.The vessel then leftthe discharge port with 'dirty ballast'in other tanks which were emptied atsea when the cleaned tanks wereavailable for ballast. At best the dityballast tanks had sufficiently settledout (decanted) so that first the waterunderneath could be pumped out,whereafter the remaining oil could bepumped to the slop tank. The controlwas by sight only, this type ofdischarging is no longer allowed. Allhandling of oils and ballast water hasto be accurately administrated andentries are to be kept on board forthree years.

The Marpol regulations first startedwith minimizing oil pollution, andover the years grew more and morestringent with the aim to stoppollution completely. The first com-pulsory modification was the small-bore discharge line, from pumproomto manifold behind the ship'sdischarge valve, through which thecontents of the cargo pipeline systemcould be discharged. For a VLCC(Very Large Crude Carrier) 200.000m3 or more. Also the ballastoverboard line had to have itsdischarge above the ballast waterline,to enable the ship's staff to actuallysee the outflowing water. When it wasgrowing dark, deballasting had to bestopped.

To enable the discharge of slop tanksashore, governments are obliged tocreate reception facilities in the portsfor contents of sludge and slop tanks.The minimum SBT capacity of atanker is regulated to ensure sufficientballast capacity for safe navigation.That ballast has generally to becarried in sidetanks and doublebottom tanks. This, to preventoutflow of oil in case of a groundingor collision. The minimum width andheight of these tanks is regulated.


An important document on board,compulsory, is SOPEP, Shipboard OilPollution Emergency Procedures, abook whichs prescribes what to do,and whom to contact in case of oil-pollution. This book must beapproved by the flagstate or Classifi-cation Society. The pages with therelevant telephone numbers are to beupdated regularly.

6.2 Annex II

This Annex regulates the preventionof pollution by Noxious LiquidSubstances, in general called'Chemicals'. The possible cargoes arecategonzed. Depending on the dangerfor environment in case of pollution,the regulations are more stringent.The cargoes are categoized as A, B,C and D cargoes. Category A is themost toxic one, and D practicallynon-toxic to aquatic life. Dependingon the type of cargo, the ship's tankshave to meet special requirements,with regard to location, distance fromship's side or bottom and shell, i.e.double hull. Pumping, piping andunloading arrangements are regu-lated. Slop handling and pre-wash(pre-cleaning after discharge butbefore leaving port) are prescribed.

To meet the various requirements, theships are divided into Types I, II andIII. A special booklet, issued by IMO,the code for the construction andequipment of ships carrying dange-rous chemicals in bulk, the so-calledBCH Code, for ships built before1986, followed by the IBC Code fornewer ships. The booklets give alisting of cargoes, defined A, B, C orD, and requirements for the ship inwhich they are to be transported, inship type I, II or III. Chemical tankershave double bottoms and doublesideskin, to protect them in case ofgrounding and collision. Stability inintact and damaged condition is animportant issue.

Another important requirement for allchemical tankers is the total quantityof residue on board after discharging.Normally, each tank has its own deep-well pump, with its own cargo line tothe cargo manifold, where theconnection with the shore is made.

All these ships have a double bottom,and the pump is drawing oil in arecess, the well. After normaldischarge, back flow of the pump isprevented, and the liquid remaining inthe well is pumped out with a specialdevice in order to get the well as dryas possible. Discharge from thedevice is not via the normal dischargeline but via a separate thin pipeline.

As with all other tankers, all cargohandling has to be accuratelyadministrated in the Cargo RecordBook. The relevant equipmentrequired for chemicals is described ina specific book: The Procedures andArrangement Manual.

Each chemical tanker has to beprovided with a Certificate of Fitness,with a attached list of cargoes that theship is fit to carry. This certificate hasa validity of five years and runsparallel with the ship's SpecialSurvey cycle. Annual survey of theequipment is mandatory after whichthe certificate is endorsed.

6.3 Annex III

This Annex regulates the carriage ofPacked Harmful substances. Thecarriage of harmful substances isprohibited, except when in accor-dance with the provisions in thisAnnex. Packages have to be labelledwith the correct name and durablemark or labelled as a marinepollutant.

The packing must be adequate. Thereare stowage requirements and quan-tity limitations. Throwing overboardis only allowed in case the safety ofthe ship is at risk or in case of savinglife at sea. This type of cargo is to bereported (type, quantity, location) toharbour authorities in each port theship calls at, also when the cargo isnot handled.

II]

6.4 Annex IV

This Annex regulates the Preventionof Pollution by Sewage, applicable toships of over 200 GT. Discharge ofsewage is prohibited, except whenthe ship has an approved treatmentplant and navigates more than 4 milesfrom the nearest land, or, foruntreated sewage, at a minimum of12 miles from land.

Ships navigating in special areaswhere the discharge of sewage is notallowed, are to be fitted with holdingtanks for the retention of all sewage,its size depending on the ship'snormal operating scheme, and theremust be adequate connections fordischarge into a reception facility.The content of the holding tank canbe discharged overboard at least 12miles from shore, and only at amoderate rate of speed of at least 4knots.

This annex also concerns theoverboard discharge of contents fromde ship's hospital. A special certi-ficate is required with a validity ofmax. 5 years.

6.5 Annex V

This Annex regulates the Preventionof Pollution by Garbage. Garbagemeans all kinds of victuals, domesticand operational waste, includingfresh fish, liable to be disposed ofcontinuously or periodically, except


Garbage

substances defined under otherAnnexes.Disposal into the sea of plastics isalways prohibited. This includesropes, fishing nets, and plastic bags.Floating waste like dunnage, liningand packing material is allowed to bedisposed of at least 25 miles from thenearest land. Food waste, paper, ragsetc. at least 12 miles from shore.When the last is ground into smallparticals, max. 25 mm, 3 miles issufficient.

Of garbage a record must be kept,similarly to substances describedunder other Annexes. Garbage likecarton, plastics, etc. can also bedisposed of by burning in anincinerator.

On ships intended for long voyageswaste from packages, i.e. wood,

carton, plastics, etc. can be disposedof by burning it in an incinerator. Thisis a simple stove, where the waste isput into the firespace, and where asimple gasoil burner ignites thewaste, and if necessary keeps itburning. The ashes may be disposedof in the sea.

6.6 Annex VI

This Annex regulates the air pollutioncaused by Nitrogen oxides andSulphur oxides, caused by thecombustion of (heavy) fuels, the so-called Noxes and Soxes. Theseproducts release with the exhaustgases in the atmosphere, and willeven-tually come down as aciduousrain. Reducing this pollution can bedone by using low-sulphur fuels orde-sulphu rizing the fuel.

6.7 Annex VII

This Annex will deal with ballast-water.,When a ship sails from one seaarea to another in ballast, it takesorganisms of the eco-system of thedeparture or discharge area to theloading area. There are various ideasabout how to prevent this type of eco-pollution: emptying and refillingballast tanks during the voyage orfiltering or changing the water bycontinuous pumping over the top.Directives will come in the nearfuture.

7. Documents

On the following pages somecompulsory documents are shown,without which leaving a port is notallowed.

Sew,age trecfiment planl

htcineratr.tr

TI2

I|{TERNATIONAL TONNAGE CERTTFICATE (1 969\

ISSUED UNDER TI{E PROVISIONS OF THEINTERNATIONAL CONVENTION ON TONNAGE MEASIJREMENT

OF SHIPS, 1969UNDER THE AUTHORITY OF THE GOVERNMENT OF THE

REPUBLIC OF PORTUGALREGISTO INTERNACIONAL DE NAVIOS DA MADEIRA

for which the Convention came into force on lst September 1987

by

Geumswtsdter Alogb

*)Dateonrr ,h ichthekeelrvasla idortheshipwaSatasimj larStageofconstruct ion[Art ic lez(6) ] ' f f i ip

MAIN DIMENSIONS

The Tonnages of the ship are:

GROSS TONNAGE

NET TONNAGE

2881

1371

This is to certify that the tonnages of this ship have been determined in accordance with the provisions of the InternationalConvention on Tonnage Measurement of Ships, 1969.

Issued at Hamburg 22nd April ,20A2

6eumsnisdter I[ogb

' l ' l ie undersigned declares that he is duly authorized by the said Government to issue this certificate.

Forrn No.S726.l/Fcbruarv. 1997. Pase I of 2

Name of ShipOfficial Number

orDistinctive Number or Letters

Port of Registry Date *)

SIDERFLY CQUT Madeira 27.08.1984

IMO No.: 841244s

Length

IArticle 2 (8)]Breadth

[Regulation 2 (3)J

Moulded Depth amidshipsto Upper Deck

[(Regulation2 (2)]

95.09 m 14.60 m 6.95 m

Ship Knowledge, a modern encyclopedia TT3

INTERNATIONAL REGISTER FOR CLASSIFICATION OF SFIIPS.ESTABLISHED I828.REGISTRO INTERNACIONAL DE CLASIFICACION DE BUQUES,FUNDADO EN I B2B.

CERTIFICATE OF CLASSIFICATIONCERTIFICADO DE CLASIFICACION

No RTDO/AST0 n0A2011 105 1 I I

NAI\TE OI.. SHIP : VERISTARNonbre del BuqueRegister No : 85L011N" de Rcgi.sto

Ori ners : IvIEMBERS

Annuclo

Flag : PANAMABurcleraPort of Registry : PANAMAPucrto dc nrcurictilrtThis is to certity that the above named ship has been entered in the Register Book with the classification symbols andnotatrons :El abujoJintruntc certiJicct que cste buclue lru sido inscrito en el Lihro Registro con los simbolos clc clasificucidn )) ilrcnc

I x HULL; x MACH; x AUT-UMS; x SYS-NEQ-1 ;Hopper dredger

Un restricted navigationDredging within 15 Miles from shore or within 20

miles from port

This cert i f icate, issued within the scope of Bureau Ver i tas Marine Div is ion General Condi t ions, is val id unt i l :Este certiJicuclo, e.rpedido cle acuerdo co,t las Contliciones Generales de lu Divisiin Nat,al cle Bureau Veritcrs es vdl,iclo tel

8 January 2006

At/E.rpedido ert Rotterdam. on/el 2l April 2002

By Order of the Secretary

This certificate is invalid w'ithout the annexes listed. Conditions of use are given on page 2/2. Esre certi,ftcado no es t:(,sitt los ettc.\o.r indicvdosen lu pcigirtn 2/2. I-as conclic'iones para la utili:.aci6n se detallan cn la pdgina 22.

Any person not a party to the contract pursuant to which this certificate is delivered may not assert a claim against Bureau Veritas for any liability ari

ol'cn'ors oromissions rvhich may bccontaincd in said certif icate. or forerrors ofjudgement, laultor negligcnce committed by personnelof the Socir

in the establishment or issuance of this cerrificate, and in connection with any activities rvhich it mav provide.

Por Orden cl

Ship Knowledge, a modern encyclopedia tI4

Name of ship

Distinctive number or letters

Port of registry

Gross torurage

Deadweight of ship (metric tons)l

IMO nunrber

Type of ship'

Date on which keel was laidz

Certificate no:ROT 0000001

Page'I.. of 3

Particulars of Ship

''MINERVA ASTRA''

9 H D W 7

Valletta

59,693

1,05946

9230098

Brilk+a*#er Oil tanker-€hemieal#

u./20a1

Cargo Ship Safety Construction Certificate

.iued nncler the provisions of the International Convention for the Safety of Life at Sea, 1974, as modified by the Protocol of 1988 relatinl

-'.iretO,

:rnder the authority of the Government of the Republic of Malta-- Uotd's Register of Shipping

:-rrs is to certify:

that the ship has been surveyed in accordance with the requirements of regulation I/10 of the Convention;- that the survey showed thatthe condition of the strucfure, machinery and equipment as defined in dre above regulation was satisft

anrl the ship compliecl rvith the relevant requirernents of chapters II-L and II-2 of the Convention (other than those relating to fire sa

svsterns and appliances and fire control Plans);' that the last tr,r'o inspections of the outside of the ship's bottom took place on - and -;

' that an Exemption Certificate has been issued.

l--.rs certificate is valid untiF 04 December 2006 subject to the annual and intermediate surveys and inspectious of the outside'': tre ship's bottom in accordance with regulation I/10 of the Convention.

, ..mpletion clate of the sun'ey on which this certificate is based 05 December 200L

.:u€d dt Rotterdam on 05 t

lcr oil tankers, chemical tankers and gas carriers only.lelete as a:propriatelap on vvhich keel lvas laid or ship was at a similar stage of conslruction or, lvhere applicable, date on which work for a conversion or an alteration or

:-rrJification of a major character was conrrnenced.k-:sert the date of expiry as specified by the Administration in accordance r+'ith regulation I./7a@) of the Convention, The day and the month of this date cor,- :r anniversary date as defined in regulation I/2(n) of the Convenlio& unless amended in accordance with regulation I/14(h).:<m2227 (2002.09)

Ship Knowledge, a modem encyclopedia il5

Certificate No. 1 01 635/1 08/02/00

INTERNATIONAL LOAD LINE CERTIFICATElssued under the provisions of the

INTERNATIONAL CONVENTION ON LOAD LINES,1966,as modified by the Protocol of 1988 relating thereio

under the authority of the Government of

ANTIGUA AND BARBUDAby GERMANISCHER LLOYD

Name of ShioDistinctive Number

or Letters Port of RegistryLength (L) as

defined in article2 (8) (in metres)

IMO Number

MAERSK DABLIN V2PW3 St.John's 277.490 9105918

Freeboard {Anewslt ipassigned as:* {z@t*e

TropicalSummerWinterWinter North Atlantic

Freeboard from deck line3885 mm (T)38d5 mm (S)38ds mm (W)

--- mm (WNA)

Type of {W1Lship:* {Wt#

{I Type "8" tt,itlt increasedfreeboard

Load Line--- mm above (S)

Upper edge of line through centre of ring--- mm below (S)--- mm below (S)

Note: Freeboards and load lines which are not applicable need not be entered on the Certificate.

Allowance for fresh water for all freeboards other than timber 260 mm.

The upper edge of the deck line from vuhich these freeboards are measured is 0 mm above/belov the top 6f the fi'eeboard (2nd)

dec:k at side,

F-

THIS IS TO CERTIFY:

1. That the ship has been surueyed in accordance with the requirements of article 14 of the Convention.2. That the survey showed that the freeboards have been assigned and load lines shovrm above

have been marked in accordance with the Convention.

This Certificate is valid unlil30th June, 2005 subject to annual surveys in accordancewith article 1a(1)(c)of the Convention.

lssued at lfamburg the l8tlt day oi April, 2002

Notss:1. lAfenaship.depels | lorn8por ls i lua ledonar iveror i r |ardwa|a 's .deFfbad:r � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �

he xirt ol deoarlure and lha sea2.!i/ninashipiiiniesh.wrtelofunitdensi(y0Baporop'iais|oad|ine.maybe8ubmef0eiby|heamountoflhefeghwateraId��

allowarc€ shall be mads proportional to lia difference belvesn 1,025 and 0E actual dsnsity

-Delete as appropriate

@her Lloyda6-

2 - , L _

drE{P\an isc


Form No. S75l / 2002-01 Page 1 of 4

116

Certificate no:ROT 0000001

Page 1. of 3

Cargo Ship Safety Radio CertificateThis certificate shall be supplemented by a Record of Equipmert of Radio Facilities (Form R) No: 9230098/ 01

Issuecl under ttre provisions of the International Convention for the Safety of Life at Sea, '1974, as modified by the Protocol of 1.988 relafinl

tl'rereto,

under the authority of the Government of the Republic of Malta

by Lloyd's Register of Shippittg

Particulars of Ship

Name of ship "MINERVA ASTRA"


Port of registry

Gross tonnage

Sea areas in rvhich ship is certified to operate(regulation IV /2)

IIvIO nunrber

Date orr whidr keel was laidl

9r{DW 7Valletta

59,693

4 1 + A 2 + A 3

9230098

01,/2001

This is to certify:

1. that the ship has been surveyed in accordance witl'r the requirements of regulatron|/9 of the Convention;

2. that the survev shorvecl thah

2.1 the ship complied with the requirements of the Convention as regards radio installations;

2.2 the functionirrg of the raclio installations used in life-saving appliances cornpiled rvith the requirements of the Convenlior

3. that an Exernption Certificate has not been issued.

subject to the periodical suveys in accordance with regulation I/9 otThis certificate is valid unlilz 04 December 2006

the Convention.

Cornpletion date of the survel'on which this certificate is based

Issuccl at Rotterdam

05 December 2001

on 05 Dec05 December

: Date on n'hich keel n'as laid or ship was at a similar stage of construction or, whete applicable, date on which work for a conversion or an a.teration ornroclification rlf a major charActer rr'as contmenced.' Delets as appropriate: lnsert the date of expirv as specified by the Adnninishation in accordance u'ith regulation lA(a) of the Convention. The day and month of this date correslthe anniversary date as defined in regulation ;,!(n) of the Convention, unless amended in accordance with regulation 1/14(hr.Forrn 2206 (2002.09)

Ship Knowledge, a modern encyclopedia I17

INTERNATIONAL OIL POLLUTION PREVENTION CERTIF ICATE(No te : Th is Cer t i f i ca te sha l l be supp lemented by a Record o f Cons t ruc t i on and Equ ipment )

Cer t i f i ca te No. 2H0-0200M

l s sued unde r t he p rov i s i ons o f t heINTERNATI0NAL OONVENTI0N FOR THE PREVENTI0N 0F P0LLUTI0N FR0l , l sHlPs, 1973,

as rpd i f i ed by t he P ro toco l o f 1978 re l a t i ng t he re to (he re ina f t e r r e fe r red t o as " t he

Conven t i on " )under the author i ty o f the Government o f

the Republ ic of Panamab y N i p p o n K a i j i K y o k a i

T y p e o f s h i p :

Si*-tenker*

StriSdheetlrc*rtriJ=tadedfhc*rge#trtstiag=undet-fuu{*i*€{2}=of=f,nnex-*=of=thr€oasecrtim*

Ship o ther than any of the above*

T H I S I S T O C E R T I F Y :

1 That the sh ip has been surveyed in accordance wi th Regulat ion 4 o f Annex I o f the Convent ion; and

2 ' fhat the survey shows that the s t ructure, equ ipment , systems, f i t t ings, ar rangement and mater ia l o ft he sh ip and t he cond i t i on t he reo f a re i n a l l r espec t s sa t i s f ac to r y and t ha t t he sh ip oomp l i es w i t hthe appl icab le requi rements o f Annex I o f the Convent ion.

T h i s C e r t i f i o a t e i s v a l i d u n t i l 1 2 0 c t o b e r 2 0 0 4subject to surveys in accordance with Regulat ion 4 of Annex I of the Convent ion.

lssued a t Tokyo on 15 February 2OO2

V a l i d o n l y w h e n t h e S u p p l e m e n t N o . S - 2 H 0 - 0 1 9 7 m i s a v a i l a b l e f o r i n s p e c t i o n .

The undersigned declares that he is duly authorized by the said Governnent to issue this certificate.

See note(s) on the reverse.Date of Init ial Survey: 13 0otober

*D" l " t " as eppropr ia te .

lOPP (PNl,l)


1998. I

1 1 8

D i s t i n o t i v e N u m b e ror Le t te rs Reg i s t ry

I l l a n a g i n g D i r e c t o rNIPPON KAIJ I KYOKAI

t999

CARGO SHIP SAFETY EQUIPMEI\T CERTIFICATEThis Certificate shall be supplemented by a Record of Equipment (Fom E)

(Form E No. R-9KK-0014SE )

Certificate No. 2NY-010lSEIssued under the provisions of the

INTERNATIONAL CONVENTION FOR THE SAFETY OF LIFE AT SEA, 1974as modified by the Protocol of 1978 relating thereto under the authority of the Government of

the Republic of Panama

bv NIPPON KAIJI KYOKAI

PARTICULARS OF SHIP

Name of Ship

Distinctive Number or Letters

REEFER

Port of Registry

Gross Tonnage

Deadweight of Ship (metric tons) {'l

Length of Ship(Regulation III/3.10)

IMO Number

Type of Ship: *2

Date on which keel was laid: +3

PANAMA

7367

127.38 m

rMo r234s67

Rernrfur/ €+F+rrker / €fttmid{arker/ €as=srdeir /

Cargo ship other than any of the above

29 June 1998

THIS IS TO CERTIFY:I That the ship has been surveyed in accordance with the requirements of Regulation I/8 of the Converrtion, as ntodified by

the 1978 Protocol .

2 That the suweY shorved that:

Z.l the ship complied with the requirements of the Convention as regards tire safety systems and appliances and fire control plans;

Z.Z tne lif'e-savirrg appliauces and the equipment of the lifeboats, lit'erafts and rescue boats were provided in accordance with

tire requirements of the Convention;

2.3 tne ship rvas provided with a line-throwing appliance and radio installations used in l ife-saving appltances in accordance

rvith the requirements of the Conventiorr;

2.4 the ship complied with the requirements of the Convention as regards shipbome navigational equipment, means of

embarkation for pilots and nautical publications;

2.5 the ship rvas provided with l ights, shapes, means of making sound signals and distress signals, in accordance witlt the

requirements of the Convention and the Intemational Regulations for Preventing Collisions at Sea in tbrce;

2.6 in all other respects the ship complied with the relevant requirements of the Convention.

3 That the ship operates in accordance with Regulation llV26.1.l. l within the limits of the trade area

4 That in implementing Regulation I/6 (b) the Govemment has instituted Mandatory Annual Surveys.

5 That an Excmption Certificate has / hrm* *2 been issued

This certificate is valid until 8 October 2003.

Issued at New York on 28 May 2002.

f o f ng Director

KAIJI KYOKAI

Date of Renewal Survey : 9 October 2001

;i-- r* o;n-t"",iti"fricot to"t"" i-"d gas iitti"ts ""1y.*') Delcte as appropriatc.*3 Date on which kecl rvas laid or ship was at a similar stage of consfiuction or, rvhere applicablc, date on rvhich work for a conversion or an altcration or modifcation of a major

charactcr rvas commenced

SE(PNI\,I)-74178P 2002.r

7t;


C E R T I F I E DNo; CRO 9gfiUtm

Page 1 ofl

COPY

ftrisoeldfta,ttiBirsu€dbthe CI,AI,DIA

Certificate of Class

LRnumbcr

Daeof btrild

Porlof Rogistsy

Grccttons

gwrnn

1Dcc,cnborl999

DETJ4IL

d236

to confirnr thathrviry be€n eurveycd by Uoyd'e RegiBedosuntcyor''c ani tqorEd by dtffir to be in complianaewift Uoyd'eRegFHc Rulecand Reguhcuu forffreChrsiffcaflurof $r$,a, tthas bcenrctignpd &ectaso

+1{X}A1 Stnoglhcncdfu Hgwy Cugoea Coffrlner Cugect in Hold end onUppcrdeck llrtdrcovur, Icc Clrr 1A frlndrb9wedtdt fcc CXarr Rulce t98S)wtth the dcrctpdvc nota rFC$Ar (ptrm)+t LlQ t Mg wtft thp dmlpttve aote SCM

Dab Sccfd furvfy fudgn€d 1 Ds!.mbcr 1999

Thlc Ccrdflcrte b vdid wrti$ 90 Noryrmber$0l

.lJnbsffi&torndcl&lt oftSp,elr/.furyy(laqgcl)rninmrfurccwtdtPmrLAnpts;rz,Secfin3.5.9ofltuxadlrcfttd@,rtatitttu(wVage 3) ntdbst@ 0ocurryloerw,tffi(*WgcZlh$ttglrltisficlritity @tt@d.(tuttohcl b4,pge3).

bsucdat llneqpmlngpn

NgnC& 1 thir crrdffarb trarUcct u ep usrr md oqrdittmc er rhoun ovcrlof.2 Tocchblidrtlre cJasificaHpcrsbE of ilrhdrip,trcquarur{ycompuhrprlnFoutforlrcdbyLRend

{rsftrfrrlnCcrdfrour ircucdcrerrplcdonof daectficadonrurveyedwuld becomilEd, hladdtHontothirccrtiflcab.

/

rc&{ rar camrraln or cras gFo

t=(J

HF

I

EC.

tFEE

Ep

fi6


I4g?lizffi Page l of 3

VNNKLARIFIG INZAKP HET VOLDOEN AAITI DE BIJZOI{DERE VOORSCHRIT'TENVOOR SCHEPtrN WELKE GEVAARLIJIG STOTFtsN VERVOEREN

DOCUMENT OF COMPLHNCE WMT SPECIAL REQWREMENTSFOfi SIffPS CARRYNG DANGEROUS GOODS

BIEDNnI.,ANDTT{E NENffiKIANDS

Hst Hoofd van de Schecpvaartinqpeetie verklaart dat hetThe Head of the Ehipping Inspection declares that the

.CLAUDI,A" PCHE

is gobouwd cu uitgenrst in ovcrwnstemming met het bepaalde in Artikel 54 van Biilage IV vrU hot: $e&gnttesluit 1965, on derhalve geschikt is voor hct vervoer van gevaarliike stoffsn aoale aan de'ontnsaijdea883gcgsucn. /

is constructed and equipped in accordancewith the provisions of Regulation 54 of Chapter II-2 of SAMS 1974,as amended, and therefore suitablefor the carriage of dangerous goods as specified overleaf

Er bs$ban gconbiircndore voorschrriften als bedoeld in bovengenoemd Artikel 54 voor het vcrvoer vsngovaarliikc stoffen van klasse 6.2 en 7 en voor het vervoer van alle gevaarliike stoffen in beperkte boeveelheden,zoals gedofiniecrd in Hoofilstuk 18 van de Algemene inleiding van de International Maritime Dangercus GoodsCodc.

There are rn special re4utramentr ar erprersed in abovementioned Regulation 54 for the carriage af dangerousgoo& afClass 6.2 and 7 andfor rte catiage of dangerous goods in limited quantities, as defined in Secfion I8of the General Introduction to the lwernational Maritime Dangercw Goods Code.

Deze verklaring is geldig totThis document is valid until

Uitgereikt te Rottedam, dcIsMat&atudmn, the

Namens hetHoofd van deFor the Head otthe

the 1'of Dccembcr 2fi)4

9tr ofFebnrrry 2000onder no.undernr. 49212000

qrlr


F.P. Hachmffifi

121

Name of ship


Port of registry

Gross tonnage

Sttip type' (Code paragraph 2.1,.21

IMO number

Date on which keel was laid or on which the ship was at a similarstage of construction or (in the case of a converted ship) date on lvhidr

conversion to dremical tanker was co[unenced.

Certificate no:

ROT 0000002

Page 1 of 5

International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bu

lssued under the provisions of the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bt(resolutions MSC. a(48) and MEPC. 1.9(22), as arnended by resolutions MSC. 16(58) and MEPC.40(29))

under the authorify of the Government of the Kingdom of the Netherlands

by Llovd's Register of Shipping

Particulars of ship"DUTCH AQUAMARINE"

P C H S

Dordrecht

4,67't

2

9191,656

08 / 1ee9

The ship also complies fully rvith the follor.r'ing amendments to the Code:

MSC 50(65) and MEPC 5e(38)

The ship is exempted from compliance rvith the following provisions of the Code:

N/A

This is to certi$':

1. 1.1 that the ship has been surveyed in accordance with the provisions of section 1.5 of the Code;

1'.2 that the survey showed that the construction and equipment of the ship and the condition thereof are in all respects satisfactthat the ship cornplies n ith the relevant provisions of the Code;

2. that tl're ship lias been proviclecl with a ntattual, in accordance with the standards for procedures and arrangements as called forbyregulations 5,5A and 8 of Arurex II of MARPOLT3/78, and that the arrangements and equipment of the ship prescribed in the marin all respects satisfactory and comply with the applicable requirements of the said Standards;

3' that the ship is suitable lbr the carriage in bulk of the products listecl on page(s) 6-1.5 provided that all the relevant operational pr<of the Code are observed;

' Delete as appropriateForm 2214 (2002.09)


PANAMA CAI\AL

PC/UMS DOCT]MBNTATION OF TOTAL VOLUME

Name of Ship: AfDAvita

Based upon the rules of nreasurement for the Panama Canal as specified in 35 Code of Federal Regulations sectioror the International Tonnage Convention of 1969 this vessel has been measured and-assigned the follorving Total\'-olume in cubic metres:

149 885.11

GL-Reg. No.NationalitySignal LeffersType of PowerType of VesselIMO-No.Keel LaidYear BuiltNo. ofPassengers

K4 factor (6 decimals)

K5 factor (6 decimals)

94690United KingdomVSTN3EnginePassenger922155421.11,200020421582

Length OverallExheme BreadthITC(69) LengthITC(69) BreadthITC(69) DepthITC(69) GrossITC(69) NetContainers above deck**:

the above

202.85 m35.50 m

182.02 m28.10 m11.55 m

4228920877

37540

Based upon e vessel tonnage of . 37540 calculated rvithvolume and an above deck container tonnage of - ., -the PC/[D{S Net Tonnage equates to:

Bunker Fuel for Ballast Rate limited to:

0.250459

not applicable

This Certifies that the above named vessel has been nreasured in accordance *'ith the Rules for Measurement of Vesselsfor the Panama Canal, and that the particulars of tonnage contained on this Certificate are correct.

Issued by: ...........9.:glg...*I:.t.Ll:. y9.............(Authority)

(Signature)Franzelius

* BB (barrels). 1le figure is the sunr of the capacities of all fuel oil (l iglrt and heary) and lubricatingoil tanks for thc vcssel's otlrl use. Tarrks uscd for both ftrcl oil and n'rter ballast arc to bc irrcluded,horvever, tanks with lneans for discharging to other vessels or shore installations are not to be included.

t+ I s tandard con ta inc r 8 ' x 8 ' x 20 ' : 36 .25 m '


Werner

123

Goxrnsnisdtet T,JsUb

SUEZ CANALSPECIAL TOIINAGE CERTIFICATE

DETAILS OF TONNAGE F|OR THE ABO\{E.NAMED SIilP WHEN PASSING THROUGII THE SI'EZ CANAL

Tlrc space measurcd for Gross Tonnage in this Ship comprises tho following and no othen, viz:

I. Space rutder &e tonnage deck including part of double boftom available for oil &ain ank

2. Space or spaces between the ionnage deck and the uppenuost deck: l,ower tween deck

Uprpertween deck

3. Closed-in spaces under or in pcrnranent constructions above the uppermost dec\ viz.:

Space between rrppermostdcck and shelterdeck wi& side opcningsForecastle

BridgcPoop

12 001.65 + 13172.47:12870.63+7 882.57

Break orbreaksTurret cbm Truik cbm

Name of Ship OfficialNumb,er

Signallctters

Port of RegistyTomageon

International Tonnase Ccrtifi cate IMGNo.Gross Net

AlDAvita 905689 VSTN3 London 4n89 20877 9221554

Roundhouses (lstTier)(2nd Ti6)(3rd ficr)(UpperTicrs)

cbm

l0 588.72 cbm

cbm

ebm

TIIffi**'*..--tb.

cbm

cbm

cbm

I 533.3Q. ctm

--"ba

111.61

cbm

gbm

cbm

cbm

cbm24.70

cbm

cbm

cbm

cbm

cbm

cbm

cbm

cbm

cbm

cffir

cbm

cbm

cbm

cbm

cbm

cbrn

cbm

cbmSide screcns cbm JQl.tQ cbm

Hatctrways '-ib''. _*--"bm

Total

cbm

cbm

Eitlrcr (l) applicable to ships with fixed burkers:(a) Engineroomas measured

ft) Pcrmanent

(2) Danube Rule:

G) Engine roomas measrued

(b) In aScrew(c) In a Paddle

cum .59.92

cbm 34.{6 cbmcbrn cbm cbm

One-half percent of the gross tonnage

Total ofTonnage ofclosed-in spaccs above the uppermost deck

98.31cbm

Excess

NOTE: for particuhr of spacc not includcd in the

Mcasurcrnart for Gross Tonnagg scc page 3

FT'RTHERDEDUCTIONS FORPROPEIIINO POWERIN THE CASE OF

THIS IS TO CERTIFY t!'at tbe Britishadopted by the International Tonnage Cornnission at Constantinople.

GROSSREGISTDRTONNAGE

DEDUCTIONS FROMGROSS TONNAGE (Details onpage 2)

NET TONNAGE IF A SAILING SHIP

/S @etails on page 4)

bunkers as measured

Total deduction for propelling power

NETREGISTER TONNAGE OF IS BYACTUALMEASTIREMENT

/S + 75 percent ofengine room as measured

/S + 50 percent ofengine room as measured

Total deduction for propellingpower _

NATREGISTERTONNAGEOF Motor /S BYDAI.{UBERULE

ship above-namcd has been re-measured" and that thc Tonnage ascertained as above is in accordauce with the rules

Given under my hand at Harrrburg

Or

Motor

der AIoUb

,,[t-u,^.^

21 156.19


6e 22nd dav of Aoril. 2002

124

FTEIFIIIiHryI

SAFETY MANAGEMENT CERTIFICATE

lssued under the provisions of the INTERNATIONAL CONVENTION FOR THE SAFETY OF LIFE AT SEA, 1974, as amended

lssued under the authority of the Government of:

Norway

by Det Norske Veritas

Name of ship:

Distinctive number or letters:

Port of Registry:

Type of Ship*:

Gross Tonnage:

IMO Number:

Name and address of the Company:as per ISM Code sec. 1.1.2)

' Insert the standard IMO

DETNORSKE VERITAS

"FELlClA"

XXXXl

KR.AGERg

Other Gargo Ship

I 1658

00000000

Benkestok ShippingRsrvikveien 323770 KrageraNorway

DNV Ship ld. No.:00000DNV Company No.:000000Certificate number:D00000/021202F

THIS lS TO CERTIFY THAT the safety management system of the ship has been audited and that it complies with the requirements of tllnternational Management Code for the SCfe,Operation of Ships and for Pollution Prevention (lSM Code), following verification that theDocument of Compliance for the Company iS applicable to this type of ship.

The Safety Managemerff:Certificate is valid until 2007-10-14 ,subjed to periodical verification and the validity of the Document ofCompliance remaining valid.

lssued at: Det Norske Veritas, Hovik, Norway

Date of lssue: 2002-12-02

q rt/--t----_------

Name

Ship Kttowledge, a modern encyclopedia

Head of Section

125

Construction olffie

I Holds

2 Aft ship

3 Engine room

4 Double bottom and wing tanks \:s-r

Vi't '

5 Foreship

6 Accommodation

##aa

sl] r

F;t

6.1

6.2

6.3

6.4

6.5

6.6

6.7

Introduction

Safety

Environment

Methods of insulation

Communication

Maintenance

Overview of the various

spaces

----74

% , ' t f -! & ,

1 Holds

Seemingly the holds are not very interesting. In general they are large empty

rectangular spaces whitout visible stiffenings (frames, floors etc.).

Nevertheless, the hold is so important that the entire construction is aimed to

enable the moving of the hold and its contents (the cargo). The amount of cargo

carried is ultimately the decisive factor for the earning capacity of the ship.

The bulkheads of the holds are asflat as possible to make them as"user-friendly" as possible. Inbulkcarriers the parts of the hold,not under the hatch opening, aremade sloped, so that the cargo

slides down towards the areawhere the grab can take it. Further-more, these ships have anincreased tanktop plate thicknessto compensate for the wear causedby grabs.

H o l t l,s e e rt in t l t c .fb mt' a rtl d i re c r i on ( m u l t i - p t r t '1to,s e,s lt i Tt )


I{old of an LNG Currie r (tnetnbrune r\:pe)

r28

In multi-purpose ships, the shipowners prefer just one very largehold. The crew can then decide onthe basis of the type of cargo howto subdivide the hold. The hold isdivided by movable bulkheadspositioned either horizontally orvertically. The bulkheads can beattached to the sides of the hold ina very simple manner. Legal safetyrequirements (intact damage stabi-lity) normally require that one ormore of these movable bulkheadsalways be in place. The actualnumber of cross frames depends onthe length of the ship.Both the sides of the wingtanks andthe tanktops have manholes tomake inspection of the tankspossible. The sides of the wing-tanks also have lashing points forcargo securing. Heavy cargo isoften seafastened temporarily by

View of a tank on a chemical tanken

means of beams and / or bracketswelded to strong points in theship's side and tanktop. This can,of course, only be done with tanksthat do not contain oil. Thehumidity in the holds can be

controlled by ventilation, recir-culation and"/or the use of driers.

The holds on cellular container-ships are divided into multiplecells, each capable of storing astack of 2O or 40 containers in foreand aft direction. The spaces (cells)

are separated from each other byguide rails. During loading anddischarging the containers areguided by the rails in the verticaldirection. In addition, the rails alsosecure the cargo in place.Most multi-purpose ships are "box

shaped". This means that the holdis rectangular and the spaces do nothave curves. This is important forthe stacking of containers. If thehatches and the holds have afacility to fasten the containers, theholds are then said to be "container

fitted".

Explanation of the images at the right:

1. Comrgated bulkhead (transverse)2. Stringer3. Main deck4. Centre line comrgated bulkhead5. Section of the web frame

Another view of the same tank


Wing tank of a tunker

129

When ships are designed to carryliquid cargoes in bulk, they arecalled tankers. The space for cargois then divided by watertightbulkheads into a large number ofseparate tanks, each with its ownentrance hatch, ladder to descendinto the tank, sounding pipe,

ventilation pipe, filling anddischarge lines, or its own pump,depending on the kind of cargo.Every tank has possibilities fortemperature measurement, ullageand/or sounding measurement,often radar level control, tempe-rature measurement, heating possi-

bilities to control the cargo tempe-rature, independent high levelalarm (95Vo full) and overfill alarm(987o full). Also means for tankcleaning with fixed or hand-operated washing machines. Thetanks are internally coated with apaint which is resistant to the cargothe ship has been designed for. Orthe tanks are constructed ofstainless steel. Furthermore, anddepending on the size of the shipthere are additional spaces in deckfor transport of materials, tools, orin case of an accident, for people.The tanks have as little stiffeninginside as possible to avoidaccumulation of dirt, and tominimise the area to beexpensively coated. The stiffeningof the bulkheads is in thesurrounding ballast tanks. Division-bulkheads between cargo tankstherefore are often comrgated.

The two pictures at the previouspage show the insides of a tank ona chemical tanker (GT 3350, deadweight 5070 tons). The transversebulkhead is a comrgated bulkhead.The hold can be inspected byentering via a (compulsory) hatchand a simple ladder. Perhaps notimmediately apparent in the photo,the double bottom is slightly tiltedtowards the keel-plate, to facilitatethe flow of liquids.

The other ship is designed for thetransport of packages of timber.The picture shows a ship of whichthe holds are made to carry themaximum amount of packages oftimber with as little lost space as

Ship Knowledge, a modent encyclopedia

possible. The hatches are trapezialso an extra layer of timber can beloaded. The stiffenings are on topof the hatches.

Some particulars of the hold:

Length: 49.7 m.Width: 10 m.Height of the coaming: 2.33 mMax. depth: 8.85 mCapacity: l493OO cu.ft. =4228m3

The ship as shown below

The maximunt amount of packages of ttmber vvith as little lost .space as possihle

130

Explanat ion o f the i rnage to the lc f t :

I . Forecastle deck

2. Breakwater on the ntain deck

3. BLrlkheacl'4-. Bal last tank shapccl to trake the holcl

box shapecl

5 . Tanktop

6. Lon-g i tLrc l ina l bu lkheac l between ho lc l and

wing tank

1 . Manholes. entrances of doLrble bottolt- t

l { . Ho les l ' o r l . i t l i r r g eon t l i ne rs

Explanat ion o f the image of the c l iagrarn be low:

l . B r i d g e2. Accor.r-rr-noclation

3. Engine-nrom br"r lkhead

1. Tanktop

-5. Bal last tank shapecl to make the holc l

box shapecl

6. Lon-si tudinal bLr lkhead wing tank

7. ( lu l l ) F loor (p la te )

8 . S ide kee lson

9. Webframe

10. Toprai l

I l . Coarnin-t

12 . Gangway

*

Q

i - ' r

I

t

tlI

'I

I

I{

$ - f

t- t l

Double hull tanker

These images are of a double hullVLCC tanker. whose maindimensions approximately are:

Deadweight:

Length over all:maximum breadth:drausht:

300 000 t292 m4 6 m1 6 m


-? '

'4-"''

ffiw

*":'

. . : _ F _ -

1-;

III

?eI

w

"l

III

7aF

I

-l4 ' /

I7

5

III

4Fa

1

1 6

1 5

ll-[ II

-;-jJ'p

t =

i ' t siT, t

l l, ,

r ll l

7 l

'|.7

l l li i t , ,

t ll l

, ,r lI t

t ,r ll l

, ,I-l g

i 3

r ll l

t it ll l

, -l l, i

r ll l

' t ll : l- ' t

t ll l

, ,t lt t

L LI

IJ

I . OLr ter s ic le she l lr . I nne r s i c l c she l l

3 . Longi tLrc l ina l bLr lkheac l-1. Bracket

-5. Webfranre(r. Str inger cleck

7 . C ross - t i e

\ l t i 1 t Kr to t t l cd ,u ,c . t t r r to t l c i t r u t t t t lo l t c t l i t t

8. Forepcak bulkheacl

9. DoLrble bottonr10. Af ierpeakI l . Machinery s l lacc

12. Cargo tanks13. Forepeak tank (waterba l las t )

l -1. Upper c leck

15. Tweenclcck

16. Af t peak bLr lkheac l

I 7 . Engine-roonr bLr lkheac l

1 8 . C h a i n l o c k e r

19 . FL re l bL rnke r

1-t-l

2 Aft ship

The most eye-catching spaces afton most ships are the engine roomand the accommodation. Besidesthere can also be working places,storage facilities and fuel or ballasttanks. The aft peak is the part of theship that is enclosed by the aft peakbulkhead, the stern and the aftdeck. The aft peak is the locationthrough which the main engineshaft runs. For support there arefloors in the aft peak.

The stern section is the sectionabove the aft peak. The steeringengine room is part of this section.Just below the steering flat is therudder carrier where the rudder-stock is suspended. The rudderstock runs via the rudder trunk(frame no 0) through the aft peak.

St e n t p o s t tt itlt,s h ctfi i n g

1. Funnel

2. Bridge

3. Bridge wing4. Accommodation

The stern borders the backside ofthe stern section. This is a platerunning the full width of the ship,onto which the name of the shipand the homeport are welded.

5. Boat deck

6. Poop deck

7. Weather deck8. Floor plate, frame no 3

As.sembly drawing

9. Floor plate, frame no 1010. Stiffeners11. Stern frame

12. Stern frame

13. Shaft generator

14. Reduction gear box


T r a n sv e rs e c ro,c,s -,s e c' t i on ctt .f'rtt me | 0

Trcutsverse cross-section at f'rcune 3

ktngitudiruil cross-section o.f' tlte engirte .fburdatiott

Explanation of the above image andof the below images:

1. Tanktop

2.Top plate for engine foundation

3. Brackets under engine foundation4. Floors

5. Longitudinal girders of the engine

foundation

Ti'uttsverse see-tlmtugh of'the c(i sli1t

3€

As.s'entb\1, drav,ing

Ship Knowledge, a modern encyclopedia 13s

Top view of the aft of a passenger liner Explanation of the images on this

page:

Centre keelson

Side keelson (watertight)

Floors

Hole in the deck for the

azipod (see also chapter 9)

SkegFloor brackets on the frames

Stiffening floor brackets

Longitudinal fl oor brackets

Strinser brackets

'/rG,N

\ t l , r , ' l t i r r ' : 1 1 r 1 , r . 1 1 , ' , , 1 t , ' t l , , ' l r i l ,

2

Bottom view of the aft of a passenger lindr

The Skeg.

This is a narrow vertical part of thehull in the aft ship. It is often presentin twin propeller ships to enhance thecourse keeping ability of the ship byenlarging the vertical lateral area, andalso to take the load of the aft ship,when the ship is in drydock.

: i t i t t h' t trnrI€rlge, a modem encyc'Iopetl 'u 136

) .

t;ir#fIQDI

Erplanat ion o f the above

The sanre sh ip (a conta iner l 'eec ler ' ) .

now seen fnrnr a t t w i th a u l inr l ' rsc ' o f

thc cng ine roonr . Here vou can sec

ba l l as t l i nes con r i ng f r on ' r t anks i n

the engine roonr . Thc l ' r 'anres in the

enginc roor l anc l thc c loLrb lc bot tonr

r r - r r - r in the t ransverse c l i rec t ion anc l

t l r e ones i n t he r v i ng tanks i n 1he

Ion s i l t t t I i t uL I t l i l t ' t ' t i o t t .

'!,1;;

l . Wc 'b l n rn rc

) . Top p la t c cng inc l oL rnc [u t i on

i. Tanktol-r

+ . Coan r i ng s tanch ion

5. LJpper c lcc l ,

6. Wcb l l 'anrc

1 . L o l l g i t r r r l r r t r r l I ' r ' l r r t t i r r r

8 . Wa tc r o r o i l t an l i

9 . Bo t t on r r i i ng t ank

10. Dc' l i ren'suctior.r I ine o1'the r,r ' in

l l . S i c l c h c c l s o n

l l . ( ' cn t l c kcc l so r t p l u t c

I 3 . ( l ' L r l l ) F Ioo r ' ( p l a t c )

On thc 1- l ic tu l 'cs bc lou ) /oL l sL 'c thc

a l ' t o1 ' t u o Ro l l - on Ro l l - o l ' l ' r c ssc l s .

Thc opcn s l l l l ccs c ln bc c losc 'c l br '

n rn r l ) s ( no t vc t i n p l ucc ) . Whcn thc

l 'anrl ls l l rc () l)cnc(l . thcv can lrc Lrscrl

t o l t r l r t l o t ' t l i s . ' l t l r t 'S ( ' r ' l t o r i n r t ' l l t ' t , r .

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c l c a r - a n c c o l ' t h c

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I . j 7

3 Engine room

The engine room is a compartmentthat spans the full width of manyships. In tankers and bulkcarriers,however, often there are bunker tanksin the sides so that in those cases, theengine room does not span thecomplete width of the ship. The backand the front are provided with twowatertight bulkheads: the engine-roombulkhead (fore) and, if the engineroom is at the after end of the ship, theaft peak bulkhead(aft).

In the vertical direction an openconnection is formed by the engineroom casing. In the casing there areseveral catheads (cranes) with eithermanual or electric tackles for themoving of auxiliaries, tools or parts ofthe main engine. Motion of larger andsmaller masses and the outside waterpressure makes the use of web framesin combination with web beams andpillars necessary.

Foundations to support the main andauxiliary engines should also transferthe mass of the engine vibrations andresulting stresses to the ship'sstructure. The foundation should keepthe engines in place when the ship isrolling and/or pitching and highlycontributes to maintain a properalignment with the propellor shaft.

The double bottom below the engineroom is sometimes higher than othersections of double bottoms toaccommodate the propeller shaft. Theexact location of the propeller shaft isdetermined by the diameter of thepropeller. When the double bottom isnot higher, the engine foundation willbe raised.

l?fi;/l l ? .0 |l l a x Iil-a;

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= i5l

Construction drav,ings of the erryine roctnt of o corttninerfeetler

138

4 Double bottom andwing tanks

The double bottom and the wingtanks are highlighted in the sameparagraph as they have the samefunction. The wing tanks arelocated at the sides of the ship ontop of the double bottom. Usuallythe two wing tanks are separated inthe sense that no fluid can flowbetween them. Sometimes. how-ever, the two tanks are joined in aU-shaped or L-shaped fashion.

The functions of the double bottomand the wing tanks are:- To increase the transverse. and

the longitudinal strength of theship.

- Additional safety when thebottom is damaged or in case of acollision (intact stability).

- To store seawater (ballast water)so that the propeller is below thewater surface even when the shiphas no cargo in the holds. This isalso advantageous for the stabilityof the vessel.

- To store fuel- To influence the list and the trim.- To compensate for uneven loadingIf the ship is equipped with aheeling pump, the pumping ofballast water from one wing tank tothe other will automaticallyminimise the list. This is mainlyused by heavy-cargo ships andcontainer ships during loading anddischarging.

Both the wing tanks and the doublebottom are, in fact, watertightcompartments. In the doublebottom, the separation of the twosides is accomplished by the centrekeelson or the side keelson in thefore and aft direction and with awatertight floor in the transversedirection. An oil tank and adrinking water tank must beseparated by an empty space, a socalled cofferdam. The wing tanksare separated by watertight webframes. The frames in the doublebottom and the wing tanks usuallyrun in the fore and aft direction.When a ship has a length ofapproximately 60 meters or less,for instance a tugboat or fishingvessel. the frames run in thetransverse direction. Sometimes acombination of the two systems isused. The double bottom is coveredby the tanktop, and therebyseparated from the hold. Severalpiping systems run through thedouble bottom, such as piping forbilge or ballast water systems.Container ships need reinforce-ments in the double bottom tosupport the corners of thecontainers.Floor plates in the double bottomcan be divided into:

- full floors, which can be reducedin weight by manholes (also foraccess)

- floors made of profiles- water- or oil-tight floors.

Vents and openings are installedfor the filling and emptying of thetanks. Every double bottom tankmust be fitted with a sounding pipeand a vent pipe. The double bottomis accessible by bolted manholes inthe tanktop; every tank has to befitted with at least one of these.Fuel tanks not in the vicinity of theengine room must have the abilityof heating the fuel stored in themdepending on the type of oil. Thisis necessary in colder climatesbecause the low temperaturedecreases the viscosity of the oil,which can make it impossible topump the oil to the engine room,and always necessary when heavyfuel is used.


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Two inra-ges o l 'ho lc l r ro 1 o f a conta iner l -eec ler

Inragc at t l ' rc lcft pagc:

v iew to thc l i r rc

Inragc at t l -rc r ight pa-qc:

v icw to thc a l ' t

| . Cen t l e kee l son

2 . S i c l c kcc l son

3. Bot tonr l l 'anre

4. Wir ter ' - or o i l - t ig l - r t f loor (p la te l

5 . Fr - r l l l ' loor ' (p la te)

6. Cent re kee lson bracket (c lock bracket )

1 . B a l l a s t l i n e

8 . B i l g e l i n e

\ l t i l t K ' r t t n L l t t l , q c . t t t t t o t l e r t t u t t t ' t l o l t c t l i t t

ljo -T

9 . Enc l ba l l as t l i nc . w i t h suc t i on

| 0. Lorrgitr .rcl inal f lunre

I l . Water ' - or o i l - t ight bu lk l - reac ls

12. Web frunre

13 . Ha tch co i i n r i r r g

l . l . Coan r i ng s tanch ion

l -5 . S i c l e bu l kheac l w ing t ank

16 . Gangway

1 7 . B a l l a s t o r f u e l t a n k

1 8 . T o p p l i r l e o l - c n ! l i r r c s c l r t

lc . ) . Poopc lcck

20 . Ve n t i l a t i on o l ' t hc ho l c l

2 I . Accor-nrnoc la t ion f ront panel

22 . Co l l i s i o r r b r - r l kheac l

23. Breakwi . r ter

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Incation of the section in the ship

Explanation of the drawings on thispage:

1. Hatch coaming plate2. Toprail3. Gangway4. Deck beam5. Longitudinal frame6. Shell plating7. Longitudinal bulkhead, tank side8. Scallop

Sect ion 1800. (a450. 3050. 36751 a.b .

Ship knwledge, a modern encyclopedia 142

I.{e

Explanation of both images

on top:

Main deck, gangway

Deck longitudinal beam

supporting the tip of

the coaming strut

Tween deck

Web frame

Longitudinal frame

Bilge bracket

Full floor

Scallop

Explanation of both images at the bottom right:

1. Bottom

2. Side keelson

3. Full floor

4. Tanktop

5. Vents

6. Heating coils

l. Synthetic pipe for ballast tank


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Explanation of the images onthese two pages:

1. Full floor2. Side keelson3. Bilge sffake4. Bilge keel5. Recess container pot6. Vents7. Drain holes8. Tanktop9. Tanktop stiffening101Bottom frame11. Portside12. Starboard side13. Longitudinal frame system14. Transverse frame system15. Floor on frame 3116. Floor on frame 3517. Floor on frame 4618. Scallops


Explanation of the image at the left:

1. Bilge plate

2. Bilge keel

3. Aluminium anodes in the

ballast tank

Bottom view of the double bottom

Explanation of the images at thebottom:

1. Bilge plate

2. Side keelson

3. Full floor4. Tanktop

5. Vent channels6. Upper frame

7. Container support

8. Bottom frame

lliev' o.f the down side of the double bottom. In the middle you can see the HFO-tank with heating coils.


Double bottom of a container feeder

146

Sidc. t,ievv

Explanation of these three images:

1. Draught mark

2. Plimsoll mark

3. Hatch

4. Railing

5. Container strut

6. Bilge strake, approximately

10 mm thick

7. Ground bar

8. Bilge keel, approximately

220 x 15 mm (for this particular

ship) The bilge keel is welded

onto a strip. When damaged, the

bilge keel should break off, with

the strip remaining attached to the

shell. Without backing strip, a

fracture in the bilge keel could

continue into the bilge strake, and

that is dangerous! Bilge keel

Crctsssectioltn of tlrc nidship


i lH trt t t f l - ti ra l la i ta ; tr i l f ia. traa ira i |ra ia. ' i . la laa e-,1

Location of the section in the ship

1. Longitudinal bulkhead2. Bilge well3. Heating coils4. Bilge line5. Cross-over line

This 3D-images shows an open wingtank and a double bottom of a RoRo-passenger ferry.

The cross-over line is visible as anopen line between the portside tankand the starboard tank. A cross-overin this case is designed to be used inthe event of a collision. Waterentering one space will flow to thetank on the other side. This willmoderate the list. The system canresud in reduced damage stability

. requirements. The majority of ferriesand passenger liners have such acrossover system.

The drawings show:- bilge wells; fluid present in the

compartment will flow to thebilge well and can then beremoved by the bilge pumpingarTangement.Heating coils; these are in theheavy oil tank. If the oil is tooviscous to be pumped, it will beheated up to a 'safe viscous'temperature.


5 Foreship

The foreship is the part of the shipbetween the stem and the collisionor forepeak bulkhead, and theadjacent section.

The space in front of the collisionbulkhead is the forepeak. Theforepeak tank is the lowest space inthe forepeak and can be dividedinto a lower and an upper forepeaktank. The forepeak tank is usuallyused as a ballast tank. If the ship isnot loaded, this is often filled withwater to reduce the trim at thestern. Often there is a washbulkhead in the peak tanks. Thisimproves the rolling behaviour ofthe ship, by delaying movement ofthe ballastwater when the tanks arenot completely filled. Just behindthe forepeak there can be anothertank that extends from starboard toport and from the bottom to thedeck: the deep tank. In the top ofthe forepeak, right below thecapstan or anchor winch there arechain lockers for the storage of theanchor chains. Above the weatherdeck on the foreship is theforecastle, a deck erection thatextends to the forecastle bulkhead.This bulkhead is not necessarily onthe same frame as the forepeakbulkhead. On the forecastle is thewindlass and other mooringequipment. Also the foremast.

The forecastle can be divided into:- The bosun's store: storage for

ropes, tools for work on the deckand cargo handling.Storage for cargo handlingequipment like twistlocks, slingsand airbags. These items areusually stored in racks made forthis purpose. If necessary, theseracks can be lifted up by theship's crane or the crane of thehatch cradle.

Explanation of the above image:

l. Hatch coaming

2. Breakwater

3. Bulwark grey with bulwark stanchions (purple),4. Transition from transverse system to longitudinal

system. For constructional purposes the transverse system


'l 'he .f 'ttrtt pilrl i.\ baing ullttcltr:d lo l ltc ,s'lt ip

The fore-ship is subject to extra large forces and stress that are caused by:

a The pitching of the ship (pitching stresses).b The foreship moving in and out of the water (panting stresses).

c Maintaining speed in heavy weatherd Ice

Strengthening for ice Where For

Closer frames (300 mm) VP a.b.c.

Extra (heightened) floors DB +VP a

Extra sister keelsons DB a

Heavier frames and/or web frames VP a.b.

Horizontal stringers on shell VP + deep tank and

wingtanks

a.b.

Thicker shell plating At certain draught c .

Panting beams VP b.

To compensate for these forces, the fore needs additional reinforce-mentsthat sometimes partly extend to the back of the ship. The bulb stem is

added to reduce the wave resistance. The bowwave causes a resistance

that has a negative influence on the speed of the ship. The additional bulb

creates a wave which extensively equalises the bowwave and thus

positivily influencing the ship's speed. (this only in the loaded condition)

is easier than the longitudinal system in the forepart.

There is no need for longitudinal framing as the

longitudinal stress in this area is minimal. Transverse

strength is stronger than longitudinal strength. This

transverse strengthening is desired to withstand the forces

caused by panting and pitching.

149

I

The bulbuous bow is in fact apiece of protruding bow thatbreaks up the bow wave before itmanages to reach the ship. Thebulb stem also has a favourableeffect on the wave system aroundthe ship. The ideal situation is onewhere the ship cuts through thewaves, whilst generating no wavesby itself. For every wave that iscreated by the ship is lost energy;compare a tugboat with a "sharp"

yacht.

The bulb is most effective at acertain draught (loaded ship). Itcould very well be that in the caseof an unloaded ship, the bulbactually produces more resistance(see also chapter Propulsion).

r 1 0

Explanation of the above image:

l . B o w

2. Forecastle deck3. Wave breaker4. Bulbous bow5. Gangway6. Stringer deckl. Bow thruster room8. Bulwark with stanchions9. Fire extinguishing l ine10. Top railI l . Vent of the wing tank12. Str inger13. Transition of transverse to

longitudinal system14. Tank top15. Side keelson

Explanation of the right hand image:

l . Side keelson2. Centre keelson3. Tanktop

4. Stringer deck5. Web frame6. Floor brackets7. Manhole

8 . Bu lb

9. Bow thruster tunnel

Ship Krtov'letlge, u rtrotlent e rtct'clopetlia t50

The picture above shows an OffshoreSupport Vessel. The number of bowthrusters already indicates that theship is equipped with a DynamicPositioning System (DP-system).The sheer strake is always theuppermost side shell- plate of a shipand on this rhip, the three sheersffakes are clearly visible.

1. Sheer strake forecastle deck2. Sheer strake tween deck3. Sheer strake main deck4. Helicopter platform5. Escape route to or from the

helicopter plafform6. Accommodation

Ship Krcwledge, a modern encyclopedia 1 5 1

1 41 3

1. Bulb \ /2. Stringer bracket3. Floor

24 274. Floor stiffener

5. Opening*

6. Stringer deck

7. Bow girder in bulb

8. Shell stringer

9. Transition of stringer deck to shell stringer

10. Bracket with flange

11. Girder bow12. Shell frame (HP)

13. Shell stringer with flange

14. Hawse pipe

15. Chain locker

16. Watertight bulkhead (collision bulkhead)

17. Forecastle bulkhead

18. Stairway to the forecastle deck

19. Weather deck

2526

Loccttion of the section in the ship

20. Forecastle bulkhead frames

2I.Emeryency flre pump / bilge pump with emergency

fire line and bilge line

22.Bilge line in bow-thruster room

23. Ballast line in fore-peak

24. F orepeak (water ballast)

25. Bow-thruster tunnel

26. Floor slab in bow-thruster room

27 . Deeptank (water ballast)

28. Floors29. Wash bulkhead at the centre line of the ship

* NOTE: An opening cannot be blanked off whereas a

manhole can be blanked offwith a manhole cover, e.g. for

access from one space to another space or tank.


Assembly drawing

152

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1 5 3

The drawing of the ship shown

above gives a clear picture of the

various stiffenings. Note that the web

frames are never isolated but are

always part of a ring frame. For

every three framings there is a web

frame. The stiffenings under the

main deck run in the longitudinal

direction. Directly underneath this is

the icebelC in this section there is an

Location of the section in the ship

extra frame for every frame. The icestrake can run all the way fromforward to the place where the ship isat its widest.

1. The forward direction

2. Mann deck

3. Deck longitudinals

4. Deckbeam

5. Double skin with longitudinal

frames

6. Longitudinal frames

7. Additional intermediate framing

for ice strenghtening

8. Transverse frame

Port side shown

Forward >


6 Accommodation

6.L Introduction

In the past, the accommodation ofthe crew was not the mostimportant aspect in the designphase. One reason for this was thelarge number of men in the crewcompared to the present day. Thirtyyears ago (circa I97O) a crew offorty manned a vessel that wouldtoday have a crew of twenty. Dueto the added workload of today'screw, pressure for improvedfacilities for the personnel isgrowing . Most cabins for examplenow have their own toilets andshowers. As a result of smaller

crews and shorter lay days, theimportance of recreational andleisure facilities has grown.

6.2 Safety

In particular safety equipmentdemands focus on the preventionof fire. These demands are stated inthe SOLAS resolution, chapter ll-2"Construction Fire protection,Fire detection and Fire extinction".The chapter consists of thefollowing parts:

Part A GeneralPart B - Fire safety measures for

passenger shipsPart C Fire safety measures for

cargo ships

Flexible support of the engines

Part D Fire safety measuresfor tankers.

6.3 Environment

a. VibrationsVibrations are usuallyaccompanied by sound or noise.Indeed, vibrations and noise oftenhave the same source. On a shipthose sources mostly are thepropellor, the engines and even thewaves at sea. Insulation techniquesand prevention of local resonanceare used to keep the vibrations inthe accommodation within accep-table levels.(ISO-criteria: vibrations of 4-5mm/sec are tolerated. Values largerthen 10 mm/sec are unacceptable.)

OLD ACCESS

EMERGENCY EXIT E.R

\ IR OUT E R

Flexible support of the (main) engine reduces the level of air sound.The flexible placing of the engine has two goals:

- reduction of the dynamic stress on the ship.- reduction of dynamic forces on the engine foundation. Therefore

less sound will be lead through the ship into the accommo-dation. If a hammer hits the foundation, the sound will travelthrough the construction and the sound can be heard in the foreship.If, however, alayer of rubber is placed between the foundation andthe hammer, the sound will be largely absorbed.

E.raruple of an obstrot't o.f'the lttenrutiottal Labctur Orgctnisotion (lI"O)

Ground plan oJ'the accorntttoclcttion on a coastal tade Liner


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2.

Sufficient mess room

accommodation shall beprovided in all ships

In ships of less than 1,000 tonsseparate mess roomaccommodation shall beprovided for -

(a) master and officers;(b) petty officers and other

ratings.

In ships of 1,000 tons and over,separate mess room

accommodation shall beprovided for -

(a) master and officers;(b) deck department petty

officers and other ratings;(c) engine department petty

officers and other ratings;Provided that(i) one of the two mess rooms

for the petty officers and

other ratings may be

allotted to the petty officersand the other to the otherratings;

(ii) a single mess room may beprovided for deck andengine department petty

officers and other ratings incases in which theorganisations of shipownersand I or shipowners and therecognized bona fide tradeunions of seafarers

concerned have expressed apreference for such anagreement.

4. Adequate mess roomaccommodation shall beprovided for the catering

department, either by theprovision of a separate messroom or by giving them the rightto the use of the mess roomsassigned to other groups...

! ' . , t ' r t t t t l t l t ' o f tu t I t t l t , t ' t t t t l i t tn t t l L t l to t t t '

: ] ; ' { , r t t i . : t r t i r t t r r I J - ( ) ) t ' \ ' l t ' t r r . t i , t t t .

, ' ' \ t t r ' t t , : i r t a n l t t t ' t ' r l o r t t t t . s l t i r t t t i n t ) ! u t | \

b. Noise nuisanceToo much noise is disturbing andirritating and therefore has anegative impact on the workingand living conditions on board theship. Noise will affect:- the communication in the engine

room and the communication onthe bridge. (The listening aspectof keeping watch is hindered)

- conversations in the commonspaces.

- the peace in cabins where a lownoise level is required anddisturbance by music etc. fromother spaces is not appreciated.

- condition of persons

(Disturbing) noises come from- propulsion installation, propeller

and auxiliaries- AC- and ventilation systems,

cabin-refrigerators- Crew; music, TV toilets, etc.Noise is expressed in decibels. Thefollowing maximum values applyfor ships:- day rooms, messroom etc.: 65 dB- cabins, sick bay.: 60 dB- galley, control rooms: 75 dB

c. Air conditioningThe air conditioning and climatecontrol requirements of a spacewill depend on the temperature,humidity and number of airchanges considered necessary. Itgoes without saying that a properinsulation of the accommodation isa prerequisite for the realisation ofa sood climate.

d. Lighting and DaylightHigh demands are set for lightingin working and l iv ing spaces.Lighting armatures should be ableto resist the vibrations on a shipand they should be easilyaccessible for maintenance.

( - r t r r i r i r t r

Windows (port-holes) in cabinsand other spaces should have suchdimensions and placing, that one isable to look outside both sittingdown and standing up. There arealso certain requirements for port-holes, like the design pressure andthe positioning on the ship (e.g. notbelow the freeboard deck).

3 .

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\ l t i1t Kttt twledge, u moclem enc'vclopedia 156

6.4 Methods of insulation

Two methods of insulation widelvused are:

a. The placement of rock wool plates.- WallsPlates of rock wool are attached tothe welding studs that have alreadybeen placed on the steel plating.The drawing shows an example offire protection and thermalinsulation. The panels of theaccommodation are free of contactwith the insulation to prevent thetransfer of vibrations. The panelsare attached to, for instance, U-profiles which, in turn, are attachedto the insulating floor.

- FlooringTo minimise disturbing sounds andto reduce the risk of fire, the floors(especially if they are directlyabove the engine room) are built assprung floors. These floors canconsist of multiple layers of steel


F'ire tail tlrcnruil htsulatiott

1. Steel plate (outside of accommo-dation or inside boundary)

2. HP-profile

3. Glass wool4. Welding stud

5. U-profile6. Accommodation panel (a galva-

nised steel plate of 1 mmthickness)

Part of accommoclatiott insuluted bygluss trool ott v,elditry pin.s

1. Weathertight door2. Insulation on welding studs,

covered by wire mesh

3. Moisture-proof aluminium foil

wool with a large density (e.g.baffles) placed on the steel deck,covered by a hard ground slab.

b. Spray insulationThis form of spray insulation issprayed on the bulkhead. Sprayinsulation can be used for thermalinsulation, sound absorption andfire resistance (melting tempe-rature is 750" C).

Applving in,sulation

6.5 Communication

Every cabin has to be equippedwith a telephone and a terminal fora central antenna for radio and TV.For operational and safety reasonsit is necessary that each member ofthe crew can be summoned orwarned at any time and any place.

6.6 Maintenance

Cleaning and maintenance of theaccommodation is a necessity forboth hygiene and appearance. Ingeneral, the arrangement of theaccommodation should be onewhich allows cleaning andmaintenance to be fast andefficient. Things that have to betaken into account are:- preventing dirt transfer from

working to living spaces- proper choice of materials (clean

and easy to maintain)

In the design phase it is importantto:- include enclosed porches where

dirty overalls can be taken off andhands can be washed.

- A locker on every deck in theaccommodation

Ilridge

Prtrt-ltole

Gallel

Spnmg.floor

157

Lockers in the accrnnmodcttion

6.7 Overview of the variousspaces

BridgeThis is where all the means ofcommunication and navigation aresituated. Many ships have a controlpanel on the bridge connected tothe engine room. From this pointaccess to an item such as the ballastsyste which is located in the engineroom can be achieved.

Cargo control roomOn board tankers, loading anddischarging is controlled from thecargo control room.

Galley.The food is prepared here. It issituated near the mess-room tokeep the walking distance as smallas possible.

LaundryA space located centrally with atleast a washing machine and adrier.

HospitalThe arrangement of this space issubject to legal demands. Further-more, it has to be easily accessiblefor a stretcher.

CabinsThese are more and more beingstandardised. For example: thecaptain, chief engineer, chiefofficer and other officers all have acabin of similar size. Besides, thereare maybe one or two other typesof cabins. Nowadays, cabins canbe finished completely at theworking place (prefab). Afterplacing on the ship only terminalsfor electricity, water, ventilation,heating etc have to be installed andconnected.

Mess-roomsDining room

Duty-deckOn large ships, the lowest deck inthe accommodation is a workingdeck where you can find the cargo-office, the captain's office, theboard room, the galley and themess-rooms. Apart from the bridgeevery space above this deck isprivate.

Duty-messIf the food cannot be eaten in themess-room, e.g. because there istoo much work on deck or in theengine room, the duty mess isused.

Day-roomThis is the focal point of socialactivities outside working hours.

Stores- provisions- bonded stores- auxiliaries and tools for the

engine room- paint locker- garbage locker.

Generally it is forbidden todump garbage overboard.Garbage is collected in anordinary trash can or containerwith a press to reduce the spaceof the garbage.

- COz-room- Bathroom and toilets for the

crew. Officers have a privatebathroom and toilet. Lowerranks sometimes have acommon facilitv.


Ship Knowledge, a modem encyclopedia 1s9

1 Pontoon hatch covers

1.1 General

The most common hatch cover nowadays on ships up to 10.000 tons is thepontoon hatch cover. Approximately 80-907o of these vessels use this system.The hatches (maximum weight 25 tons) are opened and closed by a hatchcradle, or a crane on the ship or on the quay. The hatch cradle can also movethe pontoon hatch covers over the ship in the longitudinal direction. Thissystem allows the hatch covers to be stacked on the coaming .

Reasons for buying pontoon hatch covers with a hatch .rudr". ur.'- the system does not require a lot of maintenance- tween decks and grain bulkheads can also be positioned with the hatch

cradle.

1. Pontoon hatch cover

2. Hatch cradle

3. Beam

4. Hatch coaming

5. Toprail

6. Hold

7. Tanktop with opened

L.2 Tlpes of hatches

Hatches can be divided into closinghatches, intermediate hatches and endhatches. If a hold is to be closed, thenthe intermediate hatches must beclosed before the closing hatches, andthe other way around when the holdis opened. Sometimes there is a shorthatch in-between with a width of onemetre or less; this is called a beam.These are not always present ornecessary. The weight of a hatch canbe somewhere between 10 and 25tons.

Why a beam?A beam acts as a small intermediatehatch and has the advantage that onecan easily open just a part of thehatch covering. This is a bie

advantage when it is raining.Sometimes the beam is left in placeduring cargo handling to absorb thestress between the sides of the hatchcoaming.

ktngitudittul drttrtin,q o.f the luLtt'h

drr(rn,gernenl (Vtri lttts orrun gements are

pos,sihle )

1,6,7,132,5,8,10,123,4,9,11

End hatches

Closing hatches

Bottom hatches

Coustul truule liner witlt u purtiuLl.t,openerl lruk'h

Sltip Knowledge, a modern encyclopedia t62

Betun between tv,o c'losirtg htttches

l . Beam

2. Closing hatch

3. Wedges

1.3 Positioning of a hatch

The positioning of pontoon hatchcovers is more difficult than thepositioning of hydraulic foldinghatches. On the port and starboardsides of a pontoon hatch cover twoprofiles called centre punches arewelded. When closing the hatch thecentre punch engages in a recess inthe top rail. The hatch is then lockedon one side while on the other side thecentre punch may have up to 60 mmof free space. As a result the pontoonhatch cover appears to move severalmillimetres over the sliding blocks in

Pontoon hatch covers. Strut,s can beplctc'etl in the U-profiles to.fasten the

der:kbud

1. Pontoon hatch cover

2. Toprail3. Gliding block4. Centre punch

5. Leading block

6. Wave breaker


Multi-purptose ship v,ith pontoon hotclt

c0vers

l. End hatch

2. Closing hatch

3. Beam

4. Intermediate hatch

Immovuble centre, truLtverse direc'tirnt

1. Hatch2. Centre punch

3. Toprail

4. Site for sealing by customs

5. Rubber packing

the transverse direction. This preventsthe hatch from getting stuck if thewidth of the hold changes by a fewmillimetres.

Note: The gliding of the pontoonhatch cover is an apparent movement,not a real one. In reality the toprail ismoving under the hatch.

1..4 Distortions of the ship

During loading and discharging theship can be somewhat distorted. Thisphenomenon is called harbourdeformation. The distortions can beprevented by the placing of one ormore beams or hatches in thetransverse direction. If, in spite ofthis, distortion still occurs, it cancause the hold walls and thereby thetoprail to move several millimetresout of position.

Stainless steel gliding blocks arewelded onto the toprail to guide thegliding of the hatches along thetoprail.

Furthermore, the gliding blocks(5mm thick) prevent the hatch fromsagging through the sealing rubber ifthere is too much weight on the hatch(deckload). Instead, the hatch rests onthe gliding blocks. The sealingrubbers are allowed to be compressedup to 10 mm to prevent excessivewear.

It is not intended that the hatchesabsorb the forces acting on a ship inwaves. This is why there is a movableand an immovable side.

Movable c:entre, Ironsver,te direc'tion

163

aJ .

4.5 .

l. Rubber gasket

2. Impression strip (fore and aftdirection)

Toprail

Pontoon hatch coverImpression strip for thecircumferential seam sealinsHold

C i rc' t t n t.f'e re nt i r.t L,r e a nt,s e ul i n g

1. Closing hatch2. Intermediate hatch3. Compression bar4. Rubber gasket

Cleat opt:rdt(.d ftlnr below

1. Control position

2. Gasket of cleat3. Handle of cleat4. Top rail

5. Pontoon hatch

L.5 Watertightness

The pontoon hatch cover has to sealthe hold watertight. This water-tightness is achieved by:

a. a gasket around the inside of thehatch cover

b. cleats on the outer edge of thepontoon hatch cover

c. wedges

a. To seal the pontoon hatch cover, arubber gasket is put in placewhere the pontoon hatch coverrests on the hatch coaming /headlegde. The gasket issupported by an compression bar.If possible, the gasket has to beswabbed with vaseline once aweek and kept clear of obstacles.In the athwart direction the gasketis in the closing hatch which restson the compression bar of theintermediate hatch.

b. Cleats make sure that the rubbergasket is pressed sufficientlyagainst the compression bar. There

are different types of cleats. Cleatscan be attached on top or belowthe toprail by a control lever.

c. Wedges placed along the fullwidth of the hatch ensure thewatertightness between twopontoon hatch covers.

Watertightness can be checked in twoways:- The hose test. A powerful jet of

water is sprayed against the joints

of the pontoon hatch cover whilesimultaneously the hold ischecked for leakage.

- With the aid of ultrasonicdetection equipment. This iscommonly used by charterers andP & I clubs prior to loading. This iscommonly used when the ship isbeing built or after repairs whenthe bureau of classificationinspects the hatches. A transmittersender of sound waves is placed inthe hold along with a detectionmicrophone on top of the pontoonhatch cover. If the detector doesnot detect anything, the hatch iswatertight. This test and the hosetest are only random indications.

1.6 Hatch cradle

Ships that are equipped with pontoonhatch covers generally also have ahatch cradle to open and close theholds. Ships with a carrying capacityof more than 10000 tons (especiallycontainer ships) need a crane (onboard or ashore) to open and close thehatches.

The lifting and lowering of thehatches by the hatch cradle is doneby:- hydraulic cylinders (up to 14 tons)- steel cables operated by winches

on the loading platform of thehatch cradle (up to 21 tons)

Hatch cradles are usually equippedwith two storage cranes. These cranesare capable of:- loading and discharging

provisions and engine parts- lifting of materials in and out of

the hold- carrying materials over the entire

length of the ship.

6.


1 .

2.3 .

Electromotor with hvdraulic

pump

Control box

Winches with steel cables for

pontoon lifting

Fixed brirlge of rlrc Itatclt crudle

4. Storage crane

5. Control bob storage crane

6. Movable bridge

7. Columns

8. Wheel with hydromotor. Two of

the four wheels are equipped with

brakes.

9. Reel for the feeder cable

r

Iitp t,iev, o.f'the hotclt c:rudle, tlrc .fi.ued bridge


Top o.f the hutch cr(rne

t65

This crane can rotate 360o, but cannot be topped or lowered.With the cradle one can also operatethe working tray for work in the holdlike:

- operating grain or separationbulkheads

- operating the supports for thetweendecks

board

The height of the working tray in thehold can be controlled by the personoperating it. The steel cables thatcontrol the movable bridge can bedisconnected and attached to abulkhead. These bulkheads can then


be positioned anywhere in the hold bythe hatch cradle. The bulkheads canthen be used as tween decks orseparation bulkheads.

Moving, 0 pontlz,t hatc'h v,ith rt

c'otttttitrcr crlne

Safety on the hatch cradle:

- an optical signal with a bell ifmoving

- emergency stops on the hatchcradle:

- on the loading platform- the bottom side near the

gangway (BB and SB)- speed brakes in the hydraulic

system will immediately comeinto action in case of a hvdraulicleak.

1.7 Side-rolling hatch covers

Hatch covers on large bulk carriersopen and close in transversedirection. On large vessels especially,the hatch coamings have to withstanddistortions of the ship as a result ofthe varying types of cargo, and thestate of the sea. The hatches areopened and closed with chains orcogwheels. These are driven by(hydraulic ) pumps located near thehatches. The individual hatchcovershave to be secured to the coamings bymeans of bolts etc.

Bulk carrier Ever7, hotch ro be t'losed

u'ith one httrch clver

;_ _ _ l

Thi,s

tlrc lt

uriLi,s

166

2 Hydraulic folding hatches

Folding hatches are opened andclosed by means of hydrauliccylinders. The location of thecylinder depends on its type.

Folrling hatch v,ith qlinders on tlte

r t ttt,vitle

a. Cylinders attached to the outsideof the hatch use the head ledgeas a fixed point. This type is onlypossible if it leaves enoughwalking space in the gangway(minimum of 60 cm).

b. Cylinders which are supported bythe beam. The pistons that pushthe hatch up or down are locatedat the main hinges.

Advantages of hydraulic foldinghatches are:- faster opening and closing (time =

money)- the hatches can cover the holds

over the entire length of the ship(there is no hatch cradle blockingtheir way)

ry

- easier to control, especially in badweather

- more hatch area per hatch; thismeans that there are fewertransverse seams and thereforefewer rubber seals (e.g. instead of10 pontoon hatch covers, only 8folding hatches are required).

Disadvantages of folding hatches are:- the high cost of acquisition- the vulnerability of the hydraulic

system

Safety devices:- Ruptured hose safety system. This

prevents the hydraulic systemfrom emptying.

- If the control button is released(dead man's brake), the systemwill stop. For example, if thecontrol button is on starboard adead man's break should beinstalled on port side. Emergencybreaks can also be installed.

- A safety hook. This prevents theopened hatches from slammingshut.

Partiullv onened hutclt

Cros.i-sec'tion of the .fokling hutclt

1. Hatch2. Cylinder

3. Stopper

4. Wheel

5. Ramp

6. Safety hook7. Main hinges

8. Hinges between two parts of the

hatch (hatch hinges)

sltip tt'itlt opened (lt,vdrauLic') folding ltatche,s. The ship i.r being loaded with titnbet' part'els


3 Tlveen deck hatches

Tween decks come in the followineversions:- pontoon hatch- folding hatch

3.1 Pontoon hatch

Pontoon hatches are mostly found onmulti-purpose ships where theirfunction is twofold (see also chapter8.1). Pontoon hatch covers can beplaced both horizontally (tween deck)and vertically (grain or separationbulkheads). The positioning of thepontoons is done with the meansavailable on the ship, like a hatchcradle or a crane. If the pontoons arenot in use, they are stored in the store-posrtron.

3.2 Folding hatch

Tween-deck folding hatches arecommon on ships that need multipletween decks above one another suchas reefers. In the case when there arethree tween-decks, there is usuallyone tween-deck in which the foldinghatch has thermal insulation. Thefolding hatches in tween-decks aremainly operated mechanically. Thecargo runner of the crane is used toopen the hatches.

'[tr c c t t d e c li.s v i r h .l? t I d i t t.q lt u I r: I t c.s r t r t u

rccf c t:

4 Entrances

4.1 Side doors

Side doors are found on ships with alarge freeboard, like passenger liners.These vessels use this door to embarkand disembark the passengers. Largerside doors (ramps) are used to loadand discharge vehicles. Generally,these doors are controlled hydrau-lically (see also chapter 10). A sidedoor locally weakens the strength of aship. This has to be compensated forby a thicker skin plating and heavierconstruction parts.

t\tt t.tltcncd ,side door, t'qttiltltctl v'itlt

Itvrlruulic (\l indcrs .l '(tr opcttirtg unrl

t ' l t t5 i71g. Al t t t ,v l ton ' r t i t t the pl to l ( ) ( l

lif'ebutt.1' trncl lltc pilot lutldct'.

4.2 Companion hatches

Companion hatches come in manyshapes and sizes. Some types arediscussed below. Storage compart-ments often need a wide entrancebecause the stored parts can be quitelarge, like engine parts, lashing gearetc. The companion hatches can beopened manually or with the aid of acrane, a hatch cradle or a hydraulicsystem.

Companion hatches on oil tanks canbe sealed from open air with a lid thatmakes the hatch impermeable to oiland gas. The lid itself is closed with

1.

2.

. \ t t t t I t t t t t . s I t ' t t t t t l t I c | < , I t r l i . t< ' fu t rga d l t t t I d

Pontoon and bulkheads in

storagePontoon hatch covers

II o ri :.rtttu I b p I u <' etl p()t1 to( )tt,\ (.t,\

lx,acttdcck

i\ .slritrt',s' ('r(rne opctls u.t'ltlding hulclr


clamps. Just above the lid is a screw-thread on a wheel that is used to liftthe lid and subsequently turn it awayfrom the expansion trunk.The expansion trunk sometimescontains a smaller hatch that is usedto take samples, determine the ullageand the temperature of the cargo.

t\ rotating xutk-licl on ut exponsirnt

trunk

4

Cro,ys sectiott ttncl top vievs, o.f an

expcrnsictrt tnmk yvitlt lid

5 Miscellaneous

5.1 Accommodation doors

Outside doorsOutside doors are weather tight. Thismeans that, if the door is closed, itwill only leak when submerged inwater. The outside doors should beable to open and close with a singlebar. The difference in the outsidedoors shown below is the number ofclosing points. This determines howwatertight the doors are.

\tpes ,f out,side doors that c.an be

opetrcd with ju,rt otrc bur

Outside door

Inside doorsThese doors are behind the weathertight doors. The bureau ofclassification can demand that thereis a fireproof zone in theaccommodation. This can then beachieved by using metal fireproofinside doors.

5.2 Watertight doors

These are used in watertightbulkheads, for instance in the engine-room bulkhead. Watertight doors canbe controlled at the actual location ofthe door as well as on the bridge. Thecontrol panel on the bridge indicatesif a watertight door is opened orclosed.

A vt'atertight door

The doors are operated hydraulically.Even if the whole room is filled withwater, the watertight doors should notleak.

5.3 Ventilation grills (louvres)

All the vents of the holds, the engineroom and the accommodation areshielded by ventilation grills. Thesecan be closed water-and airtight by acover in case of bad weather or fire-

Ventilcrtion {!rill with coyer

Ventilatbn grill fitr the tu.:cotnnrcsdationOy'e n, iew oJ' the v'ttte rti ght dort rs

can be controlled Jntnt the bridge

Ship Knowledge, a modern encyclopedia r69

5.4 Manhole covers

Manhole covers cover the accessopenings that are part of every tank,except for the cargo tanks. Manholesmake it possible to inspect a tank.

iq: f. . i io:q

Cross-section and top vievv rsJ'u mortlrcle

c0ver

5.5 Vent locking devices

Thnk bleedersEvery fluid-containing tank musthave a means of venting in order toprevent over-and underpressureduring emptying or filling. For thispurpose, every tank has a ventingpipe. This pipe ends on the freeboarddeck in a tank bleeder that ensuresthat no seawater gets into the tank.In case of submersion of the tank

Some types of venting pipes

bleeder, the ball present inside thetank bleeder will float upwards until itis pressed against a rubber ring. Thismechanism seals the pipe from theseawater. Tank bleeders can beimplemented with:- an overflow, capable of guiding

the contents of the tank to anotherlocation

- an ullage opening where thedepth of the liquid in the tank maybe measured.

- a flameproof mesh (only in oil tanks)

Draw,ing of the inside of a vent

1. Plastic ball

2. Rubber gasket

3. Vent opening

4. Air and water release pipe

Ruised tttnk verfis

Mushroom shaped ventsMushroom shaped vents are onlyused for the venting and ventilation ofthe accommodation. They have to beclosed in case of fire or bad weather.There are two ways of closing them,either manually rotating the top partor with a stop valve. They are amechanical back-up when the air-conditioning does not work; undernormal circumstances thev are closed.

Mu,shntom shuped vent with u Innd

wheel

High speed pressure valvesHigh speed pressure valves are tankbleeders with the specialcharacteristic that they let the gasescape only when a certainoverpressure is reached, and notbefore that. The velocity of theescaping gas is so high (with aminimum of 30 m/sec) that it cannever catch fire. The gas rapidlydiffuses into the air and will not flowback to the ship.

Pres.vure / vucuum volve (P.V v,alve)

They will also let air into the tank incase of underpressure, for exampleduring the emptying of the tank. Toensure that no flames can get inside ofthe tank via this route, a fire resistingwire mesh covers the suction of thevalve. The type of high speedpressure valves discussed here is themost widely used type on tankers. Atthe same time it is a safety device.

sror|ltc


i'"1

. ' . ,Tlte urrows depict tlrc potlt o.f the

escQprng g,as

I

The ttrrow,s depit:it tlte patlt o.f the gu,s

l'lov,'ittg irt

All the parts mentioned in this sectionare either galvanised or made fromstainless steel. The classificationsociety determines which type ofmaterial is used.

5.6 Entrances to the ship

Accommodation ladderEvery ship needs means of gettingpeople on board safely. Most vesselshave two accommodation ladders.one on starboard and one on portside,preferably where the ship's side isstraight. In general, the accommo-dation ladder is made of lightweightmetal aluminium that makes it easy tohandle. The staircase of theaccommodation ladder is attached toa rotating platform so that, ifnecessary, it can turn away from theship. On the quay the accommodation


Sicle vieu, of an ac'c'otntttodorion ludder and top vievt, o.f tlte plutfornt

Top platform

StepsBottom platform

Roller

Hand-rail

Rule

Synthetic rope

Steel cables attached to

the winch

GangwayMany. vessels have an aluminiumgangway in addition to an accommo-dation ladder. This is used wheneverthe accomodation ladder cannot beused. The gangway is put into theright position by either a crane or bymanpower.

Pilot ladderThere are strict regulations governingpilot transfer. There are regulationsfor the pilot ladder, the bulwarkladder, the safety means and for theways in which these are arranged.The pilot can refuse using the pilotladder if the position or quality of theladder is not in asreement with theregulations.

ladder rests on a roller, which is at thebottom of the stairs. This rollerensures that the accommodationladder does not jam as a result ofchanges in draught or movements ofthe ship. Lowering and lifting of theaccommodation ladder is done by anelectrically driven winch.Compulsory safety measures:- a safety net hanging under the

gangway.- a life buoy at the gangway with

light

t I d ed uc c' o r rt od ttti on

Gangv'ay 0n u plssenger line r

t7I

liA$l.tOPE$*hout larctr

mln. dlam.Itmm ^^

t? t:QulRED *

IY PILOT

Ahrrye iletddG af ihlp

ltDGr noPesft$n, &nu lOmm

STEPSilurt rs-t rSrhrlt

'drfplrldo

r0cp ffirtbc e rprrdrr

H.lghtrughrdby plbc

This drawing instructs how tlrc. pilot ladder and all the atailkries involved should be positioned in otder.frtr tlrc pilot to safel.v

board the ship. Taken with kind permi,ssion from: "Witherby & Co.LTD" itt London

dE

ACCOtft{OSnON LADDERgtouE nrt irmly egrhlt dtQ'r d&ShouldLdeft

ilexlmum 35'dopG

l-owrrpb6rm hodlontd

| il3H trendnllrprarrl

Ofrcen h cdnG.cc wlth brldSt

PILOf IADDERllurt oacnd etlst 2 mcilrier

rbo*o lo*urplctfom

ladderto rcrGfrmty 'gdnrt

r l '


Ship Knowledge, a modent encyclopedia 173

* f.,

t ) , , t "

1. Onboard loading gear1.1 The opt for own cargo gear

1.2 Overview of ship's cranes

1.3 Statutory demands

2. Revolving cranes

2.1 The position of cranes on the

ship

2.2 Securing the cranes

2.3 Load control

2.4 The ship's stability

2.5 Safeguards

2.6 Drives

2.7 Classification of cranes

3. Conventional type crane3.1 Topping with a steel cable

(runner)

3.2 Topping with hydraulic

cylinders

3.3 The crane cabin

4. The revolving crane of the

low-type4.1 The crane's construction4.2 The advantages and disadvan-

tages of the low-type crane4.3 Bulk crane

5. Automated pallet crane

6. Derricks6.1 Hoisting diagram6.2 Stabilisingpontoons

7. Gantry cranes7.1 Revolving gantry crane7.2 Gantry crane with a trolley

and a fixed jib

7.3 U-gantry with a cable trolleywithout a fixed jib

8. Side-loaders

9. Ramps9.1 Several types of ramps9.2 Quarter ramps

10. Registers and certificates

1. Onboard loading gear

Transhipment is moving cargo into and from a means of conveyance, like aship or a truck. Most cargo is moved with the aid of loading gear. Only verysmall and lightweight cargo is still moved by man-power. The loading gear iseither present on the ship (self-discharger) or at the transfer yard. In the lattercase the quay has a large affay of mobile cranes capable of moving across thelength of the quay. These cranes used to move exclusively on rails, butnowadays an increasing number of cranes are equipped with ordinary wheelswith air-tyres and steering capabilities. This allows the cranes to move freelyacross the entire quay.

A ntolti le Lftrrtc ot1 pnctttit(tt it '- lyra,s

1.1 The opt for own cargo gear

There are many types of cargo gearfor ships and just as many insentivesfor choosing one or the other:

- The charterer (who rents theship) demands it. Why, is not thethe shipping company's concern,but if not in possession of a self-discharging ship, the order goes to acompetitor who does have one!

- The area of navigation demands itbecause the ports in that area lackcranes. This is often the case inAfrica, South-America, Asia and insmall ports and factory sites allover the world.

- In order to transport special cargo.This requires special attention,however is paid better in general.Special cargo is a one-time, large-scale transport like a completefactorv. moved in sections.

Ship's cranes reduce the stability andthe carrying capacity of a ship; theyalso cost money and requireattention. On a general-cargo ship,two cranes, including foundation,represent l07o of the total buildingcosts. Refrigerated vessels often have7 or more (light) cranes on boardwhich may cost as much as 20Vo ofthe total building costs. As acompromise it is possible that a shipis built without cranes, but with thenecessary foundation (strengtheningin several places on the ship) andpiping systems. If cranes are thenrequired, they can be installedwithout radical changes to the shipand without extra loss of time (if thecranes are ordered in advance).

l \ ntttbile (()nf(riner rrune tnt rtt i ls

Ship Knowleclge, a modern encyclopedia 176

type of ship dead weight crane capacity number of cranes

general cargo

feeders

(300 TEU)

feeders

(600 TEU)

containers /

general cargo

bu lk

bu lk

refrigerated

cargo

<3000 dwt

5000 dwt

9000 dwt

10000 dwt

6000 dwt

70000 dwt

10000 dwt

2 5 t

4 0 t

4 0 t

40 to 120 t

25 to30 t

0

7 t o 4 0 t

none or 1 or two

2

2

3

6

none

4 to7

1.2 Overview of shipts cranes

1.3 Statutory demands

The statutory demands for loadinggear, including lifts, ramps, hoistabledecks etc. are laid down in the ILO-convention 152 (International LabourOrganisation). Compliance with theregulations is under the supervision ofthe Shipping Inspectorate and Classi-fication Societies like Llovds andVeritas.

Classification of loading gear can beaccording to:- National law, which states that the

ship checks the gear annually anda class check is done every 5 year.

- International regulations whichstate that the gear has to be checkedevery year by the ClassificationBureau.

Division of tasks.The inspections, certification andresponsibilities are divided asfollows:- All ILO-152 tasks directly related to

cargo handling (cranes, ramps etc.)are the responsibility of theClassification Society.

- All IlO-tasks related to safety,like entrance to the ship, hold orcrane entrances and safety in theholds as well as supervising theClassification Societies are theresponsibility of the ShippingInspectorate.

- All tasks that do not result from theLO- 152 treaty like hoisting gear inthe engine room, store cranes etc.are the responsibility of theshipping company, in compliancewith national law.

CertificatesThe items checked by the Classifi-cation Bureau are noted in theRegister of Ship's Lifting Appliancesand Cargo Handling Gear.

Excerpts from the ILO- 152 treaty:Every seagoing vessel must have aRegister of Ship's Lifting Appliancesand Cargo Handling Gear.The inside cover of this resister muststate :- The rules for the five-yearly

inspections as stated in the ILO-rules and the rules of theClassification Society.

- Rules for the annual inspections- Test certificates must be present for

all parts of the loading gear that canwear through use and ageing, like:- the crane (complete)- the runner/topping lift wire(s)- the blocks and sheaves- the hoisting winch- the crane hook- attachmentsThe certificate must show whichrequirements are met for every part.

- Certificates are marked by a stampwith the signature of the surveyor,the surveyor's number and the dateand place of testing.

- The bottom of the jib must show:- the maximum hoisting capacity- the range that goes with it

(the horizontal distance betweenturning point and vertical runner).These figures must be clearlyvisible from the place where thecargo is hooked on to the cargohook.

Example:SWL 60 t (40 t)/16 m (28 m)SWLmeans Safe Working Load and is60 tons with a range of 16 metres and40 tons with a range of 28 metres.

Itttlit'ction ot''SWL crncl range of'a lrtrge sheoilegs.flocrtirtg crutlte


2. Revolving cranes

The picture below shows a ship withtwo common revolving cranes. Thecrane house is attached with aslewing bearing to a pillar, which ispart of the ship. The slewing bearingis a very large double-turningbearing. An electrical or a hydraulicmotor grabs in the pinion of theturning ring, which is a large ring-shaped cogwheel that rotates thecrane. The crane cannot rotateunrestricted by because of theelectrical lines runnine to and fromthe crane.

The crane cabin is a steel constructionwith windows that give the cranedriver a wide view of the area ofactivity. The wire drum(s), driveengine(s) and the controls andsecurity are all located in the cranehouse. The diameter is 2-3 metres.

The crane jib is hinged to the cranehouse, making lowering and toppingpossible. The crane jib consists of oneor two box beams. The jib is designedin such a way that it has the desiredstrength, while its weight is minimaland its stiffness is maximal. Thedifferent types of revolving cranesthat are discussed below can bedistinguished mainly on the basis ofwhere the jib is attached to the cranehouse.

,,i i' t: :: S il i: l:\:,Feeder with deck (rune,r

l. Foundation2. Slewing bearing3. Crane house4. Jlb

2.1 The position of cranes onthe ship.

Masts and cranes used to be placedexclusively on the center line, butnowadays they are more and moremoving towards the side of the ship.

The following remarks can be madeon this:- Positioning on the centre line of the

ship is best for the ship's stability.The crane driver has a good view ofthe holds, but not of the quay.There is also no preference whichside of the ship should be berthedagainst the quay.

- If all the cranes are positioned onone side of the ship, there is anadverse effect on the position ofthe ship's centre of gravity.Therefore, only large ships, wherethe mass of the cranes is very smallcompared to the ship's total mass,have this kind of arrangement. Forthe crane driver the view of theholds is not so good compared tothe situation where all the cranesare on the centre line, but the viewon the quay is greatly enhanced. Inaddition, the reach of the crane onthe quay is also much improved.

- The change in position of the centreof mass away from the centre lineis prevented when the cranes arepositioned in an alternating fashionon the two sides the ship. But nowsome cranes are not on the side ofthe quay, which is bad for the viewand reach of these cranes. This isnot a disadvantage when the dis-charging is done from ship to ship(for instance with barges).

- If remote controls are used, the viewfrom the crane cabin is of noimportance. The crane driver canposition himself wherever the viewis the best.

t ,a. \. 1r\ . ' a . l . a .<,

Container,fbeder willt revolving deck crene .\'


Deck t'rune

178

The. crane jibs secured in their supports

1. Pillar2. Slewing bearing3. Crane house4. Jib5. Support on neighbouring crane6. Support on bridge house

2.2 Securing the cranes

All crane jibs undergo additionalstress when the ship sails in waves.Therefore all jibs have a boom cradleas support to which they can befastened during the voyage. This canbe done in several ways:- a fixed or moveable support,

somewhere on the deck- a fixed support against the forecastle,

deck erection, the groyne or thepoop deck.

- A neighbouring crane as support ifthe crane jib's length equals thedistance between the two cranes.

- A support against the crane cabin towhich the jib can be fastened whenthe crane is not in use.

2.3 Load, control

a. Slewing velocityRevolving cranes often have a verylong cargo runner to which the load isattached. If the crane revolves, theinitial velocity of the load will besmaller than the velocity of the jib.

This initial velocity then builds up.When the jib has reached its finalposition and stops there, the load willstill have momentum, which sends itpast the position of the jib. The skills

The runner is the hoisting rope;manufacturers of winches oftencall the free hanging part of therunner the hoisting rope and thepart that goes from the winch tothebead of the jib the runner.

of the crane driver make that the loadarrives at its proper location.

An objection to the revolving crane isthat the horizontal momentum of theload makes it difficult to accuratelyposition the load. High loading anddischarging speeds can not beobtained therefore. In many craneswith a large range, the angularvelocity, when revolving, is reducedautomatically. This should be donebecause:- The forces of accelerating and

decelerating increase with thesquare of the range.

- The centrifugal forces, which give

the load the tendency to leave itscircular trajectory, increase as afunption of the crane's range.

- Crane drivers can control the loadup to a maximum angular velocityof 2.5-3 m/s.

b. Lifting capacityThe maximum lifting capacity of adrum winch is, on average, 10-25tons. If the range increases, this forcecauses a greater moment on the crane(tipping moment). For this reason, themaximum load of all cranes dependson the range (inversely proportional).In some cranes, the maximum pullingforce of the winch is automaticallyreduced when the range increases.This prevents that loads are liftedwhen the range is too large.

c. Lifting velocityIn some cranes it is possible to switchthe winch manually from single workto double acting. In double acting, themaximum lifting force is larger andthe lifting velocity smaller (inversely

proportional). Often this happensautomatically; if the winch has to liftheavv loads it will slow down.

1. Support on deckhouse2. Support on the forecastle


Midship deck c'ranes (SWL 40 torts and range 28 metre,v)

r79

2.4 The ship's stability

When working with cargo gear, thestability (GMo) of the ship must bepositive to such an extent, that itremains positive when a load is beinglifted. Modern revolving cranes areallowed to cause a list of no morethan 5 degrees. Too great a list can beprevented or reduced by pumpingballast water or fuel. In many ship'sthis is automated by an anti-heelingsystem that automatically pumpswater from one wing tank to another.

In general, revolving cranes arehardly bothered by trim (the diffe-rence in draught foreward and aft).Most cranes can tolerate a trim of 5degrees, but there are also cranes witha maximum trim of 2 deerees.

One of the reasons for a maximumlist and a maximum trim is that theslewing engine must overcome alarger part of the load's weight (thisincreases with the sine of the crane'sangle with the vertical).

2.5 Safeguards

Some safety measures of revolvingcranes are typical for these types ofcranes, others apply to all crane types.General rules:- A zero voltage device shall be

present. If the power supply isrestored after it has been intemrpted,the crane must not start to operate on itsown. Nowadays the main switchshuts off automatically. Itcan be turned on again when thecrane driver is back in place andresets the controls.

- An overload safety shall bepresent. If any part of the craneexperiences an overload, this part isimmediately shut down. In case ofan electrical crane motor anyoverload should also activate thebrakes. If this does not happen, theload or the jib falls down, and whenthe crane is revolving it will be dif-ficult to stop it.

- Emergency stops shall be present.Red emergency stop buttons shallbe present within reach of the cranedriver and wherever the regulationsrequire them. When pushed, allmovement of the crane is made


impossible. Emergency stops canonly be reset locally.

- A hoist-limit switch shall be pre-sent. This is a limit switch thatdefines the highest position of thehook.

- Empty-drum safeguard. Thehoisting cable shall be wrappedaround the drum at least three timesin order to acquire sufficient liftingcapacity (friction).

- Sometimes an inclination-limitswitch is present. This shuts downthe crane when the angle ofinclination becomes too large.

Specifically for revolving cranes:- A limit switch for the highest and

lowest position of the jib. This isalso the maximum and minimumoutreach limit.

- Turning-limit switch

2.6 Drives

Every crane has at least three engines:one for the runner, one for the toppingof the jib and one for slewing. Theengines can be driven either hydrau-lically or electrically. The hydraulicengines are powered by an electricmotor; the actual forces in the crane,however, are generated by thehydraulic engine.

a. Hydraulic crane drivesThe runner and the slewing bothrequire revolving hydraulic engines;the topping of the jib is done with ahydraulic cylinder. The main slidevalve is controlled with the mainlever via the driver valve. The engineautomatically stops moving in adirection when the crane reaches anextreme position. This is done withthe aid of a limit switch and an end-switch. Of course, movement in theopposite direction is still possible.

The main slide valve often has a veryingenious construction that adapts theforce and velocity of the winchengine to the position of the controllever. The main slide valve also keepsthe brakes off when necessary.Furthermore, if the oil lines of ahydraulic engine are closed, the mainslide valve can absorb the extra load.

b. Electric drivesThe electrical drives of the ship'scranes receive their electricity fromthe ship's switchboard. For thispurpose, the ship's 3-phase current ischanged by an adjustable converterinto either direct current (DC) or analternating current with an adjustablefrequency. The control lever operatesthe converter, which sends current tothe engine and keeps the brakes off.In contrast to the hydraulic engines,the electrical engines can not absorbthe forces of a load if the powersupply is cut off. In case of a stop-command, the brakes are appliedinstantaneously to overcome thisshortcoming. However, as a result ofthis, the brakes of an electric winchengine get worn faster than the brakesof a hydraulic winch motor.

As in hydraulic drives, excessivelifting, slacking, topping and slewingare prevented by a limit-switch. Ofcourse, moving in the oppositedirection is still possible.

2.7 Classification of cranes

Revolving cranes can be dist in-

guished into the following types:

- conventional type- low type- automated pallet crane- revolving gantry crane

r80

8

3. Conventional type crane

The advantage that the conventionalrevolving cranes have over the lowtypes is that during topping andslacking, the load remains at the sameheight. This horizontal level luffing /load travel is achieved by using thehigh position of the pulley block andthe way that the runner reevesthrough. This ensures that it slacksthe same distance as the top of the jib

rises. When lowering, the same thinghappens in reverse.

Conventional cranes can differ in theways that the jib is slacked andtopped:- with a cable (runner)- with (two) hydraulic cylinders

3.1 Topping with a steel cable(runner)

In topping and slacking with a cable,the crane jib is attached to the cranehouse as low as possible, just abovethe turning ring. A larger distancebetween the tip block of the runnerand the fulcrum of the jib means asmaller force in the runner. Further-more, the centre of gravity will belower.

A possible danger in these types ofcranes is that in case of a sudden list,a steep crane jib can smash againstthe crane cabin. This effect isamplified by the forces in the runner(running part). To prevent this, stopsare used, but if there is a load hangingfrom the runner, both the load and thecrane can be damaeed.

The runner can be connected to thetop of the jib, or to a point halfway.

3.2 Topping with hydrauliccylinders

The fulcrum is attached higher to thecrane house if the crane jib is movedvertically by hydraulic cylinders.This is because the cylinders areattached to base of the jib at one endand to the base of the crane house atthe other end. The cylinders arepositioned to be on the sides of thecrane cabin when the jib iscompletely topped. This means that


8T?ryping w'ire to u ltoittt sontewhere on tlrc jilt

Topping w'ire to the top of the jib

although the load can smash againstthe crane cabin, it cannot damage thecylinders.

Some typical numbers that apply tothese cranes are:- maximum lifting capacity of

16-60 tons- maximum reach 22-34 metres

Using hydraulic cylinders for thetopping of the jib has a number ofadvantages over topping with a steelcable:

1. Jib2. Crane house3. Hoisting rope (runner)4.Hanger / topping lift5. Cabin6. Pulley7 . Hanger pulley8. Turning point of the jib

-r!q r - Ae Y!t)

- Slamming of the jib as a result ofwaves is prevented because double-acting hydraulic cylinders canabsorb both pulling and pushingforces.

- Cylinders ire easier to maintainthan cables. The latter have to bereplaced every five years.

- The jib cannot shoot through thetop-position. This allows craneswith hydraulic cylinders to have asmaller range (2 metres) thancranes with runners (3 metres).

In the case of double runners, hookblocks are used instead of hooks.

Hanger crane

I8I

maximum range

minimum range3

Topped crane

with the topping

cylinders

adjacent to the

crane hut

3.3 The crane cabin

The drawing below shows the aran-gement of the crane winch, which isdriven by an electric-hydraulic motor.An electric motor drives the hydrau-lic pump that, in turn, supplies oil tothe hydrautc lifting and revolvingmotors. The oil absorbs the heat thatis generated in this process and it issubsequently cooled in an oil-coolerby an automated ventilator; then it ispumped back to the hydraulic oiltank.

1. Crane cabin2.l-ever for topping and revolving3. Lever for lifting4. Jib5. Hydraulic motor6. Oil tank7. Oil filter8. Oil cooler9. Limit switch10 Drum for topping11. Drum for hoisting12. Pulley block

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Hook block for double runners

Revolving crane with hydraulic topping cylinders

1. Jib2. Crane house3. Hoisting rope4. Topping cylinder5. Crane cabin6. Pulley7. Hoisting winch8. Cargohook9. Hook block with swivel

side view

stowed position

Crane cabin

182

side viewmarilmum range

minimum range 1 10

Revolving crane of the low t.vpe with hydraulic topping cylinelers

4. The revolving crane ofthe low type

In cranes of the conventional type thecrane houses are 8-15 metres abovethe slewing bearing. However, incranes of the low type, this distance isapproximately 5 metres. The cranecabin extends only just above thefulcrum of the forked jib, which fusesinto one box-beam jib further awayfrom the crane. The drum of thehoisting winch, which also serves as apulley, is placed on top of the cranehouse. The lifting capacity of thesecranes can vary between 10 and 150tons, the range between 12 to 35metres.

4.1 The crane's construction

The figures above show one of manyversions of the low type cranes. Apeculiarity of this crane is that thehorizontal position is merely used to"park" the crane in the boom cradle:

the boom rest. When operating, thecrane should remain topped at least15", as indicated by the minimum andmaximum range. All revolving cranesgive the load a certain freedom ofrotation. The runner itself, however,also has the tendency to entwinewhen being loaded or unloaded. Forthis reason, the hook is alwaysconnected to the runner via a swivelbearing, allowing the two parts torotate independently.

When a double cargo runner is used,the hook block must not rotaterelative to the crane jib because thiswill cause the two parts of the runnerto get entangled. An electric-hydrau-lic hook rotator is used to prevent thisand to prevent undesired rotation ofthe load.

Hctok rotator

1. Jib2. Crane house3. Runner4. Topping cylinder5. Crane cabin6. Hoisting winch7. Hook block8. Cam disc9. Outlet air-cooler10. Floodlight11. Fulcrum of the jib

12. Crane foundation13. Hook rotator

A crane of the low type

Somewhere on the crane jib there is acable reel that slacks and hoists thepower cable via a number of guidesheaves, ensuring that it never hangstoo loose or too tight and that itexactly follows the cargo-hook. Thiscable reel is controlled by the cranedriver with the same (right) lever thatthe driver uses to control the hoistingwinch.

4.2 The advantages and disad-Yantages of the low crane

- The jib of a low crane is muchhigher compared to a conventionalcrane where the top of the cranehouse is at the same height. Thisway the crane can still operate,even if there are many containersstacked on top of each other.

- The low crane has a lower weightand a lower centre of gravitycompared to a conventional cranewith the slewing bearing at the sirmeheight. This offers more stabilityand increases the cargo capacity.

- Ifcontainers are stacked at thesame height, the low crane givesthe bridge a better view.

More containers.fit beneath the jib without obscuring the view


I J t r l k t ru t t '

l . Pedestal

2. Slewing bearing

3. Crane house

4. Ilb5. Grab6. Cabin

( ' r r t t t e l t t t t t s < '

1. Drums for wires

2. Hydraulic power pack

3. PLC control cabinet

4. Cabin

5 Automated pallet crane

The automated pallet crane or palletswinger is a special type of revolvingcrane that is mainly used onrefrigerated vessels. The pallet cageis suspended from four runners thatrun through sheaves at the sides ofthe jib. Changing the positions of thesheaves on the jib can alter the reachof the cage. In addition, on the end ofthe jib there is also a regular runnerwith a cargo-hook.

The cage has no freedom of rotationrelative to the j ib. When the j ib

rotates, the cage has to follow, hencethe name pallet swinger.

The lifting capacity can vary between8 to 20 tons and the reach between 9to 20 metres. Pallet cranes can besemi-automated. This means that theycan "remember" pre-programmedpositions of loading and discharging,and after the starting-command hasbeen given, they can execute the hoistpath completely automatically.

, \ ' l r ip wi t l r l t t t I l ; t t ' t r t r t ' ,s

4.3 Bulk crane

The bulk crane is aloading grabs andbulk carriers.

unit designed forloss on standard

l i c t I ' t ' t ' t r i t I t 1 t r t I I e t - , r t t ' t l t q c i ' t t t I d { ' o t t \ ' ( ' t t I i r t t t t t | ( ' t ' i l | l ( \

Ship Knotvledge, o modern encltclopeditr 184

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6 Derricks

i . s a ( . t ' c l l t t v ' ) 1u l l c t - t ' ugc

It is not uncommon for general cargoships to have revolving cranes with alifting capacity of approximately 150tons. I f these vessels have even

l . Mast2. Jib3. Topping lift and running part of

the hoisting rope4. Hook block5. Cargo-hook

Ship Knowledge, a modern encyclopedict

fi

6. Hook of auxiliary hoist1. Slewing bearing8. Mast foundation / pedestal9. Hatch10. Anti-heeling tanksI 1. Top of the mast

A t larr i t ' l i i t t t l t r tL ' 1t r ; t i t i tur . t

heavier cranes, with a lifting capacityof 150-500 tons, they are calledheavy-lift ships. This type of shipcarries "heavy cargo' and specialloads. Heavy-lift ships usually havesome special features like:- A strengthened tank top. The

tank top is the top side of thedouble bottom, and also the lowestdeck of the hold.

- A powerful anti-heeling system,with a large pump and much largerballast tanks than, for example, aRoRo-vessel.

- One or more stabilising pontoons- Spreaders to which the slings are

attached. The cargo is suspendedfrom the slings.

In revolving cranes, the entire toppingmoment that is working on the craneis transferred to the ship's construc-tion via the slewing bearing. Thissystem, however, is not suitable forvery large forces like the ones onheavy l ift ships. Instead, derricks(mast cranes) are used.

A feature of a derrick is that the craneis built on, around and in a heavy,fixed mast. The crane house isreplaced by a slewing platform towhich the j ib is attached in twoplaces, whilst still being free to rotate.The pulley block and the fixed topblocks are located in the top of themast. The top of the mast is free to

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\ l t t rn ' t ' - l i . f i ,s l t i l t wi t l t r t l te ' r r r t ' l t i t :< ' t ' o, l ' t 'u t 'g() , \ ' t r , \p( 'n( let l . fntnt l t t ' ( ) { ' t ' ( t r tc . \ 'v i th .spt ' r , t t r lcr , ;

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rotate relative to the mast and itrotates together with the jib. Thederricks described here often have nocrane cabin. The crane is remote-controlled by a control panel thateither lies somewhere or is strappedonto the shoulders of an operator. Thecranes depicted here are all drivenelectrically.The hook block is made so heavy thatit slacks itself. This is necessary, butrequires a large weight because therunner is a very thick and thereforetough steel cable that does not slackeasily.

6.1 Hoisting diagram

The capacity of a crane depends onthe range and the maximum load ofall the parts of the crane, together aswell as apart. The right side of thegraph shows the important impact ofthe range. The heeling angle is alsoclearly visible.

\

5.00 10.00 15.00 m.00 25.00 30.00

Radlua lml at moln deck level

Hctistittg diagrum tor a clerrick

6.2 Stabilising pontoons

Stabilising pontoons are employedwhen the heeling tanks fail to reducethe list to an angle of less than 3". Thepontoons are necessary when theGMo may get smaller than 1 metre.They are rigidly attached to the sidesof the ship at a distance of 0,5 metrein such a way that the ship andpontoon essentially become one.

A pontoon consists of four tanks thatcan be filled and emptied indepen-dently. The pontoon increases theGMo of the depicted ship by0.4-0.8 metres. The pontoon cantransfer both downward and upwardforces. After use, the pontoons areemptied and brought back on board.

7 Gantry cranes

Gantry cranes are deck cranes thatcan move, over the cargo, along theship in longitudinal direction. Manydifferent types of cranes can beattached to the gantry. Ships lacking

Multi-purpose ship vvitlt ltatc'h c:rudle

their own cargo gear often use asimple gantry crane as a hatch cradle.Gantry cranes specifically for thehandling of cargo can be distin-guished into three main types:

Gantry cranes with a revolvingcrane on topGantry cranes with a moveablecable trolley with jib.

Gantry cranes with a double portaland cable trolley without a jib.

Gantry cranes are always sensitive totrim; 2" often is the maximum.Cranes that have a cable trolley areeven more sensitive and in this case alist of 2o is the maximum. If there is arevolving crane on top this maximummay be a little bit higher, but it willnever be more than 5".

In general, the four-point suspensionof the hoist gives the gantry crane anexcellent load control. This ensuresthat the load stays in line so that it canbe deposited at the right place.

A disadvantage of gantry cranes istheir massive weight that shifts thecentre of gravity to a higher point.This reduces the stability and thecarrying capacity. An advantage isthat the ship hardly needs anystrengthening; only the guide rails ondeck need a strong foundation.

A characteristic of gantry cranes isthe large reel on the side for thefeeder cable.

11 s 61t,\ - I ift s hi p vt, it h,st a b i li,s i rt g p o nt o otr

i ib angle 930 49'

2751

270

203 r

130

186 r

00

162 rlift capacity 2751

range 5.0 m 18.8 m 25.0 m 27.Om 27.5m


The portal uses train wheels to rideover the guide rails. The travellingpart uses pinions to mesh into thetoothed rack, which is attached to thedeck. Clamps on the sets of wheels fitaround the rails without actuallytouching them in order to prevent thegantry from tipping over.

7.1 Revolving gantry crane

The revolving gantry crane is mostlyused for containers and timber. Therevolving crane cannot be topped. Onthe end of the jib there is a rotatinghead that, when the crane isrevolving, is automatically kept inlongitudinal direction. The fourrunners suspend a fully automatedspreader that can pick up, for instance,containers from stacks or timber.

(iuntrt, crane y'ith trcile.t, und.f'ixcd .lib

The name parallel-swinger comesfrom both the swinging motion of thejib and from the automated parallel-mechanism that prevents the loadfrom rotating. The depicted crane-type is driven electric-hydraulically.

7.2 Gantry crane with atrolley and a fixed jib

Some gantry cranes are equipped withfolding side beams. Then the trolleycan have a fixed jib. The trolleyattached to the portal beams is a cranehouse that travels on rails; there arealso wheels underneath the flanges ofthe rails to prevent tipping over.

The trolley has a fixed arm with fourrunners to which different spreaderscan be attached. This type of gantrycrane is used mainly for containersand timber. The propulsion is eitherelectrical or electric-hydraulic. Simi-lar to the traveling of the portal, withaid of pinions and toothed racks, thetraveling of the trolley is also bypinions and toothed racks.

U-gctrtlr '_t, v'ith trollct) ()n u cottl(t i lrcr-slti lt

7.3 U-gantry with a cable trolleywithout a fixed jib

The forces in a crane are distributedmore equally in gantry cranes withtwo beams and a cable trolley withouta jib than in a gantry crane with afixed or rotating jib; there are moretorsional forces in the latter. Thisallows the structure to be only slightlyheavier than structures with only onebeam. However, the crane cabinshould be placed higher than in theother two types of gantry cranesbecause the load always remainssome distance below it.

Similar to the other types of gantrycranes, this type can best be used formoving containers and parcels oftimber, paper or other bundled cargo.

rct'olv'irtg guntr): crutt(. ,s' i lt ' vicw urul .froti viev:

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Slip Knowledge, a modern encyclopedia

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t87

8 Side loaders

Side-load systems are used for thetranshipment of small cargo units likepallets, rolls of paper and generalcargo. The system comprises of oneor more doors in the side of the ship,and one or more elevators situatedbehind these doors to transport thecargo from the ramp, at quay level, tothe holds or vice versa.

The advantages of this loadingsystem are:- It has hardly any impact on the

ship's stability because it addsalmost no weight. Furthermore, theramp lies low.

- A high transfer capacity. The cargodoes not have to be transportedover unnecessary distances. Thisminimises the waiting period.

- If the route over the quay to theship is covered, loading anddischarging can also be done whenthere is rain or snow.

The disadvantages are:- The doors in the side of the ship

reduce the longitudinal strength.This has to be compensatedelsewhere by applying extra steelstrengthening.

- The elevators reduce the availablecargo volume

- It is unsuitable for heavy loads- There is a maximum size for the

cargo to fit the dimensions ofthe elevators.

Some characteristics of side-loadsystems:- The maximum work load (of the

elevator) is 8-20 tons- The lifting speed of the elevator is

0.33-0.66 m/s (20-40 metres/minute)- The locks of the side doors have to

be checked before departure.

I"ttrl; lilt 1;luccs poper rclls ort the ramp


Slti lt tvith tlrree side-dortrs

rl

Paper rutlls ott tlu: eLevator. Tlrc ('ilrgo is trun,sported b_y tlrc lift to thc tween deck or the

Low'er lnld

-r

t

I

\I

II' , .

l " 1 : t

A lork li./i picks up paper rolls to conre\: them to the lnkls

188

Side cmd top view of an elevator-systenx

l. Opened side door2. Door-lifting mechanism

3. Hydraulic lifting system4. Control room

5. Guide

6. Elevator7. Roller conveyor for tween deck8. Tweendeck

9. Lower deck10. Cargo (paper rolls)11. Ramp with roller conveyor12. Quay13. Maximum quay height14. Wing tank15. Double-bottom tank16. Counterweight

9 Ramps

RoRo-vessels ure ships where thecargo is driven on board via ramps.Loading and discharging can takeplace quickly because all the cargo isdriven on board. An advantage of thisis that the ship is independent fromthe shore facilities.

In general, ramps have sufficientlength to be used both in high and lowtides. Opening and closing is donewith a winch or hydraulic cylinders.There are many safety measures forlocking and sealing the side doors andramps.

The most important types of rampsare:- Straight ramps, extending

straight from the fore, the aft orfrom the side.

- Quarter ramps, having an angleof 45' relative to the centreline.

- Slewing ramps, here the angle canbe varied between +45" and -45"

relative to the centreline.

Driving from the supply deck to theother decks also proceeds via ramps.These can be distinguished into:- fixed ramps- adjustable ramps- car decks that also serve

as ramps

9.1, Several types of ramps

- Straight rampsThe use of straight ramps on a shipmeans that the ship depends on thepresence of an extending quay in theberthing place onto which the rampcan be placed. This requires a longquay and, if loading and dischargingis done via the foreship and theaftship, the full length of the ship hasto fit in the berthing place. However,this is not necessary if the straightramps extend from the side of theship.


- Straight ramp in the fore shipThe bow visor door in the fore shiP

has a very complicated shape becauseit is part of the streamlined profile ofthe ship's bow. The inside of this doorhas a flat edge with a rubber seal tomake the door watertight. This outerdoor or visor absorbs the forces of the

waves. For this reason there are high

demands for fatigue, strength, locks,

seals and safety. The stem shouldhave a compulsory second watertightdoor that is part of the collisionbulkhead. This second door is flat. Asthis door is placed at the collisionbulkhead usually it is not possible to

use this door as a ramp.

7Principle r1f tuto-part ranrlt

1. Outer bow-door

2. Bow-door cylinders

3. Bow-door lock for open position

4. Inner bow-door in collision

bulkhead

5. Two-part ramp

6. Ramp cylinders

7. Deck

8. Quay9. Maximum quay height

- Straight ramp in the aft shipThe aft ship can suffice with just one

watertight door, which, if it is flat, is

used as a ramp. In the picture on theright this is the case. The closed rampprotrudes above the aft ship.The pictures below show ramps thatare not part of a door.

hvo-1tart stern dolr

- Straight ramp in the sideStraight ramps can also be located onthe side and they are comparable to

the straight ramps in the stern and tothe side loaders discussed earlier. The

ship designer tries to make the sideramp in such a manner that, whenclosed, it forms a seamless wholewith the ship's skin. There are alsohigh demands for locking, sealing andsafety measures for these types oframps.

Ship with quarter romp and straight ramp

in the sitle

I

Stern tloor uncl romp combined

Rcunp with.flap


Onened bou,-visor and bow-door

r90

9.2 Quarter ramps

\ quarter ramp makes an angle of.rpproximately 45" with the ship's.L'ntre l ine. This l imits the orien-:.rt ions of the ship in berthing to the.itle where ramp is located. Quarterr';.rnrps can do with less quay lengthrhan straight ramps.

- Fixed inboard rampThe fi-qure on the next two pagesJepicts a ship with a fixed ramp thatlc'ads to the lower hold. This costs\pace because nothing can be storedrunderneath the ramp.

- Hoistable car decks\ hoistable car deck is depicted in thet'igure to the right. These can be usedi.r\ tween decks, allowing two layersof cars to be nansported above each other.

s-5;

When the tweendeck is full, the ramp,complete with cars, is hoisted to thetweendeck position. The lower deckcan be loaded when the ramp hasbeen hoisted.

Slr i l t v i th qu(t r t ( r t 'u tnp

a#-- &L: I

jpw' r . .4- /

: ' .1$l

tl

J

{?"

' r i 1 t t t ' i l l t L lL tu r t c r r t t u t l t i t t t l r v - t l oc l i

Sltip Knowledge, a modent encyclopedia

. J

t9I

Ro Ro vessel:

1. Straight stern ramp/door2. Hoistable ramp3. Shell door4. Fixed ramp with cover5. Door6. Car-deck access ramp7. Hydraulic Power Pack8. Hoistable car decks


@I

Ship Knowledge, a madem encyclopedia 193

10 Registers and certificates

Naneof Ship

IJRNumb6

O6cialNunb€r

PortofRegisFy

Orm6

&tEof Issue

Clasr tlddor of Ulting ApPliance (if applicable)

Suveyor?Signatue -

Uoyd'3 Regbt€rOtrcof Isarc ad StanP .

Lloyd's Register of Shipping

Reglster of Shlp's Uftlng Appllancesand Calgollandling Geal

.tuarGLO-RA?tT." " ?-t?-7t-7-€"

PE.hM.nnsTE4a"nll ...-- -" "

a(-..scttee-y.dacl.e.alffiUEr&4rl**-,sa,eeze&larT

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Front page of the cergo handling gear register

W

PART t THOROUGH S(AMINATiI OFTIF'NNG APFI.IANCES

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A page of the cargo handLing gear register


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lrlo. 2 dcct calc rr No.2 cer6o hold rtsDorrd

No3 &cL oc I No3 o6o told elrrbord

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Tffu ctfub h fue ffi funtn,lorn lon es notmunilcil W dp lrrtanlriaforrrtl l,rllnnr Olfreawrbw ooNt ILO Coapa$bt No. 752.

nfU([.AAOUnllrr tLrllLthrC$|?f{, q.lrctofic* n Hrrr6gr!.C tsdcrE'}|{B

Method of te,sting (frqgment)

ftc oglpucnt trrc bcco.rd8ncd ttc ttodqfrLAilo|.doo.

W

Test certificate of elevator system (fragment)


CIRTIFICATB OF TEST AI{D THOROUGHBXI\MINATION OF LIFNNG APPTIAI{CES

]{aCa{PSCHI??IRSGNAG�|T

*rlEt

sMK rerGantrmonr

$rfin!O&.lnEl.r

C.l.trrDCGMlbrrdrlllttADltlldrn

a{a!rolcwu

CV Schccpvurtoodcncntry Shgclgncht

Ilitutitn md d*rlpdm of lilthg qplilu (with di*ingultr!1; nuorbcnor nrrte if uy) wltldt hrvc bccn ud erd tlFsoughly cru*d

2tutlcoothchodzontrl or?.dior.twhkh brrlodrpplicd

,f6tb.dilonF)

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No.2 Qrgo lJftrt Fr.ltXlrtrrboerd

No 3 Clrgo IIft er R. 1l8 rhrtoerd

No I Cer6o IJf, lt lr. 1O2 r$orrd

No 5 Cr4o Llfi rt h. 9 rrerDold

20.0

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20.0

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15.0

16.0

r6io

195

F?'tjr

1. Anchor equipment

1.1 Purpose

The purpose of the anchor gear (orground tackle) is to fix the position ofa ship in shallow water by using theseabed. Reasons for doing this canbe:- The ship has to wait until the berth

becomes vacant- To load or discharge cargo when a

port does not have a berth for theship, either temporarily or perma-nent.

- To help with manoeuvring if theship does not have a bow thruster

and lor no tugboats are available.- In emergency cases to avoid

grounding

1.2 Legal demands on theanchor and mooring gear.

A certificate for the anchor andmooring equipment is only issuedafter all the requirements from theClassification Society are met. Thetable on the opposite page indicatesequipment numbers used to deter-mine the minimum weights and dimen-sions of the anchors, chains, ropesetc. The equipment number can befound on the midship section drawing.

Atu' l t r t t ' t t , i r tch r t r t gerrcrul pt t r l )o. \ ( , s l t i l t v ' i t l t tnr t r t t ' i t tg dt 'unt ur t r l x ' t t r '1 t i t tg, lu:ut l ( l l re

rttunbct's ra.f'ar lo tltc li.st rnt tltt: oltltosilt: pa,qe).

1. Forecastle deck2. Stem

3. Anchor

4. Anchor pocket

5. Hawse pipe

6. Anchor shank

7. Guide roller

8. Chain stopper with

securing

9. Anchor chain

10. Windlass

I l. Control levers for

the brake band

and winch operation(up or down)

12. Spurling pipe

13. Chain locker

l .tutgitudirtal t

tlrc l'rtre' sltip

Ship Knowledge, a modern encyclopedia 1 9 8

1.3 Overview of anchorequipment

1 .2.

3 .4.5 .5.7.8.9.10.l l .12.13 .t4.

15 .

Storage part of the mooring drum

Pulling section of the drum(working part)

Brake band

Gear box

Electro-motor

Spurling pipe

Chain in the gypsy wheel

Dog clutch

Guide roller

Warping head

Hatch to chain locker

Guide roller, guide pulleys

Fairlead

Chain stopper,hawse pipe below

Bollard (double)

Forecastle deck

EOUIPM€NT STC)CKLESSBOWEfTNUMBER ANCHORS (W€I6HT}

1 i T L J D L l N K C F l A l N ( ) A R l . f i S T C ) W I N G L l N b . S i MOORING LINES

OUANTI'TY LFNGTH ME}LEACH

(m) (kN)

coNV. t".rt*P Po()t"ft) TOTAI., ru? ru3ANCHOR ANCFIOR LET.JGTH

(kg) tkS) (n i ) (mm) ( tnm)

55G 600 1740fln, 660 1940660- 720 21007n 7& nffi780- 840 zffi840. 910 zffi910. 980 2850980-1060 3060

1060-1140 3300f&4ao 3640122G1300 378013fi)-1390 405013fi!-r480 4d!201480-1570 4590157G.1670 4890167G1780 5250

440 36 32/140 38 U440 40 36467,5 42 36467.5 M 384,6�7,5 4tt 40495 4ti 42495 50 4495 50 652z-,5 52 465?2,5 * 485n,5 56 50550 58 50550 60 52550 62 54577,5 64 56

130514/,O15751710184519802140m524752655283530403244344536703940

t "ENGTH

(rn)

190190190190190190190an200200200ax)2Wuo220no

MRL

(kN)

340370405w/1805205606006456907447858358go940

1025

4444444444444555

1@ 130160 145160 160170 170170 185170 N170 215r80 m180 250180 270180 285180 305180 325190 g?s190 335190 350

The equipment number can be calculated with the equation:(&' + 2HB + 0.IA), where:

= displacement (weight of the ship) this term gives the influence

of the displacement and the currents on the sli1t.= width and height, this term which determines the influence of Jrontalwinds. (m2)

= the lateral surfuce of the ship (above the water), which deterntines the

influence of side winds. (m2)

L.4 Anchors

Anchors are the final safety recourceof a ship. From the ancient times ofthe first boats, the men using themhad a stone on some sling to keep theboat in position. Later developmentsshow combinations with wood,ending in the stock-anchor with

BH


Pool arrclutr (HHP) Tjtpe HG "Pool N"

tutchor

Hal I anc'lut r ( c'onvetiionul crnc hrt r )

1. Crown / shackle

2. Shank

3. Flukes

4. Crown pin

5. Crown plate

6. Anchor chain with swivel

wooden stock. When propulsion orsteering fails, the seafarer has to relyon his anchoring equipment. It istherefore of utmost importance thatthis equipment is in good condition.A regular check of the condition ofthe anchor itself, the crown, anchorshackle, the chain cable, windlass,brake band and anchor securingiurangements is a master's obligation.In general, ships have two bowanchors and sometimes a sternanchor. There are two bow anchorsfor safety. Under normalcircumstances one anchor is suffi-cient, but under severe weatherconditions or in strong current bothanchors may be needed. Also, if oneanchor fails. the second anchor is aback-up. A ship is not allowed to sailfrom any port when one anchor hasbeen lost. In general the Classifi-cation Bureau may allow departure,under the condition that replacement


is carried out at the earliest oppor-tunity and that the vessel takesadditional tug-assistance leaving andentering port.

The stern anchor is used to preventships (coastal-trade liners forexample) from rotating due to thechanges in a river-current.Anchors can be distinguished as:- conventional types- HHP-anchors (high holding power)- SHHP-anchors (super high holding

power)Common conventional anchor typesare: Spek, Hall, Union, Baldt. Spekanchors have the advantage of beingfully balanced. Accepted HHPanchors are ACl4, Pool and Danforth.CQR and plow-type anchors are onlyused on small craft. Various copies ofaccepted types are made all over theworld. The conventional type is stillused a lot and serves as a standard fornewer types of anchor (see table).Conventional anchors are alwayscast. Newer types can also consist ofplates (or other components) that arewelded together. If the flukes arehollow, they tend to be more resistanttowards bending forces.Some anchors are fully balanced;this means that the centre of gravitylies so low that the anchor alwaysleaves the water with the flukesvertical.

This has the following advantages:- an anchor recess that completely

envelops the anchor can be used.

The total ltolding.t'orce is supplied by tlrc

anc:hor atul (the weiglt ) rt'tlte chaitt

Tlrc dashed lines in the drav;irtg show

tlwt it is not clartgerous d'a ,ship.floats

uv,a:*.fbt' a certain distctnce (a ship',s

Length ) .from the o riginal ttnclto r-

posrtt0n.

- the shell cannot be easily damagedduring heaving when the anchorflukes leave the water verticallv.

The crown plate ensures that theflukes of the anchor penetrate the seafloor. In certain types of anchor, theflukes prevent the anchor fromburying itself too deep in the seabottom. The navy uses a speciallydeveloped HHP-anchor with an opencrown plate (bottom plate). Theadvantage of this type of anchor isthat it digs into the bottom veryrapidly. For dredging and offshorejobs there are special anchors whichhave to be laid down by anchor runboats and are certified as recoverablemooring systems. HHP-anchors areallowed to be 257o hghter in weightbecause their holding force is twice asstrong as that of a conventionalanchor. The SHHP-anchors can be50Vo Iighter in weight, because theirholding force is even larger, namely 4times as large as with a conventionalanchor. However, this type of anchoris not accepted by Class for normal

HHP-anchor +t'itlt rut open crcu,n plate

200

ships and can only be used on yachtsand special craft.

For Offshore and Dredging specialvery high holding power anchors arein use, which have to be laid down inposition by a tugboat, a so-called'anchor run boat', and also have to belifted out by the same boat, using aseparate wire attached to the crown ofthe anchor. These anchors arecertified as Recoverable MooringSystem. An example of such anchoris the Flipper Delta-anchor.

1.5 Anchor chain

The chain runs from the chain locker,through the spurling pipe, via thegypsy wheel of the windlass throughthe hawse pipe, to the anchor. Theanchor chain consists of links withstuds to prevent kinks in the chain.

2 *f

8l mm U3 Chcin Qualin,

The required strength and length ofthe chain can be determined with theaid of the equipment numbers in theprevious table. This table alsodistinguishes two main types ofmaterial-quality, namely U2 and U3.Not included in the table are thequalities Ul, which has becomeobsolete, and U4, which is anoffshore quality.

The anchor chain is composed oflengths (shackles), each with a lengthof 15 fathom (15 x 1,83 = 27.5 m).The shackles are interconnected by akenter shackle.In order to keep track of the outboardchain-length, the paying out andheaving in of the anchor can bemonitored by markings near eachkenter shackle. The markings can bewhite paint and./or wire wound aroundthe studs. The kenter itself is red.

The paid out chain length can also bemonitored electronically, by sensorsthat carefully register how manytimes the gypsy wheel rotates. An

^ ({

"r:f;!(,

1. 3rd length or 'shackle'

2.6th length or 'shackle'

3.7th length or 'shackle'

advantage of this system is that whenthe anchor is hove in. the winchautomatically slows down when theanchor chain is almost completelyinside and stops completely when theanchor is home.

A D-shackle connects the anchor andthe chain. A swivel is usually fixed onthe chain and allows the anchor torotate independently from the chain.The swivel can also be connecteddirectly to the anchor.

Description of the images below:

1. Anchor shank

2. Anchor / link

3. Swivel4. Open link5. Enlarged link6. Kenter shackle

7. Crown shackle

Kenter slnckle

half link

locking pin

stud

l .2.3 .

Stud link c'hctin


Dffirent w,a)-s to connect the anchor to the chain

201

Spek anchor

PooI W anchor

Danforth anchor

Pool N anchor

AC-14 anchor

Ship Knowledge, a modern encyclopedin

Flipper Delta-anchors on a deck of an AHTS

Hall anchor

202

Baldt anchor

I l'tt'r'

i "

* r o f r ICERTTFICATE FOR ANCHOK CFIA.TN CABLEAI{D CHA,IN CABLE FITTINGS

Thiscert i fcnteisisgledtot lr lbooeC|ienttocert i fythattheAnchorChainCahleanrlChainCabIeftt ingsf,detniIedherein,hcoe�� dlh he Rules and Regulations of Lloyd's Register of ShiVpittg. and abo in accordnnce with the schedulcs under tlw UK Anchor and Chabt Cable Rutes 1970 = Statutorv

Instrumm R 7453 (British Flag Ship Only)t

ShouItI tlu Anchor Chsin Cable or ftttin*s tlzwibed abwe be lost or destroved, this cntiftcate is tu be returneil to the Secretary of LloVd's Register of Shipptng,I.ondo4forcrmceIIatitm.IfkeAnihorCIninQbIearfttittgisitnpairedciother.wiseaI|ered,fastodestrtritsidenti|yzdththeceitifcate,thefactsaretofrcpttrte.{ttttheSecretary,oroleolLR'sSuroaprsinordertlnt thcc.eftifcatemaybealEteilaccordingly.

L-R Office

Qingdao

Date

31luly 2{F1(lertificate numtrer

QDO s1s8ffi/7(ilient/ Manuiachrrer

Zib o Anchor Ch ain Facto{i/,Laiwu Steel Group, ttd.

Purclraser

Chongqing Marine & Industries Co., Ltd.

Chain mar'rujachrrer (lt different from above) Order nunrbet on manufacturer

22l,6

:esting

house name and address (if different from atrove) Work's order nunrber

N,f aterial certificate nu mbers

fino8(B

PARfiCULARS OF FINISHED CHAIIf CABLE AND ETTTINGS

Chain grade

U3aNominal Diarneter (mm)

4{t.oTotal length of drain cable (m)

Nil

Length of link (mm)

NiIBreadth of link (mm)

NilMass (tomes)

NiI

Number of enlarged shackles

NilNumber of swirels

NilNumber of lugged joining shackles

End Shackle:15 (Fifteen)Number of lugless joining shackles

Nil

Prcof load applie.d kN/+

8%.0Break lo'ad applied kN/s+

12ffi.O

Approved altemative procedure for bre-ak test applied

Yes n No trBreak test t'r€quency Eaclr (27.5m) f"ngth fl Every four (77.5m1length fJ F:ch batch (fittings) m

Manufacturing process

ForgedHeat hreatrent

Quenched and Tempered

MECHAMCAL PROPERTIES. FINISHED CABLE AND FTTTINGS

CastnumberCable/Fitfng

YieldshengthN,/run2

lensilestrengthN,/mmz

Elong.Red. ofArea

q

lmpact value -Joule Location in

Iernp "C II

-a 3 Average wdd

T2(Fr183 End Shackle 59r 747 ?2 63 o \ffi 779 186 183 baee

CHEMICAL COMPOSITION - AS STATED BY MANUFACTURER

Cast number c% si% Mn% P% S% At% N % Cr% Cu% Nb% Ni% V % Mo%

Tmnl83 o.gz 03L 1.46 o.0m 0.m9 0.043 0.offi 0.07 o.x7 o.m 0.08 0,m 0.m

IDENTIFICATION MARKS

a) LR and Office

LRQDO d=4*g=E€

b) Certificate number

a1f'068ry7-(1-15)c) Proofloadandgrade

Pt8lbKN U3

Signature -Surveyor to lJoyd's *m

Z.s.Lu ror D.e.Liu and !;ti ffir,e" . il,

To be conptred by the Surveyor vertfying tbe equipmeot after Placing onboard Signahrre - Surveyor to lJoyd's Register of Shipphg

Date

3L.072001Date

f delete where not applicable Chain cable placed on board (name of vessel)


1.6 Hawse-pipes and anchorpockets

The hawse pipe is a tube that leadsthe chain to the forecastle deck. Awater-spray in the pipe cleans thechain during heaving of the anchor.

A w'ater-sprq' installatirnr in tlte hav"se pi;te

During heaving, the flukes of theanchor should be parallel to the ship'sshell. A collar protects the part of theship's shell around the hawsepipe. ln

addition to this, the plating is extrathick in this area.

Anchor pockets are sometimes madein the bow into which the anchors canbe completely retracted.

The advantages of the anchor recesses:- the anchors are protected from

direct contact with waves.- a loose anchor cannot bang against

the shell (important on passengerliners)

- damage to the shell by floating icecan be prevented.

- prevention of fatigue damage to theanchor itself

- mooring wires do not get fouled

Cfudtr stzpper w'ith ternioner

Tettsioner

1. fixture 3. chain

2. cable stopper 4. guard

1.7 Chain stopper / cable stopper

The chain stopper absorbs the pull ofthe chain by diverting it to the hull.The chain stopper's holding forceshould be min. 80Vo of tensilebreaking strength of the anchor chain.Furthermore, the hawse pipe's resis-tance absorbs 20Vo and the windlassshould have a holding force of 457oof the minimum break load.

In most types of chain stoppers, thechain runs over a roller, equippedwith a tensioner. The securingconsists of a hook onto which botheyes of a steel wire are attached. Thiswire is put through a link of the chainand tensioned. This securing fixes theanchor in the recess therebypreventing banging of the anchoragainst the shell.

Cable stoppers are to be divided intoanchor securings for when the vesselis at sea. and for when the vessel isriding.at anchor. When the vessel is atsea, the anchor is held by the brakeband, and a securing wire orpreferably a high tensile chain,through the chain cable and attachedto a strong point on the focsle deck.The windlass should not be engaged.

When riding at anchor the chain forceon big ships is held by a transverse,hingeable bar, a strong back,incorporated in the guide roller abovethe hawse pipe secured on top of aflat link of the anchor chain, so that avertical link cannot pass. The chainforces are then transferred to the shipsconstruction. A wire as anchorsecuring at sea is insufficiently strongand vulnerable to chafing especiallywhen not lashed throueh a link of thechain under a stud.

L.8 Winches

Anchor winches or capstans are usedto heave in and pay out the anchorsand anchor chains in a controlledway. The same winch can be used tooperate a mooring drum. A clutch isused to connect / disconnect thegypsy wheel or the mooring drum tothe main shaft. The anchor can behoven if the gypsy wheel is coupledto the main shaft.

SpindI.e chuin stopper

S|titrt tt'ithoul un rutc:ltrtr 1xtt:ket

Anchrtr purtly in pocket


,,\ttchrtr utd mr oring u,int' lt

Cltur,<:ltttt'h rtut nrrcl ut

Winches on tlte fbrccu,stle and on the

quarler deck o.t''a c'ar.lbrr;,

Tlte ntain .vhcli i.s nttating, the u,urping

ettd is tlrc ttnll, pnrt tlrut is ulso rotuting,.

Tlrc glpsy u,ltecl ard both clrurns ttre

discorutt:cted.

l. Bearing2. Sliding claw3. Fixed claw

1. Main shaft

2. Gear box

3. Electric motor

4. Warping drum

5. Drum (storage part)

6. Drum (working part)

7. Gypsy wheel

8. Control lever for the band brake

9. Clutch with control lever

The winches can be powered by:- electricity; an electric motor rotates

a cogwheel. The advantage of usingan electric motor is that the noise islimited. Especially on passengerliners this is important.

- hydraulic systems. The cogwheelsare driven by a hydraulic motor,which is connected to a hydraulicpump system located below thedeck. Advantages of this system arethat there is no risk of (electrical)sparks and furthermore, the systemis gearless.

- electric-hydraulic. The set of pumpsis incorporated in the winch insteadof below deck. This means thatthere is no need for piping systemsfor the hydraulic oil.

- steam.

1.9 Chain locker

The anchor chain enters the chainlocker via the spurling pipes. Chainlockers are high and narrow, makingthem self-trimming. This means thatthe stacked chain can not fall over inbad weather. A grill on the bottom ofthe chain locker makes sure thatwater, rust and mud can fall through.A (manual) bilge pump can drain thewater.

Pipe outside tlte chctitt ktc'ker where tlte

end Iink is conrtected, The w,Jrcel is used

to se(:ure a pitt through tlte end link.


1. Nest sheave

2. Hammer

3. Set pen

4. Bitter-end connection

5. Brake band lever

In emergencies, the chain can bereleased by the bitter-end released

outside the chain locker.

Possible types of chain releasedevices (bitter-end connection):- remove the pin out of the last

link of the chain with a hammer.The pin is located either belowdeck outside the chain locker or ondeck, next to the windlass.

- a weak link in the final joint ensu-res that the chain breaks loose whenthe stress becomes too high. Thebreaking force must be less thanthe maximum holding force of thechain.

- The hand wheel can be usedto release or attach the chain.

2 Mooring gear

2.L Winches

- DrumIf the drum is made of one part, itserves both as head (storage) and asdrawing and pulling drum. Thesetypes of drums are only suitable for

steel wire and certain synthetics. Ifforce is applied to a synthetic hawser,it may not slip through the layers ofrope below. If this does happen, therope gets foul. Sorting the rope outagain takes a lot of time. If the drumconsists of two parts, then the smallpart is the working drum and the

other part is the storage part. The


Anchrsr windloss with mooring gear oml

v,arping head

1. Working part

2. Storage part

3. Warping end

4. Gipsy

tension in a rope (with a maximum oftwo layers) may only be applied onthe working drum.

Suppose that the diameter of the drumis 30 cm, and 5 windings fit next toeach other in two layers, then thepulling drum can pull in 10 metres ofrope.

If the MBL (minimum break load) ofthe ropes is 1007o, then the holdingcapacity of the drum is 807o, and thepulling force is approximately ll3 ofthis. This rule applies to all the drumsmentioned.

- warping drumThe warping drum is used:- to heave in extra ropes, set them up

and then fasten them on thebollards.

- to move the ship alongside the quay

over short distances. If the warpingdrum is used, the gipsy wheels andthe drums must not be coupled tothe main shaft which would engagethe anchor cable.

A rope may never stay on thewarping drum because then theforce exerted by the ship may wellexceed the pulling force of thewarping drum. The warping drumcan absorb equal amounts of pullingforce and brake force; the brakeforce of the drums, however, is threetimes as much as the pulling forcedue to the band brake.

- Self tensioning winchesSelf tensioning winches can be set toa certain holding force. If this value is

exceeded. then the winch automa-

tically adjusts the length of wire to

the new force (too much holdingforce: slacking; too little holdingforce: heaving). This system isfrequently used by ships that load anddischarge quickly (container ships

and RoRo-vessels) or if there is a

large tidal range in the port.

Conftol for" the self tensioning winch

1. Control lever for the winch

2. Cooling fan

3. Control for the self-tension setting

- capstanThe capstan consists of a warpingdrum with a vertical drive shaft that isdriven either electrically, hydrau-lically or electro-hydraulically. Thecapstan is usually placed on the aft-ship and, if the ship is very long, on

the sides. If the capstan is combinedwith a gipsy wheel, it can be used tocontrol the (stern) anchor i.e. avertical anchor windlass.

Windlas,s with cutclnr securing, guide rcller cud ltitter-end connec'tions

206

.Lil

il1

Capstan

2.2 Mooring gear auxiliaries

One or more winches can be placedon the foreship, depending on the sizeof the ship and the preference of theowner. As shown in the picture, thewarping drum, bollard and fairleadare preferably positioned in a straightline.

Hawses, leadways, guide pulleys andbollards.A rope is guided from the shore via apanama chock, through the bulwarkto a bollard or winch. The panamachock must be able to withstand largeforces, because the direction of therope changes inside the panamachock. The panama chock must becurved to prevent wear of the rope.

Roller fairleads can be made ofvertical and horizontal rollers. Theirfunction is the same as the panamachock. However, the roller fairleadscause less wear to the ropes.

Panama chock and roller fairlead

Rollers on deck serve to change thedirection of the ropes. Both the rollerfairleads and the guide pulleys areable to withstand a maximum of 32tons of pulling force depending on theship's size.

Bollards transfer the mooring forcesto the ship's hull. The outsides of thebollards have a nose, which preventsthe frst few windings of the ropefrom slipping upwards. Above orbelow this, there is an eye to whichthe rope stopper can be attached. Thestopper absorbs the forces in the ropetemporarily so that the rope can be

1. Warping head

2. Drum

3. Bollards

4. Eyes to connect the stoppers

5. Guidd roller (fairtead)

6. Centre lead

7. Leadway

8. Head line

9. Forward spring

Bollard

1. Guide roller

2. Nose

3. Stopper eye

taken off the warping drum andplaced on the bollard. The doublebollard is provided with two ridges toprevent the rope from moving. Astopper lug has been fitted as ropestopper.

For the non-moving parts like panamachocks, the allowed force is 1/5 of themaximum static force that this part isable to sustain.

Foredeck of a tanker

Roller fairlead

pcuwmt chock

Ship Knowledge, a m.odem encyclopedia 207

1. Head lines2. Spring

2.3 Emergency towing systemfor tankers

In recent years a number of environ-mental disasters involving tankershas shown how difficult it is to makea connection whith a ship in distress.The IMO demands that tankers with acarrying capacity of more than20,000 tons have an emergencytowing connection foreward and aft.

Rope can be made from either naturalor synthetic fibres. Nowadays, with afew exceptions, most ropes are madefrom synthetic fibres. The syntheticfibres are manufacfured from mineraloil products that have undergone achemical process. The rotation of thethreads is opposite to the sffands,preventing the rope to unlay. Belowsome (of the many) types of ropes arecategorised according to the way theyhave been stranded (plaited).

1. Fibre (filament)2.Tfuead3. Rope yarn4. Strand5. 3-Strand rope

The drawing above shoyvs how a rope

can be composed

Some rope-types have a mantle. Thepurpose of the mantle is to keep thestrands in the core together. This hasthe advantage that the strands in thecore can be arranged in a parallelfashion: this gives the maximumtensile strength. The mantle itselfrarely contributes to the tensilestrength. The threads in the core neednot be resistant to wear as the mantleprovides the wear resistance. There-fore it is important that the wearresistance of the mantle is higher thanthe wear resistance of the core. Amantle keeps the cable round andcompact, which reduces sensitivity towear.

Some core-types that can be presentin core-with-a-mantle-cables :- braided- stranded- parallel strands- parallel threads

The characteristics that are importantwhen using or buying rope:

- MBF. (minimum break force) Thisis the minimum force in kN neededto break the rope.

- Elasticity.- Density. The larger the density, the

heavier the rope. It is important toknow whether the density is smalleror larger than 1.000 t/m3, in otherwords: does the rope sink or float.

- UV-resistance. After several years,sunlight can degrade the rope.

- Wear resistance.

- Construction. The number of

3. Rigging

3.1. Cables and ropes

GeneralCables on ships are used:

a. to moor the ship and maintain itsposition and for towing.

b. for the cargo gearc. in fishing and dredging

The cables mentioned in a. areusually made of rope and calledhawsers or lines. The cables used inb. and c. generally are steel cables.The latter are described in more detailin the section "description ofcommon cables".


- Parullel.fibre cctre with mantle

4.r2-strand braided

- 3-strcutd

Buoy of an emergenc)'- towing system

Braided

208

GRIPOTENE. fiI OCTOPLY - 1 0 0

S o ô " "

J a n

o 7 0

r.- Anc ' "- - 5 C

?a

r 0

0

TCLL values/A q t ren r l n l a i l p r i l

polypropylene 52%pofyamide 55"/"steel (laid) 607"polyester 70"i"aramid 70"/"Dyneema > 1009i,

A o f t r c ra l end 9 t l es !de le (m tne res ,dua l s t r ene lh

B end ol Dyneema leslrngresduai Slrenglh I 30".

- non-conductiveThis ,qraplt .sluttr,,s the TCLL-t,trLtLes.for a _ small backlasht t tt tn b e r oJ' rt ryt e -t.t, gt e,s

sinks whereas HMPE floats. High-grade cables are relatively newproducts and strengthwise they arecomparable to steel cable of the samediameter. However, the price is 5-10times as high as of steel cables.

Advantages over steel cables are:

- light-weight- easy to manage

b. PolyamidePolyamide is better known as nylon.Polyamide ropes sink (density1.000 t/m3) and absorb water afterbeing a few days in contact withwater. The absorption of water adds4Vo to the rope's weight. This canreduce the MBF by l}Vo. Polyamideshave a large elasticity. A consequenceof this is the backlash when parting.The rope sweeps over the deck andendangers the people present there.Certain types of polyamides can bespliced and re-used after the rope hassnapped. However, especially cheapropes are disposed of when they snap,and a new rope is ordered.

c. PolyesterPolyesters are very resistant to wearand very durable, both in wet and dryconditions. In mechanical charac-teristics polyester resembles nylon,except that it is more resistant towear. Furthermore, polyester is moreexpensive. The density of nylon(1.14) is lower than of polyester(1.38) and the energy absorbing

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strands and the way that the rope isplaited, the presence of a mantle.

- Water-absorption, expressed as aweight percentage of the rope.

- Backlash or snapback. This indicatesif, in case of breaking, the rope falls"dead" on the deck, or snaps back.Rubber has a large backlash.

- Creep limit. This is the lengtheningof the cable in time under constanttension

- Chemical durability. This indicateshow well the rope can resist (theaction of) chemicals.

- A knot or splice in a cable canreduce the strength by as much as50%o.

- TCLL-value (thousand cycle loadlevel). This is the cyclic load level asa percentage and as an absolutevalue of the maximum load underwet conditions. This is the load atwhich a cable will break when it hasundergone the load a 1000 times.For example, if the TCLL-value of a100 tonf. cable is 50Va, or 50 tonf,then the cable will break if subjectedto a 50 tonf load a 1000 times

3.2 Description of common cables

a. High-grade cablesb. Polyamidec. Polyesterd. Polyolefinese. Natural ropef. Steel cables

a. High-grade cablesAramide and High ModulePolyEthylene (HMPE) are high-gradecables. Kevlar, Twaron and Technoraare aramide brand names andDyneema and Spectra are HMPE-brands. The difference between thetwo types is that the aramide has alower (thus better) creep, but aramide

Tttwi t t .q v ' i t 'c wi t l t u st rL ' rL ' l t ( , r


capacity of nylon is higher, making itmore suitable to absorb large forcevariations. For this reason, nylon isoften used as a stretcher, to protectsteel cables from large shock loads.

d. PolyolefinesThere are two types of polyolefinerope, namely high perfonnance ropesand standard ropes. The differencebetween these two lies not just in theMBF, but also in the qualities likeUV-sensitivity and wear resistance,which increase the durability of therope. High performance ropes canalso be found with a mantle. Poly-propylene, polyethylene and mixturesof these compounds are polyolefines.Many high perfornance ropes like theTipo-eight are also polyolefines.

Polyprop is a polyolefine-rope that isoften used. Its advantages are:- it floats- it is relatively cheap

The disadvantages are:- not very resistant to wear- low TCLL-value- short lifespan

An ey'g i.s .spliced irio a rope

e. Natural ropeNatural fibre rope has been replacedon most ships by synthetic ropes. Ingeneral, the only type of natural ropestill in use on ships is manilla rope.Manilla rope is manufactured fromthe abaca fibre that is present in theleaf stalks of the manilla plant.


Although the resistance to chemicalsand UV-light is good, the MBF isabout 2-8 times smaller than the MBFof synthetic ropes. Manilla on ships isused for the pilot ladder, boat ropes oflifeboats and helicopter-nets. Thereason for this is:

- manilla is less sensitive to fire andburns slower

- manilla is rough and hairy, thereforeit does not slip easily, especiallywhen wet.

f. Steel wire ropesSteel cables or wire ropes haveadvantages and disadvantages. Theyare strong, cheap, have little elonga-tion under tension, have a high wearresistance, but they are heavy, andthey rust.

They are used where the circum-stances allow or demand it. forinstance for hoisting and luffing wiresin cranes, mooring wires for tankersand bulkcarriers, anchor wires indredging and offshore, towing wiresfor fishing and tugboats. In case offire they are not immediatelydestroyed.

Steel wires are available in numerousconstructions, depending on therequirements. There are basically twosteel tensile strength grades: 1770N/mm2 and 1960 N/mm2. Cables aremade of a number of strands, turnedin a long spiral around a core. Thestrands consist of a number ofusually galvanised wires.

For flexible wire, the core is rope, andwhen flexibility is not necessary, thecore is steel. A steel core makes astronger wire. Rope core when oiled,lubricates the wire. but allows defor-mation under stress and bending.Steel wires need maintenance.Regularly greasing is essential.

triAl{rllA il 3-STRAND

The strength is optimal whendifferent sizes of wires are used in thestrands. so that the section isoptimally filled with steel. Likeordinary rope, there are right handand left hand laid cables. Analogue tosynthetic rope, the direction ofrotation of strands and wires is mostlyopposite, called'ordinary lay'. Otherconstructions and ways of lay areCross Lay, Lang's Lay, Non-Rotating,etc. Each luy is used for specificpurpose. During the fabricationprocess the wires in the strands can bepre-formed into the helical formwhich they get in the finished state, toreduce internal stresses in the rope.That prevents unspinning, and abroken wire does not stick out.

The construction of steel wire is given

in a formula.For example: Galvanised, Diam.36 mm. 6 x 36 ws + iwrc. It means36 mm diameter, 6 strands with each36 galvanised wires, warrington seal(ws), and an independent wire ropecore (irwc). Warrington seal is ameans of constructing a wire ropefrom wires with different diameter, sothat water ingress is limited.

Steel wire is mostly galvanised, butuntreated steel wires also exist, andfor special purposes stainless steel isused.

tauattlatt

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210

6X36WS + IWRC 1960 N/frtlMz

. galvanised

. 1 9 6 o N / m m '

. regular lay

. right hand' yes. lang lay. ungalvanised'dry. left hand lay

' i ' l ')

"$i','r i,ii1,

NominalDiameter

(mm)

8

9l_ot t1 2

NominalDiameter

(mm)

8

1 0

L 2

1"4

NominalDiameter

(mm)

8

10

t 2

t 4

NominalDiameter

(mm)

8101,2t4

MBF(kN)

4 4 , 75 1 , O6 9 , B9 4 , 4

1OO, O

MBF(kN)

3 7 1 6

5 8 r 78 4 , 6

tL5

QUALTWTENSITE STRENGTH

WPE OF LAYDIRECTION OF tAYGREASINGON REOUEST

TOTAT NUMBER OF STRANDS . 13TOTAL NUMBER OF WIRES - 265TYPE OF CORE . IWRCNUMBER OF OUTER WIRES .8a,

NUMBER OF OUTER STRANDS . 6

\ : t ir t (l(t r(l w i r( ntJ'tt ' tt ' i l lt,stt:t: l (o r(,,qen( t 'o l pu rpo.st: u.st,

QUALITYTENSILE STRENGTHTOTAL NUMBER OF STRANDSTOTAL NUMBER OF WIRESTYPE OF CORENUMBER OF OUTER WIRESNUMBER OF OUTER STRANDS

. galvanised, 1770 N/mm'' 7. 133.WSC' 3 6. 6

WPE OF tAYDIRECTION OF tAYGREASINGON REOUEST

. regular lay

. r ight hand lay

. n O

. ungalvanisedo greased. left hand lay

6X19 + FC

Ltt t t l t t t ' t l t i r t ro1te, ntr t i r t l t t t ,s t ,d i t t .s t t tu l l d i tut tc lc t ' ,s ot t x ' i t tc l tc .s

QUALITYTENSILE STRENGTHTOTAL NUMBER OF STRANDSTOTAL NUMBER OF WIRESTYPE OF CORENUMBER OF OUTER WIRESNUMBER OF OUTER STRANDS

\.\ it't ' tt4tc v;illt f ibrc crtrt'

. galvanised, 1770. N/mm'. 6

. 114

. f ibre' 7 2

. 6

TYPE OF LAYDIRECTION OF LAYGREASINGON REOUEST

. regular lay

. r ight hand lay

. n O

. ungalvanised

. greased

. left hand lay

19X7

MBF(kN)

3 4 , g5 4 , 47 B ' 3

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QUALITYTENSILE STRENGTH

. ga l van ised

. t96o N /mm'

. regu lar lay

. r ight hand lay' yes. lang lay. ungalvan ised' d r y. left hand lay

MBF(kN)

4 1 , 16 4 , 39 2 , 6

1 , 2 6

TYPE OF LAYDIRECTION OF LAYGREASINGoN REQUEST

TOTAL NUMBER OF STRANDS . t9TOTAT NUMBER OF WIRES . 133TYPE OF CORE . WSC

NUMBER OF OUTER WIRES , 72NUMBER OF OUTER STRANDS . tz. ' r , ! r t l i r tr t t t ' , t i , : l r t t t l t t ' i x,, t r ,s t ' r l r t .s h o i ,s t i t t ,q n t l tc

Slip Krtowledge, a ntodem encl'clopedia

7X19

211

3.3 Load testing equipment.

All equipment intended to be used in

lifting gear needs to be certified.

Regulations for lifting equipment and

testing are internationally harmo-

nized. This means that materialqualities are checked, workmanship isjudged and that a load test has to be

carried out under the supervision of a

regulating body. For ships this is

normally the Classification Bureau.

All the items in hoisting gear must be

covered by a certificate, stating an

identification and a test. The load test

is carried out to guarantee a SafeWorking Load (SWL) or the Working

Load Limit $fLL). A crane as a

complete unit is tested by lifting a

weight, and carrying out the normal

movements like hoisting, lowering,

slewing and topping. When the power

to the crane is intemrpted, the brake

has to hold the load. The weight for

testing is heavier than the WLL. For

the smallest cranes this means 25 Vo

overweight, for the biggest cranes

it is 5 tons more than the WLL.

Individual small items belonging tothe crane, such as the hook, shackles,etc. are normally tested at twice theWLL.

ksting lifeboat dcryits using w,ater bags

Test weights can be steel weights with

a known mass; the modern variant isa water bag, which can be filled withwater till the required mass isreached. A certified load cell indicates

the weight. Water bags are available

up to 35 tons.

Testirtg the crcute using w,ater bags


3.4 Various parts

Various parts explained on these pages:- End connections- Shackles- Turnbuckles or Bottle screws- Thimbles- Sockets.

A Talurit clamp, is an aluminiumbush, which is pressed under highpressure at the position wherenormally a splice would be, replacingthe time-consuming splicing. Thepressing makes the original ovalshaped bush into a cylindrical clamp,with the strength of the replacedsplice. A talurit clamp is not to beused in bending situations.

- end connectionsEnd connections are needed to be ableto connect a wire to something else.Often shackles are used for theconnection.

Sufett, ltook

1. Brand or type marking

2. Chain size (chain 718 of an inch)

3. Class, grade 8 (high-grade steel)

4. Safety pin

5. Spring

- ShacklesShackles can be divided into bowshackles and D-shackles. These canboth come with or without a lockingpin. Their general purpose is toconnect certain parts to each other orto the ship. The Safe Working Load

(SWL) can vary from 0.5 ton up toover 1000 tons.

- TlrrnbucklesTurnbuckles are used to connect andtension steel wire or lashing bars. Thebottle screw consists of two screws.one with a left screw thread, and theother with a right screw thread. Theseare connected by a house.

l. House

2.Thread, one left-, one righthanded

3. Gaff4. Eve

- thimblesA thimble is usually made ofgalvanised steel. Its function is toprotect the eye of a cable from wearand damage.

ThimbLe

End links

Description of the above image:

1 Gaff socket with rolled

connection2 Cast spelter socket

3 Rolled eye terminal

4 Thimbled talurit eye

5 Spliced eye with thimble

6 Thimbled flamish eye, swaged.

7 Wedge socket (not allowed in

hoisting).

- Safety hookA safety hook is depicted in the figurebelow. It prevents the load fromfalling out of the hook, even if theload is resting. The hook can only beopened by pressing the safety pin.

3. 4.

High tensile steel shackles. 7b obtain

this high streng,th, a.fterforgirtg the

sluckles are subjected to heat treofinent( Qu e nc' he d an d Tempe re d )

1. Bow shackle with safety pin

2. Bow shackle with screw-bolt

3. D-shackle with safety bolt and nut

4. D-shackle with screw-bolt

Ilottle screw to tightett the foremast stult


Cable-laid slings are very heavycables, constructed from steel cableswith varying diameters, to fill theavailable diameter as well as possible.Eyes are spliced at each end. Thebuilt-up rope diameter can go as high

This is the correct vvay of ultplying tlrc yt,ire clunrlls to a c'able (oll U-bolts on the non- as 350 mm. The calculated MBL can

pulLirtg pttrt of'the cabLe) go as high as 4000 tons.

- Steel wire clampsA steel wire clamp can be used toquickly make an eye in a cable. TheU-bolt of the clamps should beattached to the part of the cable that isfree from pulling forces. The boltsshould be attached to the "dead" part,where no pulling forces are acting onthe cable.Steel wire clamps may not be used forlifting purposes, with an exception forguys and keg sockets to make surethat the cable does not slip.

(C'ontpul,utl'1:) v;ire clanrp otr a keg,sot'kef

- SlingsWhen lifting objects, often slings areneeded. A sling is a wire with at eachend an eye spliced or clamped. Theeye can be long or short, all depen-ding on the purpose. When the item tobe lifted has lugs welded on it, a slingwith talurits and shackles can be used.In other cases long eyes are moreversatile. These eyes can be talurit-clamped, but better is a flamish eye,with a swaged clamp. A flamish eyeis a very simple but very strongsplice. From a wire with an evennumber of strands, the strands areturned loose over the double length ofthe eye. Over that length the wire is


split in two sets of strands. Half thenumber of strands are laid in a bendin one direction, the other half intothe other direction, meeting togetherin opposite direction, forming an eye.The strands are turned into each other,forming a wire. Where the ends cometogether a conical steel bush is placedon forehand, which is pressed to-gether, preventing the wire ends fromjumping loose.

The strongest sling is the grommet. Awire is turned around a circular rod.say six times the circumference,forming a cable, wherafter the rod ispulled out, and the wires, acting asstrands, remain, turned around them-selves. The ends are put away insidethe rope. A grommet is very flexibleand very strong. The heaviestgrommets, for offshore lifts, reach acalculated MBL of 7500 tons.Testing is not possible, but the MBLof the individual wires is a knownfigure, found from a breaking test of asample.

Modern slings are fabric. Woven frommodern fibres very light and strongband-type slings are made, with onedisadvantage: they can easily bedamaged by sharp items. Butstrength-weight ratios can beextremely high, when modern fibresas Dyneema, Aramide, or othercarbons are used. Very flexible andsoft slings are made from Dyneemain long straight threads, not laid,inside a canvas tubing. This type ofsling is very friendly to machined orpolished steel objects.

3.5 Forces and stresses

- Some definitionsSafe Working Load (SWL) orWorking Load Limit (WLL) is themaximum acceptable load on an item(shackle, hook, wire, derrick, crane,etc.).

Cable-lttid sLirry Spreatlcr w'itlt hook. SWL 6000 totr.s

214

I

ii

I

1 0 0

90

80

70

50

40

302520

1 0

0

Minimum Breaking Load (MBL) isthe guaranteed minimum load atwhich an item, when tested todestruction as a sample for a largenumber of identical items, will fail.So, on average, most items will fail ata higher load. The load-stretchdiagram below shows that the testedchain actually failed at a higher loadthan the MBL. The diagram alsoshows that proof loading by themanufacturer is done to 2.5 times thesafe working load. For a re-certification test, the proof load willbe 2 times the SWL. Normally usedfigures for the ratio WLL/IVIBL (or

SWLA4BL) are:

F o r c h a i n s : l : 4For steel wires and shackles: I : 5For ropes: | :6

o r l : 7

0 1 0 2 0 3 0 4 0 5 0 6 0o/o stretch

Load/sttztch diagrrun ryf tt grade 8 cltain

- Forces in wiresThe figure on the right shows theforces in a wire when a weight of1000N is lifted. and how the force ina rope or wire increases as a functionof the angle between the components.When that angle exceeds 90" theincrease is excessive. Between 120"and 150" the forces run up to 1950N.The angle is therefore not allowed toexceed 120'. The material used forthe wire does not influence theforces.

=io lv t. , I

IIII

z-

Blocks v,ith rmns ltorn,s o.f'lrcuvy cargo

gcar (100 ron,t SWL)

A nrcdiwn-speed engine lteing ktuded

v,ith ov,rt c(rgo geur

Hcut ' t ' -dul t ' hort ' .s l tucklas reut lv . for t t 's t i t tg,

l ooou


1. Propulsion

2. Engine types

3. Fuel

4. Cooling

5. Lubrication

6. Starting

7. Exhaust gas

8. Combustion air

9. Shafting

10. Electricity

11. Heating

12. Heat exchangers

13. Pumps

14. Safeguarding

15. Firefighting

16. Vibration and noise

17. Fresh water

18. Start up arrangement

19. Valves

20. Bilge-line arrangement

21. The ballast arrangement

22, Fire-fighting arrangement

, .

!t'

.|

1 Propulsion

The ship's propulsion is normally done by propellers. In most cases by onlyone. That propeller is rotated via a shafting system driven by a diesel engine.Again in most cases the propeller is one with a fixed pitch, with a so-calledmonobloc casting. The shafting consists of the propeller shaft or tail shaft andat least one intermediate shaft.

As a consequence of the fixed-pitchpropeller, the main engine is nor-mally a directly reversible dieselengine. A reversing gearbox is onlyfound in combination with smallengines.

More than one propeller systems arefound on fast ships, such as passengerships and ships which are restrictedby draught, or where the total powerneeded is too much for one propeller.

The following is a description of anormal engine room of an averagecargo-ship.

In most ships the engine room isinstalled aft and is compressed to aminimum length, to leave as much

length as possible for cargo, and tomake the ship not longer than neces-sary. However, in the finer built hulls,such as the bigger container-ships theengine room is located more forward,say one third from aft. Modernpassenger-ships and Ro-Ro vesselshave their engine room spread over alarge part of the ship's length, limitedin height, to create a minimum loss ofvertical space where cabins orvehicles can be located.

A ship's engine room is complex,complete, and compact.

An engine room of an average cargo-ship normally contains one mainengine.

F.:4 --

.

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Explanation of these 3D-images:

1 .2 .3 .4.5 .6.t .8 .9.10.

Bottom plating

Side keelsons

FloorsTanktopTop plate engine foundation

Foundation gearbox

Engine

Shafting

GearboxSea inlet box

2 Engine types

Propulsion diesel engines can bedivided into three groups:

1. High-speed four-stroke dieselengines, RPM above 960.

On this page you see an exampleof a high-speed engine.

RPIIG Revolutions per minute-)D -plnto,s ot'engine r00m parts

arger

2. YaIv e protection covers

3. Control panel

4. Protection of fuel pumps

5. Protection of camshaft6. Crankcase cover7. Nameplate

8. Camshaft cover

9. Aircooler


d

sit

r {

9'oo?

a

High-speed V-engine .t'or.ferr1- or Ro-Ro

Medium-.speetl engine. I c.vlindet's in line

219

2. Medium-speed four-stroke dieselengines, RPM ranging 240-960.

On this page you see two examplesof medium-speed engines

M e d i u m- s pe e tl V- en gine.

3. Low-speed engine (crosshead) two-stroke diesel engines, RPM rangebelow 240.

The high-speed and medium-speedengines drive the propeller via areduction gearbox to reduce theRPM. The slow-running engine isdirectly coupled to the propeller.

Lotv-speerl ettgine ,for lorg,e contuiner-

'';lt i 1t '


Medium-speed finr-stroke rliesel engitta, RPM rtutging crrourul 500

220

IJeloyu' : Lovy -,rpeecl ertgine .fo r

huLk carrier rtr ttLnker

Cylinder

Piston

Exhaust valve

Crossheadbearing

5. Crankpin bearing

6. Crankshaft7. Flywheel

8. Crankcase door

9. Crankcase bed10. Exhaust gas

receiver11. Piston rod12. Connecting rod

13. Turning gear

14. Cylinder cover

15. Air receiver

16. Turbo-charger

17. Sump18. Foundation bolt19. Fuel pump

20. Camshaft

2I. A-frame

22. Cooling water(aircooler)

23.Lub. oil l ines24.Tie rod

l .2.3 .4.

Low - spe erl en gine ( c' ro.s s lt e u d ) hto -

stroke diesel engine, RPM runge80 to 120.

The high-speed engines are found inthe smaller ships, such as ships forinland navigation; medium-speedengines in all kinds of midsizevessels, tugboats or where height is arestriction, (e.g. Ro-Ro ships) Theslow-running diesel is commonlyused in all ships over 30,000 tons dwt.


IlI

^ ; , . \. . . .p , I) 4 4

. 6 / ' * , . i i ,

,

l .

2.3 .4.5 .6 .l .8 .9 .10 .

l l .12.1 3 .14 .1 5 .1 6 .n.1 8 .1 9 .

20.2 t .22.^ 1L 3 .

24.25.26.27.28.

29.

Crankshaft with counter

weights

Connecting rod

Stepped piston

Cylinder l iner

Fire ring with jet-cooling

Cylinder head

Individual cylinder j acket

Cylinder crankcase

Crankshaft-bearing cover

Lateral crankshaft-bearin s

bolt

Crankshaft-bearing bolt

Cylinder-head bolt

Camshaft fuel injection

Fuel pump

Fuel injection pipe

Push rod

Camshaft valve control

Rocker arm

Exhaust valve withpropeller

Inlet valve

Starting valveInjection nozzle

Charging-air pipe

Exhaust-gas pipe

Cooling-water pipes

Charging-air coolerExhaust- gas turbochargerAdjusting device for

lnJectlon tlme

Adjusting device for valve

timing

30. Governor actuator

\ . \i..\r-

\i

\ l t ip Knov' ledge, a modem encvclopedict 222

= @ yq a ) c 0o c oA ; e O

iII

\

223Ship Knowledge, a ntodern encyclopedia

3. Fuel

The criterium for the choice betweenthe engine types, apart from the sizeof the ship, the available space andthe required power, is the fuel whichcan be used. Diesel oil (MDO) is best,produces least dirt, but is expensive.The so-called heavy fuel (HFO) ismuch cheaper, but requires additionalsystems as pre-cleaning and heating.It produces sludge and dirtier exhaustgases. It contains more sulphur thandiesel. This heavy fuel can only beused in medium-speed and slow-running engines. High-speed enginesrequire high-quality diesel oil.

The heavy fuel has a higher viscosityand cannot be pressed through injec-tors without treatment. It needsheating to increase viscosity andpurifying to eliminate water and dirtparticles, too big to pass the injectors.Heating is done in fuel heaters,mostly by electric heating. Thecleaning is done in separators, centri-fuges where water and the heavyparticles are separated from the oil.

The fuel is stored on board in tanks,the bunkers. In cargo-ships often inthe double-bottom tanks. Fuel issupplied normally by a bunker boatthrough a hose, straight into the ship'stanks. From this tank it is pumped to

t ' t t< ' I t t t t i t t i I ' o I t l tn t t t I t t r :4< ' ( ' ( ) t t I ( | i t t { ' t ' - \ | t i l )

Ship Knowledge, a modent enctclopeelict

a

&a

E @ &I Booster

pumpa

Supply pumps

I t t L ' l : \ . \ / ( ' / / /

I " t t c l l t t t n t l t s

a smaller tank in the engine room, thesettling tank, a high, vertical tank,where water and heavy dirt sinksdown, and via a high suction the oil ispumped through the separators to theday tank, the clean-oil tank. Thewater and dirt go straight to thesludge tank. From the clean-oil tankthe fuel is pumped by the lowpressure fuel pump to the highpressure (HP) fuel pump whichpumps it to the injector. There is oneHP pump per cylinder. Surplus oil,depending on the demand of theengine, flows back to the day tank.The dirt from the separators goes tothe sludge tank, to be disposed ofashore or by an incinerator.

Diesel oil@ Heavy fuel oil

4. Cooling

All diesel engines produce heat andneed cooling. This can be achieved byair cooling, but more common isliquid (water) cooling. This can bedone directly when the salt coolingwater is pumped in and vra a filter,passes the engine and is again pumpedoverboard. This is used in very smallships only, and also only when theship is always in fresh water.

\1, i r t t , t ' i t t | < ' t I r I t r r

The bigger ships use a closed-circuitcooling system with water containinginhibitors, to protect the diesel engineagainst corrosion. The cooling liquidis then cooled in a heat-exchangeroutside the diesel engine. The coolingmedium is again seawater passing afi lter and a heat-exchanser. and

l ) r r r i l i t t

224

finally pumped overboard. A separateseawater pump is then required. Insmall ships the heat-exchanger canbe installed in a sea-chest which hasnatural circulation for seawater. Thatsaves out another pump.

C o olittg -w ctte r p utrtlt.s

5. Lubrication

Each diesel engine needs lubrication.Normally this is done by pumping oilthrough the bearings and forcedupwards from the crankcase towardsthe cylinder liners. Small engineshave a built-in oil pump, largerengines have an external pump.

Ct, I i n der lubricato r,y

Oil is pumped through a filter into theengine. All the bearings have aseparate outlet. After use the oil dripsdown into the crankcase, from whereit falls into the main-engine sumptank below the engine. From that tankit is pumped via an oil cooler and afilter system to the engine again. Thequality of the filtering is critical forthe engine's service life. The filter


system can be complex. In a smallengine it is only a filter, to be ex-changed every so many hours. In bigships the oil is pumped through avery complicated micro-filter whichhas a built-in self-cleaning systemvia back-flushing. There are twoparallel filters to avoid stopping theengine during filter change. Thelubricating-oil pump is mostly ascrew- or gear-type pump, where theoutput and pressure is constant,

Ct, li nd e r lub ric'ctt i ort

contrary to a centrifugal pump.Lubrication in large engines is muchmore complicated. The lubricatingoil also has a cooling function,particularly for the pistons.

In large engines, with a crosshead,these systems can be divided intocrankcase lubrication, cylinder lubri-cation and cylinder-oil cooling.

To othercylinders

To othercylinders

Crankshaft position

Engine load

6. Starting

Sta rting - a ir re c e ive rs

Small engines are started using anelectrically driven starting motor onbatteries. The larger engines, however,are started using com-pressed air,released in the cylinders, through thestarting air valves on the cylinderheads, in the same sequence as the

combustion sequence. The main airline from air vessel to enginecontains a distributor, a rotating disc,driven by the engine crankshaft, withholes, leading air through to theappropriate cylinder. When theengine is turning, fuel is injected, andthe air injection can be stopped. Thecompressed air is held in compressed

Sta rt i n g - ai r c 0 n'rp re s,s o r s

22s

air vessels, and kept under pressure

and refilled by air compressors. Therequired pressure is approx. 25 bar.

M ain s tartin g -ai r vu lv ct Starting-air bottle,s

7. Exhaust gas

The combustion produces exhaustgas. This is a very hot mix of carbondioxide, nitrogen oxides, unburntoxygen, sulpur dioxide, and carbon(soot). The sulphur oxides areharmful. With water they form acids,corrosive to the steel exhaust pipes,and not environmentally friendly.This of course also counts for carbondioxide, and the nitrogen oxides.Pressure is put on reduction of Noxand Sox.

The heat in the exhaust gas can beused to warm up fuel, and for otherpurposes, such as accommodationheating. In the exhaust-gas pipe a heatexhanger can be built in which wateror another liquid is pumped through.When the liquid is water, and itevaporates, the heat-exchanger iscalled an exhaust-gas boiler. When itdoes not evaporate, the heater iscalled an exhaust-gas economiser.

8. Combustion air

The air needed in the cylinders forcombustion, is normally drawn fromthe engine room. In small ships onlyan opening to atmosphere is suffi-cient, in big ships electrically drivenventilators supply the engine roomwith a large quantity of air, also tokeep the engine-room temperaturesufficiently low. The performance of


The output of the engine is limited bythe temperature of the exhaust gas.When the temperature in the cylinderbecomes too high, damage can occurto outlet valves, cylinders etc. There-fore the air must have a certain over-capacity for cooling purposes

The quantity of air can be boostedfurther by compressing the air beforeit goes into the cylinder. The air canbe compressed by using the velocityof the exhaust-gas. In the exhaust-gasline a turbine is fitted, driving a rotary

the engine can be boosted by supply- compressor. The air rises in tempe-

ing the cylinder with air of a higher rature due to the compression. Bypressure. More air means more fuel cooling this air after compression, thethat can be burnt. And that again pressure rises even more.means more engine output.

Cooling water from the main systemis used for this air cooling, and also tocool the whole unit.

9. Shafting

The shafting arrangement transfersthe torque produced by the engine tothe propeller. In the most common,most simple and most reliablesystems this is a monobloc casting.Controllable pitch propellers are alsoquite common, but more complex,expensive and more vulnerable tofailures. They have, however, theadvantage of the optimal pitch youneed for each speed and a constantRPM, which gives the possibility of amain-engine driven (shaft) generator.

I. E.rlruust-gu,s inlet

2. Exhau,st- gas turbitrc

-1. Air-inlet.filrer

4. Rotary clmpressor

5. Compres.sed air outlel

Muin engine Jl,vv,lteel witlt intermediate

shaft and nnitt lubricttting-oiL puttll,)s,

electric motors

226

Shafiing looking afi

Normally the shafting consists of oneintermediate shaft and the tail shaft.

The intermediate shaft is needed tocreate access when the tailshaft needsto be withdrawn. The intermediateshaft is then to be laid aside. In thesystem are a number of bearings: oneor two bearings on the intermediateshaft, and the bearings in the sternbush. The total number can varydepending on the length of the systemand the weight of the shafts.

The aft-most shaft, the tail shaft, issupported by the stern bearing. It islocated inside the after-peak tank, outof sight. This bearing is part of thestern tube, which is completely filledwith lubricating oil so that the tailshaft rotates in oil.

At the aft side of the stern tube acomplicated sealing system is fitted,to keep seawater outside and the oilinside the stern tube. This seal islocated just forward of the propeller.The outer seal is protected by asurrounding ring, the rope-guard. Atthe forward end of the stern tube,where the shaft leaves the engineroom a similar, but less complicatedseal is fitted, again to retain the oil inthe stern tube and not leaking it into

the engine room. The propeller isfitted on the tail shaft, normally witha press-on fit. The after end of the tailshaft is conical, fitting precisely in theconical hole of the propeller. Some-times it is secured against turning bya key. But this is old-fashioned. Thenormal way nowadays is the so-calledkey-less fitting, where the propellerduring the push-up is pressed by highoil-pressure on the conical surface.

A controllable pitch propeller is fittedwith bolts on a flange at the after endof the tail shaft. Such a shaft has to bewithdrawn outwards, which oftenmakes removal of the ruddernecessary. The shafting of a control-lable pitch propeller (CPP) is muchmore complex, due to the hydraulicfunctions needed by the propeller, andwhich is distributed through hollowshafting.

A fixed-pitch propeller is normally aright-handed propeller. A controllablepitch propeller is left-handed, this tocreate astern properties similar tothose of a fixed-pitch propeller.

10. Electricity

A ship has a considerable powerconsumption. Steering gear, lighting,ventilation, all the pumps, compres-sors, air-conditioning, etc. A dieselgenerator supplies the power.

At least two diesel generators areneeded. When one fails, the other cantake over. To allow proper main-tenance of one diesel generator whenthe ship is in normal operation, andnot to be at risk of insufficientredundancy, a third diesel generator is

l. diesel engine2. generator

normal. All three are identical, andpach is capable of taking the completeelectrical power demand at sea. Theelectricity produced is normally 3-phase current. When more than onegenerator is running the electricoutput can be connected through acircuit breaker to the bus-bars of thethe main switchboard in so-calledparallel mode. A synchroniser-panelis installed in the switchboard, whichonly allows the circuit breaker to beclosed when the generator which is tobe switched on, is in phase with theother already running generator(s).Together they then feed one system.The diesel output power is controlledby a governor on each diesel enginethat regulates the fuel quantity, whilekeeping the RPM constant. Big shipsusually have generators that produce440 volt and 60 Hertz (3-phase).

1. Generator2. Engine3. Gearbox4. Shaft

Various methotls of driving a shcrft generator,


Diesel generator

tlle "pow,er take off' or PTO

227

A shaft-driven generator or PTO-generator (PTO means power-take-

off) is becoming popular, mostly incombination with a controllable pitchpropeller, to answer the requirementof the constant RPM. The mainengine produces the rotating energy,burning cheap heavy fuel instead ofexpensive diesel oil. Parallel runningbetween the diesel generators and theshaft generator is normally onlypossible for a short period i.e. thetime to take over the load.

Turho t^harge:r

To ensure electric power for essentialfunctions (navigation lights, steeringgear, bridge equipment, lighting inengine room and accommodation,etc.) in case of a total electric powerfailure, a so-called black-out, shipsare equipped with an emergencygenerator. This generator feeds theemergency switchboard. It switcheson automatically when this switch-board does no longer receive powerfrom the main switchboard.

Large main engines produce so muchheat in the exhaust gas that steam canbe produced in an exhaust-gas boilerto the extent that a steam-turbinegenerator can supply the necessaryelectricity for at least the normalelectricity demand at sea. A steamturbine then drives the alternatorthrough a reduction gear box. Thissaves a diesel generator and the fuelfor it. Such a system involves acomplicated steam system, of highquality, with the necessary safetydevices, a condenser, circulatingpumps, cooling-water pumps, feedwater and condensate pumps andaccurate water treatment.

Electrical consumers are divided intotwo groups: essential and non-essential. In case of a power failure,the non-essential users are to be


switched off. Essential users such assteering gear, main engine luboil fueland cooling-water pumps, navigationlighting and bridge equipment, aremaintained as long as possible.

11. Heating

The heat produced by the engine isnormally not sufficient for heating theship, and the engine is not alwaysrunning. Most ships therefore have asmall oil-fired boiler, for accom-modation heating and fuel heating.This oil-fired boiler can be combinedwith the exhaust-gas boiler. Ordinarycargo-ships can do with a small

Snrull boilcr

boiler. Tankers generally have bigboilers as they use steam to keep theircargo pumpable by heating, and oftenhave steam-driven cargo pumps forthe discharge of their cargo. In thatcase also the ballast pumps are steamdriven.

Instead of steam, other liquids can beused for heat transfer, e.g. thermal oil.The advantage is that the system issimple. A disadvantage is that the oilbrings a fire hazard with it.

12. Heat exchangers

Heat is produced at various places.This heat must be disposed of. Or, on

the other hand, liquids or air must beheated. Therefore a number of heatexchangers are found in every engineroom:

Fresh cooling-water coolers: for coo-ling water

Fresh cooling-water heaters: pre-war-ming of diesels

Lubricating-oil coolers: one for eachauxiliary diesel engine, attached tothe engine, two for the main engine

Air coolers: for combustion air

Air heaters: for general heating, air-conditioning

Oil heaters: for fuel

Types: Straight-tube coolers, U-tubecoolers. Plate coolers.

Rolu rt '-v'tutc steeri ttg geur

1-3. PumpsLiquids are to be pumped through allthe systems. For different mediadifferent pumps are used:

- For cooling water normallycentrifugal pumps: low pressure,large quantity;

- For lubricating oil: screw typepumps: constant supply, constantpressure;

- For boiler feed water: two- orthree-stage centrifugal pumps orpiston pumps;

- For fire pumps: high pressurecentrifugal pumps;

- For highly viscous fuels: gear typepumps;

- For dirty water, etc.: piston pumps,membrane pump.

plate crnle;r

228

To keep the engine room dry, thereare so-called bilge pumps. There arenormally three systems. A small pumpcapable of dealing with the normalsmall daily quantities. Pumpingoverboard is not allowed. This smallpump pumps the dirty water (waterand oil) into a bilge holding tank.From that tank the water is pumpedby another small pump through abilge water separator overboard, onlywhen it is sufficiently clean. If not, itgoes to another storage tank, thesludge tank. A second, bigger pump,can pump the bilge water from theengine room straight overboard, butthis is only allowed in emergencies. Athird possibility is to use the directsuction of the main cooling-waterpumps. This huge capacity is for bigleaks in emergencies.

Stnall hilge ltump of tlrc bilge-water

\epurutor

14. Safeguarding

The various machinery in the engineroom is safeguarded by controlsystems. A simple diesel engine of20 hp already has a lubricating oilpressure alarm. When the lubricating-


oil pressure is too low, a red lightcombined with a penetrating highnoise will draw attention. The biggerthe engine, the more safeguards. Forexample there are alarms for:Cooling-water too hot, cooling-waterpressure low, lub oil level low, returnlub oil temperature too high and soforth.

In a modern engine room which isarranged for controlled operation, allthese alarms are brought to a controlroom where on screen the abnor-mality is shown, and remedial actioncan be taken. By human action, oreven automaticallv.

When cooling water is too hot, forinstance, the flow can be raised byopening a regulating valve. When thewater temperature is too low, thatsame valve can reduce the flow.When that remedy fails: alarm.

15. Fire-fighting

Fire-fighting can be divided intoprevention, alarming and real fire-fighting.

Prevention means to prevent by allmeans that the three requirements:heat oxygen and something combus-tible are together. The moment that itnevertheless happens then, the soonerit is detected, the more chance there isto fight it successfully. The maindetection system is smoke detection.Ignition detection (flame detection) atstrategic locations can be faster. Heatdetection is another addition to thesystem. Mostly a mix of these detec-tors is installed.

When smoke, excessive heat or lightflashes are detected. alarm bells areactivated. The equipment to fight thefire is available in the engine room.

Portable extinguishers of variouskinds, fire hoses with water fromvarious pumps, portable foamextinguishers, and when the othersystems fail, a total flooding instal-lation using carbon dioxide, highexpansion foam, or water relatedsvstems.

16. Vibration and noise

Diesel engines produce vibrationpulses. Each combustion inside acylinder produces a pulse conveyedvia the foundation of the diesel engineinto the ship.

The propeller is also a source ofvibration. Firstly, the pressure fieldaround the blades of the rotatingpropeller give pressure variations onthe aft ship above the propeller.Secondly the blades when rotatingthrough their cycle meet water with adifferent velocity at each location ofthat field. These actions producepulses.

Each part of a ship has its ownresonance frequency. When thepulses induced by some machinerymeet the resonance frequency of aship's component, and the pulse issufficiently strong, vibration is theresult. Noise is generated by air-vibration. Main sources are theexhaust system, the combustionexplosions and the turbo chargers.

Tar* iop

L E).nr$f g|. nolte (m hrtloe wint)a.NrtF]n'€nob. (h€ngfloroori)

3. S|nrctn+onF JFf!. ('t #o.rrnodstbn)

Vbration ,tlurce,t

L7. Fresh water

Ships navigating the seas, make theirown fresh water. Salt water, evapo-rated into steam and then brought intoa condenser, produces condensate.And that is fresh water. When thepressure in the boiler is reducedbelow atmospheric, the boiling tem-perature is lower than 100 degrees C.This phenomenon creates the possi-bility to use the hot cooling water

Centri.fhgul planp,t

229

[' re s h v'at e r gen e rutl r

after having done its work in coolingthe main engine, to make fresh water.The cooling water is led through aheat exchanger inside the lower partof a drum, where the pressure isreduced using an ejector. The heatexchanger is submerged in clean sea-water, that is boiling in the low-pressure atmosphere. The vapour

(steam) goes to the high part of thedrum, where another heat exchangerwith cold seawater acts as a con-denser. From the tubes condensate isdripping. Below this condenser aconical dish is situated, where thecondensate is collected. Through adrain line in the centre of the dish,the fresh water is transferred outsidethe drum.

A second way of making fresh wateris filtering. Salt water is pumpedunder high pressure through a mem-brane with openings so small that saltmolecules cannot pass. The waterpasses and comes out as fresh water.This process is called reverseosmosis.

The most common valve types are:

Gate valves

Gate ,-olve

l . Housing

2. Wedge

3. Spindle4. Sealing rings

5. Plug

A gate valve has a housing betweentwo flanges where a wedge slides inand out, leaving the throughputcompletely open or closing thethroughput completely or for partialflow restriction. The housing hassealing rings as seats for the wedgesides. The wedge also has a sealingring at both sides, giving it doublesealing. Normally the wedge ismoved upwards and downwardsusing a threaded spindle guided bythe removable top part of the housingand screwed into the wedge. Thebottom of the housing is oftenprovided with a plug, allowingchecking the tightness of the valvewithout opening up. Materials forhousing and wedge are cast iron, caststeel or bronze. The sealing rings areoften bronze. All kinds of variationare possible, depending on the typeof liquid, possible galvanic actionand fluid velocity.

L8. Start up arrangement

In case of a total black-out, emptybatteries and loss of starting ai1, theship's crew must be able to startsystems from zero. Usually the firstbuild-up of power is done with asmall air-compressor manual-start-diesel sometimes hand operated, bywhich a small air vessel can bebrought under pressure, capable ofstarting a diesel generator. When thatdiesel is running and producingelectric power, the systems can beactivated one by one.


L9. Valves

In ships many pipeline systems areinstalled, for the transport of variouskinds of liquids, gases, and energy.In those systems valves are necessaryand fitted in large numbers to stop orregulate flow, to connect numerousspaces or items to a system, or toisolate the system from open air oroutside connections.

reverse osmosis plunl

230

Advantages:- 100 per cent throughput- Two sealing surfaces- Short building length- Tightness control in situ

Disadvantages:- Vertical dimensions, especially

when fitted with hydraulic actuator- Weight

Additional strengthening is neededwhen used in high pressure systems.In use for: cooling water, ballastwater, bilge systems, cargo (oil)

systems, firelines, foamlines, etc.

Globe valve

Globe valve

1. Housing

2. Separation

3. Disc4. Spindle

It has a ball-shaped housing betweentwo flanges, with a horizontal sepa-ration at half height, so configuredthat upper and lower part are opentowards one flange each. In theseparation is a circular hole, whichcan be closed with a disc, which ismoved up and down with a threadedspindle. When the disc is kept loosefrom the spindle, the globe valve actsas a non-return valve. Materials forhousing and cover are cast iron,bronze, stainless steel, etc. Disc andseat may be of bronze or stainlesssteel. This depends on the type ofliquid pumped.

Advantages:- Easy maintenance- Easily adjustable flow- Non-returnpossibility

Disadvantages:- Restricted flow, turbulence- Remote control only manually

(extended spindle)

In use for: cooling water, steam,various clean water systems,

Butterfly valve

Buttefly valve, 1000 m.m nominal

diameter

1. Ring

2. Disc

3. Handle

A ring-shaped body, with thediameter of the pipeline that it is usedfot a circular disc in the ring, whichcan be turned by a spindle. The ring isclamped between the flanges of theadjacent pipelines. The ring isprovided with a rubber lining on theinside, forming a seat for the disc. Inopen position, the flow is hardlyrestricted: the disc is positioned in thedirection of the flow. By turning thedisc 90 degrees or nearly 90 degrees,the disc is closing against the rubberlining of the ring. The rubber liningcan be vulcanised, or inter-change-able. There are also types with aremovable seat. Materials: ring ofcast steel or cast iron, disc of bronze,rubber lining of neoprene (oil

resistant). Also fabricated withflanges on ring.

Advantages:- Extremely short building length- Light- Nearly unrestricted flow- Depending on type: easy overhaul- Simple actuator (only 90 degrees

movement)

Disadvantages:- Difficult flow regulation

In use for: cooling water systems, seawater valves (overboards), cargo sys-tems in VLCCs and ULCCs

Ball valve

t\

F:'//

Ball valve

Ball-shaped housing between twoflanges. At half length dividing flange.Inside the housing a seat ring for bothflanges. A ball, with a tubular hole inthe centre. Stem upwards, for rotationof ball, max. 90 degrees. Open means100 per cent through-pass. Flow regu-lation by partial rotation of ball.Materials depending on use.

Advantages:- Double seal- Unrestricted flow when

completely open, no turbulence.

Disadvantages:- Expensive- Heavy- Difficult adjustment of both seals

In use mainly for chemicals.(Stainless steel housing and ball,PTFE sealing rings)


Apart from the above valve typesthere are numerous variations on themain types:

- Needle valves for accurate flowregulation are a variation of aglobe valve.

- Spring-loaded valves are valveswhich can be closed by a spring,remote triggered. They are oftenbasically a globe valve.

- Safety valves which open at apressure higher than desiredagainst a spring, are also oftenglobe valves.

- Spade valves are gate valves witha flat closing spade.

- Non-return valves exist innumerous types:* swing checkvalves in the

discharge of a cargo pump,* globe valves with loose disc in

cooling systems,* weight loaded swing check-

valves in inert gas systems, etc.

20. Bilge-line arrangement

The bilge-line arrangement is animportant safety system that isrequired by law. Rules made up bygovernments and classification socie-ties have to comply with internationalSOLAS-rules.The law states that the bilge-linearrangement, the ballast-line atran-gement and the fire-fighting arran-gement must be three independentsystems that can take over the workof the other systems if necessary.The purpose of the bilge-line arran-gement is to pump water, which hasentered the ship unwanted, out of theship.The ingress of water into the engineroom or the holds after grounding,collision or as the result of fire-fighting can have serious conse-quences.

Condensation can occur when warmair hits a cold surface. In the mostfavourable circumstances the waterflows down the sides into the bilgewell and from there it can be pumpedoverboard. When the water remainson (relatively cold) cargo or seepsinto the cargo, damage to the cargomay occur.


The pump capacity of the bilge pumpis between 100 and 300 m3/hour. Ahole in the side of the ship at 5 mbelow the water line means that acertain capacity, depending on thesize of the hole is needed to removethe amount of incoming water. Theformula to determine the capacityneeded is:

V = & x

V = volume in m3/s incoming water,a = area of the hole in m2D = depth of the hole below the

surface.G = Gravity (9.81)

In the example this means that a holeof 5 * 5 cm makes up for 90 m3ftrourand a hole of twice that size 0.I * 7.Icm) produces 180 m3 water/hourflowing into the ship.

Ships without hatch covers, so called"open ships" have to have additionalpump capacity in the bilge-line arran-gement to remove incoming seawateror rain (SOLAS art 59 sub 2). Smallamounts of water can accumulate inthe ship as a result of rain, especiallyin "open ships", or by condensation.

As soon as the holds are empty andclean, the bilge-line arrangement hasto be tested. When it has been foundin order, this is noted in the ship'sjournal.

For some kinds of dangerous goods,the bilge arrangement has to have thecapability to pump bilge water fromany individual cargo hold. Certifi-cation takes care of what kind ofdangerous goods may be transportedby a ship. The valve (in the engineroom) in the bilge well must be fittedwith a safety device to ensure thatdangerous goods can not accidentallypass into the environment or insidethe ship.

To determine the amount of fluidinside a bilge well or a ballast tanktwo systems have to be present.

- Manual.Sounding with sounding tape using asounding pipe that ends in a tank or abilge well to measure the height ofthe fluid.

- With a remote control systemThe fluid level can be read from anindicator in the engine room. (remote

control). A float is placed in the bilgewell and when the fluid level rises, sodoes the float. When the float reachesa certain level, an alarm is activated.

>+--r i( * I - -:

--);r><l-

high level alarm

>*1rl\t--11"---

low level alarm

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t i r t rt s r t.f r t r rr g r r c t i c f'l ( ) u I -,\ x' i t (' I t a,\'

As soon as the alarm in the bilge wellis activated, the bilge alarm on thealarm panel in the engine room isactivated as well. With an un-mannedengine room a muster alarm soundson the bridge.

The bilge-line arrangement consists ofthe following parts:

1. Bilge pumps2. Mountings3. Main bilge line4. Suction lines5. Bilge well6. Ejector7. Bilge water cleaner / separator

1. Bilge pumpsThese pumps must be available forimmediate use when the ship is beingemptied, even though they may beused for other purposes according tothe regulations.

They must be self-priming. Thismeans that they do not need help totake care of the water in thecompartment where they are situatedafter they have been started.

232

2. Mountings (fittings)

In shipping mountings mean safetydevices, valves, filters, distributorsetc. Several suction lines are mountedon a manifold. The suction lines arefitted with valves to open or close thelines. To keep the capacity as high aspossible, one valve at a time shouldbe opened. When more valves areopened at the same time, the suctioncapacity in the well is reduced. Checkvalves are used as non-return valves.

Example:The fluid removed from the bilge wellmust not be allowed to flow back tothe bilge well. A non-return valve isplaced in the suction line.

Distribuot thut can be .fitted vvith non-return valve,s (bilge arrangement) or stopvalves ( bal I a st arran gement ).

1. Suction of the pump2. Suction from the bilge well3. Hand wheel to operate the valve4. Stop valve

The manifold is made of cast iron onthe outside, with a bronze lininsBronze is seawater resistant.

When a stop valve is opened there aret'wo possibilities:

1. The water can flow in twodirections

2. The water can flow one wayonly. A non-return valve canachieve this. These valvesexist in two main designs:

1. The valve can be opened orclosed as is needed

2. The valve is automaticallyoperated and is solely usedfor safety reasons.


nvo ntpes of nott-return valves.

1. Hinge point2. Direction of flow3. Closed valve (dotted lines: openvalve)

3. Main bilge line.The main bilge line is situated in theengine room and runs from themanifold to the suction side of thepumps. The suction lines run from themanifold to the compartments that areconnected. The main bilge line ismade of galvanized steel. The bilgearrangement in the engine roomconsists of one (compulsory) directsystem and one indirect system. Theindirect system operates through amanifold.

4. Suction linesThe suction lines run from themanifold through the double bottomto the bilge wells. Every well isconnected to the manifold by aseparate bilge line. This enables us tooperate the bilge lines from themanifold in the engine room.

Bilge wells are usually situated at thefore and aft ends of the holds, both onstarboard side and on port side,because the water flows to the lowestpoint in the hold. The position of thispoint is determined by the trim of thevessel. The suction lines are made ofgalvanized steel. Synthetic lines arenot allowed because of the poor fireresistance of the material.

5. Bilge wellA bilge well has two compartments,separated by a bulkhead that extendsto half or three quarters of the heightof the well. A lid with small holescovers the well. As soon as the waterreaches a certain height, it will flowto the well next to it. The suction partof the bilge line is situated in that partof the well.

Hold v,ith t:overed bilpe well

1. Tank top2. Lid of the bilge well

On emergency system that has itssuction point at the lowest point in theengine room is compulsory. Thissystem must be connected to thesuction line of the seawater cooling-water pump or the general servicepump when no seawater cooling-water pump is available.

6. EjectorThe ejector creates a vacuum by thespeed of the water flowing past it. Thepressure of the water flowing throughthe ejector is created by the fire-fighting pump, which can build ahigher pressure than the bilge andballast pumps. (See section 13)

7. Bilge-water cleaner/separator.According to the MARPOL-treatybilge water from the engine roommust go to a separator to separate theoil from the water before it may bepumped overboard. This is to preventpollution. The oil goes to a dirty-oiltank. This separator is compulsory forships of more than 1000 GT.

The residue of oil in the water that ispumped overboard may not exceed 15ppm (parts per million).

233

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21. The ballast arrangement.

The ballast arrangement is used topump seawater (weight) in or out ofthe ballast tanks. There are fewerrules for the ballast system than forthe bilge arrangement as it is lessimportant for the safety of the ship.

Reasons for taking ballast on board orshifting ballast are:- To improve the stability of the

ship, especially when the shipdoes not carry cargo.

- To alter the trim- To reduce bendins moments or

shear forces- To control the list during loading

and discharging. Many ships use aanti-heeling system for thispurpose.

An anti-heeling system is used tominimize the list (in port). Pumpswith a large capacity (1000m3/hour)are placed in the vicinity of two tanks(one on port side and one on starboardside). These pumps can transfer waterfrom one tank to the other at greatspeed. The system is fully automaticand much used on ships with cranes,container vessels and Ro-Ro vesselsto reduce the list that can occur durinscargo handling.

5 P.S.lx.

t r - -v

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- ALL PIPE-LINES OEL. YARO

8EDXFD SUCL/DISCH. EAILAST PUMPS SEE DtrG:J5-t

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Dk HroR. oPCRATED BuTTERrry v L!€

Forepeak tanks, deeptanks, double-bottom tanks, and wing tanks areusually used for ballast water.

The advantage of using ballast in-stead of fuel in the double bottom isthat welding is allowed on the tanktopas a means of fastening the cargo. Theowner of the vessel determines theballast capacity. The duration of thevoyage and the purpose of the shipwill be taken into account whendeciding on the available space forballast and the capacity of the ballastpumps. Ballast pumps are usuallyalso suitable to act as bilge pumps andthus they form an integrated part ofthe bilge affangement, to the extentthat a ballast pump may even serve asmain bilge pump.

Contrary to the valves in the bilgearangement, the valves in the ballastarrangement have to be two-wayvalves as the tanks must be filled oremptied according to the demand.Double bottom tanks can also befilled directly from outside throughthe sea-inlet. The wing tanks also canuse this system, but the draughtdetermines the efficiency of thissystem as the water will not gethigher into the tanks than the draughtallows. Nowadays the ballast systemis often designed as a ring line.

5 P.S.fi.

2 P.S.IK.

Remote controlled valves are used toempty or fill the ballast tanks.

Ballast lines inside the double bottommay be made of synthetics.

Synthetics for piping systems.

More and more pipes on board aremade of synthetics, not only foraccommodation and sanitary meansbut also in ballast systems. The mainadvantage is the corrosion resistanceof synthetics. The small weight isanother adventage. The pipes areeasier to handle on board as well ason the yard and the reduced weightallows the ship to carry more cargo.

Disadvantages are the sensitivity totemperature changes and the lowerstrength compared to steel.

Classification Societies often statethat "synthetic pipes may be usedwhen they have no adverse effect onthe continuity of vital installations incase of fire or breakdown".

Means for repair of synthetic pipesiue compulsory when a vessel makesuse of synthetic pipes.

r P.s.TK.

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TK.r s.B.

BOWIHR.-ROOM

2

s{o-'

TK.2 S.B.

TK.s s.B.

1. Duct keel2. Tank wall3. Ring l ine

4. Branches to the double-bottom tanks and winstanks

5. Direction of engine room6. Bow-thruster room7. Filter


8. Two-way valve

235

Bollu,st line ntttde of s1:n7hg1i.; .\'ibre,s.

I Tank sounding system2 Engine-room bulkhead3 Ballast pump4 Pressure line5 Suction line

I lullast ptttlt l) irr the crtg,ine room, litta,s' uttd (,stop1 t,crh,e.t

6 Main ballast line1 Stop valves (butterfly valves) to open or close the lines

to the ballast tanks8 Butterflv valve

1 Valve (butterfly)2 Operating handle3 Valve casins

Butlcrflv vuLve


J

II

I-5o7 ' 1

III

2

Bal last arran-qement on a lar-9econtainer vessel. Each tank has itsown connect ion . Ba l las t ing andLrnballasting of each tank simulta-neously is possible.

I Overboard2 Ballast distributor3 Anti-heeling system.t Lines to the tanks (in the duct

keel)Valves with remote controlFilter'Pump

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Slt ip Knowledge, a trtoclent ettct 'clopedia 237

The numbers in above drawing correspond with the list on the previous page


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Heeling system to move water ballast.fromport to starboard or reverse, to control the

list during loading and discharging, inde-pendent of the ballast system.

Ship Knowledge, a mndern encyclopedia 239

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REMARK AS IHE \ESSEL IS SUITAELE FOR CARRYING DANGEROUS GOOOSACCOR0ING tMO REG. 54. THE VAL\€S MARKED V,/ITH t MUST HAIEPOSSIBILITY TO BE BLOCKED lN CLOSED PCSITION (6*)

sucnoN / D|SCHARGE To 8E DoNE W|THIWO BALLAST TANKS SIMULTANEOUS (=2, Ott 125)

ALL LINES MADE OF MILD STEEL ANDHOT GALVANIZED AFTER MANUFACruRINGDIMENSIONS ACCORDING'RECON' STANOARITLIST R-STD-IOO2 --NORMAL WALLED' COLUMN 1FS�D sucr. rRou cRoss-o!€R sEE owG: 16-l (2r))f505) DRtvrNc rforlrD rnoM n-rr puMp sEt D$G: J5-z


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1. Bilge arrangement (yellow)2. Ballast arrangement (blue)3. Overboard (for bilge and ballast)4. Engine room bulkhead5. Main bilge line, from distributor to ejector and

overboard6. Engineroom bilge line, port side, starboard side,

midship and aft. All fitted to the main bilge line.7. Direct bilge iurangement from the engine room8. Suction distributor chest9. Ejector

4


BiLge und balhst arrengement on a c'ontainer feeder

241

Jo

Tbp view of the forepart of the engine room

1 Engine room bulkhead (insulated)

2 Pumps3 Ballast distributor4 Fire-fighting pump

One way stop valve

Non-return valve

Automatic non-return valve

Pump

Filter

Manifold (3 way)

&&D(

c@ts88Common symbctls


22 Firc-frghting amangement

Fire on board ships has probablymore often caused the loss of a shipthan grounding, collision or badweather. A good fre-fighting arran-gement, conforming to legal require-ments is therefore a necessity.

The fire-fighting arrangement has totransport seawater to the firehydrants. The system consists oflines, pumps, valves with couplings,hoses, nozzles and spray installations.

A minimum of three fire-fightingpumps is compulsory on all ships.One of these pumps must be situatedoutside the engine room. This is theemergency fire-fighting pump. Asclose to the pump as possible, while

still on deck, an isolating valve mustbe placed. When shut, this valve,ensures that the rest of the bilgesystem remains isolated in the eventof bilge lines in the emergency pumproom comparfrnent becoming damaged.The emergency pump may not bedriven from the engine room but mustbe driven independently by a dieselengine or electrically driven by anemergency generator.

Both main pumps must deliver suffi-cient pressure. This pressure shouldbe enough to get at least a pressure of4 bar at the highest point on the ship(the bridge). There must be enoughhydrants (connection point for firehose) to ensure that every location on

the vessel can be reached by at leasttwo hoses. In case of fire in the engineroom an isolating valve outside theengine room must be shut to keeppressure on the fre line from theemergency fire pump.

5 #ar. rrcDco(

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sl-c€ slslEll FonE9{P }SEE SLAAT'W DUG. f. T. FORES'IP

1. Arrangement in the engine room2. Arrangement on deck3. Filter4. Isolating valve5. Hydrant6. Supply from general service

pump7. Main fire pump8. Suction9. Emergency fue pump10. Sea valve

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F ire -fi g htin g ar ran g ement


2

243

1. Propellers

1.1 General

1.2 Fixed propellers

1.3 Controllable pitch propellers

1.4 Nozzles

1.5 Rudder propellers

1.6 Electrical rudder propellers

1.7 Propeller shafting

2. Water-jet propulsion

3. Rudders

General

\pes of rudders

Steering engines

3.13.2

3.3

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1. Propellers

L.1 General

In order for a ship to obtain a certain constant speed, a force needs to be exertedon the ship. The magnitude of this force depends on the ship's resistance at thatparticular speed. If the ship is travelling at constant speed the force exerted onthe ship equals the resistance of the ship. The force that moves the ship cancome from an outside source like a towing line or the wind, but generally theforce is generated by a power source on the ship itself (engine). The propulsionsystem usually consists of the engine or turbine, reduction gearbox, propellershaft and propeller.

The efficiency of a propeller takes animportant place in the design-processof the propeller because its efficiencyand the ship's f\rel consumption aredirectly rclate{/

The efficiency depends on the flowfield of the propeller, which dependson the ship's underwater body, thepower of the propeller, the number ofblades, rotations per minute, themaximum possible propeller dia-meter, the blade surface area and theship's speed.

If the diameter of the propellerincreases, the rotations per minutecan decrease; this generally increasesthe efficiency and reduces the fuelconsumption.

The propeller pitch is the distance inthe direction parallel to the propellershaft that a point on the propellercovers in one revolution in a solidsubstance. Similar to a point on acorkscrew turning in a cork. Whenrotating in a fluid a propeller willhave a (small) slip. Rotations orrevolutions per minute areabbreviated as rpm.

the p ropul sion svstent

1 Engine

2. Engine shaft

3. Reduction gear-box; this reducesthe number of revolutions of theengine (e.g.1000 rpm) to an

acceptable rotation rate of thepropeller (e.g. 200 rpm) The

reduction is 5:1.4. Shaft generator; this supplies the

ship with electricity when theengine is running

5. Stern tube with bearing

6. Propeller shaft

7. Propeller

In short, the diameter of the propellershould be as large as possible so thata maximum amount of wake, causedby the ship's hull, is used. The choicefor high efficiency with a large-diameter propeller and a low numberof revolutions per minute is easilyjustifiable, but requires a significantinvestment.RPM and the number of blades haveinfluence on vibrations on board andthe resonance frequency of the ship.Most ships use a 4-bladed propellerwhile 5-blade propellers are morecommon when a large power (20000kW) is necessary.


However, more and more ships usethe 5-bladed version nowadays, evenwhen less power is needed. The 3-bladed propellers are used on shipswith a high number of revolutions perminute and a low power (700 rpm,600 kw).

The shape of the bladesEvery propeller is designed indivi-dually, based on the specific demandsset for this propeller. As a result ofthis, there is a large variety in shapesof blades.

Difterent tltpes o.f bktdes attctchecl to rt

lrub. This utmbhrution can never be

u sed .for actu(t l propul.si on

The remarks for each shape of bladeapply to both the fixed and thecontrollable pitch propellers.

Blade 1: Is hardly used anymore.BIade 2: Is used when there are

strict demands regardingnoise and vibrations onboard.

Blade 3: Is used when the rpm ishigh and, consequently, thediameter is small. A largeblade surface areasomewhat reduces theefficiency, but it is veryfavourable for the ability tostop the ship and for thereverse propulsion force.Is used in nozzlesIs also used in nozzles ifthe noise and vibrationlevels have to be limited toa minimum..

Ship resistanceA ship encounters the following typesof resistance:

a. Frictional resistanceThe friction between the water andthe ship's skin is the cause of this typeof resistance. The water in theboundary layer will be accelerated bythe ship's speed. This boundary layerbecomes larger when the shell isfouled.

boundary layer

wake

Tlrc u,ake r4f the ship

b. Pressure resistanceThe ship's momentum pushes thewater aside at the bow and as a result,the pressure of the water increases.This increase in pressure will alsotake place at the aft. The pressure willfall where the boundarv laver isreleased.

c. Wave resistanceThis is a result of wave-systems alongthe hull that originate from thedifferences in pressure. The use of abulb at the stem can significantlydecrease the wave-making resistance.The bulb generates its own wavesystem, which is designed to beopposite to the ship's wave system.These two wave systems thenneutralize each other.

If the rate of flow of water (or air) ishigher, then the pressure will belower compared to the pressure inparts of the water where the rate offlow is lower. So in waves, water in atrough has a higher speed than waterin a wave top. See also chapter 4'design' and Bernoulli's law.

In oil tankers and container ships itcan be seen very clearly that the bulbprevents an increase in pressure nearthe stem. The improved streamline ofthe ship's underwater body reduces awave system around the ship. Insuppliers and hopper suction dred-gers, there is a large wave systempresent around the ship.

Trail erin g hoplter suctiott d redger

v'ithout a bulb

d. Added resistance in wavesThis type of resistance is caused bythe pitching and rolling of the ship.

e. Air resistanceThis depends on the vertical areaabove the waterline. which varieswith the draught.

Types 'd' and 'e' are variable, depen-ding on wave direction and winddirection as experienced by the ship.

Blade 4:Blade 5:

LNG-tanker v,ith a vveLl-desi.cned buLb

Sultplier witluttrt u bulb

Conkirter ,ship witlt n bullt


Fixed right-handed propeller on a tanker (deadweight 30,000 tons). Propeller being

polished to reduce roughness, for less rotation.friction and le.ss fuel consumption.

Pressure and suction sides of thepropellerThe approach velocity of the water isa result of the ship's movementthrough the water. If the ship is lyingstill, this Ve = 0. The approachvelocity can be calculated bysubtracting the wake velocity fromthe ship's speed. The speed ofrotation of the propeller and theapproach velocity result in the speed(V). This V hits the propeller blade ata certain angle:

ct = 9o-10" at service speed

The speed of the incoming watercreates an under-pressure on theforward side of the blade (suctionside) and an over-pressure on the aftside of the blade (pressure side). Thepropeller blade acts as a wing profile.Propellers are usually viewed from

I

l s Ve = approach velocity =

ship's speed - wake speed

U = speed of rotation of thepropeller

T*r = angular velocity x radiusV = resulting speedA = lift

W = drag

P = resulting force

S = propulsion force (thrust)

T = shaft moment

Ship Knowledge, a

A drawing of the upper fixed propeller

blade of a right-handed propeller seen

from above

1. Cross-section of propellerblade

2. Propeller shaft3. Suction side4. Pressure side5. Leading edge6. Trailing edge

1 .

Forces on the upper

propeller blade when

the propeller is rotating

and the ship is moving

aft, therefore the pressure side is alsocalled 'the face' and the suction side'the back'.

CavitationAs described above, the propellerpressure of a rotating propeller is notjust the result of the water-pressureon the pressure side, but also of theunderpressure on the other side of thepropeller. Propellers that rotaterapidly can create an under-pressurethat is so low that watervapourbubbles are being formed on thesuction side of the propeller. Thesegas-bubbles implode continuously onthe same spot and cause damage tothe suction side of the blade. This iscalled cavitation. Severe cavitation causes:- a reduction in propulsion power- wear of the blades- vibrations that bend the blades- noise in the ship- high cost to rectify

A proper working propeller oftenshows, light cavitation wich is notharmful.

Cavitation damage on a rudder blade

due to mi,ssing plug.

Cavitation damage on a rudder blade

248

Propeller Turningdirection

Sailing

direction

Direct propeller

effect

Indirect propeller

effect

Aft Fore Aft Fore

right-handed right ahead starboard ponright-handed left astern port starboard port starboard

left-handed right astern starboard port starboard portleft-handed left ahead port starboard

Wlteel e.ffec'r o.f propellers

The influence of the propeller on theship's manoeuvring abilityPropellers can be divided into right-handed and left-handed propellers.Ships with a fixed propeller usuallyhave a right-handed version.A right-handed propeller can berecognised in the following way.Stand aft of the propeller, look at theface and hold on to the top blade withboth hands. If the right-hand side ofthe blade is furthest away, it is a righrhanded propeller. If the ship is goingahead, a right-handed propeller isrotating clockwise.If a propeller is rotating, the ship hasthe tendency to turn to a particularside, even if the rudder is in the mid-ships position and there are noadditional forces acting on the ship.This effect is called the propellereffect or wheel effect (see the moduleon manoeuvring).

Propellers with adjustable blades(controllable pitch propellers, cpp)are often left-handed. When the shipgoes astern, the effect of the propelleris the same as in a right-handedpropeller going astern. Going aheadthey have the same effect as a left-handed propeller. This is done not toconfuse pilots. When going astern,the efficiency of the propeller candrop below 50Vo, depending on thetype of blade and the type ofpropeller.

1.2 Fixed propellers

The propeller blades of a fixedpropeller have a fixed position. As aconsequence the direction of rotationof the propeller has to change if theship is going astern. This is realisedwith a reversing clutch or a reversibleengine. A reversing clutch, andtherefore also the fixed propeller, iseconomical in ships up to 1250 kW.


The diameter of fixed propellersvaries between 36 cm and 12 metres.The choice of a fixed or controllablepitch propeller (CPP) in ships up to7000 kW depends on, among otherthings, the need for a shaft generatorand the need for easy manoeuvringqualities.

Advantages of a fixed propeller overa controllable pitch propeller are:

a. They are less fragileb. The propeller does not revolve

when berthing, so it poses lessdanger to mooring boats and thereis less risk6f ropes gettingentangled in the propeller.

Disadvantage: in adverse weather, thepropeller may turn too heavily, thiscan hamper propulsion.

Instcr llation o.f u .fhed riglrt-lmnded

propeller v,ith shuft

Fixed propellers also have a limitedRPM for manoeuvring.

Alternative propeller designsPropellers with tip plates have beeninvented around 1850, but have onlyrecently been rediscovered. Tip platesare attached to the blade tips. Theplates prevent the water from flowing

[;'i.red riglt-handed propeller ol a cotttcriner v'essel (CT 80942) with a rever,sible

etryine. Tlrc trtntpeller v,eighs 95 tons, has 6 blades artd n tlicrmeter of 8.95nt.

249

from pressure areas to the suctionareas of the propeller too fast. Thisincreases the efficiency by reducingthe energy loss. The improvedhydrodynamics of the water-flowcaused by the tip-plate propellers alsocontribute to the reduction ofvibrations and noise of the propeller.

Another development is the contra-rotating propeller. This systemconsists of two propellers placed onebehind the other, which are driven by

m&l:.

/ ' r t t l te l l t r wi t l t r ip l t lu tc, :

means of concentric shafts (inner andouter shafts) with opposite directionsof rotation. Both the number ofblades and the diameter differ. Theprinciple behind this system is that,normally, water is brought intorotation by the propeller, whichresults into a loss of energy. Adding asecond propeller rotating in theopposite direction reduces the loss of

energy. The combined propellers canreduce the fuel-consumption by l5%a.

1.3 Controllable Pitch hropellerc(adjustable pitch propellers)

The blades of this type of propellercan be turned, thereby changing thepropeller pitch. These propellers aremore complicated than fixed-pitchpropellers. The mechanism thatadjusts the propeller pitch is locatedin the boss of the propeller. It isactivated from the engine room,remotely controlled from the bridgeby a hydraulic cylinder. The moststriking feature of the controllablepitch propeller is that it only rotates inone direction, making the reversingclutch or the reversible ensine

obsolete. Unlike the fixed-pitchpropeller, the controllable pitchpropeller is an integrated part of thepropulsion system. This makes itpossible that power and necessarypropulsive forces can all becontrolled by simply changing thepositions of the blades.

The figure on the next page showscross-sections of a propeller bladeand the forces that act on that part ofa rotating propeller blade.

On the left are the cross-sections andforces when the ship is going ahead.All the vectors point backwards, theship is going forward.Now the blades are rotated towardsthe zero-position. This means that thepropulsive forces above and beloware equal in magnitude, but oppositein direction. The nett propulsive forceis zero, but the propeller still absorbsa large amount of energy that isconverted to turbulence of the wake.To go astern, the blades are rotatedeven further, resulting in a forwardpropulsive force.

Safety precautions1. The position of the blades can be

changed manually without loss ofpropulsive force.

2. If the hydraulic system fails, theblades can be locked in the aheadposition.

[ ) ru$ir re t t . f r t < 'ot t t t r t l lublc p i tch l tntpt , l ler n i t l t lu t tpal lcr r l t r r . l t . ' l ' l tc l t i tc l t ud. i t ts tntcnt o l

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t t t t t t t l tcrs . \ ' ( ' ( ' n( . \ t 1tu,qc ) ' l 'hc I i ,qurcr u1ryt l : lo u l t r r tpt ' l l t r vv i r l t r r d i t tnr t t tcr t4 2.5 nt( l t ' ( . \ .

\ ' l t , t lc l t t ' .s t t t f ' t t ( ' ( )n l t 'o- t 'o1( t t i t t ,q l t rop<: l l t r

Slip Knowledge, a modent encltclopedict 250

Advantages of a controllable pitchpropeller

1. It can propel the ship at all speeds,even at very low speed withoutloss of power.

2. It can change quickly from aheadto astern and vice versa.

3. Improved efficiency on ships withalternating loads like fishing craftsand tugs.

4. It can easily be combined with ashaft generator (see on the right).

5. It can stop a ship with maximumpower.

Disadvantage:It is a vulnerable system due to thehydraulic components and manysealing rings. A damaged sealing ringresults in oil pollution.


Neutral

also be used as:- additional power supply during

navigating- emergencypropulsion**

** If the shaft generator is to be usedas an emergency propulsion, the mainengine must be disconnected from thereduction gear box in order to preventthe cog wheels from being damaged.

Class does not prescribe this systemand the maximum speed it can obtain.The system is sometimes used onsmall ships.

1. Propeller blade (tip speed 31,4 m/s)

2. Boss

3. Watertight / oil tight seal

4. Stern frame

5. Propeller shaft, 240 rpm

6. Stern tube

7. Intermediate shaft (to engine shaft)

8. Reduction gear box (1:2.5)

9. Mechanically driven lubricating oil pump

10. Collar shaft (thrust)

11. Actuating motor, coupled to a

mechanism of bars that serves the

blades

The shaft generator can supply theelectrical power on a ship as longas the main engine keeps running.With controllable pitch propellersthe generator frequency can bekept constant because the rpm ofthe engine remains constant. Theengine drives the shaft generatorvia the reduction searbox.

relation to the aft body.Not only does a nozzle increase thepropulsive force, it also reduces noiseand vibration levels. Furthermore, theincoming water-flow is more homo-geneous in anozzle, minimising local

Controllable pitclt propeller irt a.fixed

rttt?.i,Le.

Forward

FlI

/4F

Backwards

\F

P _ _ f f i h,^ ---M fuI I I I I

\7 tr

I ',,. The purpose of a nozzleis to increase

E' i:lif *il *ffi#,'":T;'HK ;flltt ;il#.,:"','J,",t1l:,*1::

Drun,irtgs o.t' 'a single propeller blade artd it.s c*tss-.sec'tions. The tr'tir:tttre.t .thttt, rhe gradient then createt 'h:^.u9ditional

i - - - - - \

r:r,trollable Ttitt:lt ltropelle.r; tlte upper blude is tlrc ltlade in rlte tlrcrt:irtgs. propulsive force' The efficiency ofthe nozzle is at a maximum when thewater can pass unobstructed. This is

If the auxiliary generators provide the why the top of the nozzle shouldshaft generator with energy, it can always be as free as possible in

2 5 1

pressure differences that areresponsible for cavitation andvibrations.

The combination of a propeller in anozzle is often called a ductedpropeller. In principle, the nozzle canbe used on every type of vesselexcept on very fast ships like high-speed ferries where they have noincreasing effect on the propulsiveforce. If the frictional resistance(caused by the nozzle) becomes

' l '1rc l i{t l ltn'r. ( 't '((tt(,d b.t ' / lra tutd(t'-

l ) t ' ( , \ \ut ' t 'o t t I l tc ot t l ,s i t l t o. l l l tc t to: , : la

larger than the increase in propulsiveforce, there is a loss of efficiency.Nozzles are often used on inlandvessels, hopper suction dredgers,tugs, fishing vessels and suppliers.The advantages and disadvantages offixed or controllable pitch propellersare the same for propellers in a nozzleand propellers without one. Forshallow draught ships the same thrustcan be delivered with a smallersystem diameter.Nozzles come in two main types:1. Fixed versions2. Rotating versions

(see Sect ion 1.5)

One particular type of fixed nozzles isthe wing-nozzle. In spite of itsmodest dimensions, this sti l l in-creases the propulsive force if thespeed exceeds 12-18 knots.

1.5 Rudder propellers

The main characteristic of rudderpropellers is their ability to rotate likea rudder, unobstructed, the full 360'.Rudder propellers are also called'azimuthing thrusters' or'Z-drives'.To achieve this freedom of rotation, aright angle underwater-gear box isdriven by a vertical power shaft. Thisvertical shaft is centered in the rudderstock.

' l \ r t t r r t t l t l r t ' 1u ' t , 1 t c l l t , t ' s i t t t t t t o . : l c . y r i t l t

.16()" nt l t r l io t t ,

A gear driven by a pinion is attachedto the top of the rudder stock. Thismakes the unlimited rotationpossible.

Nowadays, rudder propellers canhave a power up to 7500 kW. Thereare several versions of rudderpropellers, namely:

L A fixed unit assembled in anassembly box. It can be equippedwith a depth-adjustmentsystem.When the ship is empty,the propeller can be lowered in

order to get sufficient propulsiveforce efficiency without the needfor ballast.

2. Deck units. The diesel-drive unitsare placed on deck; the rudderpropeller is attached to the back ofthe drive unit. These types canalso have a depth-adjustmentsystem.

3. A retractable unit. Is can bewithdrawn entirely into the shipand is only lowered when theship is at sea. When in topposition, the propellers can bepart of a tunnel thruster and arethen called'retractable thrusters'.Not used for main propulsion.

4. Bow thrusters or stern thrustersare also called tunnel thrusters.They are based on a transversepropeller and a right angleunderwater gearbox. These areused exclusively to position thebow with a starboard or port sidethrust.

Types I and 2 function as main pro-pulsion units while type 3 is anauxiliary propulsion unit. Type 4 isfor low-speed manoeuvring.

The most important advantage of arudder propeller is its ability to giveoptimal thrust in each rudderposltlon.

?F

" t '

/ 'I t

#l=f r ' , ' , , ,

: l 1

tt ]*.;iW

I i t t t l l tn, . l ta l l t ' r i t t u wi t tq-r t t t : . : .1e,

Sltip Knotvledge, a modent enct,clopedio

l l t q l t r t t t l t , t l t t t l t l t c r l t t ' i l l t t t r o t r : i n t t t l l t i t t g t l t r t t s l t ' t ' s t u t t l u l t t t n ' l l t r L t . ; / a t

252

Except for the tunnel thruster, allrudder propellers can steer the ship360o, thereby giving the ship excellentmanoeuvrability. Nowadays, modernelectronic equipment for satellitenavigation can be employed to couplethe rudder propellers to the dynamicpositioning system (DP-system). Thiscan keep a ship in a predeterminedposition irrespective of the influencesof currents and wind. Retractablethrusters are often used for thispurpose. When the ship is in position,the azimuth thrusters are lowered andthe ship switches to DP. Otheradvantages of the rudder propeller arethe very compact engine room (becausethere is no need for a long propellershaft); this results in lowerinstallation costs as compared to aconventional propeller.

Rudder propeller installations areoften used on passenger liners, cableships, floating cranes, suppliers,dredgers, barges etc.

1. Horizontal connectins shaft fromengine

2. Horizontal gearbox to verticalshaft

3. Vertical shaft4. Yertical gearbox to horizontal

propeller shaft5. Nozzle

6. Fixed pitch propeller

C ro,ss-ser:tiott of u rudde r p ropel Le r


Schemutic presentutiott o.f the comrnund pnth from bridge contrutl to the ruclde:r

propelle r

Aeriul plnto,qrctplt ol'a ,supplier shov,s tlrc ct2ttintul nunoeurring

c'upabilities of a rudder prolte.ller in combinatiort. vvith a bow, thruster

2s3

,aal* ^ r^r-'oi*t irer.

ti -5**

Thejoy st ick on the control panel is aso-cal led'one-man operarted. joy st icksystem' which controls the ent i repropulsion system and the rr-rdders.

SSP diesol-€lectic

Conventional diesel-direct

Conventional diesol-electric

*orh-

-En

\ I t i 1 t K tt t ttr I c d,q t,, rt trr r ttl c rt t c t r L'.t' c I r t pe tl i ttL . I J

1.6 Electical rudder prcpelle$

(Brands: Azipod, Dolphin, Mermaid,ssP)

The difference between the rudderpropeller of paragraph 1.5 and theelectric rudder propeller or poddedpropulsor is that the latter has itspropulsion engine located outside theship. The electrical engine withadjustable rpm is placed in a pod thatis attached to the bottom of the ship.Every pod has a propeller attached toit, driven by the electric motor. Thereare two main types: a fixed pod witha rudder or a 360 degree rotating podwithout a rudder. Both these types caneither push or pull. The propeller isthen located on the back or the frontof the pod, respectively.The electric rudder propeller does notrequire gearboxes, clutches, propellershafts and rudders.

The diesel engines can be placedanywhere on the ship, as long as thereis space available, unlike the shipswith a mechanical drive where theengines are connected to the propellerby a long shaft and other parts.

So this propulsion system is acompact system that simplifies thedesign and construction of the ship ascompared to conventional propulsionsystems. Although the system wasoriginally developed for icebreakers,it is now in use on suppliers, cruiseships, tankers, ferries and ships with aDP-system.

Advantages are:1. It is possible to separate the power

source and the propulsion system2. It can combine the power supply

of the auxiliaries and thepropulsion system

3. Few vibrations and little noise4. Excellent manoeuvring

capabilities5. Lower fuel-costs

Cros,s-section of the azipod instaLlation

1. Propeller2. Bearing and shaft labyrinth (seal)3. Hydraulic steering unit with

toothed rim

4. Collector rings for the\-tr/nsmission of data and power

5. Ship's bottom

6. Electro-motor

7. Bearing (radial and thrust)

energy for all the ship's systemslike propulsion, AC, galley,watermakers etc.

3. Main grid, 11000 volts l60Hz4. Bow thrusters

iFo

/a\v/

I

3.

4.

Schematic representation o.f'tlrc propulsion s))stem w,ith pod,r.

1. Azipod with a 1200 volts cyclo-converter

2.Five diesel engines coupled to 5generators (2 times 11.2 MW and3 times 8.4MW. These supply the


n "7 Propeller shaft ing

Tbc s t c rn t r r bc con t l i ns t hc bc lu ' i t t gs

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o

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2 5 6

The lubricating agent between thepropeller shaft and the shafting canbe: a. oil

b. water

a. Lubricating oilApproximately 70Vo of all ships useoil as a lubricant for the propellershaft. When oil is the lubricant, thebearing is usually made of whitemetal, and sometimes of syntheticmaterial. The disadvantage of synthe-tics is that they poorly transmit thefrictional heat between bearing andshaft. At the front side of the frontbearing there is a sealing case, whichprevents oil from leaking into theship.

The sealing system at the backsideconsists of a sealing case and mostlythree sealing rings. These sealingrings are made of synthetic rubber.The space between the two bearingsis completely filled with lubricant.The aft seal prevents oil from leakingto the outside. The lubricant pressureis only slightly higher than the waterpressure. So if seawater shouldsomehow enter the two water-seals,the higher lubricant pressure preventsit from reaching the propeller shaft.Seawater could seriously damage theunprotected propeller shaft. Thehigher lubricant pressure is main-tained by a small pressure tank (A),which is placed a few metres abovethe load line.Tank A is part of the main lubricatingsystem, tank B contains lubricatingoil for the seawater sealing rings. Theoil in the main lubricating system isself-circulating due to the fact thatwarmer oil rises upwards. Tank C isboth the drainage tank and the storagetank. If oil leakage should somehowoccur, it is usually limited to smallamounts. If not, drydocking isneccesary. A chrome steel bush isfitted around both the propeller, shaftaft near the propeller and forward inway of the aft peak bulkhead. Thespace between the bush and the tubecontains lubricant. The aft chromesteel liner is attached to the propellerboss with bolts, the chrome-steel linerof the forward bush is attached to thepropeller shaft with a clamped ring.Around both bushes, attached to theship, are non-rotating housings,where the sealing rings are fitted.


Stern l:eoring and seals

outer seal 4. 11. inner seal

Outer and irmer seals

CIosed s\,stem w'ith lubricating oil

1. Propeller boss2. Propeller shaft3. Chrome-steel liner4. Seawater seal5. Oil seal6. Stern frame7. Aft bearing8. Propeller shafting

9. Clamped ring10. Oil tank11. Fastening with bolts on the

stern post12. Bolt attachment on the aft peak

bulkhead13. Stern tube14. Forward bearing

1 4 .

257

Advantages of placing a chrome-steelbush are:- it prevents the propeller shaft

from getting into contact withseawater

- very resistant to wear

During dry docking, measures shouldbe taken to determine how much thepropeller shaft has sunk. This is

indicative of the wear of the aftbearing. A special depth gauge, the socalled 'poker gauge', is present on

board that can measure the sagging ofthe shaft. Normal sagging is zero.

b.Water as a lubricant

When water is the lubricant for thepropeller shaft, the bearings are madeof rubber or synthetics. Water lubri-cation can be achieved with both open

and closed systems. In the open

system, the water is pushed out wherethe propeller shaft leaves the ship,thus preventing seawater from ente-ring the ship. In the closed system, thewater is pumped round the shaft, fromfore to aft. This means that the wateralways has a slight over-pressure as

compared to the seawater. The navyuses water lubrication because enemyvessels can detect lubricating oil. Insome countries water lubrication iscompulsory for local shipping toprotect the environment.

1. Propeller boss

2. Shaft

3. Bearing (rubber, lignum

vitae, tufuse)

4. Stern tube

:4t+;4..;*

h

I::'trlL speerl ultead

2 Water-jet propulsion

The main principles of thewater-jet are:- the impeller (propeller) draws in

seawater through an inlet- the same impeller adds head /

pressure to the water flow- when the water is pushed through

a nozzle- the nozzle converts the water pres-

sure into a high-speed jet- the acceleration of the water flow

generates a thrust force that gives

the ship its speed- for sailing astern, the waterflow

exiting from the nozzle can bereversed in the forward directionwith the reverse plate and reversesection.

tI\'B' SrllCl {l}ttfi

PruP {2) rrErrfi

The same principle as for a waterjet is applied in an aircraft jet

engine, but here air is the mediuminstead of water. The principle isbased on Newton's law F = fiI X 4,where F is the force in Newton, mthe mass of the water and a is theacceleration of the water.

The waterjet has an electronicsteering system. This means that theorders from the bridge areimmediately processed by micro-processors. This makes it possible for

the water-jet, engine and gearbox to

be controlled directly from the bridge.

Along with yachts, a lot of passengerand car ferries, rescue and patrol

boats are nowadays equipped withwater jets. In 1998 the first cargo-ships were built with water-jetpropulsion. The maximum speed ofmodern water-jets lies around 10-75knots (appro-ximately 135 km/h).The fastest ferries can reach a speedof appro-ximately 50 knots.

Sl t i p tl ri v e n lt.t, tv' u t e r,i e I 1t rt t Stt r I's i r t n

Wr t I c r I u b r i c o t i u t t t u i I s I t cr.fi,\' )',\ t e n t


nfi$iot (J)

258

( r r . r r , r - .srr '1r ot t t t l ' \ r ( t l ( t ' . j ( l ( \ \ ' l i r t ,v i l l i Pt t tPtr l .s i r t t t . l t ' t ' t )

l . In let2. Driving shaft3. Impeller4. Hydraulic steering cylinder5. Jetavator, steering part

6. Hydraulic cylinder that alters thedirection of the propulsion

7. Reversing plate, can be movedby the cylinder

8. Reverse section9. Sealing box to prevent water

from entering the shipl0.Combined guide and thrust

bearingI l .Nozzle

\rr1r' t ' icn tt,f u vr.ttct' jcl

i t r l l t t l t t ' t t t l

i i rTr f i311' r t f 'u wulcr ic l

I tcr i t tq ( ' ( )u) , \ ( , to l t r t t ' t ,s idc


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,cnt l l t ru,s l

,ft-

'4;' +<

A , -@ r,ii

'4#' )

Et

259

The advantages of water jets are:- no rotating parts under water.

This makes it safe to manoeuvrein shallow waters.

- less resistance, especially athigher speeds, because there areno fittings (e.g. the rudder)suspended below the ship.

- excellent manoeuvring capabili-ties. For instance, a ship cannavigate sideways without anyproblems.

- less sensitive to cavitation thanpropellers on fast ships.

- high efficiencies of up to 72Vo

3. Rudders

3.1 General

The function of a rudder is to steer theship. The rudder is usually located inthe water-flow aft of the propeller.Depending on the type of ship, thearea of the rudder is approximatelyI.67o of the underwater lateral area(length x draught).

The rudder should be shaped in sucha way that the water-flow can bedirected as effectively as possible,coupled to a minimum resistance.

Giving the horizontal cross-section ofthe rudder a wing-profile satisfiesthese two demands. In fact, the rudderis a vertical wing, on which a liftingforce is generated by the water-flowin the same way that an aeroplanewing, propeller blades and a nozzleget a lift. This is also known as therudder force. The drag should be assmall as possible. The lifting forcegives a turning moment around theship's centre of displacement: this iswhat rotates the ship. l'l L

Setting in tlrc heel of a,flap ruckler

For slow speed manoeuvring therudder should cover the propellerdiameter as much as possible in orderto make optimal use of the water-flowof the propeller.

The force that the steering enginemust supply depends on the torque(force x distance) that must be appliedto rotate the rudder.

This force is the resultant (N) in thedrawing. The total momentdepends on:- the position of the rudder stock

compared to,the point ofapplication of N

- the distance between the rudderstock and the leading edge of therudder (balance).

When the rudder is free hanging, therudder stock must also be able toabsorb the total bending forces of therudder (spade type).

Depending on the rudder-profile, therudder stock is located at 25-477oabaft the leading edge of the rudder.

Crnic:ul c'ounectiott betv;een tlte rudder

,stock unrl the rudtler blurle

A r:ontrolltrltlc pitt;h propeller uncl ct.flttp

rudder o.f u multi-purpo,te ve,sse l. 7'1rc

mulersicle o.f tlrc rudder stor'li c'utt bc

seen in tlrc nLdder.

Most rudders are hollow and empty.The inside is stiffened with horizontaland vertical profiles.

Section 3.2 will only describe free-

hanging rudders. In smaller vessels(like fishing boats), however, ruddersare still supported in speciallyconstructed heels, or with marinerrudders at half height (bigger ships)

Suspension of the rudder.The drawings and photos will give anidea of how rudders are supported.

velocity of water-flowliftdragresultant forceunder-pressureover-pressuredistance between the rudder-stock and the point ofapplication of NHoriz.orttcLl uo.rs-seclion oJ'tlrc rudder blatle ol'a balance rudder


+

V =L =D =N =

t -

4+F.t otjer stocr rurlF;lrt N *

260

Construction of part ot'tlrc cli ship tf ct

contuiner .feeder

Top view

1. Transom2. Steering flat3. Aft perpendicular = rudder axle4. Rudder5. Rudder trunk6. Space for the rudder stock7. Ice-protection8. Rudder domp'(Gddwood)9. Stern post or propeller post

lO.Wash bulkhead on centre line11.Wing platel2.Centre line propeller shaft13.Side keelsonl4.Floor plate

Side view c$'the ship's centre plane

12.

Frame ctt aJi

perpendicular

(frcune 0)

Frutne number 2

Cctnstntction of'parf o.f the aJi shtp of a crtntainer feeder


3.2 Tlpes of rudders

The most common rudder-types are:1. spade rudder2. flap rudder3. mariner rudder4. fish-tail rudder

1. In terms of construction, the spaderudder is very simple because it hasno supports. For this reason it is avery cheap rudder and it is widelyapplied, from yachts to fast ferries.The rudder becomes narrower fromtop to bottom.

. ' \ .spr t t l t ' r r r t l r lc t on ( t t tc . f ( t ' , l t t ' r ' ly

strs l t t ' r t t l t ' t l ln tnt l l tc t 'L t t l t la t ' t l r t t t t t '

2.The flap rudder has a hinged flap atthe back of the rudder blade. This flapis moved mechanically by the flapguide at the top of the rudder in sucha way that the flap's turning angle istwice as large as the turning angle ofthe main rudder blade. The steeringmethods of the flap differ per type offlap rudder. When the maximumrudder angle is 45o, the flap has amaximum angle of 90o with respect tothe ship. In this rudder position it is

Ship Krtotvledg,e, a nrodent encyclopedicr

possible that 40Vo of the ship'spropulsive force is directed sideways.In combination with a bow thrustersuch a ship could navigate transversely.

Advantages of flap rudders are:- extra manoeuvrability (that is, if

the main rudder blade is as largeas the spade rudder

- course corrections can beperformed with smaller rudderangles. This means that the shiploses less speed and thereforeconsumes less fuel

Explanation of the image on theright:

1. Rudder blade2. Rudder-stock in rudder trunk3. Flap4. Hinge line5. Steering engine6. Steering engine foundationl. Gland and bearins8. Rudder dome9. Bearing with a diaphragm bush10. Flap actuator

Disadvantages are:- the price- vulnerability- the larger rudder forces require the

rudder stock to be bigger.

' l v r t t . l l t tp t ' t tL ldcr t t t t t t l t ' t ' t t l t t rq t ' t t r t ' ,go . i t ' t ' t ' '

f " l t t l t r L t r l t l< ' t

262

3. The mariner rudder is used onlarge ships like container ships, bulkcarriers, tankers and passenger liners.

Tlp slpn pest j5 )ntsgratad ints thsship's construction and the marinerrudder is attached to the stern postwith the ability to rotate. This resultsin a robust rudder. Disadvantages ofthis construction are that there is alarger risk of cavitation at the suspen-sion points and that the cast construc-tion is more expensive

cone bl@k

Rernot,al of' c'omplete rudrle r w'ei glrt

approsimatel" 120 tons

Crn*truction of a muriner rudder

Current.flo\t's at maximum rtrclder angle


4. The fishtail rudder isgenerally used on smal-ler ships with a speed ofless than 14 knots. Themanoeuvring qualitiesof this type of rudder liesomewhere in betweenthose of the spaderudder and the flaprudder.

View of motor ranker 'Stcttus' itt dr,vdrtck

[;'itting of pintles to trey' bu,sltings

Aligtunent of ruclcler and stoc'k in slutlt

Muriner ruclcler

Water l low when lhe helm rs lurned

Top vieu, o.f a .fish tuil rudder

263

3.3 Steering engines

1. General

When it is decided, on the bridge, toalter the course, the automatic pilot orthe helm is used to activate thesteering engine, which, in turn,rotates the rudder-stock and therudder. The rudder carrier supportsthe rudder-stock and the rudder. Therudder carrier also functions as abearing around the rudder-stock, andit seals the rudder trunk to preventseawater from entering the ship by agland. SOLAS demands that everysteering engine should be equippedwith 2 sets of pumps and,consequently, also 2 servo sets,serving the hydraulic pumps. Both theram and the rotary vane steeringengines operate by hydraulic power.Both types of steering gear areequally common in shipping. Themagnitude of the steer or ruddermoment is expressed in kNm (kilo-Newton-meter). In general thegreatest rudder moment occurs at30-35 degrees.

\2. Ram steerin[ engines

/In ram steering engines, the rudderstock is rotated by a tiller that, in turn,is controlled by the rams. A ramconsists of a cylinder and a piston.The tiller and the rudder stock areoften linked by a conical connection.Ram steering engines may have 1ram, two rams or 4 rams. If thecylinders are double-acting, thesteering engine can still operatethrough one of the cylinders when theother one fails. This is also arequirement of SOLAS.

1. Rudder stock2. Tiller3. Ram (piston + cylinder)4. Hydraulic lines5. Electro-motor6. Protection of coupling between e-

motor and hydr. power pack7. Pump in tank filled with oil

(power pack)


, Double-acting cylinders in a ram steering engine of a small ve,ssel

This steering engine has even,

cznt.poneti in pair,s

2

Ram,sfeering engilrc on ct large ,sltilt

(turning the rudder to starboard)

,*"

Ram steering engine of a large .rhip

264

3. Rotary vane steering engines

Arotary vane steering engine consistsof a fixed casing. Inside the casing isthe rotor to which wings are attached.This arrangement divides the houseinto four chambers, two high-pressure, two low-pressure ones. Avalve block directs hydraulic oil athigh pressure into the chamberssimultaneously, pushing/rotating therotor and subsequently the rudder. Ifthe rudder is rotated to the other side,the high-pressure charnbers becomelow-pressure chambers and viceversa. The rudder stock is located inthe centre of the rotor; the rotor ispressed onto the conical section of therudder stock. The wings and the fixeddivision blocks are provided withspring-loaded plates which are theseals between the high- and low-pressure oilchambers.

The advantages of a rotary vanesteering engine over a ram steeringengine are:- it takes up less space- it is easier to build init has an integrated bearing- it has a constant rudder moment

The disadvantage:- it is not easy tJ\pair and

maintain. )

Schematic overview of a rotary vane steertng enginet

1. Space for rudder stock2. Rotor with wings3. Fixed division blocks with oil lines4. Chambers (filled with oil)5. Electric motor6. Hydraulic pump in oil reservoir7. Valve block


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l. Preface electricity

2. Electrical installations

3. Insulated and earthed dis-tribution systems

Basic design criteria

Type of service

Type of operation

Electromagnetic compatibi-

lity EMC.

Equipment

Generators

Electric motors

Cables

Switchboard and switchgear

assemblies

Circuit breakers and

contactors

Type-approved equipment

Starting devices

Emergency generator

Automation

7.1 Alarm, monitoring andcontrol systems

8. Communicationsvstems

8.1 Internal communication system8.2 External communication svstem

9. Navigation and nauticalequipment

10. Dangerous areas

11. Operational settings

11.1 Factory acceptance tests11.2 Harbour acceptance tests11.3 Sea trials

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L. Preface electricity

This chapter has the intention to explain the sequence of design, installation andcommissioning of the electrical installations on board. Electricity comes in twobasic types Direct Current (DC) and Alternating Current (AC). DC is eitherproduced by static electricity as lightning, by a chemical process in batteries,fuel cells or by a dynamo converting mechanical energy into Direct Current.

DC can be stored in an accumulatorand later retrieved when required,allowing for various capacities ingeneration and consumers. Anexample is a conventional diesel-electric submarine. In modern shipsDC systems are limited to smallinstallations or transitional sources ofpower. UPS units or unintemrptedpower supply units are a combinationof a battery-charger converting ACinto DC, a battery storing the DC anda converter converting the DC intoAC. These units are often used forcomputer power supplies where anuncontrolled shut-down would leadto loss of information or crash of theprogramme. Small units are used intransitional lighting fixtures. Dis-advantages of DC systems are DCgenerators with collectors andbrushes, complex switch-gear. Motorswith collectors and brushes allrequire a lot of maintenance and getmore complicated when the sizeincreases.The basic result of the simplestgenerator consisting of a movingmagnet inside a coil is an alternatingcurrent, AC. Even a bicycle dynamois such a device. For larger sizes thepennanent magnet has been replacedby an electric DC magnet suppliedthrough slip rings; Later the main-tenance unfriendly slip rings werereplaced by an exciter, a sort of

rotating AC transformer with recti-fiers on the rotor. First AC wasalternating current single phase, laterit became rotating current 3-phase.Alternating current allows for simpleswitch gear. The current goes down tozeto every cycle and the arc over anopened contact extinguishes itself asthe voltage is zero.

Alternating current is a very suitabletransport medium of energy forlighting, small power and for controlsignals. The conversion of AC singlephase into rotating energy requires anauxiliary coil to define the direction.

Small electric single-phase motorshave an auxiliary or starting winding.A logic evolution after the single-phase AC system is the three-phaseAC or rotating current system.

Ligltnilry, alwavs ctn intpres,sive yvctste of energt,

AC generatrsr under nruintetnnc'e


The permanent magnet of thegenerator now rotates within threewindings physically spaced 120degrees from each other, creating anAC current in sequence in each ofthese windings. This rotating currentmakes it possible to power a simpleAC squirrel-cage motor having thesame three windings similarly spaced.Reversing is done by changing twophases, thereby changing the direc-tion of the rotation field. A furtheradvantage of this three-phase systemis that when the load is equallydivided over the phases, the sum ofthe three phase currents is zero, sothat the zero or starpoint-conductorcan be deleted or reduced in size. Thiseffective distribution system is widelyused on ships and shore installations.

2. Electrical installations

Electric installations in ships are avery complete part of electricalengineering as they cover everyaspect of power generation, switch-gearing and distribution to every typeof consumer.

Also all types of automation andremote control are part of it as well asinternal and external communication,navigation and nautical equipment.However, the basic difference withshore based electrical installations isthe necessity to be self-supporting:that is, either to have the personneland necessary spares on board, or tohave the required redundancy to beable to reach the next port in case of afailure of a single system orcomponent.Some types of ships and offshoresystems require this redundancy, notonly in cases of electrical or mecha-


r y " W t r y t . re

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nical failure but also in case of otherevents such as fire in a space orflooding of a space.

The way an installation is operated, isessential to appraise it, such asmanned engine room versus unman-ned, computerised control systems,one man on the bridge (the NAV-INotation).

All the above considerations willhave their consequences for the basicdesign, including the location ofequipment and the cable routeing.Applieation of high-tech control andcommunication equipment and alsoapplication of high-powered semi-conductor drives requires a study forelectromagnetic compatibility (EMC)and the application of EMC mea-SUIES.

3. fnsulated and eartheddistribution svstems

The first AC ship's installations weresmall; the cable insulation quality waspoor and redundancy by duplicationwas rare. To be able to continue tooperate with a single earth fault theseinstallations were insulated, withoutearthed neutrally. This enabled theship to continue to operate whilesearching for the earth fault. Nowa-days the installations are large and thecapacitive coupling of the cablenetwork to earth is large. Conse-quently the current resulting from thefirst earth fault can be something likesome amperes, which is equivalent t0a heater of some kilowatts at alocation you do not know. It is alsotherefore wise to promote the 3-phase4-wire neutral earthed distributionsystem, also because all other conditions,as voltage surges due to switching,are more alike to shore installations.

,\ ' ,,{1/-i IJt irl::<'

269

Marine electric equipment used to bespecially made for ships but is nowhigh-tech industrial equipment onlyadapted to the shipping environment.

4. Basic design criteria

The criteria, such as type of service(the expected location of the serviceof the ship), the type of operation bycrew (both in the engine room and onthe bridge), the redundancy criteria,basically take into account a singleelectric or mechanical failure. and themaintenance criteria for being self-supporting or being supported by ashore-based maintenance system,form the basis of the design.

The basic design inclusive of suppor-ting information as short circuitcalculations, one line diagrams,selectivity diagrams, material lists,lay-out drawings and an operationaldescription is to be approved by theClassification Society. Also therequested Notation (quality code oncertificate) of the ship is taken intoaccount. Basic one-line diagramsshow the principal lay-out of theelectric installation indicating quan-tities and ratings of generators,electrical arrangement of main-busbars, showing also any separationand the division of the essentialconsumers over the busbar sections,power-supply circuits to distributionboxes and panels throughout the ship.A basic one-line diagram tells more ofthe electric installation than pages ofspecifications.

Selectivity is a sequence of settings ofprotective devices in order to switchoff a faulty circuit as close to thisfault as possible, leaving as manyhealthy circuits live as possible. Thisrequires expensive and fast circuitbreakers. When more cicuit breakersare in series as in the case with sub-switchboards and further down-stream circuit breakers the solution ismore difficult. Maintenance on boardmodern ships is usually by a plannedmaintenance system, dividing therequired checks and tests over themaintenance period. Furthermore, bymeasuring more parameters of the

rlrc laurtfiiis of the.firsr

installation and diagnostic program-mes the expected failures can bepredicted and appropriate measurescan be taken at the next suitable portof call.

4.1 Tlpe of service

Inland Waterways: this type of ship islimited in its operation area. Assis-tance in the form of help by a firebrigade or tugs is more likely to beavailable. The requirements for fire-pumps, emergency battery capacity orfuel tank contents are less than therequirements for unrestricted service.Also the requirements for commu-nication equipment for inlandwaterways are less than those forcoastal service.

Coastal service: coastal service shipsoperate in a limited area, in generalcovered by a local communicationstation and covered by some sort ofservice organisation. So again therequirements for battery rating,communication equipment and redun-dancy in essentials is limited, as helpis available at short notice.

A brontl-nev, coctstguurd vessel .f'orc'oastaL seryice at tlte ./'itting-out cluay o"f

tlte building ))ard

Th,o tliesel-elec'tric' inluul wotenN'oy ferries in senice behteen k.rel tuul Dett Heldet

the Netlterlands.

Tlte tv'o " Blue Star S iste rs " c(ie r lcwrclting of the secottd ve,s'sel ortly Jou r month.s afte r


Unrestricted service: no help is to beexpected from shore and thus therequirements for redundancy, battery-time, emergency generator capabilityare maximal by SOLAS rules

4.2 T\pe of operation

Manned: manned engine rooms utrerare nowadays as they require more(expensive) crew and the engine roomenvironment is usually warm, dampand noisy. Modern automationsystems as remote-control systemsand alarm and monitoring systems,make it possible to operate mostengine rooms unmanned, at leastduring part of the time. In the normalday shift the engineers can executeplanned maintenance and repair orreplacement of defective parts. Forsmall simple ships with simpleelectric installations and for smallships for countries where personnel ischeap, it may be feasible to design amanned engine room and delete theexpensive and complicated auto-mation for remote control, alarmand monitoring systems. Automaticstarting of a stand-by generator set,automatic closing to a dead busbarafter failure of the running set andautomatic starting of all essentialelectric consumers is, however, aSOLAS requirement for all ships,whose propulsion depends on elec-trical power, also for those withmanned engine rooms.

Manoeuvring stand in engine roon of 50

,vear old possenger sltilt "Arwstasis"


Unmanned: Notation UMS.Most of the ships nowadays sail withunmanned engine rooms. As a conse-quence they require a fire detectionsystem, automatic safety systems formachinery, remote control systemsfor machinery, automatic controlsystems for air compressors, auto-matic starting of stand-by pumps forpropulsion auxiliaries as seawaterpumps, freshwater pumps, lubricatingoil pumps, fuel oil pumps, propellerhydraulic pumps and an alarm andmonitoring system.

Above systems must be arranged insuch a way that under normal opera-ting conditions no manual inter-vention by engineers is required.Alarm and monitoring functions andsafety functions must be independentfrom each other.

Engineer safety systems (dead manalarm) must be fitted in case a singleengineer is in the engine room formaintenance or fault finding. Usuallyautomatically started when an alarmis accepted at the engine controlstation.

One man on bridge: Notation NAV 1.Periodic operation of the ship underthe supervision of a single watchkeeper on the bridge is becomingnormal practiid on modern ships. Theprinciples are the same as those for anengine room with one man on watch.The requirements are as follows:alarm and warning systems asso-ciated with navigation equipmentshall be centralised and be both visualand audible for efficient identi-fication. Other possibilities for theNotation of the navigation functionsare Integrated Bridge Navigation

B r i d g e c' rnts o Le,,lLlSS "Disr: ov e h- ", a h i g h -

speed ltassenger ferrv

Systems (Notation: IBS). Theserequire in addition duplicated gyro-

compasses, differential global posi-tioning system, route-planning capa-bilities, auto-track capability, andelectronic chart display.

5. Electromagnetic compa-tibility (EMC).

The shortest definition of EMC is thecapability of neither to disturb nor bedisturbed by the environment. This isapplicable to all equipment on boardof a ship. Disturbance is both radiatedand conducted through the connec-ting cable network. EMC appears tobe a complicated and time consumingexercise. It starts with listing thesensitive equipment and verifyingtheir acceptance limits and thenlisting the disturbing equipment. A lotof this work has been done. This hasbeen laid down in IEC 945(International Electrical Committee).IEC 945 defines the susceptibilitycriteria for navigation and nauticalequipment. Also the disturbingsignals, frequency and power, or theenvironment one can expect on theopen deck and inside a wheelhouseof a normal ship, are defined in thisstandard.

Most navigation and nautical equip-ment has been tested for approval tomeet these criteria.

Top deck of a ntodern ship slnwing the

comproni,se in instctllation o.f' a trans-

mittittg disturbing ruclar aerial cutd tlrc

VHF receiver aerials.

271

Auxilian, engine room of a.ferry

6. Equipment

6.L Generators

A generator is a simple device toconvert mechanical energy intoelectrical energy. Usually theygenerate rotating current 50Hz or60Hz leaving for direct-drivenmachines of the following enginespeeds of 500/600 RPM, 6001720RPM, 7501900 RPM, 1000/1200RPM, 1500/1800 RPM and 3000/3600RPM. The higher figures are mostlyfor smaller generator sets or turbine-driven machines.

Main -engine driven generator

6.2 Electric motors

Electric motors are simple devices toconvert electrical energy intomechanical energy. AC squirrel cagemotors have the same RPM restric-tion as AC generators. Motors areavailable in different casings forfitting on a foundation or flange forfitting to a pump. Also variousprotection classes against the ingressof solid particles and water are


available, and for use in an explosiveenvironment increased safety "non-

sparking types" and flame proofmotors are available.

6.3 Cables

Cables form the connections betweenthe different parts of the electricinstallation and are nowadays avai-lable as low-smoke , low toxic andeven fire-resistant types. Applicationof such more sophisticated cables willreduce the consequences and damageof a fire. The commercially attractivePVC insulated types are vulnerable incase of fire. The insulation burns.

causing short circuits. They generatehigh quantities of toxic and corrosivegases which will damage a lot moreof the installation than that damagedby the fire only. However, a disadvan-tage of the low smoke types of cablesis that their mechanical properties areconsiderably less.

Cable troys and pipes in the corridor

behveen the.frtrward and aft engine rocnn

of a stone-dwnping vessel

Electric driven pumps

272

6.4 Switchboards and switch'gear assemblies

Switchboards and other switchgear

assemblies basically serve to connect

and disconnect generators and

consumers to the main Power suPPlY

system. They contain also the

protection devices of the generators,

the cables and the consumers against

overload and short-circuits. Switch-

boards and other control-gear assem-

blies can be operated bY engineers,

but servicing and maintenance and

repairs should be carried out bY

specialists.

Laws in most countries issue a cleat

instruction of how to Power a Part of

an installation safely, to eaffY out

repairs and power up safelY after-

wards. It also defines skil ls and

responsibilities of the operators and

maintenance people. The main diffe-

rences between an industrial switch-

board and a marine switchboard are

protection class IP23 with closed

doors. In case of open doors, protec-

tion class IP20, handrails, door catchers

in open position, measuring and indi-

cation instruments to be able to

synchronise and for load sharing of

both power and current etc.

When electric power is required forpropulsion of the ship, the source of

power is to be duplicated and the

main busbar in the main switchboardis to be divided in two Partsconnected by a removable link for

small installations up to full-size

circuit breakers with selective protec-

tion devices for large installations.

Duplicated essential consumers shall

be supplied each from a side of the

switchboard, or when supplied from

distribution-boards from separatedistribution-boards, each suppliedfrom a side of the main switchboard.All of this with the same target that a

single fault does neither impair the

propulsion system nor imPair the

habitability for the crew. This single

failure also includes a fire or other

damage to a cable tray. Therefore the

power cables and control cables to

essential duplicated consumers shall

be separated.

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.fttt 'tort'testirtg

I Gcnerulrtr cin:uil brctrker

2, \ t t . r i I i t t r t ' .q{ ' I I ( r ( t | ( , t ' pr t t t c I

Synchronising equipment must consist

of a check synchroniser, blocking a-

synchronous closing of circuit

breakers in any mode, also manual.The final emergency mode of closing(pressing the mechanical controls at

the circuit breaker front) is allowed to

be unprotected. Further the synchro-

nising equipment is to consist of a

double voltmeter and a double

frequency meter giving the voltage

and frequency of the busbar and those

of the incoming machine. These

instruments may also be replaced by a

multi-function instrument per gene-

rator which enables the read-out of

voltages between the Phases and

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between the phases and the neutral if

applicable, phase currents, Power,reactive power, frequencY etc.

Having the voltage and frequencYright, this still does not mean that the

busbar and incoming machines are

synchronous. Synchronising lamps

fitted between the same phase of the

busbar and the incoming machine

indicate synchronism when dark. Two

of these lamps are normally fitted to

avoid confusion with a broken bulb.

A Delta voltmeter gives the same

indication. The flashing of the lights

or reading of the voltmeter also gives

an indication of the frequencY

difference.

l r l f l I


A synchronoscope operates like anAC motor with the stator connected tothe busbar and the rotor with thepointer connected to the incomingsupply. When synchronous thepointer is standing still at l2 o'clock.The frequency of the busbar and theincoming machine is thus the sameand the voltage synchronous. If theincoming machine runs too fast, thepointer rotates clockwise; if too slowanti-clockwise

6.5 Circuit breakers andcontactors

A circuit breaker is designed to closeand interrupt a short-circuit current afew times only without maintenance.A contactor is designed to withstandthousands of times the startingcurrents of electric motors. A circuitbreaker is therefore not suitable tostart a large motor. Switching capa-bilities are given under different con-ditions. Some manufacturers give acapacity only once possible.

Circuit breaker Mustt:rpact NT 1600 A

Moulded case circuit breakers,especially the current limiting typescan be replaced as a complete unitonly.

A synch r t t i l i . r in ,q pt t t tcLshrtvt ' i t r g, :

l. Circuit breuker clo,sin,q pu,sltbttttott,s

2. \.bl t nr ete r ltu,s lxLr-gute r(tto r

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6.6 Tlpe-approved equipment

Type-approved equipment is equip-ment tested to be suitable for themarine environment as stated in theclassification rules.

The marine environment is defined asfollows:

- Temperature air 45o centigrade(other figures can be agreed onrestricted services)

- Temperature seawater 32ocentigrade (other temperatures canbe agreed on restricted services).

- Maximum humidity 95Vo non-condensing.

- Trim t 5o

- Pitching * 5o

- List t22.5" roll t 22.5"

- Vibration, Shock, radiated andconducted interference EMC

- Susceptibility to radiated andconducted interference EMC

- Voltage and frequency variations

- Total harmonic Oist6rtion

- Functionality of the equipment ingeneral, performance data,accuracy etc.

All essential equipment shall beselected from the lists of type-testedequipment. If an equipment is notlisted at least it shall fulfil therequirements for type-testing asavailable from the ClassificationSocieties.

6.7 Starting devices

Staning devices are used to limit thein-rush current of a consumer whenconnected to the main power supplyto an acceptable value. That is to avalue that does not disturb the properfunctioning of the other devices in theinstallation. Starting devices are alsoused to limit the starting torque of anelectric motor, so to protect a delicate


gearbox from the harmful forces ofthe direct-on-line starting by staningstar/delta or starting slowly by afrequency converter.

A starter drawer

6.8 Emergency generator

An emergency generator is a gene-rator with the same characteristics asa main generator but located in aspace separated from the maingenerators and independent of anyequipment outside this space. Sostarting equipment such as- an airbottle with a non-return valve of theengineroom starting air system, aseparate fuel tank, an emergencyswitchboard in the same space as thegenerator set to limit the possibilityof failure of the emergency system incase of failure of a space. This all toensure continuity of emergencypower as much as possible.

For large ships and ships carryingmore than3? passengers, the requiredcapacity of the batteries for emer-gency lighting and communication istoo big to handle practically. Aseparate emergency generator with itsautonomous fuel tank, startingsystems and switchboard, whichautomatically starts when the mainpower fails is required. Also thesupply cables to the various emer-gency consumers is to be away fromthe spaces containing the main powersources.

An initial starting system, that is astarting system capable of starting theemergency generator without anyhelp from outside with all normalstarting gear out of order, is to beprovided. This initial starting systemmay consist of a hand-started diesel-driven air compressor in case of air-started engines or a spare battery.

An engine-control system under type approval test in an EMC laboratory

An emergency generator

275

T'he engine contrctl console o.t'' "Blue

Stut's" dnring tlrc corntnis,sir,tning,

c0ntamutS:

I Main engine I c'ontrol and

utstrurnent(firon

2 Emergencl, telegraph port shaft

J Viscositl: crmtroller.fuel main engine,s

l a r d 3

4 Main engine 3 c'ontrol arul

instrunt.entation

5 Mctin engine I and 3 RPM and

Tt trboblower RP M indicators

6 Propeller pitch and RPM indic'otor.r

pitch control.y alsct change-over

,r v-stent .fo r bri d ge control

7 Mctin engine 2 control and

iltstrutnetttttiott

8 Viscosity controller.fuel main engine,s

2 a r d 4

9 Etnergency telegraph stbd shaft

I0 Muirt engines 2 and 4 RPM and

turboblowe r RPM indicctto rs

I I Main engine 4 contntl tutd

in,strumentatiort

I 2 Vi scosity controller .fhel auxil iary

enSmes

l3 Autornatic teLephotrc s),-stem

l4 Alarm and mr nitoring vi,sual di,splat,

Luuts

I5 Operator ket,boardr

7. Automation

Automation is intended to make theoperation of the installation morecomfortable, easier, and last butcertainly not least, make it possible tooperate the system with less crew. Italso facilitates automatic observationof systems, registration of failuresand registration of service time. Thisto organise planned maintenance. Itstands to reason that no computersystem is able to motivate a crew toperform. Automation is also intro-duced to execute actions which aretoo complicated to be handled by acrew member within the availabletime. This is for instance applicable toa thruster-control system of a shipwith 8 thrusters where the 8 azimuthand rpm control levers are substitutedby a single joystick, creating thesummary of the desired results ofthese 8 thrusters

However, the level of automation isdependent on a lot offactors, such as:- requirements of the owner- function of the ship- cost reduction- qualifications of the crew- complexity of the installation- rules and regulations of the

Classification Society and theflagstate (registry)

It will be clear that first of all acost/availability analysis has to bemade before starting planning ofautomation.

Integration of systems, introductionof distributed control systems consis-ting of programmable logic control-lers with remote input and outputmodules, connected through a two-wire bus system is now normalpractice for larger systems. Anoperator friendly software package ona PC type work station is simplifyingcontrol and supervision in an unstop-pable process. It reduces cost ofcabling and manning. The problem isthat the Rules and Regulations of boththe Classification Societies and thelaws of the national authorities are notsuitable to include the constantprocess of change and improvement.Rules have to be made or read moreflexible to express their intendedfunction and not the way things aredone in practice. Basically becausethese ways change all the time.Redundancy both in hardware andsoftware, is a logical requirement.Software shall be made in a structuredway and testing of the different partsand later the total system shall formpart of the acceptance procedures.Software shall also be well docu-mented, inclusive of changes andextensions. For essential systems, thatis, systems required for sailing andfor the habitability of the crew,sufficient back-up or emergency con-trols shall be fitted.

A summary of the most importantsystems which are available:

- Engine room alarm andmonitoring system, usuallyconsisting of simple displaysgiving status and analogue values.

- Marine operator work stations;more sophisticated systems alsoincluding control and presentationof engineroom systems bysophisticated graphics trends, thatis, figures stored over a period oftime; analyses, calculatingrelations between figures;calculation of running hours.Whatever you can think of, tomake it more comfortable for theengineer to control and supervisean installation as well as possible.Automatic logging of all figures asrequired by the authorities etc.

Etrgine control systemjitted to an engine


- Tank gauging systems, fromsimply sounding figures heights tomore sophisticated giving of tankcontents in m3 or even !r tons.

- Reefer monitoring systems. Herealso from simple failure alarms tocomplete datalogging of thereefer temperature, CO2 contentover the whole voyage (to provethat transport was not to blame forcargo arriving damaged).

- Generator control and powermanagement system, fromminimum automatic starting of astand-by generator in case offailure of the running generatorand sequential restarting of allessentials to a complete load-dependent start-stop of thegenerator plant. Inclusive ofautomatic power reduction in caseof failure of a running generatoruntil the next generator has started,synchronised and taking load.

- Propulsion remote-control systemsfrom straight-forward remote-control systems where each handlecontrols a single engine orpropeller, to more state-of-the-artsystems where the desired result isinput, such as for example "move

25 metres to port, rotate with therotating point astern through 90'clockwise". Track following, evena link in location, water depth andspeed are feasible.

So in automation there is no technicallimit and therefore a balance inexpected results and cost shall be thebasis for the design.

\

7.L Alarm, monitoring andcontrol systems

Alarm and monitoring systems areavailable in all sorts and sizes startingfrom a little self-contained unit for 10digital alarms with a common outputfor a group alarm and an audiblealarm with accept and reset facilities.Alarm and monitoring systems areintended to monitor and registerautomatically all the essentialparameters of the installation anddisplay any abnormality occuning. Itsaves time-consuming watchkeepingrounds, registers more and probably


more accurately the events, but iscertainly no real replacement for anengineer finding a slowly growingsmall leak in a flanse.

The alarms are presented by anilluminated "LED" and a nameplate.Depending on the size and intendedNotation such as "manned" or"unmanned" engineroom larger sys-tems often composed of distributedinput units linked together through aredundant network, still presentingthe alarms as simple illuminated"LEDs" with a nameplate for identi-fication. It can also initiate groupalarms to the bridge instructing thebridge crew to reduce power or warnthem for an automatic shutdown ofthe propulsion system. Most morecomplex systems facilitate a graphicdisplay on a visual display unit orworkstation with all kinds of softwareto enable analysing of the retrieveddata. Automatic preparation of aengineer's logbook only to be signedis also possible.

Essential automation systems shall becomposed of type-approved equip-ment and be subject to an acceptancetest at the manufacturer's works underconditions as real as possible.

8. Communication systems

8.L Internal communicationsystems

Talk-back systemThe main station is normally installedin the wheelhouse and can communi-cate with each sub station. The sub-stations only can make a connectionto the main station and not to theother sub-stations. Normally thissystem is installed in the wheelhouse,engine room, steering-gear room andon fore-deck and after-deck.

Automatic telephone systemWith this system, which is identical toyour telephone at home, duplexconversation between telephones ispossible.

Sound powered telephoneThis system is independent of thevessel's main power supply and meetsthe demands for emergency commu-nication between vital positions onboard such as wheelhouse and engineroom. Most automatic telephonesystems operate nowadays through aUPS system. Therefore the sound-powered system is getting obsolete

Public address systemWith this system one way commu-nication is possible. It is used toaddress large quantities of people andto page people. It is also used to givethe general alarm signals. The systemand cable network shall then meet therequirements for general alarmsystems such as: duplicated ampli-fiers, separated circuits, fire resistantcables and other require-ments toensure that a single failure in the shipdoes not abuse the rest of the systemoutside the damaged area.

8.2 External communicationsystems

GMDSS stands for Global MaritimeDistress and Safety System. It usesthe satellite communications nowavailable through the InternationalMaritime Satellite (INMARSAT)

System.

INMARSAT is a co-operative organi-sation, which includes about sixtycountries. They fund and takecompensation according to eachmember's use of the system.Geostationary satellites are sitedabout 36,000 kilometres over theequator to provide complete globalcoverage except in the extreme northand south arctic regions. The system

NAV-I Briclpe la\,-out

277

provides automatic communicationwith an override facility for distresscalls. Several service standards areprovided.

9. Navigation and nauticalequipment

Normally the following equipment isinstalled:

One RADAR with ARPA functionand rotating transmitting/receivingaerial usually X-band (frequency

8-I2 GHz), wave length 3cm.A second radar is to be providedfor ships bigger than 500 GRT.This is usually an S-band radar inthe frequency range of 3-4 GHz,wave length 10 cm. The reason toselect two radars with differentfrequency-bands is their differentcapability to cope with theenvironmental conditions suchas fog, rain, sea-clutter etc.Two independent automaticposition fixing systems: GPS or,more accurate, DGPS withomnidirectional satellite aerial andfor DGPS also a parabolicdifferential aerialOne EchosounderOne log with speed and distanceindication /One magneti( standard compassOne gyrocompassOne automatic pilot

Bridge wtng console.


Today's state-of-the-art wheelhousescan be arranged for operation andwatchkeeping by one person only.Apart from wheelhouse layout requi-rements with respect to an all aroundview (view from the operator's posi-tion), facilities as route-planning(location usually a chart table), thecommunication GMDSS console andthe navigation workstation with off-normal alarms and watchkeeper well-being check are to be fitted.

L0. Dangerous areas

Dangerous areas are those areaswhere due to the continuous or part-time presence of gases or flammableliquids or even explosive dust, therisk of explosion exists.

Dangerous areas are, for example, thetanks of a tanker and the deck above,the cargo-handling area, pump roometc., but also the car-deck of a ferrywhere cars are stowed with fuel intheir tanks, a helicopter refillingstation on a yacht and a paint store orthe hold of a dry-cargo ship certifiedfor the carriage of dangerous goods.

yft, deck IWW Tanker a danserctus

Cost-effective solution number one isnot to install any electrical equipmentin dangerous areas. The dangerousareas are divided into the followingzones:

Zone 0 Areas where an explosive-gasatmosphere is continuously present orcan be present. For example, a cargotank of a crude oil tanker, oil productstanker or chemical tanker carryingflammable liquids other than lique-fied gases having a flash point notexceeding 60 'C and for liquefiedgases the cargo tank and the secon-dary barier spaces.

Zone l Areas where an explosive-gasatmosphere will be periodicallypresent during normal operation. Forexample, spaces adjacent to andbelow the top of the cargo tankscarrying crude oil, oil products etc.with a flash point not exceeding60 "C. Spaces separated by a singledeck or bulkhead from zone 0 areas,also cargo pump rooms and enclosedand semi-enclosed spaces in whichpipes containing above cargoes arelocated. Also areas on open deckwithin 3 metres of any cargo tankoutlet, cargo valve, cargo-pipe flange,cargo-pump room outlets, 6 metresradius from high pressure dischargevalves and2.4 metres above deck.

Detail of cargo-deck. Electrical controland monitoring equipment. The tank'level indication sy,ttem with tlrc bluecables is executed in intrinsicallv safetechnology and tlrc pump controls on theri g ht in exp lo s ion- proof e.re c'ut i on.

Zone 2 Areas where an explosive gasatmosphere is not present duringnormal operation and, if present, for ashort period of time for tankerscarrying products with a flash pointabove 60'C.

This is the only zone defined for thedry-cargo ships and for Ro/Ro spacesof ferries if sufficiently ventilated.The explosive-gas atmosphere isconsidered not to be present duringnormal operation.

Caution. Liquified natural gas (LNG)

and the vapours from kerosine areheavier than air and any opening to adeck or lower space shall be subjectto further study with respect to thezoning.

GMDSS console.

278

Engine-t'oriro! room "Bltrc Sttu"''. Dtn'i.ug,;eutriuls, spet'itLlists tneu,turesltu.fi RPM nnd

I o rq LLe to rle t c rm i t rc u c t u(tl p o w e r, .fi t c I c r t ns' tt tl't p I t ( ) tL e t c.

The gases are divided into the

following groups:

- Group I: methane such as expectedin coal mines

- Group II: General industrial gases

and gases from combustibleliquids and combustible solids

- Group IIA: Propane- Group IIB: Ethylene- Group IIC: Hydrogen

Apart from the gas group, certifiedsafe equipment shall also be selectedon the basis of the maximum surfacetemperature during operation. This

surface temperature shall be belowthe ignition temperature of the gas

emitted by the cargo as is stated in thecargo lists. Temperature classes andmaximum surface temperatures are asfollows:

T 1T2T3T4T5T6

below 450'C300 "c

200 "c

135 "C

100 "c

85 "C

LL. Operational settings

Before a ship goes into service, trialshave to be performed; first in thefactory the testing of the separateparts, afterwards the equipment wheninstalled and finally at sea.

11.L Factory acceptance tests

Setting for operation starts in the

factory of the equipment makers. The

individual equipment like generators,

motors, switchboards and control-gear assemblies, transformers, alarm

and monitoring systems, controlsystems and all other essential electricparts equipment are tested to prove

that the equipment performs as

specified.

ll.2 Harbour acceptance tests

After the equipment has been instal-led on board the ship and connecteilinterconnected Harbour AcceptanceTests (HAT) are carried out to prove

that the equipment is capable of

functioning together. An example are

the load tests of a diesel-generator set

or a switchboard combination. Further

tests may include load dePendentstart-stop by a power managementsystem with automatic reduction ofpropeller pitch and/or RPM of electric

driven thrusters in case of overload of

the generator plant. A lot of this can

be done in the harbour as it does not

require sailing conditions.

11.3 Sea trials

After successful completion of the

HAT, the Sea Acceptance Tests (SAT)

complete the programme of executing

those tests which do require sailing.They consist of manoeuvring tests,stop tests, etc. All these tests shall be

well documented to be able to use the

facts and figures obtained as a

reference for later.

Water rcsi,s'ltutcc lrt ltttttl tcst r1f gene-

rlt()rs

Fe rrv a Longsitlc .l'ittin g-o ut cl trctv tfu rin g ltn rho u r oc( ept utlcc te sl s


1.1. Wood1.2. Steel

Consbrrction materials for ships

1.3. Aluminium and its alloys1.4. Copper and its alloys1.5. Synthetic materials

2. Corrosion

2.1. The corrosion process2.2.Protective layers

3. Paint

3.1. General3.2 Conventional paint3.2. Binary paint3.3. Comparing the two paintingsystems

4. Painting

4.1. Pre-treatment4.2. Applying the paint-layer4.3. Thickness of the layer4.4. Tlpes of paint4.5. Painting systems

5. Cathodic protection

5.1. Chemical reactions5.2. Electro-chemical reactions5.3. Sacrificial element5.4. Sacrificial anodes5.5.Impressed current

6. Antifouling

6.1. Fouling6.2.The shell, the ideal surface forfouling6.3. The purpose of antifouling6.4. Tlpes of antifouling used

7. Docking

7.1. Why dry-docking?7 .2. Methods of dry-docking7.3. Preparing for dry-docking7.4. Dry-docking7.6. Refloating

8. Maintenance and repairs

8.1 Maintenance8.2 Repairs8.3 Modern ship-repairs8.4 Conversion

:.jfu''"-

1,. Construction materialsfor ships

This chapter is not about materialsscience, but about what materials areused in the construction of ships, andtheir characteristics. The emphasiswill be on corrosion and main-tenance.

1.1 Wood

Until the end of the 18th centurywood was the only constructionmaterial for ships. Some of theseships had longer lives than their steelsuccessors. Mine hunters have usedwood as a construction material thelongest of all the large ships. The onlywood still found on modern ships isused for dunnage, decks, stairs andinterior, especially on cruise ships.Though there certainly are very hardtypes of wood that do not rot, mosttypes of wood must be protectedagainst rotting. Wood used on decksdoes not get slippery and, unlikemetals, it is not weakened by fatigue.A wooden overlay on a steel deck toavoid excessive corrosion must beapplied with great care. Water mustnot be allowed to become entrappedbetween the wood and deck, to avoidexcessive corrosion.

L.2 Steel

Since early 1800 the construction ofvessels gradually evolved from wood,via composite building (woodenplanks on steel frames) to l00%o steel.Composite building was a mixture ofiron framing and wooden side shelland deck, which allowed the buildersto build vessels up to approximately90 meter in lenght. The "birth" (1830)of the steam engine for ships speededup the actual use of iron throughoutthe construction of the vessel. Animportant milestone was reachedwith the building of the famous"Great Eastern" between 1853 and1858. A ship with a lenght of 200metres. a beam of 25 metres and adepth of 17 metres. Around 1875 thesteelmaking process gradually im-proved to what it is nowadays. Up totoday (2003) steel is still the mostpopular material for the constructionof ships because of its:

- technical and economical benefits- strength- suitability for welding- adequate resistance to brittle

fracture- low cost & availabilitv

Steel-making processThe various types of steel arefabricated on the basis of iron (ore)

and/or scrap materials, in a steel-making process in which the basicmaterial is heated up to approxi-mately 1600' C. Then the refiningprocess is initiated. Within thisrefining process certain excessiveelements such as carbon, sulphur andphosphor will be removed in theshape of so-called "slag". Dependingon the quality and type of steelneeded, the refining process within achosen steel-making process (basic

oxygen converter, electric furnace &open-hearth process) will be com-pleted. The differences in strength,toughness, hardness and weldabilitywill be obtained by the addition ofparticular elements during the steel-making process in combination withthe heat treatment during thefabrication of the plate material,forgings and castings. Additions cancontain carbon, silicon, manganese,nickel, vanadium, chrome, etc.

Steel typesSteel used as a construction materialfor ships and other structures can besubdivided into groups:

a. Plate materials and profiles- Mild Steel (MS)

Yield strength 235 N/mm2- High Strength Steel (HS)

Yield strength 265 - 390 N/mm2- Extra High Strength Steel (EHS)

Yield strength 420 - 690 N/mmz

Yield strength is the maximumallowable stress without creatingplastic deformations and is used bydesigners to establish the actualdrawing dimensions.

b. Steel forgingsTypical examples of forgings arecrankshafts, propeller shafts, rudderstocks, engine components such aspiston rods and crossheads etc.


c. Steel castingsCastings are fabricated for complexconfigurations such as stern frames,complex rudder components, anchors,pump casings, etc.

Stainless steelStainless steel is an alloy of steel,Cr (chrome) and Ni (nickel) andsometimes other elements. Thesurface of the steel is a neutralisationlayer, which is an oxidised skin in thecolour of the metal. This protects thematerial beneath it from oxidation(conosion). Stainless steel is morenoble than ordinary steel and willtherefore corrode less.

L.3 Aluminium and its allovsJ

Aluminium is a very soft metal, butby choosing the right elements toform alloys, the strength and stiffnesscan be increased significantly.Aluminium is also non-magnetic,making it suitable for mine hunters.Even though alum-inium is not anoble metal, corrosion is limitedbecause the metal is covered by avery dense oxide-layer that protectsthe rest of the metal. If chemicals orelectric currents remove the oxidelayer, then corrosion will take placerapidly. The main advantage of usingaluminium is its low weight. Despitethe fact that aluminium is much softerthan steel. it is much more difficult towork with. A drill gets stuck easily, itis much more difficult to get thesurfaces smooth, a grindstone is soonclogged and it is impossible to weld itwith a common welding apparatus.Alumi-nium is utilised for completeupper parts of passenger ships, minehunters, yachts, lifeboats, high-speedlight-weight motor ships and for partsthat need to be lightweight or non-magnetic like the wheelhouse of afishing vessel or the surroundings ofthe standard compass on larger ships.

1.4 Copper and its alloys

Brassilrass is an alloy of the moderatelynoble copper and the less noble zinc.Aggressive water like seawaterdissolves the zinc leaving the remai-ning copper very porous. Thereforebrass is never used for parts that can


Ca,st steel rudtle rltorn

come in regular contact with sea-water. For contact with fresh waterand oil. brass is suitable for use innipples, thermometers, manometersand many other shiny appliances. Thebinnacle of the standard compass isalso usually made of brass.

Bronze (gun metal)Bronze is an alloy of the moderatelynoble copper and the less noble tin.Bronze is seawater resistant and istherefore used in propellers, valves,coolers and almost all other parts thatcome into contact with seawater.Nowadays, the ship's bell is stillmade of bronze, but better alloys havebeen developed for the propellers.Bronze is still common in heatexchangers and pumps. Bronze ismore noble than steel (iron) and cantherefore affect the ship's steel. Invery aggressive water, tin tends toslowly dissolve. This causes a bronzepropeller to roughen slowly.

Materials for propellersNowadays every propeller factory hasits own alloys for the differentapplications of propellers. Usuallythese alloys are similar to bronze, butwith a more complicated compo-sition. In almost all cases the alloyscontain little or no iron (non-ferroalloys) and behave nobler than steel,which can cause corrosion of thesteel. In exceptional cases, thepropellers are made of stainless steel.The strongest nowadays is a copper-nickel-aluminium allov.

Materials for heat exchangersThe housing, pipes and tube plates ofa tube heat exchanger are almostalways made of copper containingnon-ferro 4lqyr. In plate heatexchanger.{ the plates are made

entirely of stainless steel or titanium.In both cases, the alloy used is noblerthan steel, which can be degraded byit. Heat exchangers can be found inthe piping system of the ship, but alsoin a sea-chest, a box in the ship's shellthat is open to seawater.

L.5 Synthetic materials

There are so many synthetics that it isimpossible to treat them all in oneparagraph. In general, synthetics arenot sensitive to corrosion. However,ultra-violet radiation in sunlight andageing can degrade the compounds.Synthetics are a-magnetic and can notbe welded. In yacht-building synthe-tics are common. On larger ships,synthetics are used for piping systemsbecause of their inability to conductelectricity and their insensitivity tocorrosion. Nowadays paint is alsolargely synthetic. The ropes are notmade of manilla anymore, but of oneof many synthetic fibres. Syntheticsare sometimes flammable, but arealways weakened by heat more thanmetals. Metals like iron andaluminium can burn like torches and,when that happens, cannot beextinguished. Luckily metal construc-tions do not catch fire easilv.

A commonly used synthetic construc-tion material is Glass-fibreReinforced Polyester (GRP). This isa composite material, consisting ofwoven or chopped (glass) fibresbound together by polyester. Othercombinations of fibre and bindermaterial can also be used, but mainlyfor high-tech applications. GRP ismainly used for parts where weight ornon-corrosive properties areimportant. With the use of a mould itis possible to make complex shapes.Because of this expensive mould,GRP products are usually standard

283

parts, produced in large series, likepiping, water-tight doors, etc. Evencomplete hulls of smaller ships (e.g.

lifeboats, fast rescue boats, yachts,minesweepers) are built in GRP.

2. Corrosion

2.L The corrosion process

From metallurgy it is known that ironis extracted from iron ore in blastfurnaces by removing the oxygenfrom ores with a carbon-excess(cokes). Almost all metals areextracted from the ore by removingoxygen or other compounds in a blastfurnace. Corrosion is the reverse ofthis process; the metal recombineswith oxygen or, sometimes, withother compounds. In many cases theresult is a dense oxide-layer thatprotects the metal underneath. In thecase of iron, however, the oxide isconverted to a ferrohydroxide bywater. This gives the underlyingmetal no protection against furthercorrosion.

Conosion can be accelerated if orga-nisms are present on the metalsurface. Outboard, this fouling in-creases the ship's resistance andinboard it can clog piping systemsand exhaust boxes. Corrosion canalso be accelerated with an electriccurrent, and with stress.

The rest of this chapter will bedevoted to steel corrosion, becausesteel is highly sensitive to corrosion.

Corrosion in u balLasttank of a tcutker

Corrosiort in a ballast tutk o.f a tonker

To protect the ship against corrosion,the following measures or combina-tions of them are taken:

- Applying a protective layer (paint)- Cathodic protection by using

impressed current or sacrificialanodes

- The choice of other materials so asto reduce potential electric tension

2.2Protective lavers

A protective surface layer can coun-teract, stop or reduce the extent of thecorrosion process. One of the follo-wing methods can be chosen:

Temporary protective layers likeconserving oil or grease. Thismethod is mostly used in spareengine-parts.Inorganic top coats like ananodised layer (a very strong oxidelayer) or enamel.Organic top coats like epoxy paint(2-component) or conventionalpaint (1-component) The first coatto be used as a primer to initiallyprotect the steel against corrosion

Ships usually apply paint as theprotective layer.

a* l l& r Y

Microscopic image of rust


3. Paint

3.L General

Paint is a liquid product that is meantto be applied on objects in a usuallyrelatively thin layer. During and afterapplying the paint it creates a filmthat has the tendency to tighten into athin continuous layer. On drying thisfilm becomes a solid hard or toughlayer that protects the surface it iscovering from corroding. Paint is alsoused to embellish objects. Paint canbe divided into:

- conventional paint- physical drying paint- oxidative drying paint- chemically active paint or binary

paints

3.2 Conventional paint

Real old-fashioned oil paint wasmade from linseed oil and turpentine.Later these were replaced bysynthetic components. Single potpaints, that behave similar to oilpaint, are called conventional paints.The paint can be used immediatelyafter the can is opened and thecontents stirred. Leftover paint can bestored in the closed can for future use.The conventional paints dry because:- the solvent evaporates (physical

drying)- the binding agent reacts with

oxygen from the air (oxidativedrying and /or polymerisation)

Examples of conventional paints usedon board:

- alkyd paint, chemical drying- acrylic paint, physical drying- vinyl paint, physical drying- modified alkyd paint or alkyd resin

slags, chemical drying

In general, conventional paintscontain the following components:

- binding agent- pigment- solvent- additives and fillers

Nowadays more and more environ-mental restrictions are being imple-mented related to the use of zincchromates, lead, etc. Also chlorinatedrubber systems and vinyl systems areno longer in use because of the highcontent of volatile organic compounds(e.g. toluene, benzene), restrictionshowever vary from country tocountry.

Water is used in both one (acrylics) ortwo-component (water-based epoxy)water-based products. These coatingshowever ate not solvent free. Insolvent-free coatings (epoxies) thinneris not normally used and if it is used,then only very little is added toextend potlife of mixed material forthe application method depending onclimatological conditions (tem-perature) .

Binding agentThe purposes of the binding agent inthe paint are:

- Coherence of the paint- Connecting the pigment- Adhering the paint to the base- Influencing characteristics like

gleam, elasticity, mechanicalstrength, wear resistance,resistance against chemicals andsunlight.

Binding agents can be composed ofdrying oils, synthetic resins, latex or acombination of these.

PigmentPigments are solid powders that givethe paint its colour and coatingproperties. Furthermore, the pigmentsoften prevent corrosion. Examples ofthese are zinc-chromate (yellow),zinc-phosphate, zinc powder (grey),lead seal (in red lead, orange, toxic,banned!). Pigments can also beadditives that contribute to charac-teristics of the paint like gleam,filling, scouring and strength.

Solvents and thinnersSolvents and thinners are volatileliquids or mixtures of volatile liquidsthat dissolve and dilute the bindingagent. After the paint is applied, theyevaporate out of the solution. In

general the vapours are harmful tohealth and environment. Thesecompounds are almost alwaysinflammable and can form explosivemixtures with air. There are strictregulations for ventilation andbreathing-protection when workingwith these compounds in closedspaces. It is difficult to distinguishsolvents from thinners; the wordssolvent and thinner are ofteninterchanged. Thinner is a much useddilutent.

Fillings and additivesAdditives are used to influence thecharacteristics of the paint like a mattsurface, a rough surface (anti-slippaint), protection of the underlyingmaterial against heat, prevention ofsagging and counteracting filmforming.

3.3 Binary paint

In binary paints or two-componentpaints, the film forming and dryingtakes place by a chemical reactionbetween two components. A bettername for these types of paints wouldbe "chemically active paint". Thecomponents are:

- the base component- the hardener

Mi.ring u'ith u ltleruler until the puinl

gets a wtifonrt t'olotrr


The temperatures of the surroundings

and the material to be painted have an

important influence on the rate of the

reaction. In dual-component paints,

the two components are delivered and

stored in two different cans. After the

base component and hardener of the

epoxy paint have been ProPerlYmixed, the mixed material should begiven a certain time prior to

application.This time is called"introduction time"; normally this

takes about 10 minutes and is

mentioned on the data sheet of the

coating supplier. Leftover paint

hardens and becomes useless.

Examples of these types of paint arepolyurethane and epoxy-paints.

3.4 Comparing the two Paint-systems

The choice for a conventional or

binary paint is governed by a large

number of factors. The physical and

chemical properties of binaries are

superior to the conventional paints.

But a tougher layer, longer gleam andgreater resistance to water andchemicals are not equally importantfor every shipping company.

Some arguments that can influencethe choice of paint-system are:

- the price of the paint- purpose of the shipis the painting done by the crew (or

the shipping company), during avoyage or during docking

- price of the pre-treatment

This last point depends on:- the number of crew members- where will the ship be sailing:

in tropical areas; the crew can doa lot of maintenance;in arctic areas; maintenance cannot be performed in water, but onlYin a dock.

The following becomes importantwhen the crew does the painting:- Conventional paint is simpler in use

than binary paint.- Single pot paint is easier to use

than dual component paints

The. pctint-layer is loosening.frrtm o bad

base or incorrcct pre-trezlment


4 Painting

4.L Pre-treatment

For a good painting-result it is

imponant that the material that isgoing to be painted, is pre-treated.

Painting should be done under

conditions where the effect of

temperature and humidity changes is

small. This is the reason that more

and more ships are being painted in

closed and acclimatised spaces. Thepre-treatment is the base of a good

protection for the material. The better

the material is cleaned, the better the

result will be. A good paint-system on

a bad base is of little value. The base

Seven years of damage to the paintlayet

The cause: badly protectetl wekled seuns

which may be caused by ins{ficient

cleoning after u,elding prior to painting.

If lutles or cracks are not wekled

properll, this may cause prrtblems with

c'leaning and pre-treatment. Thi.s in tunt

can couse small bli,vters, that cause de'

tucking of' the paint-Iayer.

material can be cleaned in the follow-

ing ways:

- with hand tools- mechanical cleaning (with

machines)- chemical cleaning, especially

degreasing- thermal cleaning- sandblasting / gritblasting- waterjets

Hand toolsManual cleaning is done with scaling

hammers, scrapers, sandpaper and

wire brushes. This pre-treatment

method is very labour-intensive andqualitatively not very high-grade. It is

used predominantly for local repairs

of the paint-layer and sometimes for

the treatment of welds and Placesalready treated with an abrasivewheel.

Mcrnual cleaning

Mechanical cleaningThis is done with mechanical scalinghammers, rotating wire brushes,abrasive wheels and abrasive discs.

On board, needle-scaling hammers or

chipping hammers are used almostexclusively. Of all the types ofmechanical scaling hammers, this oneis the best, although it is not very fast.The roughened surface is a good basefor the paint layer.

A revolving bruslr

Rotating wire brushes, abrasivewheels and abrasive discs can yield

the same result as the needle-scalinghammer, with the difference that the

surface may become polished. If the

If the ntill scale is not properly rcntoved,

it t"'ill eventuall.v Let go

286

A pnewntttic sc:crling hutntner

metal surface is too smooth. themechanical bonding between themetal surface and coating will bepoor, leading in most cases to prema-ture failing of the coating system.Almost all methods of cleaning withmechanical devices require breathingand hearing protection. The waste ofremoved old paint layers should becollected and disposed of properly.

Chemical cleaningChemical cleaning removes the oldlayer of paint and rust. For local paintjobs, paint-stripping compounds areused. In manufacturing, the cleaningis either done with acids or withstaining. In all cases the cleanedmaterial should be thoroughlyflushed with fresh water.

Thermal cleaningFor local removal of paint, a paintstripper can be used. The heat softensthe paint, which can subsequently beremoved by tools. The paint stripperis not used on alarge scale because ofthe fire-hazard and the toxic vapoursthat are released upon heating.

GritblastingGritblasting is done by blastinggranular materials at high speed withhigh-pressure air against the steel.The material is cleaned thoroughlyand the surface is roughened which isessential to achieve a good mecha-nical bonding with the coating. Theroughness can be adjusted byadjusting the size of the grit materialduring the gritblasting. The surfacebecomes covered with microscopicpits that are good for the tacking ofthe paint layer. The first layer of paintshould be applied immediately aftergritblasting to prevent moisture in theair for forming a new layer of rust onthe bare steel.


Gritblasting is not done on a largescale on board because it requires aspecial installation. It can be done indock though. This method is suitablefor treating large areas; 20 m2 perhour is feasible. Another advantage ofgritblasting is that it can be used toremove the rust from complicatedconstructions, where other tools cannot reach every nook and cranny.However, removing thick layers ofpaint or rust with this method takes alot of time and is therefore notefficient. In the dock, gritblasting isusually limited to the outside of theskin and possibly the tanks. Whengritblasting, it is important to payattention to personal safety-protec-tion for the ears, eyes and lungs.

WaterjetsIn this method, a high-pressurespraying pistol is used to spray waterunder a pressure of 200-250 bar onthe surface. In a drydock it is used toremove chlorides, algae, barnacleshells etc. from the shell. When thewater pressure is over 700 bar it iscalled high pressure hydro-jetting andover 1700 bar it is called ultra-highpressure hydro-jetting. One of the bigadvantages of hydro-jetting is that thesoluble salts are removed and there isno 'dust'. The speed, quality andpressure determine the cleaningeffects of this method. One of thedisadvantages is that the surface isnot roughened by this method.Waterjetting can be done on board,but is done more and more in dock.Due to the fact that it causes no dustit can be done while others are busywith repairs to for instance thepropeller.

il

Locvtl gritblasting. Irz sotne c:otuilries

sudblusting is still applied, itt ntost

c'orufiries, hov'ever, it is no longer

ollonecl tlue to heulth (luttg) prctbletns.Ht,drut-.i etting of tlt e .skin

Adv-ont'ed tecltnique.frtr gritblastirtg, tt'ith spec'iol cure to prevent exce.ysive

i nc'onveni cttce ca used bt,'d us/'.

287

4.2 Applying the paint-layer

Before the paint is applied one has tomake sure that:

the surface is clean of moisture,dust and greasethe surface shows no signs ofcondensation, and there is noopportunity for the forming ofcondensatethe outside temperature does notexceed 40oC, or becomes lower'than the minimum processingtemperature of the paint. Somepaints can be used even at -5oC.

the right paint is prepared;the binary paint is mixed in theproper proportionsthe paint is stirred well before use,for instance with the aid of ablenderthe correct tools are being used:brush, roller or spray. The paintspray is only used for large areas.Spraying makes sure that the paintlayer is distributed evenly, and thelayer thickness can become biggerthan when a brush or a roller isused.

The material that is going to bepainted should be at least 3 oC

warmer than the dew point of thesurrounding air. This can be tested bybreathing against the surface. If thereis condensation on the surface. it hasto disappear within minutes.

The dew point is the temperature atwhich condensation starts, because atthat temperature the maximumwater-vapour pressure is reached.The relative humidity is then l00%o.If the temperature then drops belowthe dew point, the water willcondense on the coldest surfaces.

Tlrc stripc,s in tlte ltnt.slt "truil" ,slnuld

(\'cn out lt\: 11rr',rr,tr,ves. Tlti.,s' i,r ttol t lta

('{t,\c.


I . l ' t l tc l t t r i r t t is uppl ia l t rx t t l t ick, i t t t ' i l l

.t(1.q. Applving pttiri l vit lt u ntllcr

P0int-spretitrg

Tltc ty,o.!1)/'ll.1'.r ore loo clo.s'c kt ettt'lt

ollrcr: l lte s1tra.\,t,t 'ort t ltc lel 'r is ltto <'lrtsa

to the ,s ' l t ip 's hul l .

Wclding rtr bumirtg on tltc tt l lrcr ,sitle

v,ill r:urt.s'e datttttgc /rt tlte puint-lrt.t'er.

Pairttittg tt, ith u bru,s'h,

drnrc in tL c:loscd spoL'e,

p rote ctt) t t t,t n e c e.l s 0 t'.\t.

ff the puintirtg i,s

breutlting

7'

Puinting the rlec'k v'itlt u Lsnr,vlt

Sailor rnt u Ttoittt irtg boartl

288

4.3 Thickness of the laver

The thickness of the paint-layer canbe expressed as the wet layer-thickness or the dry layer-thickness,usually reported in micron or pm,10-6 m. lp = 0,001mm

Theoretical coverage (m2llitre) =

l0 * solids in 7odryfilm thickness

This equation shows that if a paintwith a high content of solids is used,fewer litres can cover more m2 with aprotective layer against corrosion. Ifthe paint is applied with airless spray,the loss of paint in the form of mist is20Vo -30Vo.

The sprayless factor to a large extentis influenced by:- shape of the construction- weather circumstances during

application- experience/skill paint-applicator

Ultra-.sonic device to measure the

thicknes,y o.f the paitt-layer

4.4 Tlpes of paint

- Structural paintStructural paints can be classifiedroughly according to the bindingagent:- one-component paints (single pot)

like:* acrylic paint and vinyl coats

(physical drying)* alkyd paint (chemically

drying)- Binary paints (or dual-compo-

nent paint) like:* epoxy paints* polyurethane paints

- Shop primersShop primers are used as temporaryprotective layers directly after thesteel plates have been rolled, cut andsandblasted.Requirements to shop primers are:- To prevent the forming of rust

during the storage of the steel andthe construction of the ship.

- They must be able to absorb thespeed of the welding without theforming of gaseous holes.

- The shop primer should also besuitable as a base for the final paintlayers.

- Not harmful to welderNowadays only binary shop primers(low zinc ethyl silicate) are used. Theshop primers give the gridblastedsteel up to nine months protection,depending on the local conditions.

- Zinc containing ethyl silicate or zincepoxy

This is used if there is a great chanceof mechanical damage. The zincsacrifices itself when the layer isdamaged. It is ailplied as a singlelayer with maximum thickness of 75and 50 micron respectively. It isoften used in tanktops and hatches.

4.5 Painting systems

A steel-conservation system is builtup of a protective primer, the coatingand the finishing layer. This systemunifies active (see section 5) andpassive corrosion prevention. Passivecorrosion protection means that themetal is sealed off from the influenceof water, air and chemicals. Each typeof paint is more or less passivelyprotecting. The permeability of a drypaint film depends on the type ofpaint, but even more on the layerthickness and the number of layers.The higher number of layers and thehigher total thickness, the less is thepermeability. In general the selectedcoating system and the area of thevessel (underwater area / topsides /ballast tanks etc.) deter-mine thenumber of coats.

5. Cathodic protection

To understand how cathodicprotection works, it is necessary tolook in more detail into the corrosionprocess. In this undesired chemicaleffect, the material can react withdifferent chemicals in its surroun-dings. The reactions can be dividedinto:

- chemical reactions- electrochemical reactions

These reactions take place exclu-sively at the surface of the metal. It ispossible that microscopic pits areformed by corrosion on the metal'ssurface. The corrosion can alsopenetrate existing cracks.

5.1, Chemical reactions

In almost all chemical reactions, thereis a charge transfer between thereactants. If this exchange of chargeis a local effect. then the reaction iscalled a chemical reaction, and theresulting corrosion chemicalcorrosion.

An example of this is the reactionbetween bare steel and oxygen fromthe air. A thin oxide layer rapidlycovering the metal, forms at thesurface. All metals form such anoxide layer. The characteristics of thisfirst (dry) layer are of greatimportance to the further course ofthe corrosion process, and to theadhesion of the paint layer.

If water comes into contact with theiron oxide, the compounds react togive the product iron hydroxide(rust). The rust is very porous, andtherefore oxidation continues. Thefirst oxide layer of stainless materialsis not affected by water. Between themetal and the oxide layer a lack ofoxygen arises which is the reason thatthe oxide layer cannot develop anyfurther.


5.2 Electrochemical reactions

Many compounds have the tendencyto dissolve charged particles (ions)

into water. Ions can move freely inwater. Compounds that alwaysbehave in this way are acids, bases,soluble salts, metals and some gases.A consequence of the ion-mobility isthat chemical reactions and theincidental electrical current are notnecessary local, they can stretch outover a much larger area. Theseelectro-chemical reactions do not just

come to a halt.

Every metal in contact with water hasthe tendency to generate positiveions. This makes the water morepositive and the metal more negative.If a metal is less noble. it will have astronger tendency to generate theseions and thus become more negative.Alternatively, if the metal is morenoble, then it will have a weakertendency to generate positive ions andwill thus be less negative. In general:- gold is more noble than copper- copper is more noble than tin- tin is more noble than iron- iron is more noble than zinc- zinc is more noble than aluminium.

5.3 Sacrificial element (galvanic

corrosion)

When two different metals are incontact with each other and withwater (even a small amount), then theless noble metal will have a lowerelectrical potential then the morenoble metal. This potential differenceand the contact between the metalsgenerates an electric current betweenthe two metals, running from theprecious to the less noble metal.

The continuous flow of current to theless noble metal causes it to generate

more ions that dissolve into the water.This way the metal slowly disappearsinto the water. This dissolving ofmetal ions is called an anodic reactionand the metal that is dissolving iscalled the anode.

Electrochemical corrosion can alsotake place if a metal is not composedhomogeneously. Objects in seawaterthat are made of brass (an alloy ofzinc and copper) are very sensitive tothis; the zinc dissolves leaving aporous copper behind. This is calledde-alloying. If there is no interven-tion, then all the anodic material(zinc) will dissolve until all of it iscompletely dissolved.

Electrochemical reactions on shipscan take place in the following places:

- between the propeller and thesurrounding steel

- between copper-containing parts(e.g. heat-exchangers) and the steelparts of a piping system.

- Between aluminium parts and thesteel parts of the ship.

Electrochemical corrosion mainlyoccurs at places where the paint isdamaged by ice, after contact withderelicts and the normal wear throughmooring and departure, tugs thatcome alongside etc. Turbulence,speed of the water and heighertemperatures of the water and salinityincrease the corroding process.

Eliminating the corrosion current canprevent electro-chemical corrosion.This goal can be achieved in severalways:

5.4 Sacrificial anodes

Cathodic protection using sacrificialanodes is called passive cathodicprotection. Blocks of zinc andaluminium are welded onto the shipin different places using steel strips.These anodes have such a lowpotential that they "suck" the currentout of the ship's exposed steel, fasterthan currents can enter the skin viathe copper-containing parts. Thesework by dissolving because they areless noble, so as long as there is lessnoble metal, the anodes work. If thepaint-layer below the waterline isdamaged, there will be an electriccurrent from the water into the metal.If the damage is extensive, then theanodes will dissolve faster. When theanodes have been dissolved. the othermetals will start to dissolve.

The pros and cons of sacrificialanodes are:Advantage:- low investment costsDisadvantage:- the limited life-span of the anodes;

I to 5 years and difficult to predict- floating ice, irregular dissolving

and other damaging factors candiminish the protection quiteunexpectedly. This can lead todamaging of the steel.

GctLvcutic c:orrosion


insulating the metal on the water-sideby painting it. This preventsthe metal from contact with theoxygen and the electrolyte. If thepaint-layer stays intact, this works.As soon as the layer is damaged,the corrosion begins.reversing the current by using asacrificial anode of a very basemetalreversing the current by creatingan opposite potential, ICCP system.(Impressed Current)

All the ;.irtt' i,s still presettt. 'l 'he

skirt

,tlutvr,,t no.finling or v)eur. Tli,s slip tlid

nol break tlue tct a c:rtrrotletl skin, but it

broke .f'rotn the in,side due to c'orro,siort irt

the bttlLost tanks

1 l o^

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Sucrificial anodes on the propeLler cfuct

o

290

- there is a chance of overpro-tection, especially when the anodeshave just been applied. This candamage the paint-systems.

5.5 Impressed current

In the ICCP-system (impressedcurrent cathodic protection), a largepositive current is applied to thewater. As a result, current flows intothe ship's steel wherever it is incontact with the seawater inducing acathodic reaction that protects thesteel against corrosion. To achievethis, a rectifier is connected to theship's steel with the negative exit.The positive exit is connected to twoor more anodes in the ship's skin.These insulated anodes are embeddedin the skin to prevent damage byfloating ice and are made of inertmaterials (inert is another word fornon-reactive). Sometimes the verynoble (but very expensive) metal

I lc',qulutrtr

Current collectors on theprooeller shaft and rudderstock

P ri tr c i 1t I e rtf' intlt rt:,s se d tr r rrctr I


platinum is used, but more often theanodes are made from a mixture ofhigh-grade metal oxides (MMO,mixed metal oxides). Oxides cannotoxidate again. The selected oxides donot dissolve in water. If the anodicreaction has no metals to consume,the reaction will produce smallbubbles of oxygen, which are notwithout harm to the skin. Thestrength of the impressed current canrange between 10 A and 600 A, the

exact value depending on the size ofthe ship, the amount of damagedpaint layer, the speed of the ship andthe salinity of the seawater. Thevoltage can be as high as 20-30 Vdepending on the number andpositioning of the anodes. Where theshell is in direct contact with theseawater, this voltage is reduced to1,5-2,5 V. The pros and cons of theICCP-system are:

Advantages:- a minimum of maintenance is

required- high reliability- action can be controlled at anv

moment- an automatic regulator can adapt

the current with the use ofreference electrodes if a change inthe water-composition (fresh,brackish, salt) or damage to thepaint-layer requires this.

- the high investment costs(compared to a sacrificial-system)will recover itself in approximately6 years.

Disadvantages:- the costs of acquisition are

significantly higher than those of asacrificial system

- If the ICCP-system is wronglytuned it can cause extensivedamage to the ship below thewaterline.l l t . l<'r<'rt t c ( |( ' ( l f t) t l (

r\trrile irr tlrc ,skitr

Spc<' iu l pui t t t lu tet 'oroutul the ur tor le

l:"urtlt in,q bnr,slt

291

- some paint systems are damagedquickly when the lCCP-system isoverprotecting (the current is toohigh).

Some remarks on cathodic protection

and related matters:

- ICCP-system is mostly used onships with a length exceeding 40metres

- Fast ships like patrol vessels andhydrofoil boats are alwaysprotected by the ICCP-system

- Aluminium ships can not beprotected passively

- In ships with a lubricated propeller

shaft, the shafting should beequipped with a strong currentcollector. If this is not the case, thecurrent will flow from the propeller

to bearings or gear wheels ofthe engine or gearbox. This cancause extensive damage.

- If the current collector is tunedwrongly and the shafting has afaulty earthing, the gear wheels andthe bearings can be destroyed veryquickly

- The rudder stock has to beequipped with a good earthing ifthe rudder is to be part of thecathodic protection system

- Stainless steel, for instance in thepropeller shaft, is protected againstcorrosion by a dense oxide layercalled the neutralisation layer. Ifthis layer is damaged it will notfully restore itself. The new layer isnot impermeable, so corrosioncannot be stopped. A wrongly tunedICCP-installation can destroy theneutralisation layer of the stainlesssteel if it comes into contact withseawater. This does not happen in alubricated propeller shafting.

6. Antifouling

The main purpose of antifouling is tokeep the skin smooth. By preventingorganisms from damaging the paint-layer and the steel under-neath, it alsooffers protection against corrosion.

6.L Fouling

Fouling is an umbrella term for

waterplants (algae and weeds) andanimals (barnacles, polyps, mussels,anemones). The number of organismsthat are consi-dered fouling is as highas 4000-5000. The fouling can bedivided into two categories accordingto the size of the adult organisms:

- macrofouling, made up of animalsand plants

- microfouling. This is a slimy mass,a sticky mix of bacteria and othermicro-organisms. The adhesion ofthe microfouling is weaker than theadhesion of macrofouling.

6.2 The shell, the ideal surfacefor fouling

Spores and larvae easily deposit ontoslow-moving rough surfaces. Asmooth surface in combination withhigh speed is a less ideal foundation.Some chemicals and metal-ions likethose from copper are toxic for theseorganisms.

Fouling in pluces where the antifouling

lns gone

The growing organisms get theirnourishment out of the water flowingalong the hull. A ship that is movingslowly (0-10 knots) has the idealcombination of a solid surface and agood supply of food. The roughnessof the shell is caused by corrosion,flaking of too many paint-layers,wrong use of cathodic protection andmechanical damage. The growingprocess of fouling is quite intricate. Itdepends on geographical, climato-logical, and oceanographic circum-stances, the season, nature of thematerial and the sailing pattern. Forinstance, the sailing pattern of acontainer ship (short berthing time)differs from the pattern of a dredger(alternating high and low speed, longand short stops) which again differsfrom the pattern of a supplier (long

stops, interrupted by intensivesailing). Fouling increases the ship'sresistance and reduces the velocity by10 or l5%o at equal engine power. Tokeep the original velocity, the engine-power has to be increased by 23-387o.The fuel consumption increases thenbv 25-407o.

Mussel Jbuling

Larvae

Acont shell,s. tnussels and other slrclls

Green ulgae.fouling


6.3 The purpose of antifouling

The main purpose of antifouling painton ships is to save money. This isaccomplished because:

- if there is no antifouling, the ship'sresistance increases and. as a result.the fuel consumption alsoincreases.

- if antifouling is used, the ship canspend less time in dock fordefouling.

- fouling causes the paint-layer to bedamaged. This increases corrosion,and thus the maintenance costs.

6.4 llpes of antifouling used

Most antifouling paints in shippingare of the self-polishing type. Self-polishing means that the paint-layer(a polymer) is slowly, layer by layer,degraded by the seawater. Thisreleases compounds that preventfouling in a controlled manner.

Freshly applied After exposurc to seawater

S e I f- pol ish ing u n t i fo u I i tt g

There are three main types of antr-fouling:- tin-containing antifouling- tin-free antifouling- copper-containing antifouling

The difference is not always veryclear; for instance, some tin-containing antifoulings also containcopper.The tin-antifoulings contain TBT,tributyltin. This toxic compound killsboth micro and macrofouling when itfirst attaches to the skin. So it worksby killing the larvae of barnacle shellsand the spores of algae. The layer-thickness of the antifouling isadjusted to the life of the paint. Thisdoes not need to last longer than fiveyears because the ClassificationSocieties demand that the ship dry-docks at least every five vears.

TBT is not just toxic to fouling butalso to many other forms of marinelife. In slow sailing or berthing, thelocal concentration of TBT canbecome so high that many marineorganisms show deformations.

In the future, TBT and copper-contai-ning antifoulings will be banned.IMO is already deliberating on thissubject. After 2003 it is likely thatonly tin-free antifoulings are permit-ted; these are already available.

7. Docking

7.1 Why dry-docking?

- The SOLAS treaty requires it.(Chapter 1, Reg 10-V) Thischapter states that every shipshould be dry-docked at least twiceevery 5 years. The max. time-lapsebetween two dry-dockings shouldnot exceed three years. Only whenspecial provisions have been madeduring construction one of the dry-dockings may be replaced by an inwater survey.

- Demanded by the bureau ofclassification. The demands fromthe Classification Societies aregenerally in compliance withSOLAS requirements.

- Damage below the waterline as aresult of :* collision* running aground* bad or no maintenance

- Inspection when the ship is goingto be sold.

7.2 Methods of dry-docking

- floating dock.- excavated dock (graving dock)- patent slip.- lift and subsequent horizontal

transport of the ship.

Floating dockA floating dock is, in fact, a pontoonwith on both sides in longitudinaldirection a vertical sponson. Thepontoon and a part of each dockwallare divided into a number of tanks. Todock, the following has to be done:

- the tanks are filled with water sothe dock submerges partly.

- the ship navigates into the dock- the tanks are emptied, the dock

rises to the surface and the shipis lifted out of the water.

The front and/or the back of thesponsons are usually equipped withbridges to connect both sides. On topof the sponsons one can find:- mobile crane- capstans and bollards

Antifouling at the end o.f its Lilb artd vt'orn out. Titne.frtr repainting. The ,rprat,irtg

pattern ort the skin i,v ,still vi,sihle. 7'1rc outermost la1,er rl'anti.fbuling i,s still lturtlvvi,sibLe rnt the ctverlatrt. In betyveen it has disttppecrred contpLetely.


Electric motors are located in the

upper part or d.y room of the

sponsons. These motors operate theballast pumps that are located low in

the tank.

The manual controls of the inlet andoutlet valves are also located in this

compartment. Opening the inletvalves fills the tanks and lowers the

dock. To raise the dock, the pumps arestarted and the outlet valves are

Repair-departnrcnt ol a dock,vard w'ith

two.flocfiing tlock,s

A.floaring dry-al6r1r. Data: length = 217

metres, widtlt (intentttL)= 32 rnetrcs,

tlraught abot,e blocks = 7.5 ntetres,

Ii.t'iing c:apucitt,= 25.000 tuts.

1. Keel blocks

2. Side blocks

3. Side sponson

4. Rails for the crane

opened.The ship rests on the keel blocks thatare placed on the tanktop of the dock.These keel blocks are 1 - 1.25 metresapart and each can carry a weight of


100-150 tons.Side (bilge) blocks are used to keepthe ship stable in the dock. They keep

the ship in balance and are Placedclose to the turn of the bilge. All side

blocks have to be placed in such a

way that the forces they exert on theship's hull are absorbed by thereinforcements present in the ship likeside keelsons and longitudinalbulkheads. The centre line bulkheadsand the cross frames of the dock alsohave to be taken into account. Thepositions of the blocks, the rise of

bottom, the bottom plugs and otherimportant data have to be indicated inthe docking plan. The rise of floormakes it necessary for the side blocksto have the correct height so that theweight of the ship is evenlydistributed over the keel and the sideblocks. The dock master is resPon-sible for the placing of the blocks asindicated in the docking plan of theship.

Excavated dockThe excavated dock (graving dock) is

closed using a door. The dock floorslightly slopes towards the opening.The pump room is also located nearthe opening. Most characteristics ofthe excavated dock are the same as

those of a floating dock.

A t,ieu, tutder the ship stancling in a dock

( no nn u I th x'k lth x' k-u r ratt ge nt enl )

Ship ,sultported b,v ,specittl doc'k ltloc:k-

ilrronge,nent witlt enLurged height (in u

grat,ing dock.

Patent slipThe patent slip lifts the ship in theathwart direction. Cradles placed onrails roll into the water, until they are

underneath the ship. If the cradles arepulled back up again, they take the

ship with them. The patent slip is usedmostly for ships with a length of up to140 meters.

"[unker being built in u drt'-dock

Huge ship in tlock

Cott,struc'tion in an e.xcavuted clock Ship on u pilett slip

294

Ship liftThe ship lift consists of a platformand below that a number of cradles(approximately l4). The cradles areused to lower the platform into thewater. After this the ship navigatesabove the platform, which is lifted inits turn by winches. The ship can thenbe moved horizontally over theshipyard in both the fore and aftdirection and the athwart direction.This method is suitable for ships up toa length of 125 metres.

t I i

r{dar6ds

Ship lifr

1. Platform

2. Cradles3. Dockyard

7.3 Preparing for dry-docking

As mentioned before, the dockmasterhas to determine the position of theship and the side blocks in the dock inaccordance with the dock plan. Ifpossible, the ship should have nocargo on board. If there is still cargoon board, then docking can only takeplace in close consultation with theclassification society. The structuralintegrity of the ship may requireadditional blocks to be placed. Theship should enter the dock preferablyon even keel. A floating dock can bepositioned with the same trim as theship. The maximum allowable trim ofthe dock differs per dock.

7.4 Dry-docking

When the ship has entered the dock,the dock master is responsible for thedry-docking. The ship must be in theexact middle of the dock. before the


dock is pumped dry. The ship ispositioned correctly by dock winchesattached to the fore and aft, both onport and starboard side. Thedockmaster gives the orders to theoperators of the winches. The exactmiddle of the dock is indicated by acable and a plumb line, which aresuspended between the two sides.Another method is to use a measuringrule to determine the distancebetween the edges of the dock andboth the ship's sides at the fore andaft. The ship will touch the dockingblocks when the draught of the sidesponsons equals the ship's draught.The draught of the sponsons is thedraught above the keel blocks. Theship is buoyant when it touches thedocking blocks. The stability of theship will decrease if the weightexerted by the ship on the dockblocks increases. The apparent rise ofcentre of gravity 'G' is faster than therise of the metacentre 'M', in otherwords: G catches up with M. Bilge orside holders have to be placed beforethe stability becomes zero (GM=0). Acritical moment for the floating dockarises when several decimetres ofwater, still present on the dock-floor,start to move. A large area of freefloating fluid can come into motion.Before the dock is dry, all water-cooled engines and auxiliaries on theship have to be shut down. If the shiphas air-cooled auxiliaries. these cankeep supplying the ship with power.If these are not present, electricityfrom the shore must be utilised. Arequirement of the shipyard is that theship is connected to the shorebasedfire-fighting installation by means ofhoses to the (international) shoreconnection.

7.5 Refloating

Before the dock is flooded to undockthe ship, the presence of all the plugs,grills, anodes, inlet and outlet valves,manhole covers etc. has to bechecked.

The ship should leave the dock in thesame ballast condition as when itentered. This means that ballast tankshave to be refilled. This is done fromthe dock with pumps and hoses.When the ship is floating again, the

engine room compartment and bilgewells have to be checked to determineif there is any leakage. Repairs todouble bottom tanks and side shellmust be tested prior to undocking.

8. Maintenance andrepairs

8.L Maintenance

Ships maintenance is usually dividedinto HULL and ENGINE mainte-nance.Hull maintenance is normally done indrydock. A ship has to be drydockedtwice every five years. This isbasically for examination by Class ofthe underwater parts. When norepairs are to be carried out, it meansonly examination, cleaning andrepainting of the ship's outside hull.Maintenance of decks, and every-thing inside the shell-plating isusually done by the ship's crew.When the ship is set dry in drydock,the outside of the hull is cleanedusing high-pressure water jets, atleast 100 Bar, to remove dirt andfouling, and to make the hull readyfor repainting. Oily spots, if any, areremoved with special solvents. Rustyspots are specially cleaned using

sand-discing, gritblasting, hydro(water) blasting, with water of 700 to2000 Bar as cleaning method. Theoriginal paint system of these spots isto be restored, whereafter the entireoutside hull can be painted as wishedby the owner. Sometimes, when theroughness of the underwater hull hasbecome too high, due to numerouslayers of paint and local touch-ups,the entire underwater part is blastedto remove all the rust and paint, andto start the paint system as from new.

The old puint-later is remlt'e

gritblasting

295

SECTION FR.4

I SECTION FR22 SECTION FR38 SECTION FR.6I

IMIRESSTD C1JRIENTMME

TYPICAL MIDSHIP SITUATION

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The paint supplier gives advice, andkeeps control of cleaning and appli-cation. Depending on the age of theship, size, speed, cost and the requi-rements of the trade, the paint systemis chosen, from simply one coat of tarto more expensive systems as vinyl,chlorinated rubber, epoxy or poly-

urethane underground followed byvarious coats of sophisticated anti-foulings.

C ktr s if i c' tt t io rt,s urv el o r

After drying, and cleaning, the vesselhas to be examined in dry-dock by theClassification surveyor, normallyaccompanied by the owner's repre-sentative and the shipyard in order toinvestigate the condition of theunderwater parts. No defects under-water are to be neglected, to prevent

unforeseen repairs during operationaltime. Emphasis shall be put on rudderand propeller, tailshaft, indents,damage, paint-condition, corrosion,fractures, weldings, and inlet andoutlet pipe-stubs. Defects affectingClass are to be dealt with. Minordefects not requested to be repairedby Class, can be left as are, as perowners choice.

As already mentioned, the rudder andrudder stock have to be examined,clearance of rudder bearings is to bemeasured and sea-inlet boxes are tobe opened up, cleaned and paintedinternally, mostly the same procedureas for the outside hull.

The tailshaft and propeller have to beexamined and the tailshaft wear-downmeasured. This gives informationabout the condition of the stern-bushbearing. Standard every five years,the tailshaft has to be withdrawn, toexamine the shaft, and to examine thestern-bush bearing. The propeller isthen suspended using special toolsfrom the yard. Simultaneously thetailshaft seal is opened up andoverhauled.

P reparing propeller nnrl ttril.shctfi .fbr

proper.t''it on ctntirul purt prior trt

installutiott on bourd

Controllable-pitch propeller shafts and keyless propeller

shafts do not need to be withdrawn at five year intervals,they can be left for a longer time.

When the clearance of rudder bearings has become too big,

the rudder has to be lifted out of the pintles, and the relevantbearings have to be renewed. The bigger the ship, theheavier the rudder. For a VLCC (Very Large Crude Canier)the rudder weight can be 100 tons or more. Rudder posts,

which often are lifted for access to the rudder, follow the

same pattern. Special lifting gear must be available at theyard.

Anchors and chain cables are to be lowered and laid out, andmeasured up, to establish the loss of thickness due tocorrosion and/or wear. When too thin, chains are to bereplaced. Inspection of anchors and chains and their

measurements are required at least every five years. Whenthe anchors and chains are lying in the dry-dock, it isAnclnr,s' tutd c'haincables ttrc Lovv'ered. Bln,stitrg rtrtd paittl irtg

tn pr(),qrcs,t..


Damttged bow

Exchange of crank shcfi

customary to clean the chain lockers,which themselves have to beexamined for class and SpecialSurvey. Another standard item of thedry-dock repair list is opening andoverhaul of sea-inlet and overboardvalves. They need cleaning, inspec-tion, disc-grinding of seats andrepacking of stern glands at least oncein five years.

Most of engine maintenance is donewhile the ship is in operation, partlyduring voyage. Items which only canbe done when the ship is notunderway are done in port. TheClassification Societies request theshipowner to show to them eachsurveyable item once every fiveyears. Surveyable items are engineparts or systems essential for the safenavigation of the vessel, and arelisted on board and ashore. Thissurvey can be done at the end of thefive year Special Survey cycle, or ona continuous basis during the wholeperiod. Under certain circumstancespart of the surveys can be done bythe ships chief engineer when he orshe is specially qualified. He then hasto submit details of what he has seenand done. Some engine parts needmore attention than once in fiveyears: coolers, pistons, turbo char-gers, etc. Maintenance of items whichare too big or too difficult or whichsimply cannot be done afloat, is doneat a shipyard. This is usually not anewbuilding yard, but a specializedrepair yard.


8.2 Repairs

Repair yards have equipment totallydifferent from newbuilding yards.Their dry-docks are deeper: A ship inoperation is heavier and hasconsequently more draught than anempty newly built hull. Also cranesdo not need to have the liftingcapacity of those in a newbuildingyard. They need height, more thanhuge lifting capacity. The workshopsare differently equipped: othermachines. for small and sometimesbig repair work. The workers need tohave a different skills from new-builders and have to be more flexibleand more used to changes. Also thelocations of repair-yards are oftendifferent from the newbuilding yards.To minimize deviation from thenormal trade, they are found in thebig loading and discharge ports orunderway on route between commondischarge and loading ports,especially for large tankers and bulkcarriers.

Repair yards are used to normalmaintenance work, but must have theflexibility to carry out repairs. Whenduring the dry-dock inspection aproblem is observed, there should becapacity to deal with thisimmediately, depending on the extentof the problem. Therefore, repairyards need to have more than onedry-dock for similar ships, and arespecialized for certain sizes and typesof ships.

A nev: bov,

The bow brought in position.

The new,bou, is ottachetl

299

Typical repairs are related to certarnship types. Bulk carriers always havework to be done to hatchcovers, crudetankers to pipelines in the tanks andpump room and to valves, hopperdredgers to bottom-valves, containerships to container guides, etc.

A repair yard always has shops and/ordepartments for hull, machinery, piperepairs, electrical repairs, wood-work,and cleaning and painting. Oftenspecific and/or specialist jobs aresubcontracted to separate companies.

Common repairs to hulls are steelrenewals, in dry-dock and afloat, suchas repairs of an indent caused by acollision with a jetty, steel renewalsresulting from grab discharge, localcorrosion or from grounding.Grounding damage can vary in sizefrom a small indent to a whole flatbottom. Fire damage also ofteninvolves steel repairs.

Repairs to shell plating often comewith the problem of shape. Nearly allships have different forms, and whena hull plate is not in the flat bottom orship's side, the curved shape has to berestored. When the newbuildingoffsets (tables measured from theoriginal newbuilding mould), areavailable, the relevant part of the hullcan be drawn up, and the shape caneasily be established from this real-size drawing. Or, when the damage ison the portside, measurements are tobe taken on the starboard side.Nowadays, there is a growing numberof new-building and repair yards thatuse more modern computer systemsfor establishing the profile of shellplates. In the dry-dock laser instru-ments measure the shell plating. Theresults are fed into a speciallydesigned computer programme whichcalculates and gives an accurateprofi le of the shell plating. Thiscomputer programme will also givethe necessary information to themachine operators whose job it is tocut the new steel plates.

8.3 Modern ship-repairs

When there is damage to the ship,usually below the waterline, the shiphas to dock at a repair-yard to surveythe damage. After the survey, theparts that have to be replaced can befabricated, e.g. the skin with thestiffenings and other strengtheningparts. Then they can be installed. Themost time-consuming factor is theretracing of the original form of thehull, which can cause a relativelylong period in dock.

When the yard uses a modern, 3-DCAD/CAM computer programmethis process can be done a lot quicker.More and more of these programmesare used by modern ship-yards.Shortly after the damage hasoccurred, the extent of the damagecan be investigated and uponinspection by the surveyor, insuranceparty and the owner, the extent ofrepairs will be agreed on. Then the

S/ir7r.r slta1rc irt -l ' t ' ibrtr

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preparations can be started up by theselected repair-yard, preferably bypreparing prefabricated sections onthe basis of the CAD/CAMprogramme if available.

Depending on the extent of thedamage the ship can proceed on itsvoyage and the lay time can bereduced as far as possible. Only whenthe sections that have to be replacedare fully constructed, will the shiphave to go to a dry dock for repairs.This way the sailing time lost is aslittle as possible, which is the primarygoal for the shipowner.

On repair yards the use of theseprogrammes is not wide spread,whereas in new-building it is quitecommon.

Ship Knowledge. a modern encyclopedia 300

Bottti ltr dutrutgc P a r t c ' u t o u l

New port ktyt'ere ..uttd brouglt in position to be attaclted

8.4 Conversion

Related to ship repairs, more than tonewbuilding, is canying out conver-sions. Existing ships are sometimesmodified into something totallydifferent from the original ship. Bulkcarriers are converted into drill shipsor into pipelayers; tankers are gettinga second life as FPSUs, FloatingProduction and Storage Units, cargo-ships or tankers are simplylengthened, an existing aft ship with

gT"';l*lt

engine room is coupled to acompletely new fore ship; originalsteam propulsion is changed to dieselpropulsion; passenger ships areupgraded with more cabins, fromemigrant transport into cruise ship, orfrom ferry into floating hospital, etc.A special field is work related tooffshore oil and gas exploration andproduction. Due to the continuouschange in requirements for certain

jobs, drilling units, storage systems,or transport barges often have to bemodified before they can carry outthe next job. This kind of work is alsonormally done at a repair yard.Sometimes they use newbuildingcapacity, for instance, to have a newmidbody built in case of a lengthe-ning, or simply the new parts neededare made.

r s E

{


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301

*

&nhe a-; L**W1. General

1.1 General1.2 Regulations

2. Fire protection, firedetection and fireextinction

2.1 Courses2.2 Combustion process2.3 Fire-fighting2.4 Portable fire extinguishers2.5 Water2.6 Drenching2.7 Fog2.8 Foam2.9 Sprinkler2.10 Fixed gas systems2.11 Detection

3. Chapter III of SOLASon life-saving andlife-saving appliances

3.1 Lifeboats3.2 Man Over Board - Boat /

Rescue boat3.3 Life rafts3.4 Life jackets

3.5 Life buoys3.6 Immersion suits (survival

suits)

4. PrecautionarYmeasures

4.1 Courses4.2 Tests and drills4.3 Personal safety gear4.4 Tankers4.5 Markings

5. Global Maritime Distressand Safety System

5.1 GMDSS5.2 SART5.3 EPIRB

6. Pyrotechnics

* ; "

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#

L. General

1.1 General

Safety on board ships is an importantissue. Normally, at sea, sometimesvery far from any possible assistance,there is nobody who can be calledupon for help. Of course one shouldhave a good ship, with sufficientstability, water- & weathertight, andproperly equipped. However, safetyon a ship is not guaranteed byavailability on board of the(compulsory) safety items and

systems. Safety cannot be bought.Most of the accidents are the result ofhuman effor.

Navigation of course, has to be carriedout correctly and safely, not to bringyour own ship into danger, but alsoother ships at sea. No risks should betaken. Safety of navigation is dis-cussed in another chapter.

Preventing by recognition, rectifi-cation and avoidance by all personnelof unsafe actions and/or situations, atall times and at all places on board is

of utmost importance.

Since July 2002 all ships (and theirashore offices) have to be certifiedunder the International Safety Mana-gement Code (ISM Code), and thecrew has to work in accordance withthe Safety Management System. TheSMS is a set of rules. accuratelY

describing how to apply safety ingeneral and how to use the safetygear. Courses and regular drills areto be held in order to achieve that thecrew is safety conscious. Thisteaches the crew to use the rightequipment in case of an accident. Ina crisis situation logical thinking ofmany people is blocked. They tend toact instinctively using the things theyhave learnt during the courses anddril ls. When situations are nottrained, and thus unfamiliar they tendto panic. In case of fire, especially ontankers, insufficiently trained people

have jumped overboard, often withfatal consequences.

1.2 Regulations

Regulations concerning safety onships are formulated by an IMOdepartment called the Marine SafetyCommittee (MSC). This Committeeis assisted by nine subcommitteeswho are responsible for the STCWtreaty. and fire prevention. At theIMO conference of November 1974the International Convention ofSafety of Life At Sea, in short:SOLAS, was passed.All the regulations of IMO, after theprocedure of ratification, have inter-national validity.

The SOLAS Regulations apply to allships over 150 GT for radio and over500 GT for radio and safety equipment.Ratification by the relevant flag states

Chapter I:

Chapter II-1:

Chapter II-2:

Chapter III:

Chapter IV:

Chapter V:

Chapter VI:

Chapter VII:

Chapter VIII:

Chapter IX:

Chapter X:

Chapter XI:

Chapter XII:

Appendix:

General provisions

Construction - Structure, subdivision and stability,

machinery and electrical installations

Construction - Fire protection, fire detection and fire

extinction

Life-saving appliances and arrangements

Radio communications

Safety of navigation

Carriage of cargoes

Carriage of dangerous goods

Nuclear ships

Management of the safe operation of ships

Safety measures for high-speed craft

Special measures to enhance maritime safety

Additional measures for bulk carriers

Certificates


An overviev, o.l'tlte inde"x ofSOLAS

304

means that they will adopt theregulations in their national laws.SOLAS starts with Chapter I dictatingthe necessary certificates a shipshould carty, and regulations aboutcontrol of same. Chapter II holdsregulations regarding the constructionof ships:- Subdivision to prevent sinking in

case of water entering the ship andprevention of quantities of watercoming inside the ship largeenough to bring her in danger.

- Stability requirements, both for theintact ship and the damaged ship.

- Regulations concerning machinery.- Fireprevention in the form of

insulation of bulkheads such that itforms a sufficient barrier againstfire not to let it spread over thewhole ship, but to enable adequatefire fighting

2 Fire protection, firedetection and fireextinction

2.1 Courses

The most important issue of course, isprotection. Protection through con-struction is, as said above, arranged inChapter II-1. It prescribes the posi-tions of bulkheads, materials ofsubdivision, use of non-flammablematerials, fire proof doors, fire-proofinsulation etc. The basis is, that thethree elements of combustion: flam-mable material, heat and oxygenshould not get together.

2.2 Combustion process

For the better understanding of thisparagraph we will now look moreclosely at the theory of combustion.

Combustion is a chemical reactionwhen some compound reacts withoxygen. This compound will form achemical bond with oxygen under therelease of heat and the formation ofnew compounds. This process isknown as oxidation. Combustion ishappening everywhere unnoticed, forexample in the human body or incorrosion like the rusting of iron. Anactual fire will only occur in case of acombination of those factors. If oneof these factors is removed. there will


be no fire and if there already is a fireit will be extinguished. Fire preven-tion and fire fighting is based on thisprinciple. The required factors areshown in the fire triangle. If just oneside of the triangle is taken out of theequation, then the fire will cease.

The ignitionTo start a process of combustion morethan the three factors are needed. Theheat that is necessary to start the firemust fulfil some requirements. For asolid or a liquid to ignite there has tobe some vapour or gaseous product.This is the case when the compound

FuelThe fire triangle

is heated until enough vapours andgases have been generated to form aflammable mixture. The lowesttemperature at which this situationoccurs is called the flashpoint.

However, it is possible that when theflashpoint is reached, the combustionwill cease after ignition. The reasonfor this is an incomplete mixing ofgas and air. The lowest temperature atwhich combustion will continue afterignition is called the ignitiontemperature. At this temperature,enough vapour is formed to sustaincombustion; the heat balance is inequilibrium. A necessity for sus-

taining combustion after ignition isthat a sufficient amount of heat isreleased in the process. This is thecase when more heat is produced thancan be absorbed by the surroundings.Combustion is also possible withoutignition from outside. If enough heatis pumped into the fuel, thetemperature may become so high thatit will ignite spontaneously. Thelowest temperature at which this canoccur is called the (spontaneous)combustion temperature.

| * Heat beams

Air

pre-ignition

Igttitiort and combustbn o.f a soLid

A catalyst is a compound thataccelerates a chemical processwithout being consumed.

An everyday example of this is thecombustion of a sugar cube. You cannot light a sugar cube with a match orlighter. However, when you put someash on the cube, you will be able toset fire to the sugar. The ash isworking as a catalyst. In essence, acatalyst reduces the energy neededfor a process in comparison with theprocess in the absence of the catalys

The fire pentacleFrom the preceding it becomes clearthat the fire triangle alone does notsuffice; the oxygen/fuel ratio is alsovery important in the ignition andsustaining of a fire. Next to this, a firecannot start without a catalyst.If there is no catalyst in the vicinity ofthe fuel then (over-)heating can stillstart the combustion process becausethe fuel will form its own catalyst.The general catalyst in combustion iswater vapour. If the two factorsoxygen/fuel ratio and catalyst areadded to the fire triangle you obtain afire pentacle.

I

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eil

Combu,stion o.f a liquid

305

Temperature

The.fire pentacle

Fire classesFire classes highlight the charac-teristics of combustion depending onthe type of fuel. The fire class is usedto determine which method of fire-fighting is most suitable for theparticular fuel.

Overviev, o.f'.fire c'lct,sses ancl the types r\f

.fLLels

2.3 Fire-fighting

When there is a fire, all attempts areto be made to get it extinguished.There are various means of fire-fighting, with different objectives:take away heat, oxygen or theflammable material, to preventcombustion as described above.Removing the flammable materialsounds easy, but is often the mostdifficult way.

Sand as an extinguishing medium isexcellent, but not on ships. In the pasta sandbox near the boilers was


C ro 5; s - 5; ect i6 n of' CO r ext i n g ui s lrc r

1. Carrying handle

2. Control lever

3. Outlet pipe

4. Snow horn

5. Blow-out pipe

Powder extinguisher

Class of flammable goods

Wood, paper,textile, plastics

Liquifyinggoods, petrol,alcohol, stearine,

Magnesium, alu-minium, titani-um, zirkonium,sodium, potassium

Cros,s-section of a pov,der extinguishe.r

F oom trolley C rct ss -,s e cti on of a .foam e.rti n g, Lti,s lrc r

306

normal, but nowadays it has beenreplaced by a portable powder extin-guisher. Oil fires when oil blows outof a hole under great pressure, can beextinguished using a controlled explo-sion. It blows all the oxygen andflammable gas away. But again, notsuitable on board a ship.

2.4 P ortable fire extinguishers

The first line of defence on boardusually is the portable fire-extin-guisher. Dry-powder, CO2 or foam.Dry-powder extinguishers, usuallywith 6 kg powder, are placed in theaccommodation and other easilyaccessible spaces. In the engine rooma 20 kg unit has to be available, andalso on tankers in way of themanifold, during loading and dis-charging operations.

The powder is available in threecategories:

A for fire in solids.B for fire in liquids, andC for fire in gases.

Usually the extinguishers are filledwith a mixture of the three powders,making them versatile. The extin-guisher consists of a closed containerwith powder, and inside a compressedgas (carbon dioxide) cartridge. A pinwhen hit, opens the cartridge,bringing the container under pressure,and blowing the powder out.

CO2 portable extinguishers are to beused in case of electrical fires in aswitchboard, and oil fires, for instancein the uptake of a galley.

Portable foam extinguishers are in usein engine rooms, but are more andmore being replaced by powder extin-guishers.

Spare charges for the extinguishers ora sufficient supply of all types of fireextinguisher ate required to be storedon board.

Explanation of the lefthand pictures:

1. valve for opening the cylinder2. blow-out pipe

3. fire extinguisher gun


When a fire is too big to be dealt withby portable extinguishers, systemswith more capacity are available:

2.5 Water

Water takes away the heat. The mostversatile, easiest and at sea thecheapest medium available for extin-guishing a fire.

Therefore ships are provided with firepumps and a pipe line system thatruns throughout the ship. Spaced atregular distances there are hydrantssupplied by the pipeline system. Sowhen hoses are connected to thehydrants all parts of the ship may bereached.The pipe-line system must besupplied by two fire pumps, situatedin the engine room, each havingsufficient capacity and pressure forthe whole system. An emergency firepump, individually driven, is locatedin a separate fire protected compart-ment. This pump is to have a suffi-cient output to supply two hoses.Near each hydrant a hose must bestored, fitted with a dual-purposenozzle: for a solid jet, and for spray.The hydrants are so constructed thata fire-hose is easy to attach. (threesystems: Snap-on, Storz, LondonFire-Brigade).

In case of a fire while the ship is inport, there has to be the so-called:International Shore Connection, astandardised piece of pipe, to whichthe local fire-brigade can connecttheir water supply to pressurize theship's fire main.

Fixed pressure water spraying systemVarious systems have been developedto spray water in or over areas, whichare vulnerable in case of fire.

2.6 Drenching

Ro-Ro vessels have in their cardecksopen sprinklers, operated from acentral fire-control room. When afire-alarm comes in, the fire is locatedby the related alarm head, and afterinspection, by an officer or via closedcircuit TV; the valve of the relevantarea of the car deck can be openedmanually. The capacity is much

higher than of ordinary sprinklerssystems. The cargo, trucks, trailers,vehicles are much more dangerousthan a cabin. Deck scuppers musthave a capacity which can cope withthe water quantity, so as not to causeloss of stability due to the free surfaceeffect of the water. This system is alsocalled: deluge system.

2.7 Fog

A relatively new development iswater fog. Fresh water is pressurisedthrough very fine nozzles so that thewater comes out as a fog. Whereassprinklers splash everything fromabove with water, the fog fills thespace with a cloud, going every-where, also underneath furniture etc.

2.8 Foam

Water can be mixed with chemicals,so that when let through a pipe whereit can be mixed with air, foam isdeveloped. There are three systems:

- High-expansion foam,- Pre-Mix ordinary foam and- Foam made in a proportionator.

The foam-forming chemical is nor-mally ox-blood or an artificial equi-valent. The mixing rate is 4-5 Vo.Bothlow and high expansion foam can beused in spaces like engine rooms, itcan fill the whole space, through asystem of nozzles, strategicallyplaced, without doing much harm tothe equipment. The water is thecoolant.Ordinary foam, pre-mix or mixedwith water via a proportionator,which is a venturi tube where in then:urow part of the tube the foamliquid is injected, is used on tankers,to lay a blanket over the deck, like onairfields on a runway. It closes a firefrom the ait and thus from oxygen.Foam in small quantities can be usedvia Foam Applicators, usually twounits in the engine room. It is a smalldrum with foam liquid, connected tothe throat of a venturi tube which isconnected to a firehose. Whenspraying water, the foam liquid issucked up and mixed with the water,producing foam.

307

2.9 Sprinkler

In each cabin, depending on area, oneor more sprinkler heads are fitted inthe deckhead. These sprinkler headsare connected to a pipeline suppliedby a pressurised vessel filled withwater. A glass crystal closes the pipe.When heat is developed in the space,the glass crystal breaks, water flowsout and is diverted by a roset in to anumbrella shaped water fountain.When the pressure in the water vesseldrops, a pressostat starts a fire pump,providing the vessel with water, tokeep the flow going. The pressostatalso triggers the firealarm.

\-omoress€c c : 5uccj.

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3) Fire pump conhol unii4l Conlrolcobinet5l Jockey pump6f Filling pipe for pressure tonk ond piparorkZf Jockey pump conhol unil8l Reduced copocity slotoge tonk lclosedl

Sprinkler s.\,,\tent


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l2| liquid level moniloringl3| Presure moniloring14| Sofety volvel5f Pressure reducer16| Pressure relieve deviceI Z| Cylinder wbe with pneumotic releose

2.10 Fixed gas systems

Fixed gas fire-systems: Filling aspace with a gas which reduces theoxygen content, or which is an anti-catalyst. It reduces the oxygencontent to a level at which fire cannotexist.. but can onlv be used in closedcompartments.

Most in use: Carbon-dioxide totalflooding systems for engine roomsand cargo holds, consisting of abattery of bottles of CO2 under highpressure (200 bar), which can beblown empty into engine room orcargo hold, creating an atmospherewith insufficient oxygen to allowcombustion. Before releasing CO2 intoa space, that space has to be free ofpeople, and all openings to outside

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rexlinguishing pump

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I ! Fire pump 9l Aulomotic odditionol supply(redundonl conshucfion occording to SOIASI I O) Srroiner

2f Test line I I l Pressure bnk

lB! Cylinder bottery {nihogen}l9| Cylinder bottery oclivotion201 Flow swilch for olorms in cose of

releose ol o Minisproy@ sprinkler2l I Tesl volve221 Secfion volve231 AAoniloring ond olorm ponel

308

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Symptoms after breathing CO2

normal CO2 -concentration

TLV and MAC-valueIncrease in lung ventilation by 507o (hyperventilation)

Increase in lung ventilation by 1007o

Light stupefaction, less accurate hearing, faster heartbeat

and higher blood pressure

Increase in ventilation by 300Vo, heartbeat and

blood pressure

Symptoms of poisoning after 30 minutes; headaches,

dizziness, transpirationDizziness, stunning and unconsciousnessBreathing difficulty, drop in arterial blood pressure,

congestion, death within 4 hours

Disorientation and dizziness

Immediate unconsciousness, death within minutes

Narcosis, immediate unconsciousness, death bysuffocation

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h O L O S I A R E O A R O

HOTO . PORI sIDE

TLV = Threshold Limit Value

MAC = Maximum Allowable Concentration

Congestion = accumulation of blood


CO z -o'lilttlers

C rtnt 1t u I sr t t'.t' s u c I i t ttt

309

have to be closed and mechanicalventilation, if any, has to be stopped.CO2 is very dangerous for people.Therefore opening of the bottles andthe necessary valves in the pipelinesto the affected location are protectedwith a number of safety measures.Opening the cabinet with the (locked)valves for opening the pilot bottlesgives a loud alarm in the engineroom. Carbondioxide, although veryeffec-tive, is very dangerous topeople. A large number of fatalaccidents has necessitated the searchfor less harmful alternatives, firstfound in Halon. For a number ofyears this was in use, but being aCFK, was abandoned in connectionwith environmental consequences.There are a number of Halonreplacements, but these are soexpensive that CO2 nowadays ismostly installed an newbuildings,again, since Halon is forbidden.

2.Il Detection

For successful fire-fighting, the earlydetection is of utmost importance.Then a person notices a fire or smoke,he has to raise the alarm. Throughoutthe ship buttons are installed, whichwhen pressed create bells ringing, foreverybody to hear.

Engine roomIn an unmanned engine room, or anengine room which is operated from acontrol room, a fire-detection systemhas to be installed. Smoke-, heat- andflame-detectors are fitted in strategic(high) locations, so that in case of fireit is detected soonest. Three types ofdetectors are in use: for smoke, heatand flames. For smoke normally aradio-active isotope which triggers analarm when the radiation isobstructed, contacts the alarmcabinet, which gives alarm. Thealarm cabinet is usually in thewheelhouse. The alarm activatesbells, ringing loudly throughout theship. At the cabinet can be seen whichloop is activated. Each loop covers acertain area in the engine room. Ineach loop also heat and flamedetectors are fitted. The heat detectorreacts to a sudden rise in temperature,the flame detector to light shattering.Testing of smoke detectors can be

Ship Knowledge, a modern encyclopedicr

><l

done using a small smoke source or aspecial gas; heat detectors use acigarette lighter, and flame detectorsan ordinary battery torch.

Cargo holdsFire in cargo holds can be detectedthrough Sample Extraction. To detectsmoke in cargo holds of dry cargoships, there is an arrangement wheregas is extracted from each cargohold,or cargo-compartment. This gas isdrawn via a pipeline, one for eachcompartment, towards a cabinet,usually in the fire control room or onthe bridge, where in its simplest formthe samples of each space arechecked one by one by leading thesamples through a glass tube with alight behind and a photo-electric cellthe other side. When the light isobstructed, an alarm is raised. Inves-tigation and action must then beundertaken by the ship's staff. The

Schematic representation of a fire-alarmsystem and a fire-fighting system

1. COz -cylinders

2. Pipes for COz-supply

3. Air-drawing installation

4. Signalling system

5. Control system

6. Indicator panei

CO2 battery has a special trigger andcan be released at wil l into therelevant hold.

Fire extinctionEach ship has to be provided with atleast two firemen's outfits, completewith breathing apparatus. This is aheat-resistant suit, with boots, glovesand helmet, to go close to a fire, whennecessary for fire-fighting or forevacuation of people in danger. In

5.

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310

case of smoke, the BreathingApparatus (BA) set is to be used. TheBA set comprises a compressed airbottle. and a smoke mask.

Tlte BA sett

A further action against fire in enginerooms, or to stop an already ongoingfire, is the closing from outside theengineroom of the valves, via whichflammable liquids, (fuel oil, diesel,etc) is coming from tanks into thevarious engine room systems. Theseso-called quick-closing valves arespring-loaded valves, which, whentriggered, are immediately closed bythe spring. Activation can be pneu-matic, hydraulic or simply with awire. Coupled to this preventiveaction is the stopping of all venti-lation to and from the engine room,and closing of openings, by flaps,doors, etc, and stopping oil pumps.

Modern ships are provided with afire-control station. In big ships this isa room in the accommodation.accessible from outside, with a fire-door to the rest of the space. The fire-control station, depending on the typeof ship, comprises the following:- a display of the fire alarm system,- the cabinet with the operation

handles of the quick-closing valves,- stop-buttons of the mechanical

ventilation.- the smoke extraction cabinet,- the remote operation cabinet of the

CO 2 fire-extinguishing system,- a firemen's outfit including a

breathing apparatus set,- other related equipment.

The fire control station is normallvalso the mustering point for thefire-defence group.

A help for everybody is the FireControl Plan, a general arrangementdrawing of the ship, showing all thesafety appliances. This plan is atvarious places posted on the walls,and also in a red container near thegangway, for the shore firebrigade,when the ship is in port or at ashipyard.

Fire alarmThe Fire Alarm, a bell ringing loudly,at intervals of a few seconds, can beactivated manually by pushing abutton in a little red box, behind glass.The alarm buttons are installedthroughout the ship. Also, when firehas been detected by a detectionsystem, it activates the alarm.Resetting of the alarm can only bedone at the main display, usually onthe bridge. On the display can be seenwhich. button, in which zone ordetection-loop, was activated. A zoneor loop can be isolated when repairsare carried out and smoke at thatlocation is inevitable (engine roomworkshop).

I-ight-v,eight ulwnirtitun.firepntof'suit, arultLirtg to g,et close to.fires und lrcat.


Cylirulc.r t'ontaitting tlte sctfefi plan, easih, ctc;ce,s'sible.t'ur tlrc .l'ire-.1'iglters

311

CALA PEVEROMUSTER LIST SAFETY OFFICER

!sl

N '

c€N

RANK

LIFE SAVING APPLIANCESNIAN OVER 6OARO ECOLOGY FRSTAID

LIFE SAVING APPLIANCESPREPARAIION

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An example of a Muster List

Muster listA Muster list, for everybody to lookat. with names and functions ofeverybody, updated every voyage,and the special tasks during fire orother calamities, is fitted on the wallsat various places: wheel house, mess-rooms and fire-control room .

3. Chapter III of SOLAS on

3.1 Lifeboats

Lifeboats on each side of the ship,capable of accommodating every-body on board on each side, or onefree-fall-lifeboat at the poop withcapacity for the whole complementare the most important items. In caseof lifeboats on both sides. one boat isthe man-over-board boat. or rescue-boat. The inventory of the lifeboats isaccurately laid down in regulations,


life-saving and life-saving appliances

and has to be checked regularly. Mainitems are food, water, a first-aid kit,medicines, a searchlight, diesel fuelfor 24 hours, two bilge pumps,distress signals, fishing gear, toolslike axes and engine-tools, spares etc.

Since a few years lifeboats have to betotally enclosed. On tankers they haveto be provided with an internal air-supply through compressed airbottles, so that the boat can get away

nffi@F

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312

I

Dffirent viev,s of a free-fall liJeboat

through burning oil on the water.Therefore also a sprinkler system isinstalled, to cool the outside of theboat.

The capacity of the lifeboats isdepending on the number of peoplecarried on board. On either side thewhole complement, as stated on thesafety equipment certificate, in one ormore boats, must be accom-modated.A free-fall boat has to take everyperson on board.

Every lifeboat must have a dieselengine, starting by batteries andbacked-up by manual-start.

Lifeboats must be able to be loweredwith a ship listing 20 degrees andwith a trim of 10 degrees. An(enclosed) lifeboat must have suffi-cient stability to upright itself.

Lifeboats and davits are made invarious ways. All systems are madesuch that no power is needed from theship's systems to lower a lifeboat.

Lifeboat installations that use gravityas an energy source are usually of the"free fall" type. The installation ispositioned at the aft of the ship,ensuring that trim and list have aminimum of influence on the launch.

Prior to the launch, the mate moves alever up and down which, in turn,controls the release hook hydrau-lically. At this point, the diesel engineis already running so that the boat cannavigate away from the ship imme-diately after the launch. The seats inthe boat are positioned with the backsfacing towards the front of thelifeboat. This helps to absorb thesubstantial forces acting during thelaunch.

The free-fall lifeboat can be liftedback on board of the ship with anauxiliary of the launch installation,even when the weather is not optimal.In most types of installations thisauxiliary is a U-shaped lever with awinch and a cable that can rotate insuch a way that the lifeboat can comeback on board of the ship. Both thelever and the winch are operatedhydraulically. The oil pressure is

These dratvings show stepwise ltotv tt

lifeboat with occ'upants is brought into

the water.

LiJbboats launched vvitlt stored power

davit.tLaunch of a free-fall boat from a height

of 20 ntetres


supplied by an integrated "power

pack". If the path of the free fall isobstructed by some obstacle(s), thenfree fall is not an option and acontrolled launch will have to takeplace.

In case the ship sinks or keels over,the lifeboat must have sufficientbuoyancy to detatch itself from thelaunching system.

The most common lifeboat/davitcombination is 'gravity davits' ateither side of the ship. The boat goes

down by its own weight, afterremoving a number of securings andseafastenings, by simply lifting thebrake handle of the winch.

Another launching method is to use"stored power davits". This system ismainly used on passenger linersbecause the system does not requiremuch space. The lifeboats arehanging in the davits. During launch,these telescopic davits extend untilthe lifeboat is clear from the ship.Then the lifeboats are lowered intothe water. The davits are extended bya hydraulic system that obtains its(stored) power from batteries.

MOB -boil vyith crurc. Tlte c'rnne c'ctrt

ul,s'o brins tlrc bortt lxrck ort ltoord.

Pcrnttuterrt MOIS -bout. If the boctt i,;

suspenrled.f rom the crene, it cun be

Ipvt,eretl fi1' pullitrg tlrc triangle.


life buoy with light and smoke

signallocker with fire hose

life buov

3.2 Man Over Board-boat IRescue boat.

Man Over Board-boat / Rescue boat(MOB-boat). In case of a free-falllifeboat, there has to be a separateMOB-boat, under a crane. Again withcompulsory inventory. Special suitsfor 3 crewmembers are important.Ships carrying passengers need tohave a fast rescue boat, capable ofbeing lowered into the water whenthe ship is still making headway.

3.3 Life rafts

Inflatable Life rafts are available oneach side for the whole complement.They are to be dropped overboard,where an attached line arranges theinflation. In case the ship sinks, theraft is released by a hydrostaticrelease. The line has a weaklink,which breaks, to prevent the shiptaking the raft down. Large shipshave an additional 6-person liferaftforward, and some very largecontainer ships with midships accom-modation, one aft. When a ship has a

4. MOB -boat

5. Lowerable raft

6. Crane for raft and MOB -boat

7. Free-fall lifeboat

A laturcltetl rn.fi

free-fall boat, one life raft has to besituated below a crane, normally theMOB crane, so that the liferaft can belowered in inflated condition.

2.3 .

Rctfi in corttr.tiner

314

Explanation of the numbers usedin the image below:

1 .2.3 .4.5 .6.7.8.

lashing strap around raft

pelican hook

connecting line

painter

weak link

ring

exposure lever

expiring date of certificate

ffi xna'r

..'ffi*,0

"*r, '-]-

The ,sinking ,ship pulls the boat line utd

the raft is inflated.

2..34.

Hydrostatic' releu,se

3.4 Life jackets

There is to be one for everybody, andprovided with light and whistle.There are mostly stored in the cabins,some-times in boxes near thelifeboats. Also a few life jackets are tobe stored in places where peoplework: in the engine room, on thebridge and in the forecastle space. Alifejacket has to be made of watertightand fire retarding material withsufficient buoyancy. Furthermore, ithas to upright an unconscious personwho is face down in the water and hasto keep his mouth 12 cm above thewater.

They have to be provided withreflective material. A whistle and alight have to be attached. In case ofchildren on board, special, smallerlifejackets need to be provided.In case of inflatable life jackets, theyneed to have two airchambers and areto be serviced every year.

:"r.{h*m

",,,'*%otd*{$

s':${*$E[ry{rVil4 ,.1: 4 , -

1

Life jacket with beLt, u v,histle utd

retlectirtg strilts.

The lust (vveak) connecfirtg line breuks

and tlte survivors can clirnb into the

inflated life raft.


Lowerable life ra.ft

Lctwerable li.te rati

a.-r...:\

3 1 5

3.5 Life buoys

They comprise a number of buoys,attached to the handrails. some withfloating line, some with a floatinglight, some without attachments. Onboth bridge wings there has to be alife buoy, installed such, that whenreleased, it drops into the sea.Attached to these buoys are a floatingsmoke light and a light signal.

Sttrttival suit. It lta.s to be w,orn itt

t'otnbination w'ith a li.fe belt to ,rtabili,ve

tlu' heutt in t 'u.te tlte persort *'eurirtg it

b e c r nte s uttc: ott,t t: i o u,t.


l. fire hose

2. pipe branching with a snap-on

coupling

3. powder extinguisher

4. life buoy

5. safety sticker F (Fire)

Lif'c buo1, t'r,ith light anrl nturking

3.6 Immersion suits (Survivalsuits)

At least three per lifeboat arerequired. Some flag states requireimmersion suits for everybody onboard. However, this is not requiredwhen the lifeboats are totallyenclosed. Hypothermia is the mostdangerous threat to people in life-boats. Especially in open lifeboats,which are still very much in use onolder ships. In that case there must befor everybody a Thermo ProtectiveAid (TPA), a protecting bag, keepingthe body heat inside. Or an Immer-sion suit for everybody. An Immer-sion suits has to be worn togetherwith a life jacket. The insulatingquality of immersion suits has to besuch that the body temperature hasnot dropped more than 2 "C after6 hours in water with a temperaturebetween 0 and 2"C.

4. Precautionarv measures

4.L Courses

To work professionally with all theabove materials and items, the shipscrew needs education. Before signingon, everybody needs a certificate ofcompetency.

This certificate can only be obtainedwhen the individual is in possessionof the proper diplomas, sufficient sea-service and a number of certificatesobtained after fulfillins certain safetvcourses.

Stfety means.font'unl, rtov vt,ith open door

Ligltt antl stnoke sigrtul

316

LEGEND:= initial training as part of the curriculum of nautical colleges in the Netherlands

f--ii-l = applicable to ships certified firr an unlimited area (GMDSS sea areas A3 and A4)f-l-]E

--l = required for at minimum 2 officers in charge of a navigational watch (prosontly all offlcers In cherge of a navlgatlonrl watch)

= mandatory

= mandatory only br designated crew (according to the vessel's manning plan or muster list)

l-tffi=llffi']= not applicable to certificates of competence < 3oo0 GT and/or < 3000 kW

-I n.a. | = not applicable

I s.s | = no refresher training required in case of 1 year sea service during the past 5 years

Ti.ct iningltrtr i"r inaccorduncevt, i th1995STCW-trenty,Tlrtable��

's| t i1l ,s,srfetyexert: i ,sesttreinc, luded.Thetubleisnrdels1,11,n,RoyuIAs,yt lci t t t i r l t � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �

Assrtciation of Dredging arul Civil engineering c'otnpanies (VBKO) anrl the Shipping Inspet'torctte. The rlc$a in the tahle has atelnptlrur1l ' \ tutLtSuncl isbasetlontl tesit t t t l t i rninthespring0f2002.7"l tet l t t t tr i -r � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �

lmnrlling large grctults of people in emergertr:ies is included here.

4.2 Tests and drills.

To respond fast and efficiently in caseof an accident, people need to betrained. Regular drills, fire-drills, andabandon-ship drills, have to becarried out, and are compulsory. It isimportant that the drills are asrealistic as possible. On completionof the drill an evaluation has to bemade, where the shortcomings of thegroup or the individuals are to bediscussed, and, if necessary, sometheory is reviewed. The drills are tobe entered in the ship's logbook.Drills on board with liferafts isdifficult. That has to be done at shoreinstitutes. The same counts fordistress signals.

4.3 Personal safety gear

During normal daily work, also safetymeasures have to be taken. Personalsafety items for normal work are:Safety helmet, Ear-protection, Eye-protection, Gloves, Safety-shoes,Coveralls, Lifebelt, etc.

Su.fety lrclttrct cutd a

.jacket. 7'li,r Life ,jacketrluring, vt,ork.

,setff-inllttting II'e

cun rnil,v lte usecl

Boat drill

Exercise How manv times?

Abandon ship MonthlvFire-fiehtine MonthlyMan over board MonthlyEmergency

SteerineOnce every three

monthsI;ire drill

Ship Knowledge, a modern encyclopedia 3 1 7

MARS 2fi)051Saved by " Safety HelmetA 2nd lllate was in charge on the deck of

a ship wtrich was at anchor and badrng

containers from barges. As a contaner

was being loaded on to the 3rd lapr by

stevedores a twrstlock fellfrom a haght

of about 8 metes. tt hit tE 2nd Mate on

his helmet and touched hrs b@ causing

an abrasion on his chest and a contusron

on his left high. Because of fie heavy

impact on his head he was sent ashore

to see a doctor.

An Xfiay was taken and ln was declared

fit to return to the vessel hn gn on light

dutbs. This emphasises the importance

of wearing personal protective equiP

ment. vrntfrout his frelmet he 2nd Mate

would probably haue died.

Srtnrt e ttrtnplcs of'.1'i l l t:r tnu.sk,s. 7'lrc lelt

one ulso prttle.cls tlte e_t't ',s.fnltt ltoi,sott.

Water atul chemit'ul ttruofbools

Working with cargo, requires therelevant safety measures related tothat cargo. Especially when workingwith chemicals. Often special suitshave to be worn, special gloves andboots, breathing apparatusses, etc.


Arrr

# a

:54 ,

I -i g h t i t t g s\',\'t(.t t t

Pipe v,itlt colttttt' r:odc ttttrl urr()t't,'s

itulicatitrg tlrc dire<'tion of thr: l iquitl. l 'htv

eihtlrtutt'c door w'itlt ntuttc untl tac'ltttit'ttl ntttrking

H@

@

Hg'

' lesting lhc flnnr puntp rlt u lttnker

4.4 Tankers

For tankers there are special safetymeasures, like additional fire-fightingsystems, such as foam to cover thedeck; fire and / or explosion preven-tion by inert gas above the cargo,alarms for full tank or risk of overfill,and special safety measures for thecargo-pump room.

C H R E E

g ' l l

i -r:rig- -

Stit 'kcr .sltotr,in,q rour ltosil ion ott boanl

t *r'

-r-*

#

a-t

I- 4rt

ffim

trf 'dirt:tt iort

3 1 8

4.5 Markings

Many items on board ships are identified by markings,often stickers. All safety gear, wherever stored, has to beindicated by a sticker. Escape routes are pointed out by asticker,

Near the life rafts instructions on how to use the life raftsare to be displayed, i.e. preparation and launching.

Markings should make something clear in a simple andfast way. For instance, on ships carrying passengers stationnumbers are useful for orientation of the passengers on theship. However, the markings are important for both crewand passengers in case of an emergency. The markingsshow the exits and the location of life-saving appliances.This is made easier by the use of iurows on the walls or alighting-system for passengerways and staircases. Theseescape route markings (green) in the accommodation arecompulsory according to the IMO-regulations. Not onlythe escape route must be marked, but also all means ofsafety. The markings on these should be photo-luminescent. This means that they light up when no lightshines on them.

There are pipes running throughout the ship, most of themin the engine room. A large variety of liquids is beingpumped through these pipes and in the interest of safety itshould be clearly indicated what liquid runs through whatpipe. This is not only important for the crew, but also forpeople less familiar with the ship. To achieve this all thepipes have a colour (either paint or coloured tape) thatstands for the liquid in that pipe.

Farbcode: Farbe: l'ledien (allgernein t:Colour codel Colour: Media (general):

BU FrischwasserBlue Fresh water

SRSilver

RDRed

YEOYellow-ochre

WHWhite

BNBrown

OGOrange

wViolet

GYGrey

MNMaroon

GN SeewasserGreen Seawater

- DamPf

: Steam

Feuerbe(anDf-ri te;enchutzFire fgr ';.i = d :'::eclon

Enflamrt+a.e Ga:e' Flarnrr.'al:e Eases

[gf1' - vg^t" isgonssystemenA. - - re^: a.'lon systems

K'afutofreF ; e s

f .r-- -.- -

O iricnt zum Krafutoffgebrauch)O,: other than fuel

Sauren, LaugenAcids. alkal is

Nichtbrennbare GaseNon flammable gases

Medien (trocken und feucht)Masses (dry and wet)

8K AbwAsser / AbgaseBlack Waste media

FD -l Fi:",3T[:1,:^Colour code Jor pipe.r

There are many large and small rooms and spaces on aship. In general each has a door or an entrance hatch. Butbefore the door or hatch is opened, it is important to knowwhat is in that particular space, especially at night or in badweather. This is why every door or hatch carries the nameof the room behind it. sometimes with some technicalmarking.

5 Global Maritime Distress and Safety System (GMDSS)

5.1. GMDSS

GMDSS is legally required, asagreed upon in the SOLAS 74Amendment in which the distressand safety radio traffic is regulated.All passenger liners and ships largerthan 300 GT are obliged to haveGMDSS. GMDSS ensures that,irrespective of the ship's location,reliable shore to ship and ship toshore communication is possibleusing radio and/or satellites. Allinformation regarding transmittingand receiving, and the frequenciesused, can be found in the "Admiralty

List of Radio Signals", Volume 5.GMDSS also includes the NAVTEXreceiver, which receives and printsweather forecasts and warnings as


well as distress messages, andwatertight (GMDSS) walkie-talkiesfor communication in case ofdistress.

5.2 SART (Search and RescueTlansponder)

Life rafts and lifeboats are difficult tosee on radar because of their poorradar-reflecting properties. To over-come this problem, a device (SART)has been developed that, on receivinga radio signal, answers by trans-mitting a radio signal of the samefrequency. This makes the life raft orlifeboat visible on the radar screen.When the ship is evacuated, oneindividual, indicated on the MusterList, is responsible for bringing theSART from the bridge, to the life raftor lifeboat. The SART has a range ofapproximately 30 miles.

SART cutaclted to the lifbraft

319

I I J

l 7

{

fi

B ritlge, sturbou rd sitlc

1. SART

2. Powder extinguisher

3. CO2 -extinguisher 2 kg

5.3 EPIRB (Emergency PositionIndicating Radio Beacon)

The EPIRB is of use in case the shiPis sinking so fast that the crew doesnot have the time to warn the world ofthe disaster. As in the case of the liferaft, the water pressure will activate ahydrostatic release and the EPIRBwill rise to the surface. As soon as theEPIRB is activated it will start totransmit the MMSl-number* of theship to a satellite which, in turn, willwarn a ground station. The groundstation then warns the nearest coastguard station. (*MMSI= MaritimeMobile Ship's Identification)

The coast guard will direct ships andaeroplanes as soon as the appro-ximate position of the ship in distressis determined. When the EPIRB startstransmitting, a bearing can be takenand the position can be determined.

Aft side of the bridge

1. EPIRB2. Life buoy with light and smoke

signal

6. Pyrotechnics

A visual form of communication arethe Distress Signals:

Red Parachute Signals, must be avai-lable in or near the wheelhouse (12)

and in each lifeboat (4). They arerockets, which can be fired out ofhand, and can be seen from a great

distance. To be fired in the hopesomebody notices. The generalmeaning is: I need help.

Hand flares, in lifeboats (6) andrescue boat (4). These are very brightburning torches, which are to be heldin then hand. Used to draw attention,or to let know the own location.

Smoke signals, in each lifeboat (2).4

tin can, when lit to be put in the water.They remain afloat and produce athick orange smoke, clearly visiblefrom airplanes.

Line throwing apparatus, 4 pieces inor near the wheelhouse. These arerockets, which when fired by a gun,

draw a long thin line behind them.The purpose is to shoot a line toanother ship, as a first step to esta-

Linethrou;ing apporetus (.four itt rnrc

bo.t)

blish for instance a towing connec-tion. With the thin line a somewhatheavier line can be pulled in, connec-ted to a hawser.

PorachtLte ligln

Hattd torclt

Smoke s i g t ru l



1 .

2.

lntroduction

lntact stability

3. Stability of damaged ships

4. Rules and regulations

5. How to take damage stability

into account on board.

tb** *

t, ' f * +

,t,4.

, , .- ,.1i,i*g{!,:ir,

'+:F#i*&.$i; ' . : - '

"*1"i, ..':.:!.ffu

' , - " , - , r

' : : - + r ' ' - : \

L. Introduction

Why does a ship float in spite of being constructed from heavy materials like

steel? The reason for this is that the gravitational force that pulls the ship

downwards is balanced by the upward water pressure on the hull. Of course a

prerequisite for this is that the ship is watertight below the waterline. When the

weight of the ship becomes so large that the upward pressure is less than the

actual weight, the ship will sink.

The water around the ship exertsa force on the ship that is directedperpendicular to the watersurface. If the ship floats, thisforce equals the weight of the

water that is displaced by the

ship. This is called Archimedes'law which states that an objectthat is totally or partially

submerged in a liquid, expe-riences an upward force thatequals the weight of the liquid

displaced.

The magnitude of the upward force

depends on the volume of the ship'sunderwater body. The displacementresulting in an upward force is calledthe buoyancy. If the ship has onlYbuoyancy and no spare buoyancyabove the waterline, then the slightestincrease in weight of the ship wouldcause it to sink. It is therefore veryimportant that the ship possesses acertain amount of spare buoyancY.The spare buoyancy com-prises allcargo and engine spaces above the

waterline, but also theaccommodation. deckhouses andother deck erections. All the spacesthat contribute to the spare buoyancymust meet the demand that they arewatertight or can be closed water-tight.

2.lntact stability

Ships are designed to float upright.

Stability is the ability of a totallysubmerged or partly submerged bodyfloating upright, when brought out ofbalance, to come back to the uprightposition when the reason for the listdoes not longer exist.

Difference is made between longi-tudinal stability and transversestability. The longitudinal stability is

normally sufficient, so it will not be

taken into consideration here. We will

look at transverse stability only.When in the following the word

stability is mentioned, transversestability is meant.

Stability for small list angles of

6 degrees is called Initial Stability.

When a floating body is brought in a

listing position, without adding orremoving weight, at the lower side of

the body a buoyancy wedge is formed

and filled, and at the high side a

wedge is lost. When the volume of

the submerged part during listing

does not change, both wedges have

the same volume.

Due to the above wedges, the centreof buoyancy (B) of the wholesubmerged part is moving from theinitial position towards the directionof the low side, where a wedge is

formed, by the formation and loss of

the wedges. The locations of B at

Metacentre (M): The point thevirtually suspended ship isattached to. If the centre ofgravity G is located below M,then the stability is positive. Ifthe centre of gravity G is locatedabove M, then the stability isnegative. The ship runs a gteat

risk of capsizing as a conse-quence of the latter. The distancebetween M and B (see below)depends on the draught and thewidth of the waterline.


varying angles are all on a virtualcurve.

A body can be brought to a list in alldirections. Not only transversely orlongitudinally. We only look at twomodels, transverse and longitudinal,which are at right angles to eachother, and we look at a ship's body.

When looked at the transverse model,the body, now a midship section of anormal ship, is brought to a list (rp),

with a small angle. The buoyancyforce has a vertical direction, a vector,originating in B, and pointing up-wards, perpendicular to the waterline.Where this line crosses the plane ofstem and stern, (the midships plane,centreline plane) the TransverseMetacentre point (M) is found.

For each angle of list there is aMetacentre Point. At a larger angle,the position of M can be significantlydifferent from that at a verv smallangle.

M I J = l b / V t l

M G = M B + B K - G K

For calculations, the location of Mcan be found with the formula:

M B = I b / V o l

MB is the vertical distance betweenthe centre of buoyancy (B) and themetacentre point (M),Ib is the transverse moment of inertiaof the waterline,Vol is the volume of the submergedpart, the displacement.

Both can be found in the hydrostatictables of the vessel. Or they can becalculated of course. Thesecalculations can be found in morespecific books.

We need to know the value of MGbecause that distance is a measure forthe righting lever. From G the centreof gravity of the ship, the weight ofthe vessel is working downward, as avector. The buoyancy, a vector throughB working vertically upwards, goesthroush M.

The MG value is found from:M G = M B + B K - G K

BK can be found in the hydrostatictables, which have to be on board.

GK has to be calculated from GK-empty-ship (found in the ship-builders particulars) plus the totalinfluence of all the added weishts.

Added weights are cargo, fuel, water,ballast, personal belongings, food,etc., everything not belonging to theempty ship.

MG can be positive (M above G),negative (M below G) or zero (M =

G). Please note that we are talkingabout initial stability, very smallangles of list.

When MG is negative in uprightposition, at a larger angle the valuecan become positive. Again it doesnot necessarily mean that the ship isgoing to capsize.

M

G

B

fF't' r l B

MC is positit,t: irt t lt is drowittg

+G--r.

tlVl

,V ( i i s t t t ' g t t t i t r ' i n t l r i s t l r , t n ' i t r t ,


The length of the lever is

GZ= MG sin (g)

This is called the static lever of initialstability.

These levers can be calculated for

various angles. The curve of theselevers is called'curve of static levers',values in m.

'When multiPlied withthe ship's weight R in the particularcondition, in metric tons, the curve iscalled 'curve of static stability', valuesin tm.

GZ = MG sin (phi)

hcoling $€lcl&gte€Bl

Wlren the ghlP rtarts lbtng bY anerilemal fiorco, GZ ttaft to incnase.

Ship Knowledge, a nodem ercyclopedia 326

t . ,

t .?

r.0

0.8

0.8

0.4

0.?

or 0 1 5 2 0 2 5 3 0 3 5 d ,

When the list incrcases, the working linesof G and B are dlverylng rcsultlng In alarger rightng mornent.

Because the centreof buoyancy B contnueato move to the low slde.

t .4

t ,2

r .0

0.8

0.0

0.4

0.2

o

hesling anglc fdegreesl

Strblllty rrducos, generallyrpaklng, aa soon ae the deck bsubmergsd orthe bllgo rls€sabove the uaterllne.

In thls phase the bllge rlses out ofwater reeulting in a dectease in ttewater plane area and also In the BM.


r ",#,i;

t , d

l , ?

t . 0

0.8

0.6

0.4

0.?

o

hsohng engle [d€gree3l

When the shlp has rcached the angle of heel atwfiich the centrcs of gravlty G and buoyancy Bare acting on the same vertical llne, the rlghtlnglever gz becomee 0 and no moment exists.

t , 4

1 .2

r .0

0.8

0.6

0.{

0.3

05 10 15 20 25 30 35 {0

hedmg angle [drer6e3l

lf the shlp le Inclined above thls angle ofh6el, the centrc of gravlty G wlll move to thewnong side of the vefilcal llne drawtthrough the centre of buoyancy B resultlng ina momentwhich will capslze the shlp.


gr lmlt ,0 -

0,8 -

0.0 -

0.4 -

0.2 -

0 -

.{t,2 -

.0.4-

.0,E -

Higlter slip,s ltave ltighe r stttbilit.t,

Both ships have the same GM value,but a different stability range (respec-tively 34" and 47'). The breadth is thesame for both vessels. The depth ofhull 2 is greater than the depth ofhull 1.

Normal GM values are very muchdepen-ding on the ship's type.Passenger ships are designed to havea low GM, 0.5 metre or so, to get along rolling time for the sake ofpassenger comfort.

Bulk carriers loaded with ore have avery high GM, due to the centre ofgravity of the cargo being very low.When loaded with grain or coal, thehold is full, and GM is lower. Tankershave similar values, where also theinfluence of free surface has to betaken into consideration. Wide shipswith shallow draught like barges, oran empty tanker or bulk carrier, have

Consider a ship with a cardeck seen in the picture.

At first water is addedon the car deck.

a

large initial stability. Narrow, slenderships, like passenger ships, or a largecontainer-ships with deep draught andwith a high freeboard have a smallinitial stability. This results for thewide ship in short rolling hauls, andfor the naffow ship in long hauls.However, when at the wide ship thedeck is immersed, the stabilityreduces fast, whereas with the narrowship, with a high freeboard, thestability only gets larger. This as aresult of the moment of inertia of thewaterline, reducing in the case of thebarge, and getting larger in the case ofthe passenger ship.

During design this all has to be takeninto consideration and carefullycalculated and all the possible cargoand ballast conditions have to bechecked for.

Positive influences on stability:A higher beam at the waterline meansa much higher moment of inertia, andthus a higher MB. When ships arelacking stability, often so calledblister tanks or sponsons are added,making the ship wider over the lengthof the parallel midbody.

Negative influences on stability:Heavy deck cargo brings G up. Infreezing conditions with fog or spray,ships with many masts and derrickscould suffer from 'icing': deposits ofice on high locations bringing G todangerously high levels. Fishingships have capsized due to icing.Heavy pieces of cargo hanging in aship's crane cause stability problems.Free surfaces of liquids in compart-ments can have a large negativeinfluence. A relatively thin layer ofseawater on a RoRo cargo-deck can,when the ship rolls, run all water to

500 m3

ru :5 3t r$ 40

gr [mj1 , U

t_, d

1 .8

c,.r'1.

?

8 1 = 8 2D 2 > D 1

The inlluence of this can beseen directly from the gz-curve.

hs8{rE angeldegrrisl


Next. the amount of water on the cardeck is increased at a constant rate.

GGV=t i=

i = moment of inertia of the freesurface area of water on deck

L = length of the cardeckB = breadth ofthe cardeck

A major negative effect is caused by a

hole in the ship. Due to a collision or

some other event a leak may becaused and water can flow into the

ship, creating a free liquid surface.

g: lml

Id1 2

one side, bringing the centre ofgravity of the 'cargo' to the ships side,and bring the ship into danger.Tankers therefore always havelongitudinal bulkheads, to limit the

sideways movement of the centre ofgravity of the content of each tank.

3. Stability of damaged ships

Suppose that a ship never can get a

leakage. This would mean that the

ship can do without additionalmeasures like transverse andlongitudinal watertight bulkheads,dividing the ship in watertightcompartments. If a shiP gets aleakage, but does not list or trim dueto this leakage, this ship would sink

slowly, upright, but would not be in

immediate danger. However, usuallythe incoming water does notdistribute evenly but will move inport- or starboard direction, therebypushing the ship over. This listing canhappen so fast that it can capsize the

ship in a matter of minutes. In recentyears there have been fatal accidents


with Ro-Ro carriers where water

entered the ship after a ramp had been

smashed away by the sea. The conse-quence of a leakage is influenced bYthe permeability of the space. If thecompartment is filled with objectswhich absorb little or no water, littleor no additional water can flow in.

A Ro-Ro ,ship v"hic:lt hcr.s cctpsi:.eclbecause the incrnning water wa,s aLlov:eclto flott .freely (tct'oss tlrc etfiire witltlt o.f'

the ship. Tlrc ,ship did rnt hov'e wofertight

bulkheads in order to allow tlrc ccLrs trt

ntove.f'ree11, to the ste.m of the ship utltin-

dercd. This lms disastrous consequences

itt cusa A,uler fktv's in.

330

Below a short explanation follows ofthe preceding. The water (a liquid)that can flow from port side tostarboard side is in fact a weight (1 mtwater = 1 ton water) that exerts aturnover force on the ship. If theliquid inside a tank or hold can movefreely, this is called the free surfaceeffect, which will cause a turn overmoment.

Permeability:The extent to which a compart-ment can be filled with water isthe permeability. The effect ofincoming water on the stabilitywill be:- maximal if the compartment is

empty (permeability = 1;- minimal if the compartment is

completely filled with forinstance Styrofoamor a liquid. (permeability = g;.

The permeability of an engineroom is approximately 0.85. Thehigher the permeability of acompaJtment, the more volumecan be occupied by leakage, thelower the remaining buoyancy.

This is further explained in the(exaggerated) drawings shown below.

NB: The list drawn is a randompicture of a complete roll of the ship.This roll (from port side to starboardside etc.) lasts only a few seconds andcan be caused bv waves.

Ilrrn over moment:A turn over moment usuallycauses a list. This can be causedby:- shifting cargo- loading and discharging of

heavy loads with a crane- waves- a collision- water on deck

Explanation of the abbreviations usedin the below drawings:

GBoB<p

Brp

MoGMKM

KDFqGoG"GZ

= Centre of gravity= Centre of buoyancy (no list)= Buoyancy by heel to port or

starboard (external force)= Buoyancy by list to port or

starboard (internal force)= Initial metacentre= Metacentrec height= The height of initial meta-

centre above the keel= Keel= Displacement (D)= - Displacement (-D)- heeling angle= virtual loss of GM= lever GZ, nghting lever, the

horizontal distancebetween the centre of gravi-ty and the vertical throughthe centre of buoyancy.

Moment of static stability= D x G Z = D x G M s i n r p


The magnitude of the translation of Gdepends on:- the length of the flooded hold or

tank- the width of the flooded hold or

tankIf the distance along which the liquidcan move in the athwart direction ishalved by a bulkhead (see drawing 4),then the negative influence on thestability will be reduced significantly.In drawing 4, the translation of G isonly ll4 of the situation depicted indrawing 3. The distance GG1 can becalculated with the formula:

(:(: _ Length tank * (Breadth tank)3vvl -

12 * vessel displacement

The magnitude of a moment isdetermined by a force (weight) andthe distance of that force to a fixedpoint. Example:

1. A child (30 kilos) and his father (60

kilos) are sitting on a seesaw. Thedistances to the turning point of theseesaw are 2 and I metresrespectively. In spite of thedffirence in weight, both the fatherand the child exert the samemoment on the turning point of theseesaw. (30x2 and 60xIrespectively). The seesaw isin equilibrium.

2.lf a weight of 100 tons is movedI metre on a ship, the same effecton the trim can be achieved bymoving I ton a hundred metres. In

both cases the moment is 100 tm.

This illustrates how even a limitedamount of liquid can cause a largemoment on the ship if the liquid isallowed to move freely over the fullwidth of the ship.The above formula shows that theamount of water is not important.

Only the length and width of thecompartment matter. Flooding of oneor more compart-ments on a ship canhave the following consequences:- deeper draught- list- altering trim- change in stabilityAl1 these changes start from themoment the water enters the ship.

The choice of (not) placing bulkheadsfor economic reasons deserves someattention. Some types of ships prefernot to have bulkheads because thesehinder the transport of cargo or theloading and discharging. Examples ofthese ships are heavy-cargo ships andRoRo-vessels. In tankers however,the presence of bulkheads is impor-tant for the separation of differentcargoes. The choice between water-tight transverse bulkheads and centreline bulkheads is of lesser importanceif both result in the creation ofsmaller watertight sealed spaces.

4. Rules and regulations

It is obvious from the previous

section that the free-liquid surfaceresulting from a leak in a compart-ment should not pose a direct dangerto the ship. The size of a compartmentis therefore subjected to regulationsas determined by the SOLAS-convention and the IMO. There arethree types of regulations:

a. Calculations of submersion and trim.This calculations check if there isenough spare buoyancy to keep theship floating after a compartment hasbeen completely filled with water*.The assumption was made that a shipsinks vertically as a result of theleakage. The spare buoyancy isenough to compensate for theincreased drausht. So the number and

SOLAS vs IMOThe SolAs-treaties must beincorporated into the nationallaws. The lMO-regulations areoptional. However, in practicemost nations also incorporate theIMO-regulations into theirnational laws.In the past, many computationalmethods have been used todetermine the number of bulkheads on a ship that are necessaryfor the safety. These are calleddamage stability calculations.

the positions of the bulkheads wererelated to the buoyancy and the sparebuoyancy**. After the Titanic disasterthese calculations were implementedby SOLAS. The experiences of theSecond World War proved that theseSOLAS-rules were not adequatebecause of the assumption that a shipsinks vertically. Instead, many shipsfirst capsized before sinking.

*The -reason was that a ship withleakage must not submerge below themaximum immersion line. This is animaginary line on the hull that runs 76mm below the bulkhead deck. Thebulkhead deck is the first deck abovewhich the bulkheads are not water-tight. This deck should remain abovethe waterline across its entire length,thus preventing leakage from leakycompartment into others resulting inthe sinking of the ship. It is assumedthat the ship sinks vertically, that is,without list.

x*The maximum distance (floodable

length L) between two watertightbulkheads is calculated for a largenumber of points P going from the aftto the fore. Every space that is createdin this way has the point P at half thislength. The volume of these compart-ments is chosem in such a way that

C)ttr rlc<'k of'n fus-llo v,ith tkxtrs trt rerluct: the Jrce ,ruiuce of'un,v liquirl.{kxrcling tlrc deck.


1. The doors in closed position

2.The doors in stored position

332

Distance from

APP in metres

00.0005.0010.0015.0020.0025.0030.003s.0040.0045.0050.0053.75

Floodable

length in metres

20.32r0.321 1 . 3 513.4217.56r7.091L5409.r408.9614.0624.023r.52

the ship has enough spare buoyancyafter the compartment has sprung aleak. The ship submerges a little butthe bulkhead deck remains above themaximum immersion line. In order toget a quick view of the maximum dis-tance between the watertight bulk-heads across the entire length of theship, the lengths L are plotted verti-cally in the points P. The resultingcurve is called the Bulkhead Graph.

A (shortened) calculation of thefloodable lengths, beginning in the aftperpendicular and the resultingbulkhead graph is shown below. Thetable and the curve are for the yacht

depicted below.Depending on the regulations, theship shall be able to survive a one-compartment damage or a two-compartment damage. A two-com-partment damage can occur if the shipis struck at a bulkhead separating twocompartments. The combined lengthof the two compartments should thenbe smaller than the floodable lengthto survive the damase.

b. Calculation of floodable lengths.(trim and stability in case of a leak,assuming certain well-defined types ofdamage)A drawback of the method describedin a. is that a possible list is not takeninto account. The method describedhere (b) to determine the number andpositions of the bulk-heads does takethe loss of stability into account andalso assumes some well-definedtypes of damage. These calculationsare called deterministic leakasecalculations.A drawback of this method is theexact definition of the damage. A shipthat is designed by this method canlive up to all the demands, but stillsink if the damage is 1 cm bigger thanthe model assumes.

c. probabilistic leakage calculations(Calculations of the chance of survivingin case of damage)This method tries to capture thepossibil i t ies that the damage isgreater than assumed in the model. Aprobability is assigned to every typeof damage, as is the probability of

surviving this damage. The sum of allthese probabil it ies is a numberbetween 0 and I and represents thechance of surviving in case the ship isdamaged. The regulations derivedfrom this method also include aminimum survival chance. Theseprobabil istic leakage calculationscurrently apply to:

- passenger liners (IMO resolutionA265) as an alternative to theSOLAS rules (resolution A265 stillencompasses some deterministicrules)

- cargo ships with dry cargo, longerthan 80 metres (measured over theclosed hull).

In order to estimate the centre ofgravity of the leakage, a number ofuncertain parameters are of majorimportance. For instance:

- What positions does the water,occupy, especially in rooms withan irregular shape.- Trim. List- The possibility of trapped

air-bubbles.

5.How to take damagestability into accounton board.

The stability must be calculated forevery voyage the ship makes, and ofcourse the stability has to fulfil thevarious rules and regulations. Theweight distribution can differ per tripas can many other parameters.Factors that are of importance to thedamage stability are:- kind of cargo (permeability)- wing and double-bottom tanks;

filled or empty- does the liquid stay in a leaky tank

or does it flow out?

A lot of calculations and thoroughknowledge of rules and regulationsare required in order to determine theinfluence of all these factors. Further-more, the chances of survival (proba-bilistic calculations) should also beincorporated into these calculations.In practice it is impossible to executethe calculations without the aid of acomputer.

B u I klt t' a tl G rupl t ( g t'u p h ttt''.f'l t nrl o b I c

lett grh )

: 5 I 5 0 !

distance from APP (m) 11250


A computer with a loading pro-gamme is required on board if onewants to be able to do the calculationson thq ship. After all the weight datahave been fed into this computer, theposition of the centre of gravity (G)above the keel (K) can be calqulated.

The regulations concerning damagestability usually only mention themaximum allowed heeling angles.Sometimes the possibility of counterflooding is incorporated.

Counter flooding is (partly) filling acompartment or tank at the oppositeside of the ship. Often used inpassenger liners, even automaticsystems are used.


Ship Knowledge, a modent enct,clopedict 3 3 5

Index

AccommodationAccommodation doorsAccommodation ladderAft shipAir conditioningAir draughtAircraft carrierAlarm, fireAlloysAluminiumAmphibiousAnchor chainAnchor equipmentAnchor Handling Tttg (ANT)Anchor pocketsAnchorsAnodesAntifoulingAnti-heeting systemAutomationB/DB/TBall valveBallast arrangementBase lineBending momentsBilge keelBilge lineBilge water cleanerBilge wellBlock coefficientBollardsBreadthBridgeBulbous bowBulk carriersBulk craneButterfly valveCabinsCable laying shipsCable stopperCablesCamberCapacity planCapesizeCapstanCar decksCargo capacityCargo gearCargo gear regis0ryCathodic protectionCatfle shipsCavitationCertificates


Chain lockerChain stopperChase vesselChemical tankersCircuit breakersClampsClassificationCoastal trade linersCoefficientsCombustion airCommunicationCommunication systemsCompanion hatchesConstruction planContactorsContainer shipsControllable pitch propellersConventional type craneConversionCoolingCopperCorrosionCorvettesCourses t

Crane vesselCranesCrew boatCrude oil tankersCruise shipsCruisersCutter suction dredgerCWLDamage stabilityDay roomDeadweightDeck lineDeliveryDepthDerricksDesign departrnentDestroyerDetectionDiagonal sffessesDiagonalsDimensionsDisplacementDiving Support Vessel (DSV)DockingDocking arrangementDocking planDocking sffessesDocumentsDoorsDouble bottom

155r69t 7 l1341562657

3 1 128328359

20r19867

204r99290292235n6n26

2312352486

14723223323329

2W25

15815052

18423115857

204208263752

20619l28

17619428954

248107

2052046752

274214t074828

22615727716837

27448

25018130122428328458

31663

t77665 1535857v+

33015828248026

1857458

310963025

21,2867

2932973796

l t 2169140

336

Double hull tanker

Dynamic Positioning (DP)

Draught

Dredgers

Drilling ship

Drills

Drum

Dry-docking

Duty deck

Duty mess

Dynamic

Electric motors

Electrical installations

Electrical rudder propellers

Electricity

Electro-chemical reaction

EMC

Emergency generator

Emergency towing system

End connection

Engine room

Engineering

Entrances

EPIRB

Equipment number

Excavated dock

Exhaust gas

Extinguishers

Fast Attack Craft

Feeders (container)

FerryFireFire fighting arrangement

Fishing vessels

Fixed Production Platforms

Fixed propellers

Flap rudder

Floating dock

Folding hatches

Foreship

Forecastle

Fouling

FPSOFreeboardFresh waterFrigatesFSOFuel

GalleyGangwayGantryGas tankersGeneral arangement

General arrangement plan

GeneratorsGlobe valve


13262255662

3t720629515815884

272269255

227 ,26829027r275208213

1 3 8 , 2 1 874

T68, T7I320199294226307584953

3052435464

249262293r67r49r492926426

2295865

224158t7r186507234

272231

GM

GMDSS

Gritblasting

Gross tonnage

Guarantee

Guide pulleys

GZHandy size

Hatch cradle

Hatches

Hawse pipes

Hawses

Heat exchangers

Heating

Heavy-cargo ships

High-grade cables

History

Hoisting diagram

HoldsHook

Hospital

Hydraulic folding hatches

Ice breakers

IMO

Impressed current

Insulated and earthed distribution systems

Insulation

Intact stability

ISM code

ISO

Jack-upsKG (GK)

LIB

LID

Landing craft

Launch

Laundry

LeadwaysLengthLifeboats

Life buoys

Life jackets

Life rafts

LightingLines plan

Load control

Load curve

Load line

Load testing equipment

Loading gear

Loading programme

Local stressLogistics

Longitudinal framing system

Longitudinal reinforcements

Longitudinal strength

3293192872780

20732652

r64t6220420722822850

20946

186r28213158r6756

106291269r573241081096 I

325,33426265979

15820725

3123r63 1 53r415630

1798624

212176889679

1008884

337

LouvresLow-speed engineLubricationMaintenanceManhole coversMariner rudderMarkingsMARPOLMaterialsMedium speed engineMeta-cenffeMGMidship section coefficientMine Counter Measure Vessels (MSV)

ModuleMooring gearMoulded dimensionsMulti-purpose shipMulti-purpose Suppon VesselMushroom shaped ventsMuster listNatural ropeNAV 1Navigation equipmentNavy vesselsNeff tonnageNoiseNoise nuisanceNozzlesOBO carrierOffshoreOffshore Patrol VesselOrdinatesPaintPaintingPallet cranePanama:tPanting sffessesPatent slipPermeabilityPerpendicularPersonal safety gearPilot ladderPipelaying bargesPitchPitching stressesPlanningPlaform Supply Vessel (PSV)

Plimsoll markPolyamidePolyesterPolyolefinesPontoon hatchPontoon hatch coversPreliminary sketchPressure valves

Ship Knowledge, a modem encyclopedin

r69220225295t70263318107282220324325295863

206244867

n0312210NL2785727

22915625153595830

2852861845296

29433r24

317t7 l65

24696756624

2092092101681627 l

170

Prismatic coefficientProductionPropeller bladesPropeller shaftingPropellersProportionsPropulsionPumpsPyrotechnics

QuarterRarn steering enginesRampsReefersRefrigerated shipsRegister tonRepairsRescue boatResistanceRevolving cranesRiggingRise of floorRoll-on Roll-off (RoRo)

RopesRotary vane steering engineRudder propellersRuddersSacrificial elementSafety planSARTSeismic Survey vesselSelf-tension winchSemi-submersible drilling unitSemisubsShackleShaftingSheerSheering forcesSheering stress curveShell expansionShip liftShuttle tankerSide doorsSide loadersSide rolling hatchcoversSkegSlingsSOLASSOLAS vs IMOSpade rudderSpecialist knowledgeSprinklerStabilising pontoonsStandardised shipsStand-by vesselStarting devicesStatic

2978

24725624626

2r8228320t9r264189505027

2993r4247n820826'53

208265252260290

37,3t13196t

2066265

2t3226,256

26848637

29565

168188r66136214t0733226274

3081867067

27584

338

SteelSteel wire ropeSteering enginesStiffenersStiffeningStoresSubmarinesSupport vesselsSurvey drawingsSurvival suitsSwitchboardsswLSynthetic ropesSyntheticsTalurit clampTank bleedersThnkersTenderTension Leg Plafform (TLP)TestThimblesTip platesTorsion of the hullTrailing hopper suction dredgerTransverse framing systemTrawlersTrial testTrimTirgsTirrn of bilgeTurnbucklesTirrnover momentTlveendeck hatchesUMSUnderwater bodyValvesVent locking devicesVentilation grillsVentsVenicalsVibrationVibration stressesVibrationsVolumesWaterjet propulsionWaterlineWaterlinesWaterplane coefficientWatertight doorsWeightsWinchesWing tanksWLLWoodYachts


2822102649898

158585934

316273212208

235,2832t3t70507464

3172132509656

1005480255526

213331,r6927128

230t7016917030

22996

15527

258243028

r6927

204r4021228254

339

Reproduced with kind permission of

Keppel Verolme BV Rozenburg - The Nethedands

/Voets & v. Leeuwen" Zuidland - The Netherlands

DurchPilotage Organisation, Rotterdan - The Netherlands

Robert Das, Ville,neuve-Loubet - France

P&O Nedlloy4 Ronerdam - The Netherlands

Robert Das

Jo tankers, Spijkenisse - The Netherlands

Frank Mohn, Spljkenisse - The Netherlands

Hans Meijer, UK

Rolls-Royce, Pemis - The Nethedands

Scheepswerf v.d. Werff&Visser, Jimsum - The Netherlands

K van Dolkunu Enkhuizen - The Netherlands

Vuyk Engineedng Center (VEC), Groningen - The Netherlands

Rik te Pas, Delfzijl - The Netherlands

Feededines BV Grcningen -The Netherlands

Martijn van Engeland, TU-Den - The Netherlands

SARC BV, Bussum - The Netherlands

Bigl-ift Shipping BV Amst€rdam - The Netherlands

Niestern Sander bv, Delfzijl - The Netherlands

Spliethoff Beheer BV, Amst€rdam - 'lhe Netherlands

Seatrade Groningen, Groningen - The Netherlands

RAH lvlanageme,nt BY Rhoon - The Nethedands

van der Giessende Noond, ICinpen aan den Ussel, The Nethedands

Anthony Veder Rederijzaken BV Rofierdam - The Netherlands

GB Shipping Services BV Mrecht - The Netherlands

HollandAmerica Line Spijkenisse - The Netherlands

Royal Navy, Den Helder - The Nethedands

Peters BV Scheepswerf, Kampen - The Netherlands

Dochilise Shipping BV, Breda - The Netherlands

Nagasaki Shipyard & MachineryWorks, Japan

VroonBY Breskens - The Nethedands

Cornelis Vrolijks Visserij Mij BV Umuiden - The Netherlands

SvitzerWijsmuller, Umuiden - The Nethedands

Smil Rofie,ldam - The Nethedands

IJoyds Register, Roterdam - The Netherlands

IHC Hollan4 Kinderdijk / Slidr€cht - The Netherlands

IHC Gusto Engineering BY Schiedam - The Netherlands

Heerema, kiden - The Netherlands

Kvaerner- MasA Sweden

Joum BV

Flying Focus, Casnicum - The Nethedands

Alls€as Engineering bv, Delft - The Nethedands

GenChart BV Capene a/d lJsel - The Netherlands

MARIN, lVageningen - The Netherlands

Bas Spruil Delftijl - The Netherlands

Germanischer Lloy4 tlamburg - G€rmany

\ililly Becker, Harnburg - Germany

llans t€n Kate,n, Rofierdam - The Netherlands

W. Smit, Lies - The Netherlands

NAPAOX Helsinki - Finland

ARlAlbacore Research LtA Canada / Be,nder Shipbuilding & Repair C.o., Inc,

Nippon Ikiji Kyokai, Tbkyo - Japan

MITSU Eengineering & Shipbuilding Co, LTD, Tokyo - Japan

Sigma Coatings Marine Division, Uithoom - The Netherlands

Ship Krcwledge, a modern encyclopedia

Cover, 6, 22123,29, 44145, 52, 56, 57 , 61, 62, 65, 68169, l@/105, lffill6l, t66,

167, 19 l, 24 I U5, 248, 263, 280 I 28 t, 28'1, 29 4, 298, 299, 300, 30 1

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198, 206, 256, 257, 311, 316, 3lg, 320

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26

28

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32.33,333

33,50, 177, 185, 186

34, 35, 36, 7 2[7 3, 294, 297

39,48, 188, lg4,lg5

40, 50, 90191, 9a93, 94195, ll0, ll2, 168, 1 84, 1 95, 209, 2U, 225, 226, 2n, 229,

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48

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63

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96

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98

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t28

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340

Wjnne & Barends BV DeHzijl - The Netherlands

ABB Industry Oy, Helsinki - Finland

DeltaMarine. Raisio - Finland

Helmen, Hoogezand - The Netherlands

Rubber Design, Heerjansdam - The Netherlands

Flinter Groningen B[ Patenwolde - The Netherlands

Coops & Nieborg BV, Hoogezand - The Netherlands

Roden Staal BV, Roden - The Netherlands

Winel BV. Assen - The Netherlands

Winleb. Winschoten - The Netherlands

MME Group, Ridderkerk - The Netherlands

Wthefty & Co LTD, London - UK

Genchart BV (Mr B. Jobse), Capelle a/d Usel - The Netherlands

Liebhen Maritime Benelux BY Uaecht - The Netherlands

Ttlle Shipyards, Kootstertille - The Netherlands

Huisman - Ifte{, Schiedam - The Netherlands

TTS - MongstadAS, Isdalsto - Norway

SEC, Groningen - The Netherlands

Wortelboer BV. Rotterdam - The Netherlands

lankhorst, Sneek - The Netherlands

hoofload. Oss - The Netherlands

Hendrik Veder BV Rotterdam - The Netherlands

MAN Rollo. T.crubrmer;r - The Netherlands

Kongsberg, Spijkenisse - The Netherlands

Econosto, Capelle aan de Ussel - The Netherlands

Marine Service Noord BY Westerbroek - The Netherlands

Wartsila Propulsion, Drunen - The Netherlands

Promac BV, Zaltbommel - The Netherlands

Kawasaki, Japan

HRPThruster Systems bv, Krimpen aldLek - The Netherlands

Siemens, Hamburg - Germany

Cedervall, Sweden

Thyssen, Hamburg - Germany

Kamewa Group, Kristinehamn - Sweden

Bot Groningen BV, Groningen - The Netherlands

Hatlap4 Uetersen - Germany

Allseas, Delft - The Netherlands

Rene Borstlap, Rotterdam - The Netherlands

TESO. Texel - The Netherlands

Croon, Rotterdam - The Netherlands

Schneider, Haarlem - The Netherlands

Niehuis & van den Berg BV Rotterdam - The Netherlands

Ajax Fire Protection Systems BV, Amsterdam - The Netherlands

Minimax GmbH, Bad Oldesloe - Germany

Heien l.arssen, Drammen - Norway

Umoe Schat-Harding BV Utrecht - The Netherlands

Fr. Fassmer & Co, Berne/Ivlotzen - Germany

Stocznia Ustka S.A., Poland

De Wolf Products, Yerseke - The Netherlands

Hammar, Germany

Royal Dutch Shipping Company Association (KVNR), Rotterdam - The Netherlands

Crewsaver, Hampshire - UK

Drager, Lubeck - Germany

H. Marahrens, Bremen - Germany

McMurdo, Portsmouth - UK

Comet" Bremerhaven - Germany

Loek Peters. Amsterdam - The Netherlands

SARC, Bussum - The Netherlands / M. Sffaten, Nijmegen - The Netherlands

r30, 167

136

136,234,237,238,239

155, 156, 157

155, 156

158,309,3r9

162, 164,165, 168

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199, 200, 201, 2M, 205,206,207

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208,209,2r0,2rr,2r3

212

214

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220

230,23r,232,233

236,242

246,247 ,250,258,259

250t251,264 .

252

252,253

253,254

256

257

258,259

262,263

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268,65,66

268, 269, 27 0, 27 r, 27 2, 27 4, 27 5, 27 6, 27 7, 27 8, 27 9

270

273

274

294

305, 306, 308, 309

308

310

313

313,314

314

315,316

3 1 5

317

3t7

3 1 8

3 1 8

3 1 8

320

331

333
