Cargo Handling.pdf

MarineOutfittings Prof.Dr.YousriWelaya

Cargo Handling

Cargo handling is usually divided into four phases:-

Terminal storage Transfer from storage area to apron cargo hook Hook to hold Stowage of cargo

When ordering a new ship the ship owner normally specifies the number, safe working load, position and any special features of the cargo handling derrick to be fitted.

Cargo handling can be divided into the following categories:

1. DERRICK RIG SYSTEMS

Although gradually being ousted by deck cranes, this system has been the most popular method of handling cargo.

a) Fixed Outreach Systems

The union purchase system is the most common outreach system.

The system utilizes two derricks and two winches with the derrick in fixed positions. One derrick is arranged over the quayside and the other over the hold. By a combination of hoisting on both winches and hoisting on one winch and

Marin

payinhold

This

b

All thTheswincthe bthrou

neOutfittings

ng out on tor vice ver

system has

It can onpoint in tinto its stDue to tderrick cthis many

b) Swingin

hese rigs hse designs h. Whilst thbasic disadugh 360o.

s

the other wsa.

s the follow

nly be usedthe hold; thtowed posithe sharing an occur if y harbor au

g Derrick R

have been usually (bu

hese rigs cadvantages o

winch it is p

wing disadva

d between is creates ation. of the loadthe operati

uthorities ha

Rigs

developedut not alwaan performof being co

2

possible to

antages:

a fixed poa serious p

d between ion is not pave express

d to enableays) include

m all the funonfined to

transfer fro

oint on theproblem of m

two derricroperly mansed their co

e accurate e a hoistingnctions of aone hatch,

Prof.Dr.

om the qua

quayside manhandlin

cks, overloanaged and oncern abo

spotting g, topping

a deck cran, i.e. they c

YousriWelay

ayside to th

and a fixeng the carg

ading of onarising from

out its use.

of the loadand slewin

ne they havcannot slew

ya

he

ed go

ne m

d. ng ve w

3


2. HEAVY LIFTING SYSTEMS

The conventional method of lifting heavy loads is shown in figure and consists of one or two hoisting winches lifting on a multi-fall system. In addition, the topping and slewing motions operate through a multi-part rope system to ensure control of the load all the time.

The introduction of patented heavy lift systems (and the introduction of heavy deck cranes) has created a decline in the heavy lift derrick. A typical patented heavy derrick is shown in figure below (Stlken Derrick). With this system loads up to 300 tonne can be lifted and it has the unique advantage of being able to operate in two holds. It is positioned between two outwardly raked tapering

Marin

tubuland tcan colum

neOutfittings

lar columnstopping dutbe operatemns for nor

s

s. Several ties. The co

ed by one mrmal cargo w

winches arontrols are man. Smallwork.

4

re providedall arrangeler derricks

d for the vaed as leverss are also r

Prof.Dr.

arious hoists in one conrigged from

YousriWelay

ting, slewinnsole, whic

m the tubula

ya

ng ch ar

5


Special precautions have to be taken when lifting heavy loads to ensure adequate stability of the vessel and correct functioning of equipment as angles of inclination up to 17o could be encountered.

The yo-yo arrangement

For loads heavier than the safe working load of a single derrick, two derricks coupled together by a yo-yo arrangement may be used. The derrick heads must be kept close together during operation.

3. DECK CRANES

This is the most recent method of handling cargo onboard ships. They have the following advantages:

Rigging time is negligible, i.e. port time is reduced

6


The safe working load can range from 25 to 90 tonne and the jib radius from 20 to 35 m. For heavy lift cranes these values could reach 350 tonne and 60 m.

Spotting cargo very accurately Readiness for action They require only one operator They provide more usable deck space and greater visibility from the bridge Greater safety is inherent in the crane over conventional cargo gear The cranes operating gear and controls can be located within a protecting

enclosure. This protection reduces maintenance and provides protection for the operator

However, cranes are perhaps less efficient with light loads. For large beam ships if the cranes are positioned on the ships centerline, they may require an extremely long jib. Therefore, fixed cranes, one at each end of the hatch, may be placed at opposite corners.

7


As shown in figure a typical crane consists of a jib which can be lowered to the horizontal for stowage purposes, and a hoisting unit which can be on a single fall of rope or multi falls depending on the lifting capacity. Facility is provided for slewing the crane through 360o. The main specifications of a deck crane are the hoisting capacity in tonne, the jib radius in m, and the hoisting speed in m/min.

Some of the patented deck cranes are shown below. They are all designed to meet the rules of all classification societies and regulatory bodies.

MacGregor Compact and Slim Crane

These electro-hydraulic cranes are intended for various duties, particularly where dimensions must be compact and air-draft is limited. These cranes can be equipped with the tools needed for handling various cargoes, such as containers or bulk materials. The standard range covers lifting capacities from 36 to 45 tonnes. Outreaches are between 20-34 m.

MacGregor Container and Multipurpose Cargo Crane

These electro-hydraulic cranes are self-contained units with all machinery enclosed in the crane house. This protects it from the weather, corrosion and damage. The standard GL range covers lifting capacities from 25 to 90 tonnes, with outreaches up to 32 m. Hoisting, luffing and slewing motions are

8


independent of each other. This means that at their maximum capacity GL cranes can operate at full speed using all three movements at the same time.

MacGregor Heavy Lift and Multipurpose Crane

The standard range covers lifting capacities from 120 to 350 tonnes, with outreaches up to 36 m. Like the previous type, hoisting, luffing and slewing motions are independent of each other.

9


Liebherr Articulated Deck Crane

This is a double girder container crane especially designed for use in harbour complexes where high turnover and continuous operation are required. The control of the turntable ensures the unchanged position (rotation axis) of the container during loading and unloading. Driver's cabin is positioned on the underside of the container rotating arms allowing unrestricted view of the containers.

Liebherr Heavy Lift Deck Crane

This crane is designed for installation on heavy lift vessels a well as multi-purpose vessels providing the following advantages:

Low height allowing for better visibility from the bridge.

10


Low weight and centre of gravity leading to improved vessel stability and moreover increased cargo capacity.

Liebherr Wire-Luffing Cranes

These are designed for bulk and container handling with the following advantages:

Hydraulic control instead of electronic. Jib brackets are directly integrated in jib beam for higher rigidity. Wire sheaves inside beam for better protection.

Marin

Twin

Theyplatfoindivslewehook

neOutfittings

n Cranes

y consist of orm which

vidually for ned parallel

ks. A variati

s

two indepeh can be normal cargto each oton of the id

endent cranrotated in

go working,her and a l

dea has bee

11

nes of equandependen, but when ifting beamen used wit

al capacity mtly. Each a heavy lift

m is connecth cranes o

Prof.Dr.

mounted oncrane ca

t is requiredcted betweef unequal c

YousriWelay

n a common be use

d the jibs aren the cargcapacity.

ya

on ed re go

12


Documents

Cargo Handling.pdf