EK Paper Batch 25 New

8/17/2019 EK Paper Batch 25 New

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OFFICER IN CHARGE OF A NAVIGATIONAL WATCH

(500 GT OR MORE)

CERTIFICATE OF COMPETENCY EXAMINATION

ENGINEERING KNOWLEDGE

(TOTAL MARKS 100 - PASS MARK 51%)

1.

a. List down the 03 systems which are attached to the main engine

(03 marks)

b. What is the function of air starting system. (04 marks)

c. What is the important of using lubricating oil (04 marks)

d. Briefly explain important of the cooling water system (05 marks)

e. Sketch and describe main engine fuel oil system (09 marks)

2. a. State the Types of steering gear system used on board. (03 marks)

b. Mention which Items are check on steering gear Prior to arrival and

departure of the port. (03 marks)

c. What are the reasons to carry out emergency steering. (04 marks)

d. Explain the procedure of emergency steering. (05 marks)

3) a. What are the types of pumps used on board ships? (04 marks)

b. Describe centrifugal pump with a aid of a diagram (05 marks)

Answer all Questions Duration: 3.0 Hours Aug .2015


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c. Discuss the advantages and disadvantages of,

i. Screw type pump ii. Centrifugal type pump (06 marks)

4. Write short notes for below topics

a.

Emergency fire pump

b.

Emergency air compressor

c.

Emergency generator

d.

Oily water separator

e.

Sewage treatment plant (03 marks each)

5. a. What is the advantage of using Spectacle flange (02 marks)

b. What is mean by blackout. (03 marks)

c. Briefly explain the immediate action to be taken during blackout

(05 marks)

d. explain emergency bilge suction (05 marks)

6. a. List down different position on telegraph. (02 marks)

b. what are the locations of Telegraph (04 marks)

c. Briefly explain

i. Remote control of main engine

ii. Central control of main engine

iii. Hand control of main engine (03 marks each)


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(500 GT OR MORE)

CERTIFICATE OF COMPETENCY EXAMINATION

ENGINEERING KNOWLEDGE (Phase iii) Batch 24

REPEAT EXAMINATION

ANSWER SCRIPT

(TOTAL MARKS 100 -PASS MARK 51%)

1.

a. Cooling water

Lubrication oil system

Fuel oil system

Starting air systems

b. Large Marine Diesel Engines are started using high pressure compressed air.

The air is admitted into the cylinder when the piston is just past TDC and

continued until just before the exhaust valve opens. There is always more than

one air start valve open: - a situation known as overlap. This ensures that the

engine will start in any position. The opening of the main air start valves is

controlled by a set of pilot valves located in the air start distributor, which in turn

are timed to operate by a drive linked to the main camshaft. In the example

shown, a small camshaft is used to control the opening and closing of the air start

pilot valves.

Answer all Questions Duration: 3.0Hours Aug 2015


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c. Function of lubrication for a diesel engine is cooling sealing and avoid fraction

in order to protect wear and tear.

d. When engine is running or a certain period engine getting heated. Without

cooling engine being ceased. In order to prevent these problem, cooling water

system is located.

e. In the system shown in below Figure, the oil is stored in tanks in the double

bottom from which it is pumped to a settling tank and heated. After passing

through centrifuges the cleaned, heated oil is pumped to a daily service tank.

From the daily service tank the oil flows through a three-way valve to a mixing

tank. A flow meter is fitted into the system to indicate fuel consumption. Booster

pumps are used to pump the oil through heaters and a viscosity regulator to the

engine-driven fuel pumps. The fuel pumps will discharge high-pressure fuel to

their respective injectors.

The viscosity regulator controls the fuel oil temperature in order to provide the

correct viscosity for combustion. A pressure regulating valve ensures a constant-

pressure supply to the engine-driven pumps, and a pre-warming bypass is used

to heat up the fuel before starting the engine.

A diesel oil daily service tank may be installed and is connected to the system

via a three-way valve. The engine can be started up and maneuvered on diesel

oil or even a blend of diesel and heavy fuel oil. The mixing tank is used tocollect recirculate oil and also acts as a buffer or reserve tank as it will supply

fuel when the daily service tank is empty.


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The system includes various safety devices such as low-level alarms and

remotely operated tank outlet valves which can be closed in the event of a

fire.

2. a) Fully hydraulic type

Electro-hydraulic type

Fully electric type

b) Item to check on steering gear.

Main steering gear Auxiliary steering gear

Remote controls

Bridge controls

Rudder angle indicators

Power failure alarms

Gyro repeater

Typical checks to be carried out

Full rudder movement

Rudder angle local and remote.

Visual inspection of gears

Visual inspection of linkage seizure

Communication between bridge, steering gear room and engine

controller room

c) Emergency Steering is done when bridge control system is failed while

the power unit in the Steering Gear room in operational condition. The reasons

can be one or more of following.


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* Faulty telemotor transmitter on Bridge .

* Faulty Telemotor Receiver located in the Steering gear room.

* Power failures to control unit due to damaged Electrical wirings/ Hydraulic

pipings and other equipment.

* Faulty feedback signals to control unit with respect to the actual rudder

angle.

*Faulty gyro or auto pilot system.

d) The following points should be followed for emergency steering operation.

– The procedure and diagram for operating emergency steering should be

displayed in steering gear room and bridge.

– Even in emergency situation we cannot turn the massive rudder by hand

or any other means, and that’s why a hydraulic motor is given a supply

from the emergency generator directly through emergency switch board

(SOLAS regulation). It should also be displayed in the steering room.

– Ensure a clear communication for emergency operation via VHF or ships

telephone system.

– Normally a switch is given in the power supply panel of steering gear for

telemotor ; switch off the supply from the panel.

– Change the mode of operation by selecting the switch for the motor

which is supplied emergency power.

– There is a safety pin at the manual operation helms wheel so that during

normal operation the manual operation always remains in cut-off mode.

Remove that pin.


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– A helms wheel is provided which controls the flow of oil to the rams with

a rudder angle indicator. Wheel can be turned clockwise or anti clockwise

for going port or starboard or vice versa.

If there is a power failure, through sound power telephone receiveorders from the bridge for the rudder angle. As soon as you get the orders, turn

the wheel and check the rudder angle indicator. A routine check should always be

done for proper working of manual emergency system and steering gear system.

An emergency steering drill should be carried out every month (prescribed

duration – 3 months) in the steering gear room with proper communication with

bridge to train all the ship’s staff for proper operation of the system so that in

emergency situation ships control can be regained as soon as possible, avoiding

collision or grounding.

3.

a. Types of pumps:

Centrifugal

Gear

Screw Reciprocating

Vane

Axial

b. Centrifugal Pumps

Rotation of a centrifugal pump impeller causes the liquid it contains to move

outwards from the center to beyond the circumference of the impeller. The

revolving liquid is impelled by centrifugal effect. It can only be projected into

the casing around the periphery of the impeller if other liquid in the casing

can be displaced. Displaced liquid in moving from the casing to the delivery

pipe causes flow in the discharge side of the system. The liquid in the impeller

and casing of a centrifugal pump is also essential to its operation. In moving


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out under the influence of the centrifugal effect, it drops the pressure at the

center, to which the suction or supply pipe delivers the liquid to be pumped.

The moving liquid acts in the same way as areciprocating pump piston on its

suction stroke.

• Diffuser type

Single stage Multi stage

• Volute type

• Volute type /Diffuser type


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Centrifugal pump

• A centrifugal pump is a rotodynamic pump that uses a rotating

impeller to increase the pressure of a fluid. Centrifugal pumps are

commonly used to move liquids through a piping system.

• The fluid enters the pump impeller along or near to the rotating axis

and is accelerated by the impeller, flowing radially outward into adiffuser or volute chamber (casing), from where it exits into the

downstream piping system. Centrifugal pumps are used for large

discharge through smaller heads

c.

Advantages of screw type pumps:

• Self priming

• Flexibility in operation

(from no load to full load)

• Efficient in dealing with small volume of liquid.

• Can handle oil of any viscosity


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Disadvantages of screw type pumps:

• Causes vibration and hammering at high speed

• Complex in construction

• High pressure but low output.

• Pressure relief valve required.

Advantages of centrifugal type pumps:

• The advantages of centrifugal pumps Include simplicity, compactness,

weight saving, high output and adaptability to high-speed prime movers.

Disadvantages of centrifugal type pumps:

• One disadvantage of centrifugal pumps is their relatively poor suction

power.

• When the pump end is dry, the rotation of the impeller, even at high

speeds, is simply not sufficient to lift liquid into the pump; therefore, the

pump must be primed before pumping can begin.

•

For this reason, the suction lines and inlets of most centrifugal pumpsare placed below the source level of the liquid pumped or using

separate priming system.

• Less pressure than displacement pumps.

4.

a. Emergency fire pump

The emergency fire pump on a ship is one of the most important but one of the

most neglected pieces of equipment. This is because on most ships unlike the

other emergency machinery emergency fire pump is hardly used. As a result the

maintenance of this not done on time. The priming mechanism, valves and even

the pump itself is sometimes not maintained. The engine side and its cooling


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system is another aspect which is neglected. Emergency fire pumps are usually

engine driven and some are run on electric motors if the ship is equipped with an

emergency generator. The pumps are located at a low elevation of the ship so

that priming is not a problem. However since these pumps are centrifugal they

require priming arrangements.

Where the regulations require an independently driven power operated

emergency fire pump to be fitted, this can be met by a self-contained

compression ignition engine driven unit, or an electrically or hydraulically driven

unit. Such units, their sea suctions, means of priming, sources of power supply,

switchboards, electric cables and hydraulic piping, as appropriate, must not be in

the compartment containing the main fire pumps, but in a position not likely to

be cut off by fire or smoke in that compartment, and be such that the supply ofwater is ensured at all times

The emergency pump should generally be situated in a well-ventilated space,

having a safe access to the open deck, and be well clear of the machinery space

containing the other fire pumps. When the emergency pump is the only means of

providing water for the operation of, or use in connection with, a required fixed

fire extinguishing installation for the machinery space, regard should be paid,

particularly to the ready accessibility of the pump controls in all weatherconditions, so that the system can be brought quickly into use. Diesel driven units

should have the air inlet so situated as to minimize the risk of engine failure due

to smoke or water ingress.

b. Emergency air compressor

Emergency air compressor is used for starting auxiliary engine at the time

of an emergency or when the main air compressor has failed for filling up the

main air receiver. This type of compressor can be motor driven or engine driven.

If motor driven, it should be supplied from emergency source of power.

c. Emergency generator


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• As the ship’s emergency generator takes over the battle functions as soon

as the main power fails.

• It shall be automatically started and within 45 s power supply at least the

services required to be supplied

d. Oily water separator

Filters used in OWS are 2 types

Coalescence type:

1. Hydrophilic material i.e. glass wool.

2. Absorbs water rather than oil.3. Has to be renewed after certain periods.

Absorption type:

1. Oleophilic material

2. Absorbs oil rather than water.

3. Frequent replacement is not required.

High rate of separation is favored by:

1. Large size of oil globule.

2. Elevated temperature of the system ( i.e. lowers viscosity of oil, density of oil-

water but oil is higher).

3. Residence time.

4. Avoidance of turbulence or agitation.

5. Laminar or stream line flow.

6. Low viscosity of oil globule.


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Operation of OWS:

The oily water separator is first filled with clean water; the oily water mixture

is then pumped through the separator inlet pipe into the coarse separating

compartment. Here some oil, as a result of its lower density, will separate and

rise into the oil collection space and the purity of this stage is 100 ppm or less.

The remaining oily water mixture now flows down into the fine separating


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Compartment and moves slowly between the catch plates. More oil will

separate out onto the underside of these plates and travel outwards until it is

free to rise into the oil Collecting space.

The almost oil free water passes into the central pipe and leaves the separator

unit. The purity at this point will be 15 ppm or less. An automatically controlled valve releases the separated oil to a storage tank.

Air is released from the unit by a vent valve. Steam or electric-heating coils are

provided in the upper and sometimes the lower parts of the separator.

The water flows in turn through two filter stages and the oil-removed pass to

oil collecting spaces.

The first stage filter removes physical impurities present and promotes some

fine separation. The second stage filter uses coalescer inserts to achieve the final de-oiling and

the oil from the collecting spaces is drained away manually as required.

Coalescer is the breakdown of surface tension between oil droplets in an oily

water mixture, which causes them to join and increase in size.

e. Sewage plant

Discarding sewage produced onboard on a ship is one of the few tasks on a shipwhich should be taken utmost care of if one wants to same him and his shipping

company from heavy fine. The sewage generated on the ship cannot be stored

on the ship for a very long time and it for this reason it has to be discharged

into the sea.

Though sewage can be discharged into the sea, we cannot discharge it directly

overboard as there are some regulations regarding discharging of sewage that

needs to be followed. Sewage on sea is generally the waste produced from toilets,

urinals and WC scuppers. The rules say that the sewage can be discharged into

the sea water only after it is treated and the distance of the ship is 4 nauticalmiles from the nearest land.But if the sewage is not treated this can be

discharged 12 nautical miles away from the nearest land. Also the discharged

sewage should not produce any visible floating solids nor should it cause any

discoloration of surrounding water.


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Generally, ships prefer treating sewage before discharging to save themselves

from any type of embarrassment. There are different methods of treating

sewage available in the market, but the most common of them is the biological

type for it occupies less space for holding tank, unlike those of the other

methods. Moreover, the discharge generated from this plant is eco friendly. It isto not that each sewage treatment system installed onboard has to be certified

by classification society and should perform as per their requirement and

regulations.

Working of a Biological Sewage Plant


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The basic principle of the working of a biological treatment plant is

decomposition of the raw sewage. This process is done by aerating the sewage

chamber with fresh air. The aerobic bacteria survive on this fresh air and

decompose the raw sewage which can be disposed off in the sea. Air is a very

important criterion in the functioning of the biological sewage plant because if

air is not present, it will lead to growth of anaerobic bacteria, which produces

toxic gases that are hazardous to health.Also, after decomposition of the sewage

with anaerobic bacteria, a dark black liquid causes discoloration of water which is

not accepted for discharging. Thus in a biological sewage treatment plant the

main aim is to maintain the flow of fresh air.


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5. a.

At the point where the branch line carrying the drive water for the hold

educator leaves the deck wash line, two valves with spectacle flanges and a

spool piece are usually fitted. These spectacle flanges prevent accidental

hold flooding when the deck line is pressurized.

It is most important that when the hold cleaning educator system is not in

use, the spectacle flanges must be turned so that the blank spool piece is in

the closed position to prevent water flooding back into the cargo hold

cleaning line.


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In addition to the spectacle flanges fitted on deck, the hold cleaning

educator bilge well space in the hold, must also be blanked off.

b. Blackout - loss of electrical power

Complete failure of power due to any kind of problem with the power generating

equipment onboard i.e. generators, is called S blackout and the whole ship looks

like more same as a house with no electricity.

c. In case of Blackout following precautions and actions should be taken:-

Never panic in such situation, be calm and composed. Emergency generator will

restore the power within 45 seconds.

Inform Officer on bridge briefly about the condition.

Call for man power and inform the chief engineer.

If the main propulsion plant is running, bring the fuel lever to zero position.


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Close the feed of the running purifier to avoid overflow and wastage of fuel.

If auxiliary boiler was running, shut the main steam stop valve to maintain the

steam pressure.

Find out the problem and reason for blackout and rectify the same.

Before starting the generator set, start the pre- lubrication priming pump if the

supply for the same is given from the emergency generator; if not, then use

manual priming handle (provided in some generator).

Start the generator and take it on load. Then immediately start the main engine

lube oil pump and main engine jacket water pump.

Reset breakers and start all the other required machinery and system. Reset

breakers that are included in preferential tripping sequence. (Non-essential

machinery).

d. Emergency bilge suction

One of the important aspect of the capacity of the sea water pump is decidedbased on the "Emergency Bilge Suction". An Emergency Bilge Suction, is a

valve, which is connected to the suction line of the main plate type heat

exchanger

sea water pump, thus when it is opened, the sea water pumps taken suction

from the engine room. This valve is distinguished by marking it with

red/orange color, and kept locked as this must be used only in emergency

situation of engine room getting flooded.

6. a. Ahead Direction Movements:

– Navigation full


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– Full Ahead

– Half Ahead

– Slow Ahead

– Dead Slow Ahead

– Stop

Astern direction movements:

– Dead slow astern

– Slow Astern

– Half Astern

– Full Astern

b. Engine control room

Engine local maneuvering station

http://marineinsight.com/wp-content/uploads/2011/02/ss.oriana-telegraph.jpg


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c. Hand Control

a position adjacent to the units In the engine-room [local control]

Central Control

a console in the control room [central control]

Remote Control

the bridge (bridge control])


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Documents

EK Paper Batch 25 New