ALL ABOUT MARINE ENGINNERING

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2/20/2014 ALL ABOUT MARINE ENGINNERING: These are Some Question With Answers for Preparation of Class-4 Exams @uk

http://crazymariner.blogspot.com/2010/01/these-are-some-eks-some-question-for.html 2

Stainless steel could be used for seawater pump shafts. It has goo d

corrosive properties.

What are the differences between c ross head and trunk piston engines?

What are the impurities in heav y fuel oil?

Impurities in H.F.O. co me in the form of solids and liquids.

Solids-------dirt, rust, and sand.

Liquids----- water and sludge

What is the safety dev ices fitted to an air compresso r?

Low L.O.pressure shutdown

High air temperature shutdown

First stage relief valv e

Second stage relief valve

A fusible plug is fitted after the se cond stage cooler , set at 1 20 deg cents

If water cooled, a jacket water safety v alve is fitted.

Explain heav y fuel oil system from bunker tanks to engine?

Fuel is pumped fro m the fuel oil D.B.tank via a transfer pump to a F.O sett

tank where it is heated. the F.Opurifiers/centrifuges take suc tion from

the sett tank v ia purifier heaters, pass through the purifiers, where any

water and impurities are remov ed and passed on to the serv tank whic h

also has a set o f heating co ils.

From the serv tank the fuel then passes v ia a flow meter to the mixing

tank from where the boo ster pumps take suction discharging to the

F.O.heaters where the correct F.O.temp/viscosity achieved for correctfuel combustion in the engine, the fuel then passes through the v iscosity

regulator which controls the heater temp, then o n to the F.O.filter (which

are heated) to the fuel pumps then to the fuel injector v ia double

skin/wall high pressure pipe. Any surplus fuel returns v ia regulating

valv e fro m the fue l pumps back to the mixing tank.D.O. can also be used

in the sy stem and is fed to the system v ia a 3 way v alve.

Note : when diesel is used, no heating is required.

These are Some

Question With

Answers for

Preparat...

AMET- STC HND

SCHEME

A B O U T M E

SANKET19

The ideal MARINE

engineer is a compo site. he

is not a scientist, nor a

mathematician, nor a

sociolo gist, nor a writer,

but he will use the

knowledge of any or all of

these disciplines in solving

problems

VIEW MY COMP LETE PROFILE
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How is leakage in the high-pressure pipeline between the fuel pump and

injector detected?

Leakage between the double skin/wall of the high pressure pipe line

between the fuel pump and injec tor is detec ted as this space between

double skin/walled pipes is led v ia drain line to a small tank fitted with a

level alarm.

Giv e an example o f the density of H.O, L.O and D.O?

H.F.O. --------- 950 kg/cu.m

L.O --------- 87 0 kg/cu.m

D.O --------- 880 kg/cu.m

What is the purpose of the sc um v alv e on a boiler?

The scum valv e on a boiler is connec ted to a shallow dish positioned at

the normal water leve l of the boiler and enables the blowing down or

remov al of scum and impurities from the water surface.

Why are quick closing v alv es fitted in a fuel system and ho w can they fail

to operate?

Quick closing valves are fitted in fuel system so that in the ev ent of a fire

in the vicinity of these sy stem or a fracture or break in these lines the

system c an be shutdown rapidly and remotely , this v alves are

pneumatically operated. If by any means control air fails to reach the

valv e the sy stem will fail.

At what temp does the department o f trade and industr y state the fuels

must be kept in the sto rage tanks?

14 deg cent under their flash points.

Why are weighed coc ks fitted to sounding pipes of fuel o il tanks?

To prevent F.O.spills from ov erflow. They also prevent vapo urs escaping

from tanks.

What are the pro perties of H.F.O?

High v iscosity

Long ignition delay i.e. low cetane index


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How does ov er speed trip work? By shutting the fuel off to the engine.

There arte various ty pes of trips, mechanical ty pes which work on the

principle of fly weights, or elec trical types which work on the principle of

speed pick up operating a stop solenoid

What fittings would you ex pect to find a start air receiv er?

Safety v alve, fusible plug, isolation valv e to main air start system.

, filling valv e from compressor, drain v alve, v alve to control air, valve to

whistle, and pr essur e gauge

How is the L.O.temp c ontrolled?

By means of a thermostatically controlled v alve which will allow L.O.to

by pass the c ooler when to o c old and div ert L.O.through the coo ler when

too hot. Preset wax elements being incorporated in these valv es for thispurpose.

Describe the duties of a duty engineer?

1. Regularly chec k and record all pressure and temp in the engine

room log

2. Pay attention to readings for dev iation from normal particular

attention being made to ex haust temp, scavenge temp and

pressures and turbocharger r.p.m

3. Adjustments should be made for s.w. Temp, changes to keep

correct temp and pressures

4. Checks should be made o n the pressure drops across fuel and lub

oil filters to see that they are operating within required limits.

5. Check all oil leve ls in auxiliary machinery , main engine sump

levels, cy linder lubricators, turbocharger and gov ernors.

6. Check aro und all bearings and crankcase do ors using palm of hand

to feel for any increasing temp.

7. ensure that fuel in the daily serv ice tanks is at correct lev els and

that is sludged and drained o f water

8. depending on ty pe o f purifiers fitted sludge and drain , check oil

level, signs of v ibration and clean if required

9. Carry out all routine assignment as recommended by engine

builders or the company .

10. At all t imes use sight, smell and hearing and this is o ften the first

sign of a fault dev eloping in the engine room

11. Check b ilge levels, stern gland, air start bo ttles and maintain

correct lev el a and pressures


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12. Record and fuel/lub oil transfer and any irregularities in log.

Why are high and low suctio n fitted on f.o . serv tank?

The high and low suctions are a safety feature to prev ent shutdown of

main engines, generators and boilers due to water c ontamination of the

fuel. Normally the low suction is kept in used if any water should find its

way into the fuel and sevr tank, it will gradually separ ate towards thetank bottom when it beco mes apparent water is present by finding it at

the tank drains or by operation of the engine, it is possible to bring the

high suction into operation and avoid shutdown

What trips are there on a generator ?

L.o.low pressure shutdown, j.cw.high temp and ov er speed shutdown

What steering gear c hecks wo uld u do before setting sail?

1)

Prior to a ships departure from any po rt the steering gear should be

tested to ensure the satisfactor y operation. These tests should

include

a)

Operation of main steering gear

b)

Operation of auxiliary steering gear or the use o f the second pump

whic h ac ts as a auxiliary

c)

Operation of the remote c ontrol sy stem from the main bridge

steering positions

d)

Operation of steering gear using the emergency power supply

e)

The radar angle indicator reading with respect to ac tual radar

angle should be checked

f)

The alarms fitted to the remo te co ntrol system and steering gear

power units should be3 checked for correc t operation

g)

Steering gear header tank levels should be c hecked.

2. During these tests the radar should be moves through itsfull travel in both port and starboard and the variousequipment items, linkages etc visually inspected fordamage or wear. The communication system betweenbridge and steering gear room should also be operated


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What would happen if the duty engineer did not report inafter answering an alarm?

The dead man alarm would activate which the dutyengineer would have to accept in the engine room, if notaccepted the watch keeper on the bridge would sendsomeone to investigate if there was a problem

Why would the bridge need to be informed that the engineis about to be stopped?

The bridge would need to be informed that the engine wasabout to be stopped to ensure it was navigationally safe todo so.ie not in busy shipping lanes or near land.

Draw a 2 stroke-timing diagram

How does the turbocharger work?

The turbocharger mainly consists of a turbine and acompressor assembled as a single unit on a shaft. Theexhaust gas from the engine flows through a water-cooledgas inlet (cooling from engine j.w. system) to a nozzle ring,which directs gases at the turbine rotor balding. This forcecauses a rotor to rotate at high velocity. The gases leavingvia a water-cooled gas outlet casing to an exhaust pipe andatmosphere. The air required for the diesel engine is drawn

in by the compressor via a combined silencer/filter. Theentry passage after the filter is then divided onto splitterswhich prevent draught losses and guide the air to thecompressor and discharge radially at high velocity to thediffuser, which charges much of the velocity to pressure.From the diffuser the air passes into the volute casing,changing the rest of the airs kinetic energy to pressurebefore being discharged to the charge air cooler and to theengine for combustion.

What would happen if the l.o.pressure just dropped tozero/?

The engine would shutdown on the low l.o.pressure trip.

How is the signal from the bridge when the helm is movedtransmitted to the hydraulic rams in steering flat/?

When the helm on the bridge is moved, electrical impulsesare produced. These impulses are transmitted via an


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amplifier or control unit to the steering flat. In the steeringflat these impulses are relayed to a servo motor (telemotor)which drives an adjusting gear and floating lever which putthe steering gear variable delivery pump on stroke, thuscrating hydraulic pressure in the system which means therams, thus moving the tiller and rudder. The pump is onlyrequired to deliver oil when the whelm is moved i. e once

rudder has matched the helm angle, the control lever, willput the pump off stroke.

How many starts do you require to get from a receiverwithout recharging?

On a reversible engine 12 starts

On engines with CPP propellers 6 starts

What is the maximum compressed air temperature thatshould leave the air compressor? 93 deg centigrade

What are the pipes used for pumping fuel around the ship-protected by/

Quick closing valves---------which can be operated remotely.In most cases from the bridge or a remote location from theengine room.

What measuring devices are there on the cylinder head of4-stroke engine?

Exhaust temperature pyrometer and j.w. Outletthermometer.

After stripping and cleaning a purifier what do you have tomake sure of on reassembly?

The mark on the bowl lock ring lines up with the mark on

the bowl.

Also if vertical shaft has been removed that height of shaftis correct

How would you check that there was excess water in thesump?

By using water finding paste

What types of valves are boiler feed check valves and why?


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Non return type valves a and are fitted in pairs one beingthe main and the other the stand by or auxiliary and theymust give an indication of open or closed positions. Theyare of non-return type to prevent back flow of boilerpressure down the feed line.

Give a shipboard use of cupro nickel and the properties that

make it suitable for this use?

Heat exchanger tubes. It has good corrosive qualities andvery good heat transfer qualities.

What is an indication in the exhaust gas of goodcombustion?

Grey smoke indicated good combustion.

What would cause a crankcase explosion?

A crankcase explosion could be caused by the formation ofhot spot i.e. the overheating of a bearing, which in turncould cause an oil mist to be generated,

. If this oil mist is allowed to build up an explosivecondition could occur where the oil mist can be ignited bypiston blow by or the hot spot itself.

Explain a main engine l.o.system?

l.o. for an engine is stored at the bottom of a crankcaseknown as sump or in a drain tank located beneath theengine. The oil is drawn from this tank through a strainerby one of two pumps in parallel, one pump being on standby. The pump discharges the oil into one of a pair of finefilters it is then passed through a cooler before entering theengine and being distributed to the various branches pipes.The branch pipe for a particular unit feed the main

bearing, for instance. Some of this oil will pass along adrilled passage in the crankshaft to the big end bearing andthen up a drilled passage in the connecting rod to thegudgeon pin in a trunk piston engine or a crossheadbearing in a crosshead bearing. An alarm at the end of thedistribution pipe ensures that adequate pressure ismaintained by the pump. Pump and filters are arranged induplicate with one as stand by. After use in the3 engine thel.o.drain back to the sump or drain tank for reuse.


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What limit does the department of trade and industry statethat the lower limit of flash point of fuel used onboard shipshould be?

65deg cent

Explain how would you start an air compressor and stop it(after overhauling)

1.

Check oil level in crankcase.

2.

Then ensure all drains are open. intercooler drain andalso unloader

3.

Check air intake filters is cleaned

4.

Ensure oil pressure gauge is open and that airpressure gauges i.e. first and second stage are

partially open to stop gauge fluctuation.

5.

If water-cooled check valves are open and cooling issupplied also check header tank.

6.

Bar machine over by hand to see if its free to turn

7. Start the machine, check there are no unusual noisesor vibration and oil pressure is correct.

8.then close drains and unloader

9.

If all seem o.k. run for 30 minutes after which can bestopped, covers removed and bearing checked. If o.k.machine can be started on automatic and run

10.

To stop the machine, always make sure the machineis unloaded and drains opened before stoppingunless automatic drains and unloaders are fitted.

What is the purpose of rocker gear on an engine?

To operate the inlet and exhaust valves on the cylinder head

Why does a centrifugal cargo pump have a relief valve?

A centrifugal cargo pump requires a relief valve, as theworking pressure of the pump has to tie in with the workingpressure of the cargo pipe work.


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Draw the timing diagram of 4-stroke engine?

Crankcase inspection: frequency, procedure and reasonsthey are carried out?

The frequency may vary from different enginemanufacturers but its roughly around 5000 hrs.

Also inspection are carried out after any work has takenplace in the crankcase

Procedure is as follows:

1.

Remove crankcase doors from the both sides of theengine

2.

Relief valves can be checked at the same time as theare off

3.Inspect condition of all bolt locking devices, replaceany damaged components

4.

Turn engine over using turning gear. ENSURE NOONE is in crankcase while doing this and that theindicator cocks are open check condition of camshaftdriving gears.

5.Start main l.o.pump and check oil flow from bearings

and piston cooling parts. Check for any leakage frominternal oil pipes and galleries.

6.

Check for any damage of cam shaft lobes

7.

Check for any evidence of water leakage from lowercylinder liner o rings

8.

Replace any damaged crankcase door joints

9. Record any defects

What is the first indic atio n of leaking exhaust v alv es?

A r ise of exhaust gas temp at the o utlet of the v alv e

What instrument measures small c hanges in crankcase pressure?

A mano meter


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What is an indication in the exhaust gas o f goo d combust ion?

Grey smoke indicates good co mbustion

If there was no water in gauge glass after blowing down?

Shut down the boiler immediately and use easing gear to relieve boiler

pressure

What proc edure does the duty engineer follow whe n answering an alarm

on UMS?

Answer alarm; ensur e wearing correct clothing before entering engine

room

Never use the ships lift, if fitted use the stairs

Once in the engine room inform bridge

Answer alarm, rectify problem

Then inform bridge when vac ating the engine roo m

What is the diffuser plate in turbo c harger?

It is found on the compressor side, it converts the velocity? Kinetic

energy from the compressor into the pressure

How can ex haust valv e leakage be confirmed?

By taking an indicator card. The card should be taken with fuel ON and

OFF the unit. If the valve is leaking, the compression pressure and

maximum pressure will be low.

How many PPMS can be pumped in marpol restricted areas?

15PPM

What is the purpose of the cy linder relief valv e and o perat ing pressure?

It is designed to relieve pressures in excess of 10% 20%above normal

The operation o f this device indicates a fault in the engine which should

be discov ered and corrected immediately

What wo uld y ou do in the ev ent of a scav enge fire?


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If a scavenge fire were to start, the 2 main objectives are to confine the

scavenge fire to the scavenge space and to minimize damage to the

engine.

In the ev ent of the fire breaking out, inform bridge that the engine is to

be brought to dead slow ahead and also inform the chief engineer .

The fuel should be c ut off to that particular cy linder.

The cylinder l.o. should be increased to prev ent seizure and wear.

If fixed fire fighting is attached to the scavenge trunking this can be

brought into operatio n, depending on severity of situat ion. But in most

cases the fire will generally subside within 5 15 minutes.

Once the fire is out and navigational circumstances allow it, the engine

must be stopped.

Do not open scavenge space doors or crankcase doors before site of fire

has cooled down. When opening up, care must be taken to keep clear of

any flame.

After opening up all sc av enge spaces must be tho ro ughly cleaned and all

debris removed. The piston rods and cylinder liner should be examined

for surface blemishes, straightness etc, and the diaphragm glands

(stuffing box) examined to ensure that t they are operational and not

damaged.

Also piston rings sho uld be checked, as blow by may hav e been the

ignition sourc e o f the fire. If po ssible the piston head in question should

be renewed at the earlie st possible moment and the damaged unit

overhauled.

On engines fitted with tie bo lts, it may be necessary to retighten the bolts

adjacent to the fire.

When starting the engine , care must be taken after switching on the fuelto the cylinder in question, and that also the cylinder l.o. quantities are

reduced to normal.

What causes white smoke from combustio n I.e., in the exhaust?

The presence o f water

What is the regulation regarding use of ev apo rators in shore?


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Evaporators should not be used within 20 miles from shore, due to risk

of pollutants being taken into the f.w.system

How would y ou blow do wn a boiler gauge glass?

Close the water and steam c ocks on the gauge glass and open the drain

Then open the steam cock a strong jet of steam should be seen from the

drain.

Close the steam coc k

Open the water c ock -- a strong jet o f water should be observ ed from the

drain

Close the water co ck and then close the drain

Then open the water coc k, the water will rise in the gauge abov e normallevel

Then open the steam co ck, the water should then settle down, finding its

correct level.

If only one inch of water was observ ed in the gauge glass (only one gauge

glass) after blowing down the bo iler gauge glass, what would y ou do?

Reduce firing rate of burner and increase feed water flow to boiler by

starting another feed pump.

How would y ou get water in the combustion spaces?

From cracked exhaust valve gages, cracked cylinder head and liner, fuel

contamination via fuel injector and under cooling of the

charge/scavenge air

What safety devices are fitted to a start air line?

Non return valv e, flame traps/arrestors, bursting discs and safety valves

What is the impo rtanc e o f M notices?

M notices are important as they convey very useful information such

as,

Merchant shipping notices (MSNs): whic h will only be used to

convey mandatory information, which must be complied with under


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British legislation

Merchant guidance notices (MGNs):whic h will prov ide advice and

guidance to relevant parties in order to improve the safety of shipping

and of life at sea

Marine information notes (MINs): whic h will prov ide informatio n

to as more limited audience such as training establishments orequipment manufacturer s

What is the c or rect metho d of starting and sto pping as centrifugal pump?

The correct way to start and stop a centrifugal pump is with the

discharge valve from the pump closed, i.e. less load on the motor when

starting and stopping

What are the pro perties of heav y fuel oil?

High viscosity , long ignition delay i.e., low cetane index

What wo uld cause the level o f the l .o .sump o r dr ain tank to r ise?

Water entering the oil, o r fuel or ev en a l.o filling v alv e passing

What are lo oking when y ou pull a pisto n?

When you pull a piston, y ou are looking for any damage to the piston

cro wn, including cracks,

The condition of piston rings are checked, plus piston ring grooves,

chec k for any scuffing of piston skirt

Check condition of top end bearing, bush and gudgeon pin, p [plus

clearance between pin and bush

Check lubrication bo res are c lear on under side o f piston

Draw a boiler gauge glass

What wo uld y ou do if you had high j.c .w. temperature?

Inform bridge and then reduce engine load and investigate problem

whic h could be insufficient flow through coo ler due to fouled coo ler or

faulty thermostatic valve

What wo uld be your first indicatio n that there was water in the sump\/


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Y our first indication would be from your l.o .puriofier or ev en possibly

from water in l.o.tests if done regularly

What is cro ss flo w scav enging?

In cr oss flow scavenging, the incoming air is directed upwards, pushing

the exhaust gases before it. The exhaust gases then travel down and out

of the exhaust port. Advantage is no exhaust valv e.

What safety devices are fitted to the main engine crankcase?

Explo sion door/re lief v alves and oil mist detecto rs.

How does oil mist detector wo rk?

The oil mist detector uses a pho toelectric cell to measure small increases

in oil density. A motor driven fan continuously draws samples of

crankcase oil mist through a measuring tube. An increased meterreading and an alarm will result if any crack case sample contains

excessive mist when compared to either clean air or to the other

crankcase compartments. The rotary valve which draces the samples

then stops to indicated the suspect crankcase compartment.

The alarm will cause an engine slowdown or shut do wn.

How is 15 PPM reached in an oily water separator?

15 ppm is achieved in an oily water separator by normally passing

through a 2 stage separator where in the first stage oil/water is passed

into the coarse separating compartment. Here some oil will rise to the

top of the compartment due to its lower density. Heating coils may aid

this. The remaining oil/water will flow down into the fine separating

compartment and moves slowly between catch plates. More oil will

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

free water (usually being at 100ppm at this stage) will then pass to the

second stage of the separator which is filter unit comprising of 2 filter

units. The first filter stage removes physical impurities present and

promotes some fine separation. The second stage filter uses coalescer

inserts to achieve the final de-oiling, oil/water mixture leav ing this stage

at less than 15 ppm.

What could start a sc av enge fire?

The main cause o f a scav enge fire is the fouling of scav enge spaces by the

blow by produc ts of incomplete combust ion caused by inc orrect


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cylinder lubrication, faulty fuel injection equipment, accumulation of

such mixtures in the scave nge space can be set alight by sparks or flame

blow by

What would prev ent water rushing out of the bo iler, if the gauge glass

were to break?

A b all v alv e is fitted below the gauge glass tube to shut off the water

What ty pe of clutch is used on an electrical windlass?

A dog clutch

What can y ou do to prev ent scav enge fires?

Conscientious maintenance of the engine and regular inspection and

cleaning of scav enge air spaces will help prev ent scav enge fire up

What are the symptoms o f a scav enge fire?

When a scav enge fire has broken out the scav enge air temp and the

exhaust temperature of the unit in question will considerably and in

some cases the turbocharger may start surging. Even hot spots on the

scav enge trunking can be found

What are the rough l.o pressure on the following o n a 2 stroke engine?

Piston co oling 6 7 bar

Cross headbearing 4 5 bar

Main bearing 2.5 3 bar

What perc entage o f engine speed does the over speed operate at?

10 15 % maximum speed

How often the emergenc y steering is tested?

At least once in ev ery 3 months

What is the purpose of the crankcase oil mist detector?

To detect the build up of oil mist in the crankcase generated from a hot

spot. The detector will then give an alarm, either shut down or slow the

engine down and give and indication of which unit the oil mist is

generated


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What proc edure wo uld you go through before taking o ver a watch?

Before taking over a watch a round of the machinery space should be

taken, checking various temps and pressures of machinery. Also

chec king oil and tank lev els.

Check the log book and ensure all parameters are met. Also ensure that

you understand any instructio ns that are handed over to you i.e , anymachinery that might be out of serv ice

How is medium speed engine rev erse (without CPP)

In medium speed diesel engines, reversing is achieved by the use of

duplicate cams for the air inlet valves, exhaust valves and fuel pumps.

Air start distributor timing is also changed by means of camshaft

movement or by a directional air supply being admitted to the start air

distribution, to reposition cams

To engage correct cams for ahead and astern movements the camshaft

slides axially in its bearings. This movement is controlled by the

camshaft rev ersing gear, which is normally a servo piston. Motion o f the

piston being directly transmitted to the camshaft.

Note: in a slow speed, o nly duplicate fuel cams required.

What do es a po sitive displac ement pump require that a centrifugal pump

does not?

A r elief v alv e

Procedure for handing over a watch?

The engineer should no t vacate the engine room until his relief arrives

He should acquaint the relieving engineer of any abnormal operating

conditions that have o cc urred during the watch

Any orders from the bridge, recor ded in the log bo ok sho uld be po inted

out

Instructions from the senior engineer should be passed on

Any repairs sho uld be reported together with information on any

machinery that has been dismantled

The presence of any other members of ships staff in the engine room


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should be reported

The engineer much ascertain that his relief if fit and able before v acating

the machinery space

What wo uld y ou do in the case of a c rankcase ex plo sion?

When the alarm sounds, the engine spe ed must be reduced to slo w and

permission obtained to stop the engine.

Inform chief engineer

When an engine has sto pped under alarm conditions under no

circumstance s must any doo rs or inspection windows be opened

Oil should continue to be c irculated and time allowed for the hot spot to

cool.

The early opening of doors c ould cause an ex plosion due to ingress of air

During co oling down period the engine roo m staff must keep c lear of the

side of the engine fitted with explosion doo rs.

After a perio d of at least 20 minutes, sto p l.o .pump, cut off all air and

engage turning gear

The access doo rs should then be opened and perso nal must keep c lear of

possible flames. Under no c ircumstances should naked lights be used nor

should anyone be permitted to smoke

Examination should then take place for any squeezed out bearing metal

or loose bearing metal in the crankcase

Heat discolored metal parts or blistering of paintwork must be

investigated. The ceiling of the crankcase and guide bars should also be

observed. If the crankcase is clear, the camshaft drive and main thrust

bearing should be inspec ted for signs of ov erheating. Should any damage

be found, then a permanent repair must be put in hand immediately

After repair, low sho uld be check for free flow. The engine sho uld then

run in i.e, 15 minutes, and then check components for signs of

overheating then half an hour at half speed, again check, the one hour

full speed then chec k again.

Note: varying times have been quoted for the cooling down period and

no set rules are available but the longer the time taken, the greater the


19/59



safety factor

What causes b lue smo ke in c ombustion i.e. in the exhaust?

Exc essive l.o.was being burnt in combustion

How would y ou know an air start valv e was leaking or passing?

The adjacent start air line for that valv e would beco me very hot

What would happen to the amperes of a centrifugal pump if it were with

the discharge valve shut?

The amps would drop as there would be no load on the pump

What causes b lac k smo ke fro m combust ion i.e . in the exhaust?

Black smoke would indicate faulty fuel injection equipment or it would

indicate insufficient air supply

What wo uld y ou do the j.c .w.temperature started to rise?

Inform bridge and reduce load on engine, investigate problem, which

would be a fouled coo ler

How is fuel supplied from fuel pump to the injector?

Through double wall/skin high pressure pipes

What prev entiv e mai9ntenece should be frequently do ne to diesel engine

start air receiver?

They should be drained of accumulated moisture

Name main engine shut downs

Low l.o.pressure

High j.c.w. temperature

High main bearing temperature

Over speed and

Oil mist detector

What is the pressure between the fuel injector and fue l pump?


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250 350 bar

Why is over lap nec essary on air start v alv es?

Overlap is necessary as if there was no overlap it would be possible for

the engine to stop in a position where no valves are open i.e. unable to

start

F.w.supplied for drinking and culinary purposes must meet specified

purity standards. How is this achieved?

These standards are met by passing the few. Through as hydro chorinator

where the water is sterilized by an ex cess do se of chlo rine provides as

hypochlorite tablets. It is then dechlorinated in a bed of activated

carbon to remov e exc ess chlorine. Any color, taste and odour which was

present in the water, will also be remov ed by the carbo n.

Another me tho d is to pass the f.w. through an ultrav iolet.

Describe the different types of cooling systems i.e. s.w. cooling system

and central cooling system

A S.W. co oling sy stem is an ar rangement that uses indiv idual coo lers for

l.o, j.w and the piston c.w. system. Each co oler being circulated by s.w

As where some modern ships use a central coo ling sy stem with only one

large S.W. circulated cooler. This cools a supply of f.w. which then

circulates to the o ther individual coolers. With less equipment in contact

with s.w, the cor ro sion proble ms are much reduced in this sy stem.

Why carry out bo iler feed water tests?

To prevent and detect contamination of the feed water i.e, a build up of

scale occurring, which could reduce boiler efficiency and can cause

serious overheating.

Also to prev ent corrosion

Prevent carryover where soluble salts and suspended solids are carried

ov er with steam

How many pumps are there in the engine room that you can pump bilges

with?

A bilge pump whic h is normally positive displacement. The others may

vary from ship to ship but can be the ballast pump, g.s .pump and main


21/59



S.W. pump. These pumps are only used for pumping bilges in the event of

emergency and have an emergency bilge suction/injection valve

connected to them

What could c ause an ex cessiv e high pressure in a refrigeration sy stem?

High pressure could be caused by lack of cooling or a fouled condenser

or ev en ov ercharge, but this is unlikely

What wo uld y ou do in the ev ent of oil sp ill?

Raise the alarm, inform b ridge and chief engineer

There should be a set drill for oil spills, which is practiced regularly

If possible co ntain the spill on deck and start c lean up proc edures using

appropriate oil spill equipment

If the oil has split into the sea: if in port, port authorities should be

informed.

If at sea: coast guard should be informed.

The time of spill should be reco rded with the place o r position of ship at

the time of spill along with approx imate quantity and ty pe of oil

Circumstances of discharge or escape would be logged in oil recor d book

and engine room log bo ok

What ty pes of pumps are use d for pumping bilges in an emergency?

High capacity centrifugal pumps (mostly main co oling s.w.pump)

What wo uld y ou do if you had a high chlo ride level in the bo iler?

To reduce the chloride level in the boiler the boiler would be blown

down, thus allowing fresh feed to the boiler

What are the nor mal j.c .w temperatures and pr essures?

Normal j.c.w. pressures are between 2- 3 bar

Temperatures 7 0 80 deg c ent

Alarm at 85 deg c ent

Shutdown at 90deg cent


22/59



Describe the boiler hot well and cascade tank. Why is it fitted and how

would you trace an oil leak?

The boiler hot well is where the condensate drains return from the

condenser. This condensate may be contaminated as some of the drains

are from f.o.heating systems or tank heating system. Normally these

drains will pass to the hot well via an observation tank, which permits

inspection of drain and their discharge to an oily bilge if contaminated.The hot well tank is also arranged with internal baffles to bring about

preliminary oil separation from any contaminated fuel or drains. The

feed water is then passed through charcoal or cloth filters to complete

the cleaning process. Any overflow from the hot well passes to the feed

water tank whic h prov ides additional feed water to the sy ste m when

required. Feed pumps take suction from the hot well to the bo iler.

To trace an oil leak to the sy stem, various heating coils to tanks would be

shut off in turn until the leak stopped, thus indicating which heating c oilwas leaking.

What is the pressure of a start air receiv er?

25 40 bar depending on the type of engine

How do y ou purify h.f.o?

Heav y fuel oils purified using a centrifugal separator, which operated by

the principle o f centrifugal force separating 2 liquids in this case fuel oiland water by means of a cylindrical interface between the two. The

positioning of this interface being very important for the correct

operation

How would y ou prepare a main engine for sea?

This may v ary from engine to engine

Have a v isual check all around the engine

Start the engine l.o.pump; engage turning gear and turn the engine

ensuring indicator co cks are open

J.c.w. heating should be on ensuring the engine is warmed through

circulate by a circulating pump

The F.O. booster pump should be running, circulating fuel around the

system.


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Note: if maneuvering on high visco sity F.O. the fuel should be heated and

circulated around the injectors to give the correc t v iscosity for the grade

of the fuel in use.

Ensure fuel injectors are vented and primed. Drain any water from air

start receiv ers and starting air manifold also co ntrol system

Check jacket heater tank lev el

Check oil levels, sump, gov ernor, turbocharger, cy linder l.o.tank, rocker

arm if on 4 stroke.

Operate cy linder lubricators by hand

Check f.o.serv ice tank i.e., drain off water/sludge

Disengage tur ning gear

Inform bridge that you are about to blow the engine over on air they

will give y ou permission. Open air star t v alv e fro m re ceiv er

Once engine is blown over on air, close indicator c ocks start j.c.w pumps,

shut off jacket heating and circulating pump

If two stroke engine, start auxiliary blower

Inform bridge you are ready to start engine

Start engine and s.w .c ooling pump

Have a good v isual check around the engine and check all parameters are

correct

Inform bridge that you are ready for stand by

Why is simultaneous injectio n of f.o and starting air into main engine

cy linder undesirable and how it is prev ented?

As it could lead to an explo sio n in the start air syste m

It is prevented by means of interlock, which prev ents fuel be ing injected

when the air start auto v alv e is open. The inte rlo ck operated a sto p

solenoid, which keeps the fuel rack to zero po sition

What is the primary func tion of ex pansio n v alv e in refrigeration sy stem?

To regulate the flow of refrigerant from the high pressure side to the low


24/59



pressure side of the system

The pressure drop c auses the saturation temperature to drop enabling it

to boil off at the low temp of the ev aporator

How would y ou know a refrigeration system was undercharged?

Undercharge will show as a low compressor pressure and large bubbles

in the liquid line sight glass

What is compression and ex plain what happens AIR IS COMPRESSED?

Compression is where the air that is drawn into the cylinder is

compressed on the upward stroke of the piston both inlet and exhaust

valv es being c losed on this str oke . A s the air is compressed by the rise of

the piston the air temp is consequently raised. As the piston reaches the

TDC fuel is injected causing ignition and v ery rapid rise in pressure of the

gases forcing the piston down

What action would you take in the ev ent of the main engine oil sump

level rising? What could be the problem and how would y ou fix it?

The action to be taken would depend o n how fast the lev el was rising and

what was causing it to rise.

It co uld be due to water or fuel entering the sump, the engine would have

to be sto pped as soo n as it was safe to do so

Tests should be carried o ut to tell if tit were water o r fuel

If it were fuel, you can normally smell this in the oil, but a flow stick test

can be done

Water has a tendency to form the color of the o il, depending on ex tent o f

contamination

If it were fuel the most likely cause would be faulty injector therefore it

would be changed

It were water it could be coming from cracked liner or liner O rings,

therefore possible liner change to solv e the problem

The oil may have to be changed depending on extent of contamination

but the l.o purifier may be able to c ope with it

How would y ou know if y ou had a cracked liner or c y linder head?


25/59



Y our jac ket water heade r tank would start to fall. Possib ly higher

temperatures on the unit

On a medium speed 4 stroke engine if the liner was cracked you would

get water contamination of the sump

On a 2 stroke engine there would b e possible water leakage from stuffing

bo x drains.

Explain the bilge system from bilge wells to ov erboard?

How would y ou test for a leaking air start valve in port?

First ensure all the engine indicator cocks are open for all cy linders then

isolate the air supply to the timing valves, this will ensure no pilot air is

supplied to the air start valves when the auto valve is opened. Then

operate the auto valve, any air discharge from the indicator cocks will

indicate a leaking or pass8ing air start valv e.

How do y ou start up/ and parallel a generator?

First check engine oil levels such as l.o.sump, turbocharger oil level,

gov ernor oil lev el, rocker arm bank oil leve l (if fitted)

Check j..c.water header tank leve l

Ensure indicator cocks are open, start up l.o.priming pump then bar

engine over (ensure turning bar is remov ed)

Kick engine on air close indicator co cks

Start the engine

Check all parameters are correct--- l.o.pressure/temperature, j.c.w.

pr/temp

Check s.w co oling pr and rocker arm l.o pr

Allow engine to warm up and when satisfied that e verything is o .k

Engine may b e paralleled as follows

Ensure the v oltage o f the machine to be paralleled is the same as the bus

bar voltage. Ensur e the frequencies of bo th mac hine are same (the

frequency of the incoming machine can be adjusted using the speed

control)


26/59



Select the machine to tbe paralleled on the synchroscope selector. The

synchroscope should then start to rotate; it should be rotating in a

cloc kwise direction slowly . If it is rotating in an anticlockwise direction,

this means the speed of the incoming machine is too slow or if it is

rotating fast clockwise, the speed of the incoming machine is too fast,

this is adjusted using the speed contro l.

When the needle of the sy nchroscope is ro tating in the clockwisedirection slowly, the br eaker of the incoming machine should be clo sed.

When the needle of the sy nchroscope is at the 5 to 12 po sition, this will

allow the incoming machine to take a slight amount of load when c oming

on the switch board and also prevent the machine tripping on reverse

power

What is the purpose of v olute casing in a turbo charger?

To change the air veloc ity into pressure.

It also ensures a constant velocity of air leaving the turbocharger by

accommodating for the gradual increase in quantity o f air that builds up

at the circumference of the compressor

How is the j.c.w. temp controlled?

It is controlled by means of a thermostatic valve normally known as an

AMOT VA LVE. This operates by diverting j.w. through the coo ler when

too hot or by passing the c ooler when cooler. The amot valves normally

use wax elements to operate the v alve

What are the reasons for no t enough scav enge/c harge air?

Blocked air filter on turboc harger or a faulty turboc harger

Give a shipboard use for grey cast iron and the properties that make it

suitable for this use?fresh water pump c asings

It has fairly good mac hining qualities and is also inexpensive

What wo uld y ou do if l.o temp started to fall?

Reduce S.W. cooling flow through the l.o cooler by throttling the S.W.

discharge valv e from the cooler

What ty pes of water tests would you do on a l.p. auxiliary

bo iler/ec onomizer?


27/59



1. Chloride test

2. PH_- alkalinity test

3. Total dissolved so lids test _ using hydrometer

4. Phenolphthalein alkalinity test

5. Hardness test

6. Phosphate reserve

What is the difference between c lar ifier and purifier?

A purifier removes water as where a clarifier removes solid impurities.

In some cases, both are used for separation purposes, firstly the oil is

purified, then clarified

What is the purpose o f a fusible plug on an air receiv er and at what temp

is it designed to melt?

The purpose of fusible plug is to act as a safety feature to release

compr essed air from the rec eiver in the event o f a fire in the vicinity.

The fusible plug is designed to melt a t 1 50 deg cent

What wo uld cause excessiv e exhaust temp?

On a single cylinder it could be an incorrect fuel pump timing i.e. late

injection causing after burn, too much fuel, leaking fuel injector or burnt

out exhaust v alve . If all exhaust temps were high, it co uld be due to high

scav enge temp, charge air co oler fouled, turboc harger air filters dirty or

fouled, high engine load

Give a shipboard use of al.bronze and the properties that make it suitable

for this use?

Pump impellers

It has good wear, fatigue and corro sive pro perties

Where on bo ard a ship would you find informatio n on the carr iage of

hazardous substances?

Information on the carriage of hazardous substances would be found in

the IMDG (International Maritime Dangerous Goods Code) which would


28/59



normally be found on the bridge.

What are the c rankcase pressur e relief v alv es fo r?

These v alves act as a safeguard to relieve exc essive crankcase pressures,

whic h may oc cur from oil vapo r igniting in the occurrence of an engine

component overheating. They also prevent flames from being omitted

from the crankcase and must also be self closing to stop the return ofatmospheric air into the crankcase

What would you do if y ou found that y ou had a cracked liner or cy linder

head?

Inform bridge that engine would have to be stopped and of the situation,

also inform c hief engineer and repair the unit as soon as it is safe to do so

Why purge the boiler furnac e?

A bo iler furnac e is purge d before burner operatio ns to ensur e that there

is no unburned fuel or gases in the furnace, which may cause a blow

back. Purging sho uld be carried out for at least two minutes

Give a rough indication of engine speed ranges i.e., slow, medium and

high speed

Slow 100 15 0 rpm

Medium 300 850 rpm

High 850 3000 rpm

What is uniflo w scav enging?

With uniflow scav enging the incoming air enters at the lower end of the

cy linder and leav es at the top. The outlet at the top of the c y linder being

a large exhaust valve. The advantages of uniflow is the simple design of

the liner and it is the most efficient

What is the c rit ical and barred range of an engine?

This is where the speed of an engine in rpm, at which the resonant

condition occurs, and is referred to as critical speed. The high stresses

associated with resonant condition start to build up as critical speed is

approached and do not come back to a safe value until speed is beyond

critical speed. The unsafe stresses either side of critical speed are known

as flank stresses either side of of critical speed are known as flank stresses


29/59



this is known as the barred speed range. The engine must not be

continuously operated at speeds within the barred range

How does generator l.o.co pewith blow by ?

Generator l.o. cope with blow by, by having a TBN of 20 30 (TBN

standing for Total Base Number which is an indication o f the quantity of

alkali, i.e., base, which is available to neutralize ac ids from blow by )

Why is a j.c.w. Safety valv e fitted on air c ompressor?

It is fitted to relieve excess pressure in the cooling system should a

coo ler tube burst and co mpressed air escape

Give a ship board use of spheroidal cast iron and the properties that

make it suitable for this use?

Cylinder heads and liners

It has high compressive strength qualities and also good wears resistive

qualities

How many PPMS can be pumped in other than Marpol restricted areas?

10 0 PPM

What are the Marpol r estricted area?

The Mediterranean sea, Baltic sea, Black sea, Red sea, Gulf areas, North

sea, Antarctic, wider Caribbean region including gulf of Mexico and the

Caribbean sea

Name the 2 most common ty pes of coolers

Shell and plate type c oolers

Shell being where a tube stack is used and fitted into a shell and c losed at

either end with end cov ers

Plate being made up of a number of pressed plates surrounded by seals

and held together in a frame

Why is gear pump used for pumping o il, while a centrifugal pump is used

for pumping water?

A gear pump is use d for pumping oil as it has a high suc tion lift, is self


30/59



priming, able to produce the discharge pressure required by the system

and can handle large amounts of vapo r or entrained gases. If is also able

to pump high v iscous fluids

A centrifugal pump is use d for pumping water , as it is unable to pump

high visco us fluids such as oil; the ce ntrifugal pump is not self priming

What sho uld y ou do to ensure that there is no water leakage into theengine cy linder before preparing main engine for se?

The engine should be turned using turning gear with indicator cocks

open, keeping a close ey e on the co cks for any sign of water discharge

Immediately prior to starting, the engine should be kicked on air

Note: 2 stroke engines should be turned at least one rev olution where a 4

stroke should be turned 2 rev olutions

Explain your companys bunkering procedures?

Most co mpanies will have bunkering procedures which will consists of a

chec k list containing procedures such as

Ensure vessel is securely moored

Scuppers are plugged

There are communications between bo th parties

No smoking signs placed

No hot work is taking place in the v icinity

Oil spill gear is available

Correct valves are opened for bunkering

The ov erflow tank is empty

This chec k list is then signed by both parties and the c hief engineer

The time of bunkers starting and finishing are then reco rded

The amount to each tank

Place of bunkering


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Type o f F.O. bunkered, this is also recorded in the Oil Reco rd Book

Note: before bunkering a set of sounding should be taken, also during

bunkering to ensur e fuel is going to correc t tanks and at the end of

bunkering

Sample of fuel bunkered should be taken throughout bunkering for

analysis

What are the uses of centrifugal pumps, positiv e displacement pumps

and gear pumps on bo ard a ship?

Centrifugal pumps s.w.cooling pumps,j.c.w. pumps, boiler feed pumps

(multistage pumps)

Positive displacement pumps bilge pumps. steering gear pumps, cargo

pumps

Gear pumps f.o.booster pumps, f.o.transfer pumps

What wo uld happen if the l.o .pr dropped to o lo w on a pump?

If the l.o.pr were to dro p too low on the l.o.pump, the stand by l.o .pump

would cut in

What is lo op scav enging in a 2 stroke engine?

It is where the inco ming air passes ov er the piston, c rown, and then rises

towards the cylinder head forcing exhaust gases down and out the

exhaust ports, just abov e the inlet port. The advantage o f loop is that no

exhaust valv e is required

What ty pe of safety valv e is fitted to a bo iler and at what pressure does it

lift?

High lift safety v alve s and are designed to operate at 10% boiler working

pressure and must also be capable of releasing all the steam the boiler

can produce without the pr rising more than 10% over a set period. 15

min for tank boilers and 7 minutes for water tube. The spring pr once set

is fixed and sealed by a survey or.

Note: the abov e test is known as the accumulation of pr test

Give possible reasons why the engine room bilge pump may not be able

to empty bilges?


32/59



The strum box from the bilge may be fouled. Bilge pump suction filter

may be blocked

A v alv e may be left open from an empty bilge

There could be a hole in the system on the suction side of the pump

Depending on type of bilge pump, the pump suction or discharge valves

may need ov erhauling

SAFETY

What is the purpose of the dec k seal on an inert gas sy stem?

To act as a non return valve and prevent the back flow of gases, i.e.,

hazardous to non hazardous

Regarding the energy bilge injection valve what is its relevant size

compared to the main S.W. injection valv e?

The valve size of the eme rgency bilge injection must not be less than two

third the size of the main S.W. injection v alve

What safety equipment should there be at a bunke r statio n?

A foam fire ex tinguisher, o il spill gear, suc h as spill absorbent and there

should also be communication of some sort

What is regarded as an enc losed space?

It is a space that can not be assumed to contain oxygen.

There are spaces such as a duct keel, a D.B.tank, a coffer dam, boiler etc

What is the duratio n of 9 liters foam fire extinguishers?

Appro ximate duration of around 5 0 sec onds

Once a fire detector has detec ted or sensed a fire, what happens?

Asso ciated with fire detectors is a circ uit connected to an alarm panel,

whic h is usually situated on the br idge, where the alarm is accepted,

usually there is a repeater panel in the engine control room. The panel

giving an indication on which deck and zone the detector was activated.

Someone will then be sent to investigate and verify if it is a fire or a a

false alarm


33/59



Where wo uld you find he at detec tor and why?

In places such as the galley, where other types of detectors would give

false alarms.

What are bo undar y coo ling and the reaso ns for it? it sho uld be

remembere d that a fire ex ists in 3 dimensions and therefore has 6 sides,

there can be transmitted through bulkheads due to radiant heat, i.e.,causing combustible materials in adjacent compartments to catch fire,

therefore this radiant heat is prevented by boundary cooling of all sides

of the compartment o n fire, using water spray ho ses

Explain the proc edure for lowering a life bo at with gravity dav its?

The life boat is held in against a cradle by ropes called gripes and the

cradle is secured by pins, with the gripes and securing pins (sometimes

known as harbor pins) are removed and released, the winch hand brake

can be released to enable the cradle to slide down and over the ships

side. A Tricing - in Pennant (wire) bring the life bo at close to the ships

side to enable it to be boarded.

The browsing lines which fasten to each end of the life boat are then used

to hold it into the ships side, the Tricing in pennant then being

released

A painte r is then led from the forward end of the life bo at and attached

somewhere forward o f the life bo at on the ship. Life boat plugs are thensecured

Once the c rews are on board the life boat the br owsing lines are released

and the life boat is lowered to the water.

The engine is started, falls released and then the painter

On what type of fire would you use a dry chemical powder fire

extinguisher?

On all classes o f fire, but it has no c ooling effec t

How is water hammer prev ented?

In order to prevent water hammer it is necessary too open up drains on

steam lines bei9ng brought into use. The water must be completely

drained so it leaves the line clear. The steam valve is then cracked open

so the line is heated and brought up to near working temp. Any

condensate found during this process drains out of the line via the drains


34/59



previously o pened. The v alve may then be opened and drains closed.

How do y ou carryout a face seal check on a breathing apparatus set?

Don face mask, tighten straps properly and turn air supply on. Then

switch air supply off and breath in the mask should stick to face. Note pr

gauge should not drop rapidly e ither. Switch air supply back on.

State the regulations regarding the emergency fire pump?

It is to be located remote from the machinery space and with

independent means of power, which c ould be a diesel engine or from the

emergency switch board

What sho uld be used with breathing apparatus sets when entering a

space or compartment?

A t ime in/ time out bo ard sho uld be used. This bo ard will normally hav ea built in clock. On this bo ard the time the wearer enter a space is noted,

plus bottle number and pr, the time the wearer is due out is calculated as

the time the low pr whistle operates at. This gives the wearer time to ex it.

What is the principle operation of a flame detector?

As flame has a characteristic flicker frequency of 25 Hz, use is made of

this fact to trigger an alarm. Flickering radiation from flames reaching

the detector lens/filter unit, which only allows infra red ray s to pass and

be foc used upon the cell. The signal from the cell goes into the selectiv e

amplifier, which is tuned to 25Hz, then to a time delay unit (to minimize

incidence o f flame alarms) then to an alarm circuit.

What is a good practice before using a dry chemical po wder

extinguisher/

It is good practice to give a DCP extinguisher a shake before use, as the

extinguisher could have been lying for a while causing the powder to

clog up

What is done to ensure that a life bo at engine will start when needed?

At least once ev ery 2 weeks, but better still once a week the life bo at

engine should be run, all fuel and oil levels checked and the gear box

should be oper ated i.e., engine run astern and ahead to check operation

Most engines are air cooled, but some are a combination of air and

water, in which case water level checked and if operating in cold c limates


35/59



anti freezing levels also.

Larger life boat engines will be battery started, therefore condition of

batte ry must be checked i.e , spe cific grav ity of elec troly te and that

electrolyte is c ov ering cell plates.

Describe a SCBA set?

Set usually consists of one or two cylinders of compressed air kept in a

harness, which is carried on the back. Cy linders usually be ing charged to

a pressure of around 200 240 bar. The high pr air is fed through a

reducing valve and then to a demand valve, which can be set in positive

pr mode, that will supply a const demand of air or in demand mode,

whic h will only supply air as the wearer demands. A non return valv e

permits breathing out to atmosphere.

The set incorpor ates a warming whistle that sounds on low air pr

A standard cy linder will allow for about 20 25 mins. Operatr ion, but

this will also depend o n a few factors, such as wo rk load of wearer.

Describe an inert gas generator?

The inert gas generator burns fuel in designed quantities to produce

perfect combustion. This produces an exhaust gas, which is largely

nitrogen and CO2 with very small ox ygen content. The ex haust gases

pass to a cooling and washing chamber to remove sulphur and excesscarbon.

The washed or scrubbed gas is now inert and passes to a distribution

system for fire fighting. The complete unit is arranged to be

independently operated in order to supply inert gas for as long as the

fuel supply lasts. On tankers the IG can be supplied and used to blanket

the oil c argo during discharging operations. Empty tanks are filled with

gas and inert gas is blown out when o il is loaded.

Explain and sketch a funnel inert gas?

In a boiler funnel inert gas system, exhaust gas is taken from the boiler

uptakes and passed through a scrubber tower where the gas is cleaned

with sulphur and ex cess carbo n be ing remov ed. The gas whic h by then is

considered inert and mainly contains nitrogen and carbon dioxide with

less than 5% oxygen is then supplied via blowers and deck seal which

acts as a non return v alve along dec k pipes to cargo banks. The inert gas

being used to blanket the o il cargo during discharging operatio ns, empty


36/59



tanks are filled with gas and the inert gas is blown out when oil is loaded.

What are the safety features fitted to a batte ry carbo n dio x ide sy stem?

A stop v alv e to sto p discharge of carbo n dio xide to the machinery space.

A safety v alv e between the starting cy linders and operating piston. This

is to prevent operation o f the system due to leaking starting bottles

Pr alarm in discharge line to give an indication of an accident escape or

leaking carbon diox ide bottle from the battery

The main engine cyl.l.o.tank is empty oil drums are on the main deck

beside run down pipes to the tank and air is hardy . What do y ou do ?

If need be, the engine should be stopped to allow filling of the tank.

Under no circumstances should you use the air hose to pressurize the

drums to speed up the pro cess. Oil drums are not a pressure v essel and it

could lead to a fatality

On what type of vessel would you expect to find a bulk carbon di oxide

system and what is normally inco rporated into these systems?

Y ou would normally ex pect to find a bulk carbo n dio xide sy stem on a

cargo or Ro Ro type vessel where hold areas need fire fighting

protection and the cargo space system is normally arranged for smoke

detection, alarm and carbon dioxide flooding. Small air sampling pipes

from the individual cargo holds are fed into a cabinet on the bridge. Air

is drawn from each hold by a small fan and each pipe is identified for its

particular hold. If smoke is drawn into the cabinet from one of the holds

it will set off an alarm. The smoke is also passed into the wheel house

where it can be detec ted by personnel on watch.

The location of the fire can be identified in the cabinet and the hold

distribution v alve belo w the c abinet is operated. This valv e shuts off the

sampling pipe from the cabinet and opens it to the carbon di o xide main,

leading to the bulk carbon dioxide, discharge manifold. A chart

indicating the amount of time the release valve is opened for and this is

done by first opening the main discharge valv e to the manifold setting off

carbon dioxide alarms

What is the gas analysis after the scrubber tower on an inert gas sy stem?

OXYGEN 0 - 1%

CARBON MONOOXIDE 0%


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CARBON DIOXIDE 14 - 1 5%

NITROGEN 85%

Where is c arb on dio xide ex tinguishers not permitte d?

In the living quarters of the acco mmodation

Note: within the acc ommodation bloc k carbon di ox ide extinguishers are

available in the cargo control room, bridge and radio room where dry

powder could damage this apparatus.

What adv antage do inert gas produc ing units used for fire fighting

installations have o ver carbo n dioxide and halon systems?

It has the advantage of being able to continuously produce inert gas. A

bo ttle sto rage sy stem, suc h as carbo n dio x ide or halon floo ding is a one

shot fire ex tinguisher which leaves a ship unprotected until further gassupplies can be found

What is and where would y ou find the international shore connections?

This is a standard size flange which is fitted with a suitable coupling for

the ships fire hoses. The flange is slotted in order to fit any shore side fire

main and enable water to be brought on board ship lying alongside.

Usually lo cated on the bridge.

Why is a hy drostat ic r ele ase unit fitted to a life boat?

In the event of the vessel sinking, the hydrostatic release operates at a

predetermined water depth, releasing the life raft lashings, allowing the

life raft to float free and inflate

What is the principle operation of a heat detector?

This type of heat detector uses 2 bi metallic strips/coils attached to a

vertical support bracket. When temp is present the bimetallic str ips will

start to move at a fixed temperature. The first strip will hit a stop, the

second strip continuing to move, thus the contact is made and triggers

the alarms

Sketch and describe a bulk carbon diox ide system

The system consisting of a large insulated vessel which holds carbon

dioxide a working pressure of 21 bars at around -20 degree centigrade.

To maintain this pressure and temperature a refrigeration circuit is


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required. One is stand by the other in operation. As it is essential to

maintain pressure in the vessel, a heater is also incorporated. The

system will discharge into the engine room and hold a main discharge

valv e opening of this valv e will shut down ventilation and activ ate the

carbon dioxide alarm, warning personnel of the imminent discharge of

carbon dioxide, all personnel must then be accounted for and space

seated before discharge of carbon dioxide. With this system, the actual

line to the engine room and other spaces where the carbon dioxide is

discharged to will hav e an indiv idual manual v alve and as the sy stem is a

bulk sy ste m and the spaces being discharged to will hav e differ ent areas,

a chart will predetermine how long valve will be opened for to give

proper discharge cov erage for each space

Fires are classified according to the types of materials which are acting

as the source, what are these classifications?

CLASS A fires burning wood, glass fiber, upholstery and furnishings

CLASS B fires burning liquids such as l.o and fuels

CLASS C fires burning gas fuels such as LPG

CLASS D fires burning combustible materials such as magnesium and

aluminium

CLASS E fires burning any of the above materials together with high

voltage electricity

Carbon diox ide gas black

Foam white

Water red

BCF green

What happens to the carbo n dio xide sy stem in dry -do ck?

It must be made inoperable

Why sho uld the bo iler no t be blown do wn o n finding oil contamination?

The boiler should not be blown down, as this will cover all heating

surfaces with oil i.e., insulating the tubes, heating surfaces

What speed do es the c entrifugal brake on a life boat winch limit the speed


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of fall of the life bo at to?

Speed of fall of the life boat to fall faster than 36 meter/ minute

Halon fire fighting system, describe it

Sketch and describe a dry powder fire extinguisher?

The outer container containing sodium bicarbonate powder. A capsule

of carbon dioxide gas is located beneath a plunger mechanism in the

central c ap. On depressing the plunger the carbon dioxide gas forces the

powder up a discharge tube and out o f the discharge nozzle.

State the capabilities of ships main fire pump

It must be capable of supply ing water to at least two hoses and nozzles in

the ship and they must produce a good jet of water simultaneously

What oxygen lev el would y ou regard as safe to enter an e nclosed space?

20% or abov e

Sketch and describe a carbon dioxide ex tinguisher

A c arbo n dio xide ex tinguisher coinsists o f a v ery strong container that is

used to store liquid carbon dioxide under pressure. A central tube

provides the outlet passage for the carbon dioxide which is released

either by a plunger bursting disc or a valve operated trigger. The liquid

changes to a gas as it leave s the ex tinguisher and passes through a swivel

pipe or hose to a discharge horn

What are the adv antages of halo n sy stems o ver carbo n dio xide sy ste ms?

Less halon is needed to extinguish a fire than carbon dioxide therefore

less storage space is required

Also the atmospheric in a halon flooded space is not tox ic although do es

contain some highly irritant gases when ex tinguishing

What are the 2 brakes on a life b oat winch?

A centrifugal brake and a weighted brake known as a dead mans brake

i.e, once you let go of the braking lever, the brake will come into action

stopping the fall of the life boat

How is the bilge injection valve brought into operation?


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To bring the bilge injection valve into operation during an emergency,

the valve is opened fully and the sea injection or suction valve is fully

closed. After it is established the bilge injection valve is capable of

lowering water level in the engine room the sea water injection valve or

suction valve may be opened slowly. This should be done in stages so

that the tank tops are no t pumped dry as this would cause the sea water

pump to loose suction

Sketch and desc ribe the mec hanical foam ty pe fire extinguisher

The outer container is fitted with water. The central container holds a

carbo n dioxide c harge and a foam so lution. A plunger mechanism with a

safety guard is located above the central container. When the plunger is

depressed the carbon dioxide released and the foam solution and water

mix. They are then forced out through a special nozzle, which creates the

mechanical foam. The extinguisher has an internal pipe and is operated

upright

What is the range of foam fire extinguisher?

Roughly 7 meter

Where are the infra red fire detec tors best situated

They are best situated in machinery spaces and boiler rooms, where

there is a high risk of fire

Briefly ex plain how high expansion foam is produced

By means of a foam generator, where from foam concentrate and sea

water 100 t imes quantity is achiev ed. The generator blows air through a

net sprayed with foam concentrate and water. The v astly ex panded foam

is then diverted away to the space to protect. The foam is an insulator

ands an absorber o f radiant heat; it also ex cludes o xy gen from the fire

What can be fitted ov er relief valv e vents on a bulk carbon dio x ide

system to give an indication of leakage?

Balloons

Sketch and describe the chemical foam type of extinguisher

The main c ontainer is fitted with sodium bicarbonate solution and a long

inner polythene container is fitted with aluminium sulphate. The inner

container is sealed by a cap held in place by a plunger. When the plunger

is unlocked by turning it the cap is released. The extinguisher is the


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inverted for the two liquids to mix. Carbon dioxide is produced by the

reaction, which pressurizes the co ntainer and forces out the foam

What testing and maintenance is done regarding sodas acid and foam

extinguisher

The extinguisher containers are pressure vessels therefore require

testing.

Containers are initially tested to 25 bar every year for 5 years and

thereafter at 4 yearly intervals to 20 bars. On soda type extinguishers

20% of contents should be discharged per year and replenished with

foam type 50% where practical the operating mechanism of portable

extinguishers should be ex amined ev ery 3 months

Sketc h and explain a foam fire fighting installation

Here an automatic foam induction system is shown. The automatic

inductor unit ensures the correct mixing of water and foam compound

whic h is the n pumped to hy drants, dec k or machinery space for use . The

foam compound tank is sealed to pro tect the contents from deterioration

and has linked compound supply and air vent valves. To operate the

system, these 2 linked valves are opened and the fire pump started.

Foam mixing is carefully metered by the automatic inductor unit. The

fire pump and compound tank must be located outside the protected

space.

Where wo uld you ex pect to find a soda ac id fire ex tinguisher? (Water)

Accommo dation areas

What is the pro cedure for entering an enc losed space?

An enclosed space entry permit is required whic h can only be ob tained

with the permission of a responsible officer . This permit will list the

conditions to one met before entry. The space should be well ventilated

before entry takes place, before entry oxygen levels must be checked

using an oxy gen meter. (Oxy gen analy zer)

Another person sho uld remain at the entranc e while the perso n is in the

space, to summo n assistance if necessary and there should also be means

of communications arranged between the person within the space and

the attendant.

Lifelines and harnesses should be av ailable at the entrance to the spac e


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If the occupant appears to be in danger the attendant should first raise

the alarm but should not enter the space unless equipped with breathing

apparatus

What is the reentry procedure once a mac hinery space has been flooded

with carbo n dio xide or halon?

Once a carbon dioxide or halon flooding has taken place, the spaceshould be continued to the bo undary cooled

Only when the extinguished fire has been left long enough to c ool do wn

can the space be reentered. Note: early reentry can lead to reignition

Reentry should be done by personnel wearing breathing apparatus

taking water spray hoses with them to co ol down any ho t surfaces. Note:

reentry should also take place from the lowest point remote from the

seat of the fire, if possible. Cooling and smoke dispersal are the first

priorities to provide an atmosphere in which others can operate and

gradually bring machinery b ack into serv ice e

Where the mac hinery space fire inv olv es elec trical equipment then the

only dry powder or carbon dioxide extinguishers can be used until the

equipment is isolated

What is the principle operation of a smoke detec tor?

The above detector of the light scatter type uses a photo cell separated

by a barrier from a semic onductor intermittently flashing light source

housed in an enclosure whose containment allows smoke but not light

inside. When smoke is present in the enc losure, light is scattered aro und

the barrier on the pho toce ll and an alarm is triggered.

What are the two ty pes of carb on dio xide fixed installatio ns use d on

bo ard ships fo r fire fighting?

Battery and bulk system

How is a life raft launched?

The life raft is simply launc hed by releasing it from its lashing a painter is

secured to the ship and the life raft container is thrown over the side.

Inflation takes place automatically the container bursting open and the

life raft floats clear. A pressurized cy linder of carbon diox ide is used the

inflate the raft. Life raft must normally be bo arded from wa

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