ALL ABOUT MARINE ENGINNERING

GENERAL ENGINEERING KNOWLEDGEWhat interlocks are there on the start air system?An interlock to prevent fuel being injectedAn interlock on turning gear and an interlock CCP system, pitch has to be on zero before starting engine.What is a shipboard use of stainless steel and the properties that make it appropriate?Stainless steel could be used for seawater pump shafts. It has good corrosive properties.What are the differences between cross head and trunk piston engines?What are the impurities in heavy fuel oil?Impurities in H.F.O. come in the form of solids and liquids.Solids-------dirt, rust, and sand.Liquids-----water and sludgeWhat is the safety devices fitted to an air compressor?Low L.O.pressure shutdownHigh air temperature shutdownFirst stage relief valveSecond stage relief valveA fusible plug is fitted after the second stage cooler, set at 120 deg centsIf water cooled, a jacket water safety valve is fitted.Explain heavy fuel oil system from bunker tanks to engine?Fuel is pumped from 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 suction from the sett tank via purifier heaters, pass through the purifiers, where any water and impurities are removed and passed on to the serv tank which also has a set of heating coils.From the serv tank the fuel then passes via a flow meter to the mixing tank from where the booster pumps take suction discharging to the F.O.heaters where the correct F.O.temp/viscosity achieved for correct fuel combustion in the engine, the fuel then passes through the viscosity regulator which controls the heater temp, then on to the F.O.filter (which are heated) to the fuel pumps then to the fuel injector via double skin/wall high pressure pipe. Any surplus fuel returns via regulating valve from the fuel pumps back to the mixing tank.D.O. can also be used in the system and is fed to the system via a 3 way valve.Note : when diesel is used, no heating is required.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 injector is detected as this space between double skin/walled pipes is led via drain line to a small tank fitted with a level alarm.Give an example of the density of H.O, L.O and D.O?H.F.O.---------950 kg/cu.mL.O---------870 kg/cu.mD.O---------880 kg/cu.mWhat is the purpose of the scum valve on a boiler?The scum valve on a boiler is connected to a shallow dish positioned at the normal water level of the boiler and enables the blowing down or removal of scum and impurities from the water surface.Why are quick closing valves fitted in a fuel system and how can they fail to operate?Quick closing valves are fitted in fuel system so that in the event of a fire in the vicinity of these system or a fracture or break in these lines the system c an be shutdown rapidly and remotely, this valves are pneumatically operated. If by any means control air fails to reach the valve the system will fail.At what temp does the department of trade and industry state the fuels must be kept in the storage tanks?14 deg cent under their flash points.Why are weighed cocks fitted to sounding pipes of fuel oil tanks?To prevent F.O.spills from overflow. They also prevent vapours escaping from tanks.What are the properties of H.F.O?High viscosityLong ignition delay i.e. low cetane indexHow does over speed trip work? By shutting the fuel off to the engine.There arte various types of trips, mechanical types which work on the principle of fly weights, or electrical types which work on the principle of speed pick up operating a stop solenoidWhat fittings would you expect to find a start air receiver?Safety valve, fusible plug, isolation valve to main air start system., filling valve from compressor, drain valve, valve to control air, valve to whistle, and pressure gaugeHow is the L.O.temp controlled?By means of a thermostatically controlled valve which will allow L.O.to bypass the cooler when too cold and divert L.O.through the cooler when too hot. Preset wax elements being incorporated in these valves for this purpose.Describe the duties of a duty engineer?1. Regularly check and record all pressure and temp in the engine room log2. Pay attention to readings for deviation from normal particular attention being made to exhaust temp, scavenge temp and pressures and turbocharger r.p.m3. Adjustments should be made for s.w. Temp, changes to keep correct temp and pressures4. Checks should be made on the pressure drops across fuel and lub oil filters to see that they are operating within required limits.5. Check all oil levels in auxiliary machinery, main engine sump levels, cylinder lubricators, turbocharger and governors.6. Check around all bearings and crankcase doors using palm of hand to feel for any increasing temp.7. ensure that fuel in the daily service tanks is at correct levels and that issludged and drained of water8. depending on type of purifiers fitted sludge and drain , check oil level, signs of vibration and clean if required9. Carryout all routine assignment as recommended by engine builders or the company.10. At all times use sight, smell and hearing and this is often the first sign of a fault developing in the engine room11. Check bilge levels, stern gland, air start bottles and maintain correct level a and pressures12. Record and fuel/lub oil transfer and any irregularities in log.Why are high and low suction fitted on f.o. serv tank?The high and low suctions are a safety feature to prevent shutdown of main engines, generators and boilers due to water contamination 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 separate towards the tank bottom when it becomes 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 shutdownWhat trips are there on a generator?L.o.low pressure shutdown, j.cw.high temp and over speed shutdownWhat steering gear checks would u do before setting sail?1)Prior to a ships departure from any port the steering gear should be tested to ensure the satisfactory operation. These tests should includea)Operation of main steering gearb)Operation of auxiliary steering gear or the use of the second pump which acts as a auxiliaryc)Operation of the remote control system from the main bridge steering positionsd)Operation of steering gear using the emergency power supplye)The rudder angle indicator reading with respect to actual rudder angle should be checkedf)The alarms fitted to the remote control system and steering gear power units should be3 checked for correct operationg)Steering gear header tank levels should be checked.2. During these tests the radar should be moves through its full travel in both port and starboard and the various equipment items, linkages etc visually inspected for damage or wear. The communication system between bridge and steering gear room should also be operatedWhat would happen if the duty engineer did not report in after answering an alarm?The dead man alarm would activate which the duty engineer would have to accept in the engine room, if not accepted the watch keeper on the bridge would send someone to investigate if there was a problemWhy would the bridge need to be informed that the engine is about to be stopped?The bridge would need to be informed that the engine was about to be stopped to ensure it was navigationally safe to do so.ie not in busy shipping lanes or near land.Draw a 2 stroke-timing diagramHow does the turbocharger work?The turbocharger mainly consists of a turbine and a compressor assembled as a single unit on a shaft. The exhaust gas from the engine flows through a water-cooled gas inlet (cooling from engine j.w. system) to a nozzle ring, which directs gases at the turbine rotor balding. This force causes a rotor to rotate at high velocity. The gases leaving via a water-cooled gas outlet casing to an exhaust pipe and atmosphere. The air required for the diesel engine is drawn in by the compressor via a combined silencer/filter. The entry passage after the filter is then divided onto splitters which prevent draught losses and guide the air to the compressor and discharge radially at high velocity to the diffuser, 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 pressure before being discharged to the charge air cooler and to the engine for combustion.What would happen if the l.o.pressure just dropped to zero/?The engine would shutdown on the low l.o.pressure trip.How is the signal from the bridge when the helm is moved transmitted to the hydraulic rams in steering flat/?When the helm on the bridge is moved, electrical impulses are produced. These impulses are transmitted via an amplifier or control unit to the steering flat. In the steering flat these impulses are relayed to a servo motor (telemotor) which drives an adjusting gear and floating lever which put the steering gear variable delivery pump on stroke, thus crating hydraulic pressure in the system which means the rams, thus moving the tiller and rudder. The pump is only required to deliver oil when the whelm is moved i. e once rudder has matched the helm angle, the control lever, will put the pump off stroke.How many starts do you require to get from a receiver without recharging?On a reversible engine12 startsOn engines with CPP propellers6 startsWhat is the maximum compressed air temperature that should leave the air compressor? 93 deg centigradeWhat 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 the engine room.What measuring devices are there on the cylinder head of 4-stroke engine?Exhaust temperature pyrometer and j.w. Outlet thermometer.After stripping and cleaning a purifier what do you have to make 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 shaft is correctHow would you check that there was excess water in the sump?By using water finding pasteWhat types of valves are boiler feed check valves and why?Non return type valves a and are fitted in pairs one being the main and the other the stand by or auxiliary and they must give an indication of open or closed positions. They are of non-return type to prevent back flow of boiler pressure 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 and very good heat transfer qualities.What is an indication in the exhaust gas of good combustion?Grey smoke indicated good combustion.What would cause a crankcase explosion?A crankcase explosion could be caused by the formation of hot spot i.e. the overheating of a bearing, which in turn could cause an oil mist to be generated,. If this oil mist is allowed to build up an explosive condition could occur where the oil mist can be ignited by piston 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 crankcase known as sump or in a drain tank located beneath the engine. The oil is drawn from this tank through a strainer by one of two pumps in parallel, one pump being on stand by. The pump discharges the oil into one of a pair of fine filters it is then passed through a cooler before entering the engine 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 a drilled passage in the crankshaft to the big end bearing and then up a drilled passage in the connecting rod to the gudgeon pin in a trunk piston engine or a crosshead bearing in a crosshead bearing. An alarm at the end of the distribution pipe ensures that adequate pressure is maintained by the pump. Pump and filters are arranged in duplicate with one as stand by. After use in the3 engine the l.o.drain back to the sump or drain tank for reuse.What limit does the department of trade and industry state that the lower limit of flash point of fuel used onboard ship should be?60deg centExplain 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 and also unloader3.Check air intake filters is cleaned4.Ensure oil pressure gauge is open and that air pressure gauges i.e. first and second stage are partially open to stop gauge fluctuation.5.If water-cooled check valves are open and cooling is supplied also check header tank.6.Bar machine over by hand to see if its free to turn7.Start the machine, check there are no unusual noises or vibration and oil pressure is correct.8.then close drains and unloader9.If all seem o.k. run for 30 minutes after which can be stopped, covers removed and bearing checked. If o.k. machine can be started on automatic and run10.To stop the machine, always make sure the machine is unloaded and drains opened before stopping unless 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 headWhy does a centrifugal cargo pump have a relief valve?A centrifugal cargo pump requires a relief valve, as the working pressure of the pump has to tie in with the working pressure of the cargo pipe work.Draw the timing diagram of 4-stroke engine?Crankcase inspection: frequency, procedure and reasons they are carried out?The frequency may vary from different engine manufacturers but its roughly around 5000 hrs.Also inspection are carried out after any work has taken place in the crankcaseProcedure is as follows:1.Remove crankcase doors from the both sides of the engine2.Relief valves can be checked at the same time as the are off3.Inspect condition of all bolt locking devices, replace any damaged components4.Turn engine over using turning gear. ENSURE NO ONE is in crankcase while doing this and that the indicator cocks are open check condition of camshaft driving gears.5.Start main l.o.pump and check oil flow from bearings and piston cooling parts. Check for any leakage from internal oil pipes and galleries.6.Check for any damage of cam shaft lobes7.Check for any evidence of water leakage from lower cylinder liner o rings8.Replace any damaged crankcase door joints9.Record any defectsWhat is the first indication of leaking exhaust valves?A rise of exhaust gas temp at the outlet of the valveWhat instrument measures small changes in crankcase pressure?A manometerWhat is an indication in the exhaust gas of good combustion?Grey smoke indicates good combustionIf there was no water in gauge glass after blowing down?Shut down the boiler immediately and use easing gear to relieve boiler pressureWhat procedure does the duty engineer follow when answering an alarm on UMS?Answer alarm; ensure wearing correct clothing before entering engine roomNever use the ships lift, if fitted use the stairsOnce in the engine room inform bridgeAnswer alarm, rectify problemThen inform bridge when vacating the engine roomWhat is the diffuser plate in turbo charger?It is found on the compressor side, it converts the velocity, Kinetic energy from the compressor into the pressureHow can exhaust valve 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?15PPMWhat is the purpose of the cylinder relief valve and operating pressure?It is designed to relieve pressures in excess of 10% 20%above normalThe operation of this device indicates a fault in the engine which should be discovered and corrected immediatelyWhat would you do in the event of a scavenge fire?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 event 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 cut off to that particular cylinder.The cylinder l.o. should be increased to prevent seizure and wear.If fixed fire fighting is attached to the scavenge trunking this can be brought into operation, depending on severity of situation. 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 scavenge spaces must be thoroughly 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 should be checked, as blow by may have been the ignition source of the fire. If possible the piston head in question should be renewed at the earliest possible moment and the damaged unit overhauled.On engines fitted with tie bolts, it may be necessary to retighten the bolts adjacent to the fire.When starting the engine, care must be taken after switching on the fuel to the cylinder in question, and that also the cylinder l.o. quantities are reduced to normal.What causes white smoke from combustion I.e., in the exhaust?The presence of waterWhat is the regulation regarding use of evaporators in shore?Evaporators should not be used within 20 miles from shore, due to risk of pollutants being taken into the f.w.systemHow would you blow down a boiler gauge glass?Close the water and steam cocks on the gauge glass and open the drainThen open the steam cock a strong jet of steam should be seen from the drain.Close the steam cockOpen the water cock --a strong jet of water should be observed from the drainClose the water cock and then close the drainThen open the water cock, the water will rise in the gauge above normal levelThen open the steam cock, the water should then settle down, finding its correct level.If only one inch of water was observed in the gauge glass (only one gauge glass) after blowing down the boiler gauge glass, what would you do?Reduce firing rate of burner and increase feed water flow to boiler by starting another feed pump.How would you 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 airWhat safety devices are fitted to a start air line?Non return valve, flame traps/arrestors, bursting discs and safety valvesWhat is the importance of M notices?M notices are important as they convey very useful information such as,Merchant shipping notices (MSNs):which will only be used to convey mandatory information, which must be complied with under British legislationMerchant guidance notices (MGNs):which will provide advice and guidance to relevant parties in order to improve the safety of shipping and of life at seaMarine information notes (MINs):which will provide information to as more limited audience such as training establishments or equipment manufacturersWhat is the correct method of starting and stopping 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 stoppingWhat are the properties of heavy fuel oil?High viscosity, long ignition delay i.e., low cetane indexWhat would cause the level of the l.o.sump or drain tank to rise?Water entering the oil, or fuel or even a l.o filling valve passingWhat are looking when you pull a piston?When you pull a piston, you are looking for any damage to the piston crown, including cracks,The condition of piston rings are checked, plus piston ring grooves, check for any scuffing of piston skirtCheck condition of top end bearing, bush and gudgeon pin, p [plus clearance between pin and bushCheck lubrication bores are clear on under side of pistonDraw a boiler gauge glassWhat would you do if you had high j.c.w. temperature?Inform bridge and then reduce engine load and investigate problem which could be insufficient flow through cooler due to fouled cooler or faulty thermostatic valveWhat would be your first indication that there was water in the sump\/Your first indication would be from your l.o.puriofier or even possibly from water in l.o.tests if done regularlyWhat is cross flow scavenging?In cross 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 valve.What safety devices are fitted to the main engine crankcase?Explosion door/relief valves and oil mist detectors.How does oil mist detector work?The oil mist detector uses a photoelectric 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 meter reading 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 down.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 isfilter 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 leaving this stage at less than 15 ppm.What could start a scavenge fire?The main cause of a scavenge fire is the fouling of scavenge spaces by the blow by products of incomplete combustion caused by incorrect cylinder lubrication, faulty fuel injection equipment, accumulation of such mixtures in the scavenge space can be set alight by sparks or flame blow byWhat would prevent water rushing out of the boiler, if the gauge glass were to break?A ball valve is fitted below the gauge glass tube to shut off the waterWhat type of clutch is used on an electrical windlass?A dog clutchWhat can you do to prevent scavenge fires?Conscientious maintenance of the engine and regular inspection and cleaning of scavenge air spaces will help prevent scavenge fire upWhat are the symptoms of a scavenge fire?When a scavenge fire has broken out the scavenge 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 scavenge trunking can be foundWhat are the rough l.o pressure on the following on a 2 stroke engine?Piston cooling6 7 barCross headbearing4 5 barMain bearing2.5 3 barWhat percentage of engine speed does the over speed operate at?10 15 % maximum speedHow often the emergency steering is tested?At least once in every 3 monthsWhat 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 generatedWhat procedure would you go through before taking over a watch?Before taking over a watch a round of the machinery space should be taken, checking various temps and pressures of machinery. Also checking oil and tank levels.Check the log book and ensure all parameters are met. Also ensure that you understand any instructions that are handed over to you i.e, any machinery that might be out of serviceHow is medium speed engine reverse (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 camsTo engage correct cams for ahead and astern movements the camshaft slides axially in its bearings. This movement is controlled by the camshaft reversing gear, which is normally a servo piston. Motion of the piston being directly transmitted to the camshaft.Note: in a slow speed, only duplicate fuel cams required.What does a positive displacement pump require that a centrifugal pump does not?A relief valveProcedure for handing over a watch?The engineer should not vacate the engine room until his relief arrivesHe should acquaint the relieving engineer of any abnormal operating conditions that have occurred during the watchAny orders from the bridge, recorded in the log book should be pointed outInstructions from the senior engineer should be passed onAny repairs should be reported together with information on any machinery that has been dismantledThe presence of any other members of ships staff in the engine room should be reportedThe engineer much ascertain that his relief if fit and able before vacating the machinery spaceWhat would you do in the case of a crankcase explosion?When the alarm sounds, the engine speed must be reduced to slow and permission obtained to stop the engine.Inform chief engineerWhen an engine has stopped under alarm conditions under no circumstances must any doors or inspection windows be openedOil should continue to be circulated and time allowed for the hot spot to cool.The early opening of doors could cause an explosion due to ingress of airDuring cooling down period the engine room staff must keep clear of the side of the engine fitted with explosion doors.After a period of at least 20 minutes, stop l.o.pump, cut off all air and engage turning gearThe access doors should then be opened and personal must keep clear of possible flames. Under no circumstances should naked lights be used nor should anyone be permitted to smokeExamination should then take place for any squeezed out bearing metal or loose bearing metal in the crankcaseHeat 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 inspected for signs of overheating. Should any damage be found, then a permanent repair must be put in hand immediatelyAfter repair, low should be check for free flow. The engine should 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 check 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 safety factorWhat causes blue smoke in combustion i.e. in the exhaust?Excessive l.o.was being burnt in combustionHow would you know an air start valve was leaking or passing?The adjacent start air line for that valve would become very hotWhat 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 pumpWhat causes black smoke from combustion i.e. in the exhaust?Black smoke would indicate faulty fuel injection equipment or it would indicate insufficient air supplyWhat would you do the j.c.w.temperature started to rise?Inform bridge and reduce load on engine, investigate problem, which would be a fouled coolerHow is fuel supplied from fuel pump to the injector?Through double wall/skin high pressure pipesWhat preventive mai9ntenece should be frequently done to diesel engine start air receiver?They should be drained of accumulated moistureName main engine shut downsLow l.o.pressureHigh j.c.w. temperatureHigh main bearing temperatureOver speed andOil mist detectorWhat is the pressure between the fuel injector and fuel pump?250 350 barWhy is overlap necessary on air start valves?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 startF.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 hydrochorinator where the water is sterilized by an excess dose of chlorine provides as hypochlorite tablets. It is then dechlorinated in a bed of activated carbon to remove excess chlorine. Any color, taste and odour which was present in the water, will also be removed by the carbon.Another method is to pass the f.w. through an ultraviolet.Describe the different types of cooling systems i.e. s.w. cooling system and central cooling systemA S.W. cooling system is an arrangement that uses individual coolers for l.o, j.w and the piston c.w. system. Each cooler being circulated by s.wAs where some modern ships use a central cooling system with only one large S.W. circulated cooler. This cools a supply of f.w. which then circulates to the other individual coolers. With less equipment in contact with s.w, the corrosion problems are much reduced in this system.Why carry out boiler 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 prevent corrosionPrevent carryover where soluble salts and suspended solids are carried over with steamHow many pumps are there in the engine room that you can pump bilges with?A bilge pump which is normally positive displacement. The others may vary from ship to ship but can be the ballast pump, g.s.pump and main 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 themWhat could cause an excessive high pressure in a refrigeration system?High pressure could be caused by lack of cooling or a fouled condenser or even overcharge, but this is unlikelyWhat would you do in the event of oil spill?Raise the alarm, inform bridge and chief engineerThere should be a set drill for oil spills, which is practiced regularlyIf possible contain the spill on deck and start clean up procedures using appropriate oil spill equipmentIf 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 recorded with the place or position of ship at the time of spill along with approximate quantity and type of oilCircumstances of discharge or escape would be logged in oil record book and engine room log bookWhat types of pumps are used for pumping bilges in an emergency?High capacity centrifugal pumps (mostly main cooling s.w.pump)What would you do if you had a high chloride level in the boiler?To reduce the chloride level in the boiler the boiler would be blown down, thus allowing fresh feed to the boilerWhat are the normal j.c.w temperatures and pressures?Normal j.c.w. pressures are between 2- 3 barTemperatures70 80 deg centAlarm at85 deg centShutdown at90deg centDescribe 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 which provides additional feed water to the system when required. Feed pumps take suction from the hot well to the boiler.To trace an oil leak to the system, various heating coils to tanks would be shut off in turn until the leak stopped, thus indicating which heating coil was leaking.What is the pressure of a start air receiver?25 40 bar depending on the type of engineHow do you purify h.f.o?Heavy fuel oils purified using a centrifugal separator, which operated by the principle of centrifugal force separating 2 liquids in this case fuel oil and water by means of a cylindrical interface between the two. The positioning of this interface being very important for the correct operationHow would you prepare a main engine for sea?This may vary from engine to engineHave a visual check all around the engineStart the engine l.o.pump; engage turning gear and turn the engine ensuring indicator cocks are openJ.c.w. heating should be on ensuring the engine is warmed through circulate by a circulating pumpThe F.O. booster pump should be running, circulating fuel around the system.Note: if maneuvering on high viscosity F.O. the fuel should be heated and circulated around the injectors to give the correct viscosity for the grade of the fuel in use.Ensure fuel injectors are vented and primed. Drain any water from air start receivers and starting air manifold also control systemCheck jacket heater tank levelCheck oil levels, sump, governor, turbocharger, cylinder l.o.tank, rocker arm if on 4 stroke.Operate cylinder lubricators by handCheck f.o.service tank i.e., drain off water/sludgeDisengage turning gearInform bridge that you are about to blow the engine over on air they will give you permission. Open air start valve from receiverOnce engine is blown over on air, close indicator cocks start j.c.w pumps, shut off jacket heating and circulating pumpIf two stroke engine, start auxiliary blowerInform bridge you are ready to start engineStart engine and s.w .cooling pumpHave a good visual check around the engine and check all parameters are correctInform bridge that you are ready for stand byWhy is simultaneous injection of f.o and starting air into main engine cylinder undesirable and how it is prevented?As it could lead to an explosion in the start air systemIt is prevented by means of interlock, which prevents fuel being injected when the air start auto valve is open. The interlock operated a stop solenoid, which keeps the fuel rack to zero positionWhat is the primary function of expansion valve in refrigeration system?To regulate the flow of refrigerant from the high pressure side to the low pressure side of the systemThe pressure drop causes the saturation temperature to drop enabling it to boil off at the low temp of the evaporatorHow would you know a refrigeration system was undercharged?Undercharge will show as a low compressor pressure and large bubbles in the liquid line sight glassWhat is compression and explain 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 valves being closed on this stroke. As 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 very rapid rise in pressure of the gases forcing the piston downWhat action would you take in the event of the main engine oil sump level rising? What could be the problem and how would you fix it?The action to be taken would depend on how fast the level was rising and what was causing it to rise.It could be due to water or fuel entering the sump, the engine would have to be stopped as soon as it was safe to do soTests should be carried out to tell if tit were water or fuelIf it were fuel, you can normally smell this in the oil, but a flow stick test can be doneWater has a tendency to form the color of the oil, depending on extent of contaminationIf it were fuel the most likely cause would be faulty injector therefore it would be changedIt were water it could be coming from cracked liner or liner O rings, therefore possible liner change to solve the problemThe oil may have to be changed depending on extent of contamination but the l.o purifier may be able to cope with itHow would you know if you had a cracked liner or cylinder head?Your jacket water header tank would start to fall. Possibly higher temperatures on the unitOn a medium speed 4 stroke engine if the liner was cracked you would get water contamination of the sumpOn a 2 stroke engine there would be possible water leakage from stuffing box drains.Explain the bilge system from bilge wells to overboard?How would you test for a leaking air start valve in port?First ensure all the engine indicator cocks are open for all cylinders 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 valve.How do you start up/ and parallel a generator?First check engine oil levels such as l.o.sump, turbocharger oil level, governor oil level, rocker arm bank oil level (if fitted)Check j..c.water header tank levelEnsure indicator cocks are open, start up l.o.priming pump then bar engine over (ensure turning bar is removed)Kick engine on air close indicator cocksStart the engineCheck all parameters are correct--- l.o.pressure/temperature, j.c.w. pr/tempCheck s.w cooling pr and rocker arm l.o prAllow engine to warm up and when satisfied that everything is o.kEngine may be paralleled as followsEnsure the voltage of the machine to be paralleled is the same as the bus bar voltage. Ensure the frequencies of both machine are same (the frequency of the incoming machine can be adjusted using the speed control)Select the machine to tbe paralleled on the synchroscope selector. The synchroscope should then start to rotate; it should be rotating in a clockwise 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 control.When the needle of the synchroscope is rotating in the clockwise direction slowly, the breaker of the incoming machine should be closed.When the needle of the synchroscope is at the5 to 12position, this will allow the incoming machine to take a slight amount of load when coming on the switch board and also prevent the machine tripping on reverse powerWhat is the purpose of volute casing in a turbocharger?To change the air velocity into pressure.It also ensures a constant velocity of air leaving the turbocharger by accommodating for the gradual increase in quantity of air that builds up at the circumference of the compressorHow is the j.c.w. temp controlled?It is controlled by means of a thermostatic valve normally known as an AMOT VALVE. This operates by diverting j.w. through the cooler when too hot or by passing the cooler when cooler. The amot valves normally use wax elements to operate the valveWhat are the reasons for not enough scavenge/charge air?Blocked air filter on turbocharger or a faulty turbochargerGive a shipboard use for grey cast iron and the properties that make it suitable for this use?fresh water pump casingsIt has fairly good machining qualities and is also inexpensiveWhat would you do if l.o temp started to fall?Reduce S.W. cooling flow through the l.o cooler by throttling the S.W. discharge valve from the coolerWhat types of water tests would you do on a l.p. auxiliary boiler/economizer?1. Chloride test2. PH_- alkalinity test3. Total dissolved solids test _ using hydrometer4. Phenolphthalein alkalinity test5. Hardness test6. Phosphate reserveWhat is the difference between clarifier 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 clarifiedWhat is the purpose of a fusible plug on an air receiver and at what temp is it designed to melt?The purpose of fusible plug is to act as a safety feature to release compressed air from the receiver in the event of a fire in the vicinity.The fusible plug is designed to melt a t 121 deg centWhat would cause excessive 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 valve. If all exhaust temps were high, it could be due to high scavenge temp, charge air cooler fouled, turbocharger air filters dirty or fouled, high engine loadGive a shipboard use of al.bronze and the properties that make it suitable for this use?Pump impellersIt has good wear, fatigue and corrosive propertiesWhere on board a ship would you find information on the carriage of hazardous substances?Information on the carriage of hazardous substances would be found in the IMDG (International Maritime Dangerous Goods Code) which would normally be found on the bridge.What are the crankcase pressure relief valves for?These valves act as a safeguard to relieve excessive crankcase pressures, which may occur from oil vapor 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 of atmospheric air into the crankcaseWhat would you do if you found that you had a cracked liner or cylinder head?Inform bridge that engine would have to be stopped and of the situation, also inform chief engineer and repair the unit as soon as it is safe to do soWhy purge the boiler furnace?A boiler furnace is purged before burner operations to ensure that there is no unburned fuel or gases in the furnace, which may cause a blow back. Purging should be carried out for at least two minutesGive a rough indication of engine speed ranges i.e., slow, medium and high speedSlow100 150 rpmMedium300 850 rpmHigh850 3000 rpmWhat is uniflow scavenging?With uniflow scavenging the incoming air enters at the lower end of the cylinder and leaves at the top. The outlet at the top of the cylinder being a large exhaust valve. The advantages of uniflow is the simple design of the liner and it is the most efficientWhat is the critical 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 ofof critical speed are known as flank stresses this is known as the barred speed range. The engine must not be continuously operated at speeds within the barred rangeHow does generator l.o.copewith 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 of the quantity of alkali, i.e., base, which is available to neutralize acids from blow by)Why is a j.c.w. Safety valve fitted on air compressor?It is fitted to relieve excess pressure in the cooling system should a cooler tube burst and compressed air escapeGive a ship board use of spheroidal cast iron and the properties that make it suitable for this use?Cylinder heads and linersIt has high compressive strength qualities and also good wears resistive qualitiesHow many PPMS can be pumped in other than Marpol restricted areas?15 PPMWhat are the Marpol restricted 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 seaName the 2 most common types of coolersShell and plate type coolersShell being where a tube stack is used and fitted into a shell and closed at either end with end coversPlate being made up of a number of pressed plates surrounded by seals and held together in a frameWhy is gear pump used for pumping oil, while a centrifugal pump is used for pumping water?A gear pump is used for pumping oil as it has a high suction lift, is self priming, able to produce the discharge pressure required by the system and can handle large amounts of vapor or entrained gases. If is also able to pump high viscous fluidsA centrifugal pump is used for pumping water, as it is unable to pump high viscous fluids such as oil; the centrifugal pump is not self primingWhat should you do to ensure that there is no water leakage into the engine cylinder before preparing main engine for se?The engine should be turned using turning gear with indicator cocks open, keeping a close eye on the cocks for any sign of water dischargeImmediately prior to starting, the engine should be kicked on airNote: 2 stroke engines should be turned at least one revolution where a 4 stroke should be turned 2 revolutionsExplain your companys bunkering procedures?Most companies will have bunkering procedures which will consists of a check list containing procedures such asEnsure vessel is securely mooredScuppers are pluggedThere are communications between both partiesNo smoking signs placedNo hot work is taking place in the vicinityOil spill gear is availableCorrect valves are opened for bunkeringThe overflow tank is emptyThis check list is then signed by both parties and the chief engineerThe time of bunkers starting and finishing are then recordedThe amount to each tankPlace of bunkeringType of F.O. bunkered, this is also recorded in the Oil Record BookNote: before bunkering a set of sounding should be taken, also during bunkering to ensure fuel is going to correct tanks and at the end of bunkeringSample of fuel bunkered should be taken throughout bunkering for analysisWhat are the uses of centrifugal pumps, positive displacement pumps and gear pumps on board a ship?Centrifugal pumpss.w.cooling pumps,j.c.w. pumps, boiler feed pumps (multistage pumps)Positive displacement pumpsbilge pumps. steering gear pumps, cargo pumpsGear pumpsf.o.booster pumps, f.o.transfer pumpsWhat would happen if the l.o.pr dropped too low on a pump?If the l.o.pr were to drop too low on the l.o.pump, the stand by l.o.pump would cut inWhat is loop scavenging in a 2 stroke engine?It is where the incoming air passes over the piston, crown, and then rises towards the cylinder head forcing exhaust gases down and out the exhaust ports, just above the inlet port. The advantage of loop is that no exhaust valve is requiredWhat type of safety valve is fitted to a boiler and at what pressure does it lift?High lift safety valve 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 surveyor.Note: the above test is known as the accumulation of pr testGive possible reasons why the engine room bilge pump may not be able to empty bilges?The strum box from the bilge may be fouled. Bilge pump suction filter may be blockedA valve may be left open from an empty bilgeThere could be a hole in the system on the suction side of the pumpDepending on type of bilge pump, the pump suction or discharge valves may need overhaulingSAFETYWhat is the purpose of the deck seal on an inert gas system?To act as a non return valve and prevent the back flow of gases, i.e., hazardous to non hazardousRegarding the energy bilge injection valve what is its relevant size compared to the main S.W. injection valve?The valve size of the emergency bilge injection must not be less than two third the size of the main S.W. injection valveWhat safety equipment should there be at a bunker station?A foam fire extinguisher, oil spill gear, such as spill absorbent and there should also be communication of some sortWhat is regarded as an enclosed 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 etcWhat is the duration of 9 liters foam fire extinguishers?Approximate duration of around 50 secondsOnce a fire detector has detected or sensed a fire, what happens?Associated with fire detectors is a circuit connected to an alarm panel, which is usually situated on the bridge, 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 alarmWhere would you find heat detector and why?In places such as the galley, where other types of detectors would give false alarms.What are boundary cooling and the reasons for it? it should be remembered that a fire exists 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 boundarycooling of all sides of the compartment on fire, using water spray hosesExplain the procedure for lowering a life boat with gravity davits?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 boat 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 releasedA painter is then led from the forward end of the life boat and attached somewhere forward of the life boat on the ship. Life boat plugs are then securedOnce the crews are on board the life boat the browsing lines are released and the life boat is lowered to the water.The engine is started, falls released and then the painterOn what type of fire would you use a dry chemical powder fire extinguisher?On all classes of fire, but it has no cooling effectHow is water hammer prevented?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 previously opened. The valve may then be opened and drains closed.How do you 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 either. 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 could be a diesel engine or from the emergency switch boardWhat should be used with breathing apparatus sets when entering a space or compartment?A time in/ time out board should be used. This board will normally have a built in clock. On this board 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 exit.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 rays to pass and be focused upon the cell. The signal from the cell goes into the selective amplifier, which is tuned to 25Hz, then to a time delay unit (to minimize incidence of flame alarms) then to an alarm circuit.What is a good practice before using a dry chemical powder 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 upWhat is done to ensure that a life boat engine will start when needed?At least once every2 weeks, but better still once a week the life boat engine should be run, all fuel and oil levels checked and the gear box should be operated i.e., engine run astern and ahead to check operationMost engines are air cooled, but some are a combination of air and water, in which case water level checked and if operating in cold climates anti freezing levels also.Larger life boat engines will be battery started, therefore condition of battery must be checked i.e, specific gravity of electrolyte and that electrolyte is covering 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. Cylinders usually being 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, which will only supply air as the wearer demands. A non return valve permits breathing out to atmosphere.The set incorporates a warming whistle that sounds on low air prA standard cylinder will allow for about 20 25 mins. Operatrion, but this will also depend on a few factors, such as work 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 CO2with very small oxygen content. The exhaust gases pass to a cooling and washing chamber to remove sulphur and excess carbon.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 cargo during discharging operations. Empty tanks are filled with gas and inert gas is blown out when oil 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 excess carbon being removed. The gas which 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 valve along deck pipes to cargo banks. The inert gas being used to blanket the oil cargo during discharging operations, empty tanks are filled with gas and the inert gas is blown out when oil is loaded.What are the safety features fitted to a battery carbon dioxide system?A stop valve to stop discharge of carbon dioxide to the machinery space. A safety valve between the starting cylinders and operating piston. This is to prevent operation o f the system due to leaking starting bottlesPr alarm in discharge line to give an indication of an accident escape or leaking carbon dioxide bottle from the batteryThe 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 you 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 process. Oil drums are not a pressure vessel and it could lead to a fatalityOn what type of vessel would you expect to find a bulk carbon di oxide system and what is normally incorporated into these systems?You would normally expect to find a bulk carbon dioxide system 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 detected by personnel on watch.The location of the fire can be identified in the cabinet and the hold distribution valve below the cabinet is operated. This valve shuts off the sampling pipe from the cabinet and opens it to the carbon di oxide 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 valve to the manifold setting off carbon dioxide alarmsWhat is the gas analysis after the scrubber tower on an inert gas system?OXYGEN0 - 1%CARBON MONOOXIDE0%CARBON DIOXIDE14 - 15%NITROGEN85%Where is carbon dioxide extinguishers not permitted?In the living quarters of the accommodationNote: within the accommodation block carbon di oxide extinguishers are available in the cargo control room, bridge and radio room where dry powder could damage this apparatus.What advantage do inert gas producing units used for fire fighting installations have over carbon dioxide and halon systems?It has the advantage of being able to continuously produce inert gas. A bottle storage system, such as carbon dioxide or halon flooding is a one shot fire extinguisher which leaves a ship unprotected until further gas supplies can be foundWhat is and where would you 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 located on the bridge.Why is a hydrostatic release 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 inflateWhat 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 strips 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 alarmsSketch and describe a bulk carbon dioxide systemThe 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 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 valve opening of this valve will shut down ventilation and activate 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 have an individual manual valve and as the system is a bulk system and the spaces being discharged to will have different areas, a chart will predetermine how long valve will be opened for to give proper discharge coverage for each spaceFires are classified according to the types of materials which are acting as the source, what are these classifications?CLASSAfires burning wood, glass fiber, upholstery and furnishingsCLASSBfires burning liquids such as l.o and fuelsCLASSCfires burning gas fuels such as LPGCLASSDfires burning combustible materials such as magnesium and aluminiumCLASSEfires burning any of the above materials together with high voltage electricityCarbon dioxide gasblackFoamwhiteWaterredBCFgreenWhat happens to the carbon dioxide system in dry-dock?It must be made inoperableWhy should the boiler not be blown down on 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 surfacesWhat speed does the centrifugal brake on a life boat winch limit the speed of fall of the life boat to?Speed of fall of the life boat to fall faster than 36 meter/ minuteHalon fire fighting system, describe itSketch 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 cap. On depressing the plunger the carbon dioxide gas forces the powder up a discharge tube and out of the discharge nozzle.State the capabilities of ships main fire pumpIt must be capable of supplying water to at least two hoses and nozzles in the ship and they must produce a good jet of water simultaneouslyWhat oxygen level would you regard as safe to enter an enclosed space?20% or aboveSketch and describe a carbon dioxide extinguisherA carbon dioxide extinguisher coinsists of a very 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 leaves the extinguisher and passes through a swivel pipe or hose to a discharge hornWhat are the advantages of halon systems over carbon dioxide systems?Less halon is needed to extinguish a fire than carbon dioxide therefore less storage space is requiredAlso the atmospheric in a halon flooded space is not toxic although does contain some highly irritant gases when extinguishingWhat are the 2 brakes on a life boat 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 boatHow is the bilge injection valve brought into operation?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 not pumped dry as this would cause the sea water pump to loose suctionSketch and describe the mechanical foam type fire extinguisherThe outer container is fitted with water. The central container holds a carbon dioxide charge and a foam solution. 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 uprightWhat is the range of foam fire extinguisher?Roughly 7 meterWhere are the infra red fire detectors best situatedThey are best situated in machinery spaces and boiler rooms, where there is a high risk of fireBriefly explain how high expansion foam is producedBy means of a foam generator, where from foam concentrate and sea water 100 times quantity is achieved. The generator blows air through a net sprayed with foam concentrate and water. The vastly expanded foam is then diverted away to the space to protect. The foam is an insulator ands an absorber of radiant heat; it also excludes oxygen from the fireWhat can be fitted over relief valve vents on a bulk carbon dioxide system to give an indication of leakage?BalloonsSketch and describe the chemical foam type of extinguisherThe main container 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 inverted for the two liquids to mix. Carbon dioxide is produced by the reaction, which pressurizes the container and forces out the foamWhat testing and maintenance is done regarding sodas acid and foam extinguisherThe 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 examined every 3 monthsSketch and explain a foam fire fighting installationHere an automatic foam induction system is shown. The automatic inductor unit ensures the correct mixing of water and foam compound which is then pumped to hydrants, deck or machinery space for use. The foam compound tank is sealed to protect 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 would you expect to find a soda acid fire extinguisher? (Water)Accommodation areasWhat is the procedure for entering an enclosed space?An enclosed space entry permit is required which can only be obtained 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 oxygen meter. (Oxygen analyzer)Another person should remain at the entrance while the person is in the space, to summon 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 available at the entrance to the spaceIf the occupant appears to be in danger the attendant should first raise the alarm but should not enter the space unless equipped with breathing apparatusWhat is the reentry procedure once a machinery space has been flooded with carbon dioxide or halon?Once a carbon dioxide or halon flooding has taken place, the space should be continued to the boundary cooledOnly when the extinguished fire has been left long enough to cool down can the space be reentered. Note: early reentry can lead to reignitionReentry should be done by personnel wearing breathing apparatus taking water spray hoses with them to cool down any hot 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 back into service eWhere the machinery space fire involves electrical equipment then the only dry powder or carbon dioxide extinguishers can be used until the equipment is isolatedWhat is the principle operation of a smoke detector?The above detector of the light scatter type uses a photo cell separated by a barrier from a semiconductor intermittently flashing light source housed in an enclosure whose containment allows smoke but not light inside. When smoke is present in the enclosure, light is scattered around the barrier on the photocell and an alarm is triggered.What are the two types of carbon dioxide fixed installations used on board ships for fire fighting?Batteryand bulk systemHow is a life raft launched?The life raft is simply launched 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 cylinder of carbon dioxide is used the inflate the raft. Life raft must normally be boarded from water level dry if possibleWhat different types of fire fighting foam are there?AFFF-synthetic typeProtein based foams (Oxs blood)Which can be low expansion for use on decks etc for fire fighting or high expansion which can be used in machinery spaces?Fire is the 3 combination factors. What are these?1. a substance that will burn2. a supply of oxygen usually from air3. ignition sourceWhat is the duration and range of a 136 liters trolley foam extinguishers?15 minutes approximately with a range of around 18 metersSketch an auto sprinkler system for the ships accommodation and explain?The sketch shows an auto sprinkler system which provides a network of sprinkler heads throughout protected accommodation zonesThe sprinkler heads in the accommodation both detect and extinguish fires. The sprinkler heads is closed by a quartazoid bulb, which contains a liquid that expands considerably on heating, i.e., in the event of a fire. When excessively heated the liquid expands shatters the bulb and water will issue from the sprinkler heat causes the water to spray out over a large areaThe water is supplied initially from a tank pressurized by compressed air and fresh water. Once the tank pressure falls as a sprinkler head issues water a salt water pump cuts in automatically to maintain the water supply as long as possible. The system is initially charged with freshwater to reduce corrosion effects.What is the water fog based on fire fighting installation?Unlike conventional sprinkler system utilizing water under low pressure in heavy large dia pipes, the water fog extinguishing system operates by using water under very high pressure in small bore pipes. This reduces the weight and volume of the system ands permits easy installation on boardThe water fog system produces micro droplets of water, thus a very large cooling surface is created with only small quantities of water. With this system the amount of water required for successful fire extinguishing is much less than conventional sprinkler systems. This allows for the use of fresh water as the medium. Also with the water fog system, the water fog is propelled into hidden spaces just like halon or carbon dioxide providing the most reliable fire extinguishing.In accommodation areas this system can use a dual purpose nozzle which incorporates a quartazoid bulb for detection and extinguishing. The water fog system is also suitable for engine roomWhat does the opening of the carbon dioxide release cabinet do?It sets off an alarm in the engine room to warn personnel that the release of carbon dioxide is eminent.It also stops all ventilationWhat checks should be carried out on a breathing set before entering a smoke filled compartment?The checks should be carried out,Ensure the bottle is fullCheck operation of low pressure whistle andFace seal check should be carried outWhy is an alarm sounded when carbon dioxide is released into the engine room?An alarm is sounded to inform personnel in the engine room that the release of carbon dioxide is imminent. The type of alarm will be visual and sound different from engine room alarm and general alarm.Carbon dioxide cannot support lifeWhere would you expect to find a dry powder extinguisher?It is usually located near electrical equipment in the machinery space and elsewhere on the shipWhat must the capability of gravity davits be with regards heel of ship?The davits must be able to lower the life boats when the ship is heeled to 15 degree on either sideWould you enter an enclosed space if the oxygen levels were recorded as 19% or below?NoWhat are the alarms fitted to a bulk carbon dioxide system?Low level alarm (loss of 5% volume)High level alarm (increase of contents over 98% volume)Leakage alarm past main discharge valve alarm when main discharge valve is openedWith regards carbon dioxide extinguishers what testing and maintenance is carried out?Being a pressure vessel the carbon dioxide extinguisher is initially tested to 225 bar and after every 10 years and after 2 such tests every 5 yearsCarbon dioxide extinguisher should also be weighed every 6 months to check for leakageWhat can you tell me about halon systems with regards to new installations and existing ones?SOLAS prohibits the installations of new or portable systems in all ships from 1stOctober 1994 and providing existing fixed installations and portable extinguishers remain serviceable and fit to purposes, they may remain in place (ref. mgn80 (AUGUST 1998))What type of detector should be fitted in conjunction with an infra red type fire detector?It should be used in conjunction with a smoke detector to give an early warning of fireWhat are water hammer and its danger?When steam lines are shut down it is possible from various causes for them to fill with water. If steam is allowed to enter a line with water, the steam starts to move the water down the line. The steam in contact with the water eventually condenses and a vacuum is formed causing the water to be pulled back to the valve which has just been opened and striking it with a heavy blow, often fracturing the valve. If the valve with a heavy blow often fracturing the valve. If the valve fractures it may end disastrously with risk of loss of lifeIs the code of safe working practices law?Yes it is lawWhat percentage halon is required to extinguish a fire in a compartment?5%What is the purpose of the 2 sets of relief valves on a bulk carbon dioxide system?the purpose of the 2 sets of relief valves on a bulk carbon dioxide system is that one set being a low pressure set being set at 24.5 bars and designed to relieve excess pressure to atmosphere in the event of over pressure. The high pressure set is at 27 bars and is required to discharge into the compartment this causes a rapid rise in pressure and in theory carbon dioxide will discharge into the compartment extinguishing the fireWhat survival equipment would you expect to find in a life boat?Oars, a boat hook, a compass, distress rockets, first aid equipments, rations and fresh waterWhat does SOLAS stand for?Safety of Life At SeaSketch & describe the battery CO2system?The above system shows a battery CO2system for a machinery space. On opening the release cabinet, this will sound the alarm in the engine room, warning personnel that release is imminent and that they should vacate the engine room. Opening of the cabinet will also stop ventilation. Before release of CO2a head count must be done to see all personnel are accounted for and the machinery space must be sealedWhen the operating handle is pulled this opens a set of CO2starting bottles which in turn supply CO2to operation piston via a safety valve. The piston in turn allows the battery of CO2bottles to be released to the engine room. This is known as a ONE SHOT methodWhat are the requirements of a fixed CO2fire fighting installation?The system must give 40% saturation of the compartment to be filled.85% of the co2charge must be discharged into the compartment within the first 2 minutesOnce a fire detector has detected or sensed a fire what happened?Associated with fire detectors is a circuit connected to an alarm panel, which is usually situated on the bridge, where the alarm is accepted usually there is repeater panel in the ECR. 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 false alarmHow much foam is produced from a 9L foam extinguisher?72L of foamWhat are the advantages of CO2systems compared to halon system?CO2is more environmentally friendly also halon system are being phased outWhat is the bilge injection valve?The bilge injection is a valve that enables the engine room bilges to be pumped out directly over board in the event of an emergency such a flooding. The valve is normally fitted to the end of a branch connection with the main sea water suction line. This enables large main sea water cooling pumps to be used as a bilge pump in an emergencyDescribe and sketch a soda acid extinguisherThe container of the extinguisher holds a sodium bicarbonate solution. The screw on cap contains a plunger mechanism covered by a safety guard. Below the plunger is a glass phial containing sulphuric acid. When the plunger is struck, the glass phial is broken and the acid and sodium bicarbonate mix. The resulting chemical reaction produces CO2gas, which pressurizes the space above the liquid, forcing it out through the internal pipe to the muzzleWhat does AFFF stand for and where would you use the type of extinguisher?AFFF stands for: Aqueous Film Forming Foam.This would be used on class B fires, fires burning liquids such as L.O. and fuelsWhat can you tell me about halon system, with regards to new installations and existing ones?SOLAS prohibits the installation of new or portable system in all ships from 1stOctober 1994 and provides existing fixed installations and portable extinguishers remain serviceable and fit for purposes, they may remain in place (ref: MGN 80 (august 1998)What type of fire detection equipment did you have on board ship?Flame detector, smoke detector and heat detectorWhy are CO2extinguishers not permitted in the accommodation?Because if used in a confined space, it could be lethalWhat action would you take in the event of fire breaking out in the machinery space?If a fire breaks out, the alarm should be raised and the bridge informed immediately. If the ship in port, the local fire authority should be called. If possible an attempt should be made to extinguish or limit the fire by any means of possible (a fire in its first few minutes can usually be readily extinguished)Ventilation fans should be stopped (should stop automatically on activation of fire alarm). Openings to the space should be sealed to reduce the supply of air to the fire and to prevent it spreading. Any fuel lines feeding the fire or threatened by it should be isolated. If practicable, combustible materials adjacent to the fire should be removedAfter the fire as been extinguished precautions should be taken against spontaneous reignitionPersonnel unless wearing SCBA should not reenter a space in which a fire has occurred before it has been fully ventilatedWhat are the 4 principle types of portable fire extinguishers found on board ships?Water Soda acid type extinguishersFoam extinguishersDry powderCO2What advantage do inert gas producing units used for fire fighting installations have over CO2and halon systemInert gas producing units have the advantage of being able to continuously produce inert gas. A bottle storage system such as CO2or halon flooding is a one shot fire extinguisher which leaves a ship unprotected until further gas supplies can be foundWhat are the various cutouts and alarms in a funnel inert gas system high O2level (above 5%)Loss of S.W. pressure /flowFan/blower failureHigh gas temp alarmWhat are the dangers of excessive lubrication in start air compressors?There is a danger that excessive cylinder lubrication in start air compressors could lead to explosions in air start lines/manifolds. Excessive lubrication can lead to carry over with compressed air, being deposited in the receiver then transferred to the air start manifold, where a leaking air start valve may allow hot gases from combustion into the air start manifold, ignite the oil vapour, causing explosionWhat is fitted in a foam or water type fire extinguishers that ensures liquid, not gases comes out on dischargeA dip lobe or internal pipe is fitted in the fire extinguisher which is connected to the extinguisher hose and travels to the bottom of the extinguisherHow is a life raft launched?A life raft simply launched by releasing it from its lashings 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 ant the life raft floats clear. A pressurized cylinder of CO2is used to inflate the raft; life rafts must normally be boarded from water level dry if possibleHow does a foam nozzle work?A foam nozzle works on the venturi principle where air is drawn into the nozzle aerating the foam solution for good quality fire fighting foamWhat type of fire forCO2EXTINGUISHER?Class B&C and electricalWhat is the duration of a 9l foam fire extinguisher?Approximately 50 secondsExplain how the emergency generator starts up in the event of total power failureThe start up of the emergency generator is initiated by an electrical relay which monitors the normal mains power supply. Falling mains frequency or voltage causes the start up relay to operate the generator starting equipment. The prime mover may be electrically cranked for its own 24 v battery and starter motor or air started from its own air reservoir fitted local to the generator engine. A manual start up may also be initiate by push buttons in the main control room and in the emergency generator room. Also when power loss occurs, the breaker feeding the emergency switch board from the main switch board opens. This breaker is interlocked with the emergency generator breaker which is normally open under normal circumstances but in the event of total power failure this breaker will close when the breaker feeding the emergency generator will feed the emergency switch boardName the trips found on a generator circuit breakerOver current, under voltage, reverse powerWhen working on batteries, what precautions should be taken?Ensure the space is well ventilated, do not smoke or use naked lights and also wear protection clothing such as apron, gloves and face shieldWhat is meant by the term type Exp?exp pressurizationThis is where equipment is pressurized to prevent any gases entering equipmentWould you enter an enclosed space if the O2levels were recorded as 19% or below?No

ElectricalWhat is the purpose of the over current protection tripThe purpose of the over current protection trip is to trip the generator in over load situations. The trip is usually set at 150% operating capacity and has a time delay of usually 20 sec. this allows for short periods of overload currents. If also protects against a short circuit in the generatorWhat is done to ensure emergency generator is always available and will startThe system should be checked regularly and operated weekly to ensure its availability if required. Fuel tanks should be kept full, ample cooling water in radiator cooling system and starting equipment should be functional i.e, batteries should be charged fully or air receiver fullDescribe how a self excited a.c.generator would workThe self excited a.c.generator basically consists of a synchronis motor where 3 phase supply is generated an a.c. exciter and a rotary rectifier and a static excitation device. The rotating diodes change a.c. into D.C. for the d.c.excitation current, which is supplied through bushes. The exciter in conjunction with the AVR is used to monitor the correct voltage under load changesHow do you ensure that batteries are always in good working order?Where lead acid batteries are used they require a constant trickle charge, but for both types of batteries a regular charge of up is necessaryCheck state of battery reaching a hydrometer; lead acid specific gravity 1270. Alkaline is 1190 but SB for alkaline batteries does not change much during charge or dischargeEnsure cells are covered with electrolyte if not top up with distilled water. Keep batteries dry and cleanTerminals should be smeared with petroleum jellyHow would you know about earth fault in the system?Finding an earth fault would be by the process of elimination i.e., circuit breakers would be opened and closed until earth fault disappeared, taking care which breaker were being opened and closed as they may be supply essential at the time. It would be good practice to start with places such as the galley and laundry where fault are commonWhat conditions are necessary to parallel two generators?The speed of both machines must be same i.e., the frequency and the voltages must be same in phaseWhat are the causes of single phasing?Single phasing can be caused when one of the three back up fuses blows or if one of the conductor conducts is in open circuitWhat are the advantage and disadvantages of alkaline batteries?The advantages of alkaline batteries are that they retain charge on open circuit and even if discharged, it can be left for long periods without adverse effectsThe disadvantages are that they require a greater number of cells to produce a particular voltageThey are also more expensive than lead acid batteriesWhat is sequential starting?Sequential starting is the automatic starting of essential equipment when power is returned after a power failure, i.e. equipment such a steering gearDescribe how synchronizing lamps are sued to parallel a generatorThis is normally used as a back up alternative way to the synchroscope; the lamps are connected between the incoming generator and the bus barsThe sequence method is the most preferred one as it displays a rotation of lamp brightness, which indicates whether the incoming machine is running fast (clockwise) or slow (anticlockwise). As with the synchroscope the lamp sequence must appear to rotate slowly clockwise. Correct synchrosnisation occurs when the top or keys lamp is dark and the two bottom lamps are equally brightWhat gas is given off by batteries while chargingHydrogenDraw a star 3 phase connectionWhat are the two main types of batteries commonly used on board shipsLead acid and alkalineWhat is meant by preference trippingPreference tripping is the tripping of non essential load when an overload condition occurs on a generator. If a generator overload develops the preference trip relay operates an alarm and acts to trip selected non essential loads. These load may trip at set intervals depending on how essential the .load first trip 5 sec, second trip 10 secWhat arte the essentials supplied by the emergency switch boardEssentials are emergency lighting, alarm, communication, water tight doors and other services necessary to maintain safety and to permit safe evacuation of the ship by life boats. Also you will find a steering gear motor, emergency air start compressor, and emergency fire pump motor are supplied from the emergency switch boardDescribe how an ac motor worksMost ac motors on ships and the induction or squirrel cage motor types, the principle of operation for which is as follows. The starter is made up of 3 separately phased windings, to which a 3 phase supply is connected. The rotor has a series of copper conductors along its axis, which are joined by rings at the ends to form a cage. When the motor is started, the rotating magnetic field induces an EMF in the cage and thus a current flow. The current carrying conductor in a magnetic field produces the motor effect, which turns the rotor. The motor speed builds up to a value just less than the speed of rotation of the magnetic field. The motor speed depends upon the EMF induced in the rotor and this depends upon the difference in speed between the conductors and the magnetic fieldThe number of different fixed speeds is possible by changing the number of poles (conductors)What would you do if you found an engineer in electric shock?First raise alarm then isolate or switch off the current. If this is not possible, pull or push the victim away from the source, taking care not to make electrical contact with the victim or the electrical source, i.e., use something non conductiveOnce the victim has been removed from the electrical source if the breathing is feasible or ceased artificial respiration should be started at once. Delay on starting artificial respiration can prove fatalNote: if artificial respiration is started once 70% of the victims recover. If there is 3 minutes delay only 20% of the victims recoverWhat is the AVR?The function of the AVR is to regulate the exciter fields current automatically, comparing the generator terminal voltage with the standard set voltage and thus maintaining the generator terminal voltage to a constant value regardless of load changesWhat loads are considered as non essentials?Loads considered as non essentials are air conditioning and ventilation, laundry, galley, refrigeration and deck equipmentWhat is single phasing of motor?Single phasing is where are the 3 phases supplying the motor becomes disconnected. The motor will continue to run it this happens and can result in motor burnout. The effect of single phasing is to increase the current in the two remaining lines and cause the motor to become very noisy due to uneven torque producedName the trips found in a generator circuit breakerOver currentUnder voltageReverse powerExplain regulation regarding power supply for steering gearThe electr