A L L A B O U T M A R I N E E N G I N N E R I N G GENERAL ENGINEERING KNOWLEDGE
What interlocks are there on the start air system? An interlock to prevent fuel being injected An 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? tainless steel could be used for sea!ater pump shafts. "t has good corrosive properties. What are the differences bet!een cross head and trunk piston engines? What are the impurities in heavy fuel oil? "mpurities in #.$.%. #.$.%. come in the form of solids and li&uids. olids'''''''dirt, rust, and sand. (i&uids''''' !ater and sludge What is the safety devices fitted to an air compressor? (o! (.%.pressure shutdo!n #igh air temperature shutdo!n $irst stage relief valve
econd stage relief valve A fusible fusible plug is fitted after the second stage cooler, set at )*+ deg cents "f !ater cooled, a jacket !ater safety valve is fitted. -plain heavy fuel oil system from bunker tanks to engine? $uel is pumped from the fuel oil ./.tank via a transfer pump to a $.% $.% sett tank !here it is heated. the $.%purifiers0centrifuges $.%purifiers0centrifuges take suction from the sett tank via purifier heaters, pass through the purifiers, !here any !ater and impurities are removed and passed on to the serv tank !hich also has a set of heating coils. $rom the serv tank the fuel then passes via a flo! meter to the mi-ing tank from !here the booster pumps take suction discharging to the $.%.heaters !here the correct $.%.temp0viscosity achieved for correct fuel combustion in the engine, the fuel then passes through the viscosity regulator !hich controls the heater temp, then on to the $. $.%.filter %.filter 1!hich are heated2 to the fuel pumps then to the fuel injector via double skin0!all high pressure pipe. Any Any surplus fuel returns via regulating valve from the fuel pumps back to the mi-ing tank..%. can also be used in the system and is fed to the system via a 3 !ay valve. 4ote 5 !hen diesel is used, no heating is re&uired. re&uired. #o! is leakage in the high'pressure pipeline bet!een the fuel pump and injector detected? (eakage bet!een the double skin0!all of the high pressure pipe line bet!een the fuel pump and injector injector is detected as this space bet!een bet!een double skin0!alled pipes is led via drain line to a small tank fitted !ith a level alarm. 6ive an e-ample of the density of #.%, (.% and .%?
#.$.%. ''''''''' 78+ kg0cu.m (.% ''''''''' 9:+ kg0cu.m .% ''''''''' 99+ kg0cu.m What is the purpose of the scum valve on a boiler? ;he scum valve on a boiler is connected to a shallo! dish positioned at the normal !ater level of the boiler and enables the blo!ing do!n or removal of scum and impurities from the !ater surface. Why are &uick closing valves fitted in a fuel system and ho! can they fail to operate?
#o! does over speed trip !ork? /y shutting the fuel off to the engine.;here arte various types of trips, mechanical types !hich !ork on the principle of fly !eights, or electrical types !hich !ork on the principle of speed >pick up operating a stop solenoid What fittings !ould you e-pect to find a start air receiver? afety valve, fusible plug, isolation valve to main air start system. , filling valve from compressor, drain valve, valve to control air, valve to !histle, and pressure gauge #o! is the (.%.temp controlled? /y means of a thermostatically controlled valve !hich !ill allo! (.%.to bypass the cooler !hen too cold and divert (.%.through the cooler !hen too hot. Preset !a- elements being incorporated in these valves for this purpose. escribe the duties of a duty engineer?
1. Regularly check and record all pressure and tep !n the eng!ne roo log ". #ay attent!on to read!ngs $or de%!at!on $ro noral part!cular attent!on &e!ng ade to e'haust tep( sca%enge tep and pressures and tur&ocharger r.p. ). Ad*ustents should &e ade $or s.+. Tep( changes to keep correct tep and pressures ,. -hecks should &e ade on the pressure drops across $uel and lu& o!l $!lters to see that they are operat!ng +!th!n reu!red l!!ts.
/. -heck all o!l le%els !n au'!l!ary ach!nery( a!n eng!ne sup le%els( cyl!nder lu&r!cators( tur&ocharger and go%ernors. 0. -heck around all &ear!ngs and crankcase doors us!ng pal o$ hand to $eel $or any !ncreas!ng tep. . ensure that $uel !n the da!ly ser%!ce tanks !s at correct le%els and that !s sludged and dra!ned o$ +ater 2. depend!ng on type o$ pur!$!ers $!tted sludge and dra!n ( check o!l le%el( s!gns o$ %!&rat!on and clean !$ reu!red 3. -arryout all rout!ne ass!gnent as recoended &y eng!ne &u!lders or the copany. 14. At all t!es use s!ght( sell and hear!ng and th!s !s o$ten the $!rst s!gn o$ a $ault de%elop!ng !n the eng!ne roo 11. -heck &!lge le%els( stern gland( a!r start &ottles and a!nta!n correct le%el a and pressures 1". Record and $uel5lu& o!l trans$er and any !rregular!t!es !n log. Why are high and lo! suction fitted on f.o. serv tank? ;he high and lo! suctions are a safety feature to prevent shutdo!n of main engines, generators and boilers due to !ater contamination of the fuel. 4ormally the lo! suction is kept in used if any !ater should find its !ay into the fuel and sevr tank, it !ill gradually separate to!ards the tank bottom !hen it becomes apparent !ater 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 shutdo!n What trips are there on a generator?
(.o.lo! pressure shutdo!n, j.c!.high temp and over speed shutdo!n What steering gear checks !ould u do before setting sail? )2 Prior to a ships departure from any port the steering gear should be tested to ensure the satisfactory operation. ;hese tests should include a2 %peration of main steering gear b2 %peration of au-iliary steering gear or the use of the second pump !hich acts as a au-iliary c2 %peration of the remote control system from the main bridge steering positions d2 %peration of steering gear using the emergency po!er supply e2 ;he rudder angle indicator reading !ith respect to actual rudder angle should be checked f2 ;he alarms fitted to the remote control system and steering gear po!er units should be3 checked for correct operation g2 teering gear header tank levels should be checked.
". 6ur!ng these tests the radar should &e o%es through !ts $ull tra%el !n &oth port and star&oard and the %ar!ous eu!pent !tes( l!nkages etc %!sually !nspected $or daage or +ear. The coun!cat!on syste &et+een &r!dge and steer!ng gear roo should also &e operated 7hat +ould happen !$ the duty eng!neer d!d not report !n a$ter ans+er!ng an alar8 The dead an alar +ould act!%ate +h!ch the duty eng!neer +ould ha%e to accept !n the eng!ne roo( !$ not accepted the
+atch keeper on the &r!dge +ould send soeone to !n%est!gate !$ there +as a pro&le 7hy +ould the &r!dge need to &e !n$ored that the eng!ne !s a&out to &e stopped8 The &r!dge +ould need to &e !n$ored that the eng!ne +as a&out to &e stopped to ensure !t +as na%!gat!onally sa$e to do so.!e not !n &usy sh!pp!ng lanes or near land. 6ra+ a " stroke9t!!ng d!agra :o+ does the tur&ocharger +ork8 The tur&ocharger a!nly cons!sts o$ a tur&!ne and a copressor asse&led as a s!ngle un!t on a sha$t. The e'haust gas $ro the eng!ne $lo+s through a +ater9cooled gas !nlet ;cool!ng $ro eng!ne *.+. syste< to a no==le r!ng( +h!ch d!rects gases at the tur&!ne rotor &ald!ng. Th!s $orce causes a rotor to rotate at h!gh %eloc!ty. The gases lea%!ng %!a a +ater9cooled gas outlet cas!ng to an e'haust p!pe and atosphere. The a!r reu!red $or the d!esel eng!ne !s dra+n !n &y the copressor %!a a co&!ned s!lencer5$!lter. The entry passage a$ter the $!lter !s then d!%!ded onto spl!tters +h!ch pre%ent draught losses and gu!de the a!r to the copressor and d!scharge rad!ally at h!gh %eloc!ty to the d!$$user( +h!ch charges uch o$ the %eloc!ty to pressure. >ro the d!$$user the a!r passes !nto the %olute cas!ng( chang!ng the rest o$ the a!rs k!net!c energy to pressure &e$ore &e!ng d!scharged to the charge a!r cooler and to the eng!ne $or co&ust!on. 7hat +ould happen !$ the l.o.pressure *ust dropped to =ero58 The eng!ne +ould shutdo+n on the lo+ l.o.pressure tr!p.
:o+ !s the s!gnal $ro the &r!dge +hen the hel !s o%ed trans!tted to the hydraul!c ras !n steer!ng $lat58 7hen the hel on the &r!dge !s o%ed( electr!cal !pulses are produced. These !pulses are trans!tted %!a an apl!$!er or control un!t to the steer!ng $lat. In the steer!ng $lat these !pulses are relayed to a ser%o otor ;teleotor< +h!ch dr!%es an ad*ust!ng gear and $loat!ng le%er +h!ch put the steer!ng gear %ar!a&le del!%ery pup on stroke( thus crat!ng hydraul!c pressure !n the syste +h!ch eans the ras( thus o%!ng the t!ller and rudder. The pup !s only reu!red to del!%er o!l +hen the +hel !s o%ed !. e once rudder has atched the hel angle( the control le%er( +!ll put the pup o$$ stroke. :o+ any starts do you reu!re to get $ro a rece!%er +!thout recharg!ng8 On a re%ers!&le eng!ne 1" starts On eng!nes +!th -## propellers 0 starts 7hat !s the a'!u copressed a!r teperature that should lea%e the a!r copressor8 3) deg cent!grade 7hat are the p!pes used $or pup!ng $uel around the sh!p9 protected &y5 ?u!ck clos!ng %al%es999999999+h!ch can &e operated reotely. In ost cases $ro the &r!dge or a reote locat!on $ro the eng!ne roo. 7hat easur!ng de%!ces are there on the cyl!nder head o$ ,9stroke eng!ne8 E'haust teperature pyroeter and *.+. Outlet theroeter.
A$ter str!pp!ng and clean!ng a pur!$!er +hat do you ha%e to ake sure o$ on reasse&ly8 The ark on the &o+l lock r!ng l!nes up +!th the ark on the &o+l. Also !$ %ert!cal sha$t has &een reo%ed that he!ght o$ sha$t !s correct :o+ +ould you check that there +as e'cess +ater !n the sup8 By us!ng +ater $!nd!ng paste 7hat types o$ %al%es are &o!ler $eed check %al%es and +hy8 Non return type %al%es a and are $!tted !n pa!rs one &e!ng the a!n and the other the stand &y or au'!l!ary and they ust g!%e an !nd!cat!on o$ open or closed pos!t!ons. They are o$ non9return type to pre%ent &ack $lo+ o$ &o!ler pressure do+n the $eed l!ne. G!%e a sh!p&oard use o$ cupro n!ckel and the propert!es that ake !t su!ta&le $or th!s use8 :eat e'changer tu&es. It has good corros!%e ual!t!es and %ery good heat trans$er ual!t!es. 7hat !s an !nd!cat!on !n the e'haust gas o$ good co&ust!on8 Grey soke !nd!cated good co&ust!on. 7hat +ould cause a crankcase e'plos!on8 A crankcase e'plos!on could &e caused &y the $orat!on o$ hot spot !.e. the o%erheat!ng o$ a &ear!ng( +h!ch !n turn could cause an o!l !st to &e generated(
. I$ th!s o!l !st !s allo+ed to &u!ld up an e'plos!%e cond!t!on could occur +here the o!l !st can &e !gn!ted &y p!ston &lo+ &y or the hot spot !tsel$. E'pla!n a a!n eng!ne l.o.syste8 l.o. $or an eng!ne !s stored at the &otto o$ a crankcase kno+n as sup or !n a dra!n tank located &eneath the eng!ne. The o!l !s dra+n $ro th!s tank through a stra!ner &y one o$ t+o pups !n parallel( one pup &e!ng on stand &y. The pup d!scharges the o!l !nto one o$ a pa!r o$ $!ne $!lters !t !s then passed through a cooler &e$ore enter!ng the eng!ne and &e!ng d!str!&uted to the %ar!ous &ranches p!pes. The &ranch p!pe $or a part!cular un!t $eed the a!n &ear!ng( $or !nstance. @oe o$ th!s o!l +!ll pass along a dr!lled passage !n the cranksha$t to the &!g end &ear!ng and then up a dr!lled passage !n the connect!ng rod to the gudgeon p!n !n a trunk p!ston eng!ne or a crosshead &ear!ng !n a crosshead &ear!ng. An alar at the end o$ the d!str!&ut!on p!pe ensures that adeuate pressure !s a!nta!ned &y the pup. #up and $!lters are arranged !n dupl!cate +!th one as stand &y. A$ter use !n the) eng!ne the l.o.dra!n &ack to the sup or dra!n tank $or reuse. 7hat l!!t does the departent o$ trade and !ndustry state that the lo+er l!!t o$ $lash po!nt o$ $uel used on&oard sh!p should &e8 04deg cent E'pla!n ho+ +ould you start an a!r copressor and stop !t ;a$ter o%erhaul!ng< 1. -heck o!l le%el !n crankcase. ". Then ensure all dra!ns are open. !ntercooler dra!n and also unloader
). -heck a!r !ntake $!lters !s cleaned ,. Ensure o!l pressure gauge !s open and that a!r pressure gauges !.e. $!rst and second stage are part!ally open to stop gauge $luctuat!on. /. I$ +ater9cooled check %al%es are open and cool!ng !s suppl!ed also check header tank. 0. Bar ach!ne o%er &y hand to see !$ !ts $ree to turn . @tart the ach!ne( check there are no unusual no!ses or %!&rat!on and o!l pressure !s correct. 2. then close dra!ns and unloader 3. I$ all see o.k. run $or )4 !nutes a$ter +h!ch can &e stopped( co%ers reo%ed and &ear!ng checked. I$ o.k. ach!ne can &e started on autoat!c and run 14. To stop the ach!ne( al+ays ake sure the ach!ne !s unloaded and dra!ns opened &e$ore stopp!ng unless autoat!c dra!ns and unloaders are $!tted. 7hat !s the purpose o$ rocker gear on an eng!ne8 To operate the !nlet and e'haust %al%es on the cyl!nder head 7hy does a centr!$ugal cargo pup ha%e a rel!e$ %al%e8 A centr!$ugal cargo pup reu!res a rel!e$ %al%e( as the +ork!ng pressure o$ the pup has to t!e !n +!th the +ork!ng pressure o$ the cargo p!pe +ork. 6ra+ the t!!ng d!agra o$ ,9stroke eng!ne8
-rankcase !nspect!on $reuency( procedure and reasons they are carr!ed out8 The $reuency ay %ary $ro d!$$erent eng!ne anu$acturers &ut !ts roughly around /444 hrs. Also !nspect!on are carr!ed out a$ter any +ork has taken place !n the crankcase #rocedure !s as $ollo+s 1. Reo%e crankcase doors $ro the &oth s!des o$ the eng!ne ". Rel!e$ %al%es can &e checked at the sae t!e as the are o$$ ). Inspect cond!t!on o$ all &olt lock!ng de%!ces( replace any daaged coponents ,. Turn eng!ne o%er us!ng turn!ng gear. EN@URE NO ONE !s !n crankcase +h!le do!ng th!s and that the !nd!cator cocks are open check cond!t!on o$ casha$t dr!%!ng gears. /. @tart a!n l.o.pup and check o!l $lo+ $ro &ear!ngs and p!ston cool!ng parts. -heck $or any leakage $ro !nternal o!l p!pes and galler!es. 0. -heck $or any daage o$ ca sha$t lo&es . -heck $or any e%!dence o$ +ater leakage $ro lo+er cyl!nder l!ner Co r!ngs 2. Replace any daaged crankcase door *o!nts 3. Record any de$ects What is the first indication of leaking e-haust valves?
A rise of e-haust gas temp at the outlet of the valve What instrument measures small changes in crankcase pressure? A manometer What is an indication in the e-haust gas of good combustion? 6rey smoke indicates good combustion "f there !as no !ater in gauge glass after blo!ing do!n? hut do!n the boiler immediately and use easing gear to relieve boiler pressure What procedure does the duty engineer follo! !hen ans!ering an alarm on @? Ans!er alarmB ensure !earing correct clothing before entering engine room 4ever use the ships lift, if fitted use the stairs %nce in the engine room inform bridge Ans!er alarm, rectify problem ;hen inform bridge !hen vacating the engine room What is the diffuser plate in turbo charger? "t is found on the compressor side, it converts the velocity, inetic energy from the compressor into the pressure #o! can e-haust valve leakage be confirmed?
/y taking an indicator card. ;he card should be taken !ith fuel >%4 and >%$$ the unit. "f the valve is leaking, the compression pressure and ma-imum pressure !ill be lo!. #o! many PP can be pumped in marpol restricted areas? )8PP What is the purpose of the cylinder relief valve and operating pressure? "t is designed to relieve pressures in e-cess of )+D E *+Dabove normal ;he operation of this device indicates a fault in the engine !hich should be discovered and corrected immediately What !ould you do in the event of a scavenge fire? "f a scavenge fire !ere to start, the * main objectives are to confine the scavenge fire to the scavenge space and to minimize damage to the engine. "n the event of the fire breaking out, inform bridge that the engine is to be brought to dead slo! ahead and also inform the chief engineer. ;he fuel should be cut off to that particular cylinder. ;he cylinder l.o. should be increased to prevent seizure and !ear. "f fi-ed fire fighting is attached to the scavenge trunking this can be brought into operation, depending on severity of situation. /ut in most cases the fire !ill generally subside !ithin 8 E )8 minutes. %nce the fire is out and navigational circumstances allo! it, the engine must be stopped.
o not open scavenge space doors or crankcase doors before site of fire has cooled do!n. 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. ;he piston rods and cylinder liner should be e-amined for surface blemishes, straightness etc, and the diaphragm glands 1stuffing bo-2 e-amined to ensure that t they are operational and not damaged. Also piston rings should be checked, as blo! by may have been the ignition source of the fire. "f possible the piston head in &uestion should be rene!ed at the earliest possible moment and the damaged unit overhauled. %n engines fitted !ith tie bolts, it may be necessary to retighten the bolts adjacent to the fire. When starting the engine, care must be taken after s!itching on the fuel to the cylinder in &uestion, and that also the cylinder l.o. &uantities are reduced to normal. What causes !hite smoke from combustion ".e., in the e-haust? ;he presence of !ater What is the regulation regarding use of evaporators in shore? vaporators should not be used !ithin *+ miles from shore, due to risk of pollutants being taken into the f.!.system #o! !ould you blo! do!n a boiler gauge glass? Close the !ater and steam cocks on the gauge glass and open the drain
;hen open the steam cock E a strong jet of steam should be seen from the drain. Close the steam cock %pen the !ater cock '' a strong jet of !ater should be observed from the drain Close the !ater cock and then close the drain ;hen open the !ater cock, the !ater !ill rise in the gauge above normal level ;hen open the steam cock, the !ater should then settle do!n, finding its correct level. "f only one inch of !ater !as observed in the gauge glass 1only one gauge glass2 after blo!ing do!n the boiler gauge glass, !hat !ould you do? Feduce firing rate of burner and increase feed !ater flo! to boiler by starting another feed pump. #o! !ould you get !ater in the combustion spaces? $rom cracked e-haust valve gages, cracked cylinder head and liner, fuel contamination via fuel injector and under cooling of the charge0scavenge air What safety devices are fitted to a start air line? 4on return valve, flame traps0arrestors, bursting discs and safety valves What is the importance of > notices? > notices are important as they convey very useful information such as,
Merchant shipping notices (MSNs): !hich !ill only be used to convey mandatory information, !hich must be complied !ith under /ritish legislation Merchant guidance notices (MGNs): !hich !ill provide advice and guidance to relevant parties in order to improve the safety of shipping and of life at sea Marine inor!ation notes (MINs): !hich !ill provide information to as more limited audience such as training establishments or e&uipment manufacturers
What is the correct method of starting and stopping as centrifugal pump? ;he correct !ay to start and stop a centrifugal pump is !ith the discharge valve from the pump closed, i.e. less load on the motor !hen starting and stopping What are the properties of heavy fuel oil? #igh viscosity, long ignition delay i.e., lo! cetane indeWhat !ould 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 passing What are looking !hen you pull a piston? When you pull a piston, you are looking for any damage to the piston cro!n, including cracks, ;he condition of piston rings are checked, plus piston ring grooves, check for any scuffing of piston skirt Check condition of top end bearing, bush and gudgeon pin, p Gplus clearance bet!een pin and bush
Check lubrication bores are clear on under side of piston ra! a boiler gauge glass What !ould you do if you had high j.c.!. temperature? "nform bridge and then reduce engine load and investigate problem !hich could be insufficient flo! through cooler due to fouled cooler or faulty thermostatic valve What !ould be your first indication that there !as !ater in the sumpH0 Iour first indication !ould be from your l.o.puriofier or even possibly from !ater in l.o.tests if done regularly What is cross flo! scavenging? "n cross flo! scavenging, the incoming air is directed up!ards, pushing the e-haust gases before it. ;he e-haust gases then travel do!n and out of the e-haust port. Advantage is no e-haust valve. What safety devices are fitted to the main engine crankcase? -plosion door0relief valves and oil mist detectors. #o! does oil mist detector !ork? ;he oil mist detector uses a photoelectric cell to measure small increases in oil density. A motor driven fan continuously dra!s samples of crankcase oil mist through a measuring tube. An increased meter reading and an alarm !ill result if any crack case sample contains e-cessive mist !hen compared to either clean air or to the other crankcase compartments. ;he rotary valve !hich draces the samples then stops to indicated the suspect crankcase compartment. ;he alarm !ill cause an engine slo!do!n or shut do!n.
#o! is )8 PP reached in an oily !ater separator? )8 ppm is achieved in an oily !ater separator by normally passing through a * stage separator !here in the first stage oil0!ater is passed into the coarse separating compartment. #ere some oil !ill rise to the top of the compartment due to its lo!er density. #eating coils may aid this. ;he remaining oil0!ater !ill flo! do!n into the fine separating compartment and moves slo!ly bet!een catch plates. ore oil !ill separate out onto the underside of these plates and travel out!ards until free !ater 1usually being at )++ppm at this stage2 !ill then pass to the second stage of the separator !hich is filter unit comprising of * filter units. ;he first filter stage removes physical impurities present and promotes some fine separation. ;he second stage filter uses coalescer inserts to achieve the final de'oiling, oil0!ater mi-ture leaving this stage at less than )8 ppm. What could start a scavenge fire? ;he main cause of a scavenge fire is the fouling of scavenge spaces by the blo! by products of incomplete combustion caused by incorrect cylinder lubrication, faulty fuel injection e&uipment, accumulation of such mi-tures in the scavenge space can be set alight by sparks or flame blo! by What !ould prevent !ater rushing out of the boiler, if the gauge glass !ere to break? A ball valve is fitted belo! the gauge glass tube to shut off the !ater What type of clutch is used on an electrical !indlass? A dog clutch What can you do to prevent scavenge fires?
Conscientious maintenance of the engine and regular inspection and cleaning of scavenge air spaces !ill help prevent scavenge fire up What are the symptoms of a scavenge fire? When a scavenge fire has broken out the scavenge air temp and the e-haust temperature of the unit in &uestion !ill considerably and in some cases the turbocharger may start surging. ven hot spots on the scavenge trunking can be found What are the rough l.o pressure on the follo!ing on a * stroke engine? Piston cooling J E : bar Cross headbearing = E 8 bar ain bearing *.8 E 3 bar What percentage of engine speed does the over speed operate at? )+ E )8 D ma-imum speed #o! often the emergency steering is tested? At least once in every 3 months What is the purpose of the crankcase oil mist detector? ;o detect the build up of oil mist in the crankcase generated from a hot spot. ;he detector !ill then give an alarm, either shut do!n or slo! the engine do!n and give and indication of !hich unit the oil mist is generated What procedure !ould you go through before taking over a !atch?
/efore taking over a !atch 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 service #o! is medium speed engine reverse 1!ithout CPP2 "n medium speed diesel engines, reversing is achieved by the use of duplicate cams for the air inlet valves, e-haust 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 ;o engage correct cams for ahead and astern movements the camshaft slides a-ially in its bearings. ;his movement is controlled by the camshaft reversing gear, !hich is normally a servo piston. otion of the piston being directly transmitted to the camshaft. 4ote5 in a slo! speed, only duplicate fuel cams re&uired. What does a positive displacement pump re&uire that a centrifugal pump does not? A relief valve Procedure for handing over a !atch? ;he engineer should not vacate the engine room until his relief arrives #e should ac&uaint the relieving engineer of any abnormal operating conditions that have occurred during the !atch
Any orders from the bridge, recorded in the log book should be pointed out "nstructions from the senior engineer should be passed on Any repairs should be reported together !ith information on any machinery that has been dismantled ;he presence of any other members of ships staff in the engine room should be reported ;he engineer much ascertain that his relief if fit and able before vacating the machinery space What !ould you do in the case of a crankcase e-plosion? When the alarm sounds, the engine speed must be reduced to slo! and permission obtained to stop the engine. "nform chief engineer When an engine has stopped under alarm conditions under no circumstances must any doors or inspection !indo!s be opened %il should continue to be circulated and time allo!ed for the hot spot to cool. ;he early opening of doors could cause an e-plosion due to ingress of air uring cooling do!n period the engine room staff must keep clear of the side of the engine fitted !ith e-plosion doors. After a period of at least *+ minutes, stop l.o.pump, cut off all air and engage turning gear
;he access doors should then be opened and personal must keep clear of possible flames. @nder no circumstances should naked lights be used nor should anyone be permitted to smoke -amination should then take place for any s&ueezed out bearing metal or loose bearing metal in the crankcase #eat discolored metal parts or blistering of paint!ork must be investigated. ;he ceiling of the crankcase and guide bars should also be observed. "f the crankcase is clear, the camshaft drive and main thrust bearing should be inspected for signs of overheating. hould any damage be found, then a permanent repair must be put in hand immediately After repair, lo! should be check for free flo!. ;he engine should then run in i.e, )8 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. 4ote5 varying times have been &uoted for the cooling do!n period and no set rules are available but the longer the time taken, the greater the safety factor What causes blue smoke in combustion i.e. in the e-haust? -cessive l.o.!as being burnt in combustion #o! !ould you kno! an air start valve !as leaking or passing? ;he adjacent start air line for that valve !ould become very hot What !ould happen to the amperes of a centrifugal pump if it !ere !ith the discharge valve shut? ;he amps !ould drop as there !ould be no load on the pump
What causes black smoke from combustion i.e. in the e-haust? /lack smoke !ould indicate faulty fuel injection e&uipment or it !ould indicate insufficient air supply What !ould you do the j.c.!.temperature started to rise? "nform bridge and reduce load on engine, investigate problem, !hich !ould be a fouled cooler #o! is fuel supplied from fuel pump to the injector? ;hrough double !all0skin high pressure pipes What preventive mai7ntenece should be fre&uently done to diesel engine start air receiver? ;hey should be drained of accumulated moisture 4ame main engine shut do!ns (o! l.o.pressure #igh j.c.!. temperature #igh main bearing temperature %ver speed and %il mist detector What is the pressure bet!een the fuel injector and fuel pump? *8+ E 38+ bar Why is overlap necessary on air start valves?
%verlap is necessary as if there !as no overlap it !ould be possible for the engine to stop in a position !here no valves are open i.e. unable to start $.!.supplied for drinking and culinary purposes must meet specified purity standards. #o! is this achieved? ;hese standards are met by passing the fe!. ;hrough as hydrochorinator !here the !ater is sterilized by an e-cess dose of chlorine provides as hypochlorite tablets. "t is then dechlorinated in a bed of activated carbon to remove e-cess chlorine. Any color, taste and odour !hich !as present in the !ater, !ill also be removed by the carbon. Another method is to pass the f.!. through an ultraviolet. escribe the different types of cooling systems i.e. s.!. cooling system and central cooling system A .W. cooling system is an arrangement that uses individual coolers for l.o, j.! and the piston c.!. system. ach cooler being circulated by s.! As !here some modern ships use a central cooling system !ith only one large .W. circulated cooler. ;his cools a supply of f.!. !hich then circulates to the other individual coolers. With less e&uipment in contact !ith s.!, the corrosion problems are much reduced in this system. Why carry out boiler feed !ater tests? ;o prevent and detect contamination of the feed !ater i.e, a build up of scale occurring, !hich could reduce boiler efficiency and can cause serious overheating. Also to prevent corrosion Prevent carryover !here soluble salts and suspended solids are carried over !ith steam
#o! many pumps are there in the engine room that you can pump bilges !ith? A bilge pump !hich is normally positive displacement. ;he others may vary from ship to ship but can be the ballast pump, g.s.pump and main .W. pump. ;hese pumps are only used for pumping bilges in the event of emergency and have an emergency bilge suction0injection valve connected to them What could cause an e-cessive high pressure in a refrigeration system? #igh pressure could be caused by lack of cooling or a fouled condenser or even overcharge, but this is unlikely What !ould you do in the event of oil spill? Faise the alarm, inform bridge and chief engineer ;here should be a set drill for oil spills, !hich is practiced regularly "f possible contain the spill on deck and start clean up procedures using appropriate oil spill e&uipment "f the oil has split into the sea5 if in port, port authorities should be informed. "f at sea5 coast guard should be informed. ;he time of spill should be recorded !ith the place or position of ship at the time of spill along !ith appro-imate &uantity and type of oil Circumstances of discharge or escape !ould be logged in oil record book and engine room log book What types of pumps are used for pumping bilges in an emergency? #igh capacity centrifugal pumps 1mostly main cooling s.!.pump2
What !ould you do if you had a high chloride level in the boiler? ;o reduce the chloride level in the boiler the boiler !ould be blo!n do!n, thus allo!ing fresh feed to the boiler What are the normal j.c.! temperatures and pressures? 4ormal j.c.!. pressures are bet!een *' 3 bar ;emperatures :+ E 9+ deg cent Alarm at 98 deg cent hutdo!n at 7+deg cent escribe the boiler hot !ell and cascade tank. Why is it fitted and ho! !ould you trace an oil leak? ;he boiler hot !ell is !here the condensate drains return from the condenser. ;his condensate may be contaminated as some of the drains are from f.o.heating systems or tank heating system. 4ormally these drains !ill pass to the hot !ell via an observation tank, !hich permits inspection of drain and their discharge to an oily bilge if contaminated. ;he hot !ell tank is also arranged !ith internal baffles to bring about preliminary oil separation from any contaminated fuel or drains. ;he feed !ater is then passed through charcoal or cloth filters to complete the cleaning process. Any overflo! from the hot !ell passes to the feed !ater tank !hich provides additional feed !ater to the system !hen re&uired. $eed pumps take suction from the hot !ell to the boiler. ;o trace an oil leak to the system, various heating coils to tanks !ould be shut off in turn until the leak stopped, thus indicating !hich heating coil !as leaking. What is the pressure of a start air receiver?
*8 E =+ bar depending on the type of engine #o! do you purify h.f.o? #eavy fuel oils purified using a centrifugal separator, !hich operated by the principle of centrifugal force separating * li&uids in this case fuel oil and !ater by means of a cylindrical interface bet!een the t!o. ;he positioning of this interface being very important for the correct operation #o! !ould you prepare a main engine for sea? ;his may vary from engine to engine #ave a visual check all around the engine tart the engine l.o.pumpB engage turning gear and turn the engine ensuring indicator cocks are open K.c.!. heating should be on ensuring the engine is !armed through circulate by a circulating pump ;he $.%. booster pump should be running, circulating fuel around the system. 4ote5 if maneuvering on high viscosity $.%. the fuel should be heated and circulated around the injectors to give the correct viscosity for the grade of the fuel in use. nsure fuel injectors are vented and primed. rain any !ater from air start receivers and starting air manifold also control system Check jacket heater tank level Check oil levels, sump, governor, turbocharger, cylinder l.o.tank, rocker arm if on = stroke.
%perate cylinder lubricators by hand Check f.o.service tank i.e., drain off !ater0sludge isengage turning gear "nform bridge that you are about to blo! the engine over on air E they !ill give you permission. %pen air start valve from receiver %nce engine is blo!n over on air, close indicator cocks start j.c.! pumps, shut off jacket heating and circulating pump "f t!o stroke engine, start au-iliary blo!er "nform bridge you are ready to start engine tart engine and s.! .cooling pump #ave a good visual check around the engine and check all parameters are correct "nform bridge that you are ready for stand by Why is simultaneous injection of f.o and starting air into main engine cylinder undesirable and ho! it is prevented? As it could lead to an e-plosion in the start air system "t is prevented by means of interlock, !hich prevents fuel being injected !hen the air start auto valve is open. ;he interlock operated a stop solenoid, !hich keeps the fuel rack to zero position What is the primary function of e-pansion valve in refrigeration system? ;o regulate the flo! of refrigerant from the high pressure side to the lo! pressure side of the system
;he pressure drop causes the saturation temperature to drop enabling it to boil off at the lo! temp of the evaporator #o! !ould you kno! a refrigeration system !as undercharged? @ndercharge !ill sho! as a lo! compressor pressure and large bubbles in the li&uid line sight glass What is compression C%PF?
and
e-plain
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Compression is !here the air that is dra!n into the cylinder is compressed on the up!ard stroke of the piston both inlet and e-haust valves being closed on this stroke. As the air is compressed by the rise of the piston the air temp is conse&uently raised. As the piston reaches the ;C fuel is injected causing ignition and very rapid rise in pressure of the gases forcing the piston do!n What action !ould you take in the event of the main engine oil sump level rising? What could be the problem and ho! !ould you fi- it? ;he action to be taken !ould depend on ho! fast the level !as rising and !hat !as causing it to rise. "t could be due to !ater or fuel entering the sump, the engine !ould have to be stopped as soon as it !as safe to do so ;ests should be carried out to tell if tit !ere !ater or fuel "f it !ere fuel, you can normally smell this in the oil, but a flo! stick test can be done Water has a tendency to form the color of the oil, depending on e-tent of contamination
"f it !ere fuel the most likely cause !ould be faulty injector therefore it !ould be changed "t !ere !ater it could be coming from cracked liner or liner >% rings, therefore possible liner change to solve the problem ;he oil may have to be changed depending on e-tent of contamination but the l.o purifier may be able to cope !ith it #o! !ould you kno! if you had a cracked liner or cylinder head? Iour jacket !ater header tank !ould start to fall. Possibly higher temperatures on the unit %n a medium speed = stroke engine if the liner !as cracked you !ould get !ater contamination of the sump %n a * stroke engine there !ould be possible !ater leakage from stuffing bo- drains. -plain the bilge system from bilge !ells to overboard? #o! !ould you test for a leaking air start valve in port? $irst ensure all the engine indicator cocks are open for all cylinders then isolate the air supply to the timing valves, this !ill ensure no pilot air is supplied to the air start valves !hen the auto valve is opened. ;hen operate the auto valve, any air discharge from the indicator cocks !ill indicate a leaking or pass9ing air start valve. #o! do you start up0 and parallel a generator? $irst check engine oil levels such as l.o.sump, turbocharger oil level, governor oil level, rocker arm bank oil level 1if fitted2 Check j..c.!ater header tank level
nsure indicator cocks are open, start up l.o.priming pump then bar engine over 1ensure turning bar is removed2 ick engine on air close indicator cocks tart the engine Check all parameters are correct''' l.o.pressure0temperature, j.c.!. pr0temp Check s.! cooling pr and rocker arm l.o pr Allo! engine to !arm up and !hen satisfied that everything is o.k ngine may be paralleled as follo!s nsure the voltage of the machine to be paralleled is the same as the bus bar voltage. nsure the fre&uencies of both machine are same 1the fre&uency of the incoming machine can be adjusted using the speed control2 elect the machine to tbe paralleled on the synchroscope selector. ;he synchroscope should then start to rotateB it should be rotating in a clock!ise direction slo!ly. "f it is rotating in an anticlock!ise direction, this means the speed of the incoming machine is too slo! or if it is rotating fast clock!ise, 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 clock!ise direction slo!ly, the breaker of the incoming machine should be closed. When the needle of the synchroscope is at the 8 to )* position, this !ill allo! the incoming machine to take a slight amount of load !hen coming on the s!itch board and also prevent the machine tripping on reverse po!er
What is the purpose of volute casing in a turbocharger? ;o change the air velocity into pressure. "t also ensures a constant velocity of air leaving the turbocharger by accommodating for the gradual increase in &uantity of air that builds up at the circumference of the compressor #o! is the j.c.!. temp controlled? "t is controlled by means of a thermostatic valve normally kno!n as an >A%; LA(L. ;his operates by diverting j.!. through the cooler !hen too hot or by passing the cooler !hen cooler. ;he amot valves normally use !a- elements to operate the valve What are the reasons for not enough scavenge0charge air? /locked air filter on turbocharger or a faulty turbocharger 6ive a shipboard use for grey cast iron and the properties that make it suitable for this use?fresh !ater pump casings "t has fairly good machining &ualities and is also ine-pensive What !ould you do if l.o temp started to fall? Feduce .W. cooling flo! through the l.o cooler by throttling the .W. discharge valve from the cooler What types of !ater tests !ould you do on a l.p. au-iliary boiler0economizer? ). Chloride test *. P#M' alkalinity test 3. ;otal dissolved solids test M using hydrometer
=. Phenolphthalein alkalinity test 8. #ardness test J. Phosphate reserve What is the difference bet!een clarifier and purifier? A purifier removes !ater as !here a clarifier removes solid impurities. "n some cases, both are used for separation purposes, firstly the oil is purified, then clarified What is the purpose of a fusible plug on an air receiver and at !hat temp is it designed to melt? ;he 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. ;he fusible plug is designed to melt a t )*) deg cent What !ould cause e-cessive e-haust temp? %n 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 e-haust valve. "f all e-haust temps !ere high, it could be due to high scavenge temp, charge air cooler fouled, turbocharger air filters dirty or fouled, high engine load 6ive a shipboard use of al.bronze and the properties that make it suitable for this use? Pump impellers "t has good !ear, fatigue and corrosive properties Where on board a ship !ould you find information on the carriage of hazardous substances?
"nformation on the carriage of hazardous substances !ould be found in the "6 1"nternational aritime angerous 6oods Code2 !hich !ould normally be found on the bridge. What are the crankcase pressure relief valves for? ;hese valves act as a safeguard to relieve e-cessive crankcase pressures, !hich may occur from oil vapor igniting in the occurrence of an engine component overheating. ;hey also prevent flames from being omitted from the crankcase and must also be self closing to stop the return of atmospheric air into the crankcase What !ould you do if you found that you had a cracked liner or cylinder head? "nform bridge that engine !ould have to be stopped and of the situation, also inform chief engineer and repair the unit as soon as it is safe to do so Why 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, !hich may cause a blo! back. Purging should be carried out for at least t!o minutes 6ive a rough indication of engine speed ranges i.e., slo!, medium and high speed lo! )++ E )8+ rpm edium 3++ E 98+ rpm #igh 98+ E 3+++ rpm What is uniflo! scavenging?
With uniflo! scavenging the incoming air enters at the lo!er end of the cylinder and leaves at the top. ;he outlet at the top of the cylinder being a large e-haust valve. ;he advantages of uniflo! is the simple design of the liner and it is the most efficient What is the critical and barred range of an engine? ;his is !here the speed of an engine in rpm, at !hich the resonant condition occurs, and is referred to as critical speed. ;he high stresses associated !ith 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. ;he unsafe stresses either side of critical speed are kno!n as flank stresses either side of of critical speed are kno!n as flank stresses this is kno!n as the barred speed range. ;he engine must not be continuously operated at speeds !ithin the barred range #o! does generator l.o.cope!ith blo! by? 6enerator l.o. cope !ith blo! by, by having a ;/4 of *+ E 3+ 1;/4 standing for ;otal /ase 4umber !hich is an indication of the &uantity of alkali, i.e., base, !hich is available to neutralize acids from blo! by2 Why is a j.c.!. afety valve fitted on air compressor? "t is fitted to relieve e-cess pressure in the cooling system should a cooler tube burst and compressed air escape 6ive a ship board use of spheroidal cast iron and the properties that make it suitable for this use? Cylinder heads and liners "t has high compressive strength &ualities and also good !ears resistive &ualities
#o! many PP can be pumped in >other than arpol restricted areas? )8 PP What are the arpol restricted area? ;he editerranean sea, /altic sea, /lack sea, Fed sea, 6ulf areas, 4orth sea, Antarctic, !ider Caribbean region including gulf of e-ico and the Caribbean sea 4ame the * most most common types of coolers coolers hell and plate type coolers hell being !here a tube stack is used and fitted into a shell and closed at either end !ith end covers 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 oil, !hile a centrifugal pump is used for pumping !ater? A gear pump is used for pumping oil as it has a high suction lift, is self priming, able to produce the discharge pressure re&uired by the system and can handle large amounts of vapor or entrained gases. "f is also able to pump high viscous fluids A centrifugal pump is used for pumping !ater, as it is unable to pump high viscous fluids such as oilB the centrifugal pump is not self priming What should you do to ensure that there is no !ater leakage into the engine cylinder before preparing main engine for se? ;he engine should be turned using turning gear !ith indicator cocks open, keeping a close eye on the cocks for any sign of !ater discharge discharge
"mmediately prior to starting, the engine should be kicked on air 4ote5 * stroke engines should be turned turned at least one revolution !here !here a = stroke should be turned * revolutions -plain your companys bunkering bunkering procedures? ost companies !ill have bunkering procedures !hich !ill consists of a check list containing procedures such as nsure vessel is securely moored cuppers are plugged ;here are communications bet!een both parties 4o smoking signs placed placed 4o hot !ork is taking taking place in the the vicinity %il spill gear is available Correct valves are opened for bunkering ;he overflo! tank is empty ;his check list is then signed by both parties and the chief engineer ;he time of bunkers starting and finishing are then recorded ;he amount to each tank Place of bunkering ;ype of $.%. bunkered, this is also recorded in the %il Fecord /ook
4ote5 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 bunkering ample amp le of fu fuel el bu bunk nker ered ed sh shou ould ld be ta take ken n th thro roug ugho hout ut bu bunk nker erin ing g fo for r analysis What are the uses of centrifugal pumps, positive displacement pumps and gear pumps on board a ship? Centrifugal pumps s.!.cooling pumps,j.c.!. pumps, boiler feed pumps 1multistage pumps2 Positive displacement pumps bilge pumps. steering gear pumps, cargo pumps 6ear pumps f.o.booster pumps, f.o.transfer pumps What !ould happen if the l.o.pr dropped too lo! on a pump? pu mp? "f the l.o.pr !ere to drop too lo! on the l.o.pump, the stand by l.o.pump !ould cut in What is loop scavenging in a * stroke engine? "t is !here the incoming air passes over the piston, cro!n, and then rises to!a to !ard rdss th thee cy cyli lind nder er he head ad fo forc rcin ing g ee-ha haus ustt ga gase sess do do!n !n an and d ou outt th thee e-haust ports, just above the inlet port. ;he advantage of loop is that no e-haust valve is re&uired What type of safety valve is fitted to a boiler and at !hat pressure does it lift? #igh li #igh lift ft sa safe fety ty va valv lvee s an and d ar aree de desi sign gned ed to op oper erat atee at )+ )+D D bo boil iler er !orking pressure and must also be capable of releasing all the steam the boiler can produce !ithout the pr rising more than )+D over a set
period. )8 min for tank boilers and : minutes for !ater tube. ;he spring pr once set is fi-ed and sealed by a surveyor. 4ote5 the above test is kno!n as the accumulation of pr test 6ive possible reasons !hy the engine room bilge pump may not be able to empty bilges? ;he strum bo- from the bilge may be fouled. /ilge pump suction filter may be blocked A valve may be left open from an empty bilge ;here could be a hole in the system on the suction side of the pump epending on type of bilge pump, the pump suction or discharge valves may need overhauling SA"E#$
What is the purpose of the deck seal on an inert gas system? ;o act as a non return valve and prevent the back flo! of gases, i.e., hazardous to non hazardous Fegarding the energy bilge injection valve !hat is its relevant size compared to the main .W. injection valve? ;he valve size of the emergency bilge injection must not be less than t!o third the size of the main .W. injection valve What safety e&uipment should there be at a bunker station? A foam fire e-tinguisher, oil spill gear, such as spill absorbent and there should also be communication of some sort What is regarded as an enclosed space?
"t is a space that can not be assumed to contain o-ygen. ;here are spaces such as a duct keel, a ./.tank, a coffer dam, boiler etc What is the duration of 7 liters foam fire e-tinguishers? Appro-imate duration of around 8+ seconds %nce a fire detector has detected or sensed a fire, !hat happens? Associated !ith fire detectors is a circuit connected to an alarm panel, !hich is usually situated on the bridge, !here the alarm is accepted, usually there is a repeater panel in the engine control room. ;he panel giving an indication on !hich deck and zone the detector !as activated. omeone !ill then be sent to investigate and verify if it is a fire or a a false alarm Where !ould you find heat detector and !hy? "n places such as the galley, !here other types of detectors !ould give false alarms. What are boundary cooling and the reasons for it? it should be remembered that a fire e-ists in 3 dimensions and therefore has J 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 on fire, using !ater spray hoses -plain the procedure for lo!ering a life boat !ith gravity davits? ;he life boat is held in against a cradle by ropes called gripes and the cradle is secured by pins, !ith the gripes and securing pins 1sometimes kno!n as harbor pins2 are removed and released, the !inch hand brake can be released to enable the cradle to slide do!n and over the ships
side. A >;ricing ' in Pennant 1!ire2 bring the life boat close to the ships side to enable it to be boarded. ;he bro!sing lines !hich fasten to each end of the life boat are then used to hold it into the ships side, the >;ricing E in pennant then being released A painter is then led from the for!ard end of the life boat and attached some!here for!ard of the life boat on the ship. (ife boat plugs are then secured %nce the cre!s are on board the life boat the bro!sing lines are released and the life boat is lo!ered to the !ater. ;he engine is started, falls released and then the painter %n !hat type of fire !ould you use a dry chemical po!der fire e-tinguisher? %n all classes of fire, but it has no cooling effect #o! is >!ater hammer prevented? "n order to prevent !ater hammer it is necessary too open up drains on steam lines bei7ng brought into use. ;he !ater must be completely drained so it leaves the line clear. ;he steam valve is then cracked open so the line is heated and brought up to near !orking temp. Any condensate found during this process drains out of the line via the drains previously opened. ;he valve may then be opened and drains closed. #o! do you carryout a face seal check on a breathing apparatus set? on face mask, tighten straps properly and turn air supply on. ;hen s!itch air supply off and breath in the mask should stick to face. 4ote pr gauge should not drop rapidly either. !itch air supply back on.
tate the regulations regarding the emergency fire pump? "t is to be located remote from the machinery space and !ith independent means of po!er, !hich could be a diesel engine or from the emergency s!itch board What should be used !ith breathing apparatus sets !hen entering a space or compartment? A time in0 time out board should be used. ;his board !ill normally have a built in clock. %n this board the time the !earer enter a space is noted, plus bottle number and pr, the time the !earer is due out is calculated as the time the lo! pr !histle operates at. ;his gives the !earer time to e-it. What is the principle operation of a flame detector? As flame has a characteristic flicker fre&uency of *8 #z, use is made of this fact to trigger an alarm. $lickering radiation from flames reaching the detector lens0filter unit, !hich only allo!s infra red rays to pass and be focused upon the cell. ;he signal from the cell goes into the selective amplifier, !hich is tuned to *8#z, then to a time delay unit 1to minimize incidence of flame alarms2 then to an alarm circuit. What is a good practice before using a dry chemical po!der e-tinguisher0 "t is good practice to give a CP e-tinguisher a shake before use, as the e-tinguisher could have been lying for a !hile causing the po!der to clog up What is done to ensure that a life boat engine !ill start !hen needed? At least once every * !eeks, but better still once a !eek the life boat engine should be run, all fuel and oil levels checked and the gear boshould be operated i.e., engine run astern and ahead to check operation
ost engines are air cooled, but some are a combination of air and !ater, in !hich case !ater level checked and if operating in cold climates anti freezing levels also. (arger life boat engines !ill be battery started, therefore condition of battery must be checked i.e, specific gravity of electrolyte and that electrolyte is covering cell plates. escribe a C/A set? et usually consists of one or t!o cylinders of compressed air kept in a harness, !hich is carried on the back. Cylinders usually being charged to a pressure of around *++ E *=+ bar. ;he high pr air is fed through a reducing valve and then to a demand valve, !hich can be set in positive pr mode, that !ill supply a const demand of air or in demand mode, !hich !ill only supply air as the !earer demands. A non return valve permits breathing out to atmosphere. ;he set incorporates a !arming !histle that sounds on lo! air pr A standard cylinder !ill allo! for about *+ E *8 mins. %peratrion, but this !ill also depend on a fe! factors, such as !ork load of !earer. escribe an inert gas generator? ;he inert gas generator burns fuel in designed &uantities to produce perfect combustion. ;his produces an e-haust gas, !hich is largely nitrogen and C%* !ith very small o-ygen content. ;he e-haust gases pass to a cooling and !ashing chamber to remove sulphur and e-cess carbon. ;he !ashed or scrubbed gas is no! inert and passes to a distribution system for fire fighting. ;he complete unit is arranged to be independently operated in order to supply inert gas for as long as the fuel supply lasts. %n tankers the "6 can be supplied and used to blanket the
oil cargo during discharging operations. mpty tanks are filled !ith gas and inert gas is blo!n out !hen oil is loaded. -plain and sketch a funnel inert gas? "n a boiler funnel inert gas system, e-haust gas is taken from the boiler uptakes and passed through a scrubber to!er !here the gas is cleaned !ith sulphur and e-cess carbon being removed. ;he gas !hich by then is considered inert and mainly contains nitrogen and carbon dio-ide !ith less than 8D o-ygen is then supplied via blo!ers and deck seal !hich acts as a non return valve along deck pipes to cargo banks. ;he inert gas being used to blanket the oil cargo during discharging operations, empty tanks are filled !ith gas and the inert gas is blo!n out !hen oil is loaded. What are the safety features fitted to a battery carbon dio-ide system? A stop valve to stop discharge of carbon dio-ide to the machinery space. A safety valve bet!een the starting cylinders and operating piston. ;his 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 dio-ide bottle from the battery ;he main engine cyl.l.o.tank is empty oil drums are on the main deck beside run do!n pipes to the tank and air is hardy. What do you do? "f need be, the engine should be stopped to allo! filling of the tank. @nder no circumstances should you use the air hose to pressurize the drums to speed up the process. %il drums are not a pressure vessel and it could lead to a fatality %n !hat type of vessel !ould you e-pect to find a bulk carbon di o-ide system and !hat is normally incorporated into these systems?
Iou !ould normally e-pect to find a bulk carbon dio-ide system on a cargo or Fo E Fo type vessel !here hold areas need fire fighting protection and the cargo space system is normally arranged for smoke detection, alarm and carbon dio-ide flooding. mall air sampling pipes from the individual cargo holds are fed into a cabinet on the bridge. Air is dra!n from each hold by a small fan and each pipe is identified for its particular hold. "f smoke is dra!n into the cabinet from one of the holds it !ill set off an alarm. ;he smoke is also passed into the !heel house !here it can be detected by personnel on !atch. ;he location of the fire can be identified in the cabinet and the hold distribution valve belo! the cabinet is operated. ;his valve shuts off the sampling pipe from the cabinet and opens it to the carbon di o-ide main, leading to the bulk carbon dio-ide, 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 dio-ide alarms What is the gas analysis after the scrubber to!er on an inert gas system? %NI64 + ' )D CAF/%4 %4%%N" +D CAF/%4 "%N" )= ' )8D 4";F%64 98D Where is carbon dio-ide e-tinguishers not permitted? "n the living &uarters of the accommodation 4ote5 !ithin the accommodation block carbon di o-ide e-tinguishers are available in the cargo control room, bridge and radio room !here dry po!der could damage this apparatus.
What advantage do inert gas producing units used for fire fighting installations have over carbon dio-ide and halon systems? "t has the advantage of being able to continuously produce inert gas. A bottle storage system, such as carbon dio-ide or halon flooding is a >one shot fire e-tinguisher !hich leaves a ship unprotected until further gas supplies can be found What is and !here !ould you find the international shore connections? ;his is a standard size flange !hich is fitted !ith a suitable coupling for the ships fire hoses. ;he flange is slotted in order to fit any shore side fire main and enable !ater to be brought on board ship lying alongside. @sually located on the bridge. Why is a hydrostatic release unit fitted to a life boat? "n the event of the vessel sinking, the hydrostatic release operates at a predetermined !ater depth, releasing the life raft lashings, allo!ing the life raft to float free and inflate What is the principle operation of a heat detector? ;his type of heat detector uses * bi metallic strips0coils attached to a vertical support bracket. When temp is present the bimetallic strips !ill start to move at a fi-ed temperature. ;he first strip !ill hit a stop, the second strip continuing to move, thus the contact is made and triggers the alarms ketch and describe a bulk carbon dio-ide system ;he system consisting of a large insulated vessel !hich holds carbon dio-ide a !orking pressure of *) bars at around '*+ degree centigrade. ;o maintain this pressure and temperature a refrigeration circuit is re&uired. %ne is stand by the other in operation. As it is essential to maintain pressure in the vessel, a heater is also incorporated. ;he system
!ill discharge into the engine room and hold a main discharge valve opening of this valve !ill shut do!n ventilation and activate the carbon dio-ide alarm, !arning personnel of the imminent discharge of carbon dio-ide, all personnel must then be accounted for and space seated before discharge of carbon dio-ide. With this system, the actual line to the engine room and other spaces !here the carbon dio-ide is discharged to !ill have an individual manual valve and as the system is a bulk system and the spaces being discharged to !ill have different areas, a chart !ill predetermine ho! long valve !ill be opened for to give proper discharge coverage for each space $ires are classified according to the types of materials !hich are acting as the source, !hat are these classifications? C(A A fires burning !ood, glass fiber, upholstery and furnishings C(A / fires burning li&uids such as l.o and fuels C(A C fires burning gas fuels such as (P6 C(A fires burning combustible materials such as magnesium and aluminium C(A fires burning any of the above materials together !ith high voltage electricity Carbon dio-ide gas black $oam !hite Water red /C$ green What happens to the carbon dio-ide system in dry'dock? "t must be made inoperable
Why should the boiler not be blo!n do!n on finding oil contamination? ;he boiler should not be blo!n do!n, as this !ill cover all heating surfaces !ith oil i.e., insulating the tubes, heating surfaces What speed does the centrifugal brake on a life boat !inch limit the speed of fall of the life boat to? peed of fall of the life boat to fall faster than 3J meter0 minute #alon fire fighting system, describe it ketch and describe a dry po!der fire e-tinguisher? ;he outer container containing sodium bicarbonate po!der. A capsule of carbon dio-ide gas is located beneath a plunger mechanism in the central cap. %n depressing the plunger the carbon dio-ide gas forces the po!der up a discharge tube and out of the discharge nozzle. tate the capabilities of ships main fire pump "t must be capable of supplying !ater to at least t!o hoses and nozzles in the ship and they must produce a good jet of !ater simultaneously What o-ygen level !ould you regard as safe to enter an enclosed space? *+D or above ketch and describe a carbon dio-ide e-tinguisher A carbon dio-ide e-tinguisher coinsists of a very strong container that is used to store li&uid carbon dio-ide under pressure. A central tube provides the outlet passage for the carbon dio-ide !hich is released either by a plunger bursting disc or a valve operated trigger. ;he li&uid changes to a gas as it leaves the e-tinguisher and passes through a s!ivel pipe or hose to a discharge horn
What are the advantages of halon systems over carbon dio-ide systems? (ess halon is needed to e-tinguish a fire than carbon dio-ide therefore less storage space is re&uired Also the atmospheric in a halon flooded space is not to-ic although does contain some highly irritant gases !hen e-tinguishing What are the * brakes on a life boat !inch? A centrifugal brake and a !eighted brake kno!n as a >dead mans brake i.e, once you let go of the braking lever, the brake !ill come into action stopping the fall of the life boat #o! is the bilge injection valve brought into operation? ;o 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 lo!ering !ater level in the engine room the sea !ater injection valve or suction valve may be opened slo!ly. ;his should be done in stages so that the tank tops are not pumped dry as this !ould cause the sea !ater pump to loose suction ketch and describe the mechanical foam type fire e-tinguisher ;he outer container is fitted !ith !ater. ;he central container holds a carbon dio-ide charge and a foam solution. A plunger mechanism !ith a safety guard is located above the central container. When the plunger is depressed the carbon dio-ide released and the foam solution and !ater mi-. ;hey are then forced out through a special nozzle, !hich creates the mechanical foam. ;he e-tinguisher has an internal pipe and is operated upright What is the range of foam fire e-tinguisher?
Foughly : meter Where are the infra red fire detectors best situated ;hey are best situated in machinery spaces and boiler rooms, !here there is a high risk of fire /riefly e-plain ho! high e-pansion foam is produced /y means of a foam generator, !here from foam concentrate and sea !ater )++ times &uantity is achieved. ;he generator blo!s air through a net sprayed !ith foam concentrate and !ater. ;he vastly e-panded foam is then diverted a!ay to the space to protect. ;he foam is an insulator ands an absorber of radiant heatB it also e-cludes o-ygen from the fire What can be fitted over relief valve vents on a bulk carbon dio-ide system to give an indication of leakage? /alloons ketch and describe the chemical foam type of e-tinguisher ;he main container is fitted !ith sodium bicarbonate solution and a long inner polythene container is fitted !ith aluminium sulphate. ;he 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. ;he e-tinguisher is the inverted for the t!o li&uids to mi-. Carbon dio-ide is produced by the reaction, !hich pressurizes the container and forces out the foam What testing and maintenance is done regarding sodas acid and foam e-tinguisher ;he e-tinguisher containers are pressure vessels therefore re&uire testing.
Containers are initially tested to *8 bar every year for 8 years and thereafter at = yearly intervals to *+ bars. %n soda type e-tinguishers *+D of contents should be discharged per year and replenished !ith foam type 8+D !here practical the operating mechanism of portable e-tinguishers should be e-amined every 3 months ketch and e-plain a foam fire fighting installation #ere an automatic foam induction system is sho!n. ;he automatic inductor unit ensures the correct mi-ing of !ater and foam compound !hich is then pumped to hydrants, deck or machinery space for use. ;he foam compound tank is sealed to protect the contents from deterioration and has linked compound supply and air vent valves. ;o operate the system, these * linked valves are opened and the fire pump started. $oam mi-ing is carefully metered by the automatic inductor unit. ;he fire pump and compound tank must be located outside the protected space. Where !ould you e-pect to find a soda acid fire e-tinguisher? 1Water2 Accommodation areas What is the procedure for entering an enclosed space? An enclosed space entry permit is re&uired !hich can only be obtained !ith the permission of a responsible officer. ;his permit !ill list the conditions to one met before entry. ;he space should be !ell ventilated before entry takes place, before entry o-ygen levels must be checked using an o-ygen meter. 1%-ygen analyzer2 Another person should remain at the entrance !hile the person is in the space, to summon assistance if necessary and there should also be means of communications arranged bet!een the person !ithin the space and the attendant.
(ifelines and harnesses should be available at the entrance to the space "f the occupant appears to be in danger the attendant should first raise the alarm but should not enter the space unless e&uipped !ith breathing apparatus What is the reentry procedure once a machinery space has been flooded !ith carbon dio-ide or halon? %nce a carbon dio-ide or halon flooding has taken place, the space should be continued to the boundary cooled %nly !hen the e-tinguished fire has been left long enough to cool do!n can the space be reentered. 4ote5 early reentry can lead to reignition Feentry should be done by personnel !earing breathing apparatus taking !ater spray hoses !ith them to cool do!n any hot surfaces. 4ote5 reentry should also take place from the lo!est point remote from the seat of the fire, if possible. Cooling and smoke dispersal are the first priorities to provide an atmosphere in !hich others can operate and gradually bring machinery back into service e Where the machinery space fire involves electrical e&uipment then the only dry po!der or carbon dio-ide e-tinguishers can be used until the e&uipment is isolated What is the principle operation of a smoke detector? ;he 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 !hose containment allo!s 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 t!o types of carbon dio-ide fi-ed installations used on board ships for fire fighting?
/attery and bulk system #o! is a life raft launched? ;he life raft is simply launched by releasing it from its lashing a painter is secured to the ship and the life raft container is thro!n over the side. "nflation takes place automatically the container bursting open and the life raft floats clear. A pressurized cylinder of carbon dio-ide is used the inflate the raft. (ife raft must normally be boarded from !ater level dry if possible What different types of fire fighting foam are there? A$$$ ' synthetic type Protein based foams 1%-s blood2 Which can be lo! e-pansion for use on decks etc for fire fighting or high e-pansion !hich can be used in machinery spaces? $ire is the 3 combination factors. What are these?
1. a su&stance that +!ll &urn ". a supply o$ o'ygen usually $ro a!r ). !gn!t!on source What is the duration and range of a )3J liters trolley foam e-tinguishers? )8 minutes appro-imately !ith a range of around )9 meters ketch an auto sprinkler system for the ships accommodation and e-plain?
;he sketch sho!s an auto sprinkler system !hich provides a net!ork of sprinkler heads throughout protected accommodation zones ;he sprinkler heads in the accommodation both detect and e-tinguish fires. ;he sprinkler heads is closed by a &uartazoid bulb, !hich contains a li&uid that e-pands considerably on heating, i.e., in the event of a fire. When e-cessively heated the li&uid e-pands shatters the bulb and !ater !ill issue from the sprinkler heat causes the !ater to spray out over a large area ;he !ater is supplied initially from a tank pressurized by compressed air and fresh !ater. %nce the tank pressure falls as a sprinkler head issues !ater a salt !ater pump cuts in automatically to maintain the !ater supply as long as possible. ;he system is initially charged !ith fresh!ater to reduce corrosion effects. What is the !ater fog based on fire fighting installation? @nlike conventional sprinkler system utilizing !ater under lo! pressure in heavy large dia pipes, the !ater fog e-tinguishing system operates by using !ater under very high pressure in small bore pipes. ;his reduces the !eight and volume of the system ands permits easy installation on board ;he !ater fog system produces micro droplets of !ater, thus a very large cooling surface is created !ith only small &uantities of !ater. With this system the amount of !ater re&uired for successful fire e-tinguishing is much less than conventional sprinkler systems. ;his allo!s for the use of fresh !ater as the medium. Also !ith the !ater fog system, the !ater fog is propelled into hidden spaces just like halon or carbon dio-ide providing the most reliable fire e-tinguishing. "n accommodation areas this system can use a dual purpose nozzle !hich incorporates a &uartazoid bulb for detection and e-tinguishing. ;he !ater fog system is also suitable for engine room
What does the opening of the carbon dio-ide release cabinet do? "t sets off an alarm in the engine room to !arn personnel that the release of carbon dio-ide is eminent. "t also stops all ventilation What checks should be carried out on a breathing set before entering a smoke filled compartment? ;he checks should be carried out, nsure the bottle is full Check operation of lo! pressure !histle and $ace seal check should be carried out Why is an alarm sounded !hen carbon dio-ide is released into the engine room? An alarm is sounded to inform personnel in the engine room that the release of carbon dio-ide is imminent. ;he type of alarm !ill be visual and sound different from engine room alarm and general alarm. Carbon dio-ide cannot support life Where !ould you e-pect to find a dry po!der e-tinguisher? "t is usually located near electrical e&uipment in the machinery space and else!here on the ship What must the capability of gravity davits be !ith regards heel of ship? ;he davits must be able to lo!er the life boats !hen the ship is heeled to )8 degree on either side
Would you enter an enclosed space if the o-ygen levels !ere recorded as )7D or belo!? 4o What are the alarms fitted to a bulk carbon dio-ide system? (o! level alarm 1loss of 8D volume2 #igh level alarm 1increase of contents over 79D volume2 (eakage alarm past main discharge valve alarm !hen main discharge valve is opened With regards carbon dio-ide e-tinguishers !hat testing and maintenance is carried out? /eing a pressure vessel the carbon dio-ide e-tinguisher is initially tested to **8 bar and after every )+ years and after * such tests every 8 years Carbon dio-ide e-tinguisher should also be !eighed every J months to check for leakage What can you tell me about halon systems !ith regards to ne! installations and e-isting ones? %(A prohibits the installations of ne! or portable systems in all ships from )st %ctober )77= and providing e-isting fi-ed installations and portable e-tinguishers remain serviceable and fit to purposes, they may remain in place 1ref. mgn9+ 1A@6@; )77922 What type of detector should be fitted in conjunction !ith an infra red type fire detector? "t should be used in conjunction !ith a smoke detector to give an early !arning of fire
What are >!ater hammer and its danger? When steam lines are shut do!n it is possible from various causes for them to fill !ith !ater. "f steam is allo!ed to enter a line !ith !ater, the steam starts to move the !ater do!n the line. ;he steam in contact !ith the !ater eventually condenses and a vacuum is formed causing the !ater to be pulled back to the valve !hich has just been opened and striking it !ith a heavy blo!, often fracturing the valve. "f the valve !ith a heavy blo! often fracturing the valve. "f the valve fractures it may end disastrously !ith risk of loss of life "s the code of safe !orking practices la!? Ies it is la! What percentage halon is re&uired to e-tinguish a fire in a compartment? 8D What is the purpose of the * sets of relief valves on a bulk carbon dio-ide system? the purpose of the * sets of relief valves on a bulk carbon dio-ide system is that one set being a lo! pressure set being set at *=.8 bars and designed to relieve e-cess pressure to atmosphere in the event of over pressure. ;he high pressure set is at *: bars and is re&uired to discharge into the compartment this causes a rapid rise in pressure and in theory carbon dio-ide !ill discharge into the compartment e-tinguishing the fire What survival e&uipment !ould you e-pect to find in a life boat? %ars, a boat hook, a compass, distress rockets, first aid e&uipments, rations and fresh !ater What does %(A stand for?
afety of (ife At ea ketch O describe the battery C% * system? ;he above system sho!s a battery C% * system for a machinery space. %n opening the release cabinet, this !ill sound the alarm in the engine room, !arning personnel that release is imminent and that they should vacate the engine room. %pening of the cabinet !ill also stop ventilation. /efore release of C% * a head count must be done to see all personnel are accounted for and the machinery space must be sealed When the operating handle is pulled this opens a set of C% * starting bottles !hich in turn supply C%* to operation piston via a safety valve. ;he piston in turn allo!s the battery of C% * bottles to be released to the engine room. ;his is kno!n as a >%4 #%; method What are the re&uirements of a fi-ed C% * fire fighting installation? ;he system must give =+D saturation of the compartment to be filled. 98D of the co* charge must be discharged into the compartment !ithin the first * minutes %nce a fire detector has detected or sensed a fire !hat happened? Associated !ith fire detectors is a circuit connected to an alarm panel, !hich is usually situated on the bridge, !here the alarm is accepted usually there is repeater panel in the CF. ;he panel giving an indication on !hich deck and zone the detector !as activated. omeone !ill then be sent to investigate and verify if it is a fire or a false alarm #o! much foam is produced from a 7( foam e-tinguisher? :*( of foam What are the advantages of C% * systems compared to halon system?
C%* is more environmentally friendly also halon system are being phased out What is the bilge injection valve? ;he 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. ;he valve is normally fitted to the end of a branch connection !ith the main sea !ater suction line. ;his enables large main sea !ater cooling pumps to be used as a bilge pump in an emergency escribe and sketch a soda acid e-tinguisher ;he container of the e-tinguisher holds a sodium bicarbonate solution. ;he scre! on cap contains a plunger mechanism covered by a safety guard. /elo! 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 mi-. ;he resulting chemical reaction produces C%* gas, !hich pressurizes the space above the li&uid, forcing it out through the internal pipe to the muzzle What does A$$$ stand for and !here !ould you use the type of e-tinguisher? A$$$ stands for5 A&ueous $ilm $orming $oam. ;his !ould be used on class / fires, fires burning li&uids such as (.%. and fuels What can you tell me about halon system, !ith regards to ne! installations and e-isting ones? %(A prohibits the installation of ne! or portable system in all ships from )st %ctober )77= and provides e-isting fi-ed installations and portable e-tinguishers remain serviceable and fit for purposes, they may remain in place 1ref5 64 9+ 1august )7792
What type of fire detection e&uipment did you have on board ship? $lame detector, smoke detector and heat detector Why are C%* e-tinguishers not permitted in the accommodation? /ecause if used in a confined space, it could be lethal What action !ould you take in the event of fire breaking out in the machinery space? "f a fire breaks out, the alarm should be raised and the bridge informed immediately. "f the ship in port, the local fire authority should be called. "f possible an attempt should be made to e-tinguish or limit the fire by any means of possible 1a fire in its first fe! minutes can usually be readily e-tinguished2 Lentilation fans should be stopped 1should stop automatically on activation of fire alarm2. %penings 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. "f practicable, combustible materials adjacent to the fire should be removed After the fire as been e-tinguished precautions should be taken against spontaneous reignition Personnel unless !earing C/A should not reenter a space in !hich a fire has occurred before it has been fully ventilated What are the = principle types of portable fire e-tinguishers found on board ships? Water oda acid type e-tinguishers $oam e-tinguishers
ry po!der C%* What advantage do inert gas producing units used for fire fighting installations have over C% * and halon system "nert gas producing units have the advantage of being able to continuously produce inert gas. A bottle storage system such as C% * or halon flooding is a >one shot fire e-tinguisher !hich leaves a ship unprotected until further gas supplies can be found What are the various cutouts and alarms in a funnel inert gas system high %* level 1above 8D2 (oss of .W. pressure 0flo! $an0blo!er failure #igh gas temp alarm What are the dangers of e-cessive lubrication in start air compressors? ;here is a danger that e-cessive cylinder lubrication in start air compressors could lead to e-plosions in air start lines0manifolds. -cessive lubrication can lead to carry over !ith compressed air, being deposited in the receiver then transferred to the air start manifold, !here a leaking air start valve may allo! hot gases from combustion into the air start manifold, ignite the oil vapour, causing e-plosion What is fitted in a foam or !ater type fire e-tinguishers that ensures li&uid, not gases comes out on discharge A dip lobe or internal pipe is fitted in the fire e-tinguisher !hich is connected to the e-tinguisher hose and travels to the bottom of the e-tinguisher
#o! 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 thro!n over the side. "nflation takes place automatically, the container bursting open ant the life raft floats clear. A pressurized cylinder of C% * is used to inflate the raftB life rafts must normally be boarded from !ater level dry if possible #o! does a foam nozzle !ork? A foam nozzle !orks on the venturi principle !here air is dra!n into the nozzle aerating the foam solution for good &uality fire fighting foam What type of fire for C%* N;"46@"#F? Class /OC and electrical What is the duration of a 7l foam fire e-tinguisher? Appro-imately 8+ seconds -plain ho! the emergency generator starts up in the event of total po!er failure ;he start up of the emergency generator is initiated by an electrical relay !hich monitors the normal mains po!er supply. $alling mains fre&uency or voltage causes the >start up relay to operate the generator starting e&uipment. ;he prime mover may be electrically cranked for its o!n *= v battery and starter motor or air started from its o!n 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 !hen po!er loss occurs, the breaker feeding the emergency s!itch board from the main s!itch board opens. ;his breaker is interlocked !ith the emergency generator breaker !hich is normally open under normal circumstances but in the event of total
po!er failure this breaker !ill close !hen the breaker feeding the emergency generator !ill feed the emergency s!itch board 4ame the trips found on a generator circuit breaker %ver current, under voltage, reverse po!er When !orking on batteries, !hat precautions should be taken? nsure the space is !ell ventilated, do not smoke or use naked lights and also !ear protection clothing such as apron, gloves and face shield What is meant by the term type -p? e-p E pressurization ;his is !here e&uipment is pressurized to prevent any gases entering e&uipment Would you enter an enclosed space if the % * levels !ere recorded as )7D or belo!? 4o
E%ectrica%
What is the purpose of the over current protection trip ;he purpose of the over current protection trip is to trip the generator in over load situations. ;he trip is usually set at )8+D operating capacity
and has a time delay of usually *+ sec. this allo!s for short periods of overload currents. "f also protects against a short circuit in the generator What is done to ensure emergency generator is al!ays available and !ill start ;he system should be checked regularly and operated !eekly to ensure its availability if re&uired. $uel tanks should be kept full, ample cooling !ater in radiator cooling system and starting e&uipment should be functional i.e, batteries should be charged fully or air receiver full escribe ho! a self e-cited a.c.generator !ould !ork ;he self e-cited a.c.generator basically consists of a synchronis motor !here 3 phase supply is generated an a.c. e-citer and a rotary rectifier and a static e-citation device. ;he rotating diodes change a.c. into .C. for the d.c.e-citation current, !hich is supplied through bushes. ;he e-citer in conjunction !ith the ALF is used to monitor the correct voltage under load changes #o! do you ensure that batteries are al!ays in good !orking order? Where lead acid batteries are used they re&uire a constant trickle charge, but for both types of batteries a regular charge of up is necessary Check state of battery reaching a hydrometerB lead acid E specific gravity )*:+. Alkaline is ))7+ but / for alkaline batteries does not change much during charge or discharge nsure cells are covered !ith electrolyte if not top up !ith distilled !ater. eep batteries dry and clean ;erminals should be smeared !ith petroleum jelly #o! !ould you kno! about earth fault in the system?
$inding an earth fault !ould be by the process of elimination i.e., circuit breakers !ould be opened and closed until earth fault disappeared, taking care !hich breaker !ere being opened and closed as they may be supply essential at the time. "t !ould be good practice to start !ith places such as the galley and laundry !here fault are common What conditions are necessary to parallel t!o generators? ;he speed of both machines must be same i.e., the fre&uency and the voltages must be same in phase What are the causes of single phasing? ingle phasing can be caused !hen one of the three back up fuses blo!s or if one of the conductor conducts is in open circuit What are the advantage and disadvantages of alkaline batteries? ;he advantages of alkaline batteries are that they retain charge on open circuit and even if discharged, it can be left for long periods !ithout adverse effects ;he disadvantages are that they re&uire a greater number of cells to produce a particular voltage ;hey are also more e-pensive than lead acid batteries What is se&uential starting? e&uential starting is the automatic starting of essential e&uipment !hen po!er is returned after a po!er failure, i.e. e&uipment such a steering gear escribe ho! synchronizing lamps are sued to parallel a generator
;his is normally used as a back up alternative !ay to the synchroscopeB the lamps are connected bet!een the incoming generator and the bus bars ;he se&uence method is the most preferred one as it displays a rotation of lamp brightness, !hich indicates !hether the incoming machine is running fast 1clock!ise2 or slo! 1anticlock!ise2. As !ith the synchroscope the lamp se&uence must appear to rotate slo!ly clock!ise. Correct synchrosnisation occurs !hen the top or keys lamp is dark and the t!o bottom lamps are e&ually bright What gas is given off by batteries !hile charging #ydrogen ra! a star 3 phase connection What are the t!o main types of batteries commonly used on board ships (ead acid and alkaline What is meant by preference tripping Preference tripping is the tripping of non essential load !hen an overload condition occurs on a generator. "f a generator overload develops the preference trip relay operates an alarm and acts to trip selected non essential loads. ;hese load may trip at set intervals depending on ho! essential the .load first trip 8 sec, second trip )+ sec What arte the essentials supplied by the emergency s!itch board ssentials are emergency lighting, alarm, communication, !ater tight doors and other services necessary to maintain safety and to permit safe evacuation of the ship by life boats. Also you !ill find a steering gear motor, emergency air start compressor, and emergency fire pump motor are supplied from the emergency s!itch board
escribe ho! an ac motor !orks ost ac motors on ships and the induction or s&uirrel cage motor types, the principle of operation for !hich is as follo!s. ;he starter is made up of 3 separately phased !indings, to !hich a 3 phase supply is connected. ;he rotor has a series of copper conductors along its a-is, !hich are joined by rings at the ends to form a cage. When the motor is started, the rotating magnetic field induces an $ in the cage and thus a current flo!. ;he current carrying conductor in a magnetic field produces the motor effect, !hich turns the rotor. ;he motor speed builds up to a value just less than the speed of rotation of the magnetic field. ;he motor speed depends upon the $ induced in the rotor and this depends upon the difference in speed bet!een the conductors and the magnetic field ;he number of different fi-ed speeds is possible by changing the number of poles 1conductors2 What !ould you do if you found an engineer in electric shock? $irst raise alarm then isolate or s!itch off the current. "f this is not possible, pull or push the victim a!ay from the source, taking care not to make electrical contact !ith the victim or the electrical source, i.e., use something non conductive %nce the victim has been removed from the electrical source if the breathing is feasible or ceased artificial respiration should be started at once. elay on starting artificial respiration can prove fatal 4ote5 if artificial respiration is started once :+D of the victims recover. "f there is 3 minutes delay only *+D of the victims recover What is the ALF? ;he function of the ALF is to regulate the e-citer fields current automatically, comparing the generator terminal voltage !ith the
standard set voltage and thus maintaining the generator terminal voltage to a constant value regardless of load changes What loads are considered as non essentials? (oads considered as non essentials are air conditioning and ventilation, laundry, galley, refrigeration and deck e&uipment What is single phasing of motor? ingle phasing is !here are the 3 phases supplying the motor becomes disconnected. ;he motor !ill continue to run it this happens and can result in motor burnout. ;he effect of single phasing is to increase the current in the t!o remaining lines and cause the motor to become very noisy due to uneven tor&ue produced 4ame the trips found in a generator circuit breaker %ver current @nder voltage Feverse po!er -plain regulation regarding po!er supply for steering gear ;he electrical supply must b e from t!o !idely separated supplies i.e., one from the main s!itch board and the other from emergency board lectrical leafs and fuses are allo! )++D over load, giving only short circuit protection "f failure does occur on one system, the standby system !ill cut in !ithin =8 sec ;he steering motor !ill have se&uential starting
What !ould you consider a minimum insulation reading resistance? "nsulation resistance must be kept above at least ) W, the higher the insulation resistance the better, companies have their o!n regulation but most companies only allo! reading above 8 ohms What is meant by the term type -e? -e ' increased safety e&uipment "ncreased safety e&uipment is based primarily on the elimination of >open sparking i.e., e&uipment does not have contacts What is the purpose of the over current protection trip "t is to trip the generator in overload situations. ;he trip i- usually set at )8+D operating capacity and has a time delay of usually *+ sec. this allo!s for short periods of overload currents. "t also protects against a short circuit in the generator What is minimum current can be regarded as fatalB A shock current as lo! as )8 mA ac or dc can be fatal #o! can you reverse the direction of motor? /y s!apping any t!o supply line connections over ra! and e-plain ho! earth lamps !orks A direct earth on one pole coil short circuit its lamp causing the other t!o to shine brightly What is load sharing? "t is e&ual balance of loads bet!een generators irrespective of load changes
When !orking on batteries !hat precautions should be taken? nsure the space is !ell ventilated, do not smoke or use naked lights and also !ear protective clothing such as apron, gloves and face shields What is the normal reading on and insulati+n test meter? "nfinity is normal reading, but reading should be kept above 8 ohms What is meant by protection discrimination? ;his is the ability of a protection system to disconnect only faulty circuits and to maintain the electrical supplies to healthy one iscrimination is advised by coordinating the current ratings and the time settings of the fuses and over current relays used bet!een the generator and the load ;he devices nearest the load having the lo!est current rating and shortest operating timeB these nearest the generator having the highest current rating and the longest operating time i.e., a motor fault on a centrifugal pump !ould not cause the generator breaker to trip What is the term -"? -" E intrinsically safe &uipment !ith circuits that do not generate enough heat to ignite a gas. ;his generally means limiting circuits to less than 3+v. 8+mA ra! a delta 3 phase connection Why do you re&uire earth lamps on **+v distribution board !hen you have them on the main s!itch board?
Iou re&uire earth lamps on the **+v distribution board as !ell the main s!itch board, due to the air gap in step do!n transformer i.e., ==+v earth lamps cannot detect earth on **+v systems due to the gap When !ould a star0delta starter used on a motor Where slo! moving high criteria load obis involves the starting time must be considered because of the heating effect of the starting current and in this case a star0delta starter !ould be used ;he star0delta starter first connects the starter !indings in star and !hen running charges over to delta. ;he star connection results in about 89D line voltage being applied to each phase !ith therefore a reduction in starting current. ;he starting tor&ue reduced to about )03 of its direct on line value What sort of starting current do you get !ith a direct on line starter? J E 9 times full load current What is meant by the terms type -p e-pB ' pressurization ;his is !here e&uipment is pressurized to prevent any gases entering e&uipment What is meant by the term -d -d E flame proof enclosure this is an enclosure that !ill !ithstand an internal e-plosion of flammable gas !ithin itself and dissipate heat from that e-plosion before reaching outside atmosphere, !hich could ignite the gas in surrounding atmosphere i.e., a ships battery locker should be classed as -d What is reverse po!er protection for?
6enerators intended to operate in parallel must have a reverse po!er protection trip. A reverse po!er relay monitors the direction of po!er flo!ing bet!een the generator and the s!itch board "f a prime mover failure occurred the generator !ould act as a motor. ;he reverse po!er relay detects the fault and acts to trip the generator circuit breaker What is the purpose of under voltage trip? "t is fitted to all generator breakers. "ts main function is to trip the breaker !hen severe voltage dip 1around 8+D+. the under voltage trip on a generator circuit breaker also prevents it trip on a generator circuit breaker also prevents it being closed !hen the generator voltage is very lo! or absent What is the function of fuse? ;he function of the fuse is to give short circuit protection and also over load protection and operates in milliseconds -plain !hat !ould happen if you !ere to lose a generator $irst the standby generator set !ould start up and automatically put itself on the board. "f this did not happen, the ship !ould >black out and after a time delay usually 3+ seconds the eme What is the function of a circuit breaker? ;he circuit breaker is an isolating s!itch that also acts as a fuse. "t has t!o designed ratings5 one normal safe !orking current and the other against overload, !hich may also have a time delay What is battery used for an board ships
they are used for supplying essential po!er to radio e&uipment, telephone e-change, fire detection, general alarm circuit etc. these system are after supplied from t!o sets of batteries !orked on a regular charge0discharge cycle they are also used as emergency supplies i.e., emergency generator startup and emergency lighting being used in this case in a >stand by role to give po!er !hen main supplies fail Where on the ship is the emergency generator located ;he emergency generator is located remotely from the engine room, usually on the accommodation in deck or at !eather deck level or above What are disadvantages and advantages of a lead acid battery? ;he advantages of a lead acid battery are they re&uire fe!er cells to achieve particular voltage an d are reasonably priced ;he disadvantages are they re&uire regular attention to keep fully charged, al!ays re&uire a trickle charge and they discharge on open circuit -plain ho! the emergency generator starts up in the event of total po!er failure ;he start up of the emergency generator is initiated by an electrical relay, !hich monitors the normal mains po!er supply. $ailing mains fre&uency or voltage causes the >start up relay to operate the generator starting e&uipment. ;he prime movers may be electrically cranked from its o!n *=v battery and starter motor or air started from its o!n air reservoir filled local to the generator engine. A manual start up may also be initiated by push buttons in the main control room and in the emergency generator room
Also !hen po!er loss occurs, the breaker feeding the emergency s!itch board from the main s!itch board opens. ;his breaker is interlocked !ith the emergency generator breaker, !hich is normally open under normal circumstances, but in the event of total po!er failure, this breaker !ill close !hen the breaker feeding the emergency board from the main board opens. ;hus the emergency generator !ill feed the emergency s!itch board. POSTED BY S AN KE T 19 AT 08:17 NO COMMENTS: POST A COMMENT
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