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During sea trial, the main engine well be kept run at load.
A.100%
B.110%
C.85%
D.different
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更多 “ During sea trial, the main engine well be kept run at load.A.100%B.110%C.85%D.different ” 相关考题
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While sailing in ballast under normal weather and sea condition, the basic parameter which is used to restrict the fuel injection of main engine isA.the exhaust temperatureB.the speed of main engineC.the turbine rotation speedD.the power of main engine
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During the dock repair,______should be measured firstly before tail shaft drawn out.A.the sinking of tail shaftB.the clearance of stern bearingC.the total flexure of shaftD.main engine crankshaft deflection
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Before "stand by" is rung on the engine telegraph, it is usual to give the main diesel engine a brief trial ahead and astern.A.with powerB.on powerC.with airD.on air
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Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?A.Baffle plates that have been bent during prior removalB.Leaks m the cooler tube nestC.Operating the engine while maintaining a high sea water outlet temperatureD.A punctured sea water strainer supplying cooling water to the heat exchanger
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材料：Spark erosion is caused by a voltage discharge between the main bearing and journal surface. The cause of the potential is the development of a galvanic element between the ship’s hull, sea water, and the propeller shaft/crankshaft.The oil film acts as a dielectric. The puncture voltage in the bearing depends on the thickness of the oil film. With increasing engine ratings, the specific load in the main bearing is increased. his will reduce the oil film thickness, and enable the discharge to take place at a lower voltage level.Since the hydrodynamic oil film thickness varies through a rotation cycle, the discharge will take place at roughly the same instant during each rotation cycle, i.e. when the film thickness is at its minimum. The roughening will accordingly be concentrated in certain areas on the journal surface. In the early stages, the roughened areas can resemble pitting erosion. but later, as the roughness increases, the small craters will scrape off and pick up white metal-hence the silvery white appearance.Therefore, to ensure protection against spark erosion, the potential level must be kept at maximum 80 mV, which is feasible today with a high efficiency earthing device. If an earthing device is installed, its effectiveness must be checked regularly. Spark erosion is only observed in main bearings and main bearing journals.问题：According to the paragraph one, a voltage between the main bearing and journal surface is produced by______.A.propeller rotationB.leakage from M/E electric control unitC.a galvanic elementD.friction between the main bearing and journal surface______engine ratings increase, the hydrodynamic oil film between the main bearing and journal surface is______.A.The lower/thinnerB.The higher/the thickerC.The lower/thickerD.The higher/thinnerWhen will the spark erosion take place on the journal surface during each rotation cycle?A.when the film thickness is at its minimumB.when the film thickness is at its maximumC.when the engine is on its compression strokeD.when the engine is on its exhaust strokeDuring the engine room watch keeping, which equipment must be noted to ensure protection against spark erosion?A.the antifouling plantB.the earthing deviceC.the main engine electric heating coilsD.the shaft generator请帮忙给出每个问题的正确答案和分析，谢谢！
考题
单选题The rate of cylinder lubricating oil metered to each cylinder of a large low-speed main propulsion diesel engine is （）A
the same, whether at sea, or during maneuveringB
adjusted during each hour of operation while at constant RPMC
higher at sea than while maneuveringD
lower at sea than while maneuvering
考题
单选题Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?（）A
Baffle plates that have been bent during prior removalB
Leaks in the cooler tube nestC
Operating the engine while maintaining a high sea water outlet temperatureD
A punctured sea water strainer supplying cooling water to the heat exchanger
考题
单选题Under manoeuvring condition the main engine may run on （）.A
gas oilB
marine diesel oilC
residue oilD
crude oil
考题
单选题In modern installations, the main engine and the standby auxiliary engines（）A
can be started at low temperature and are free from preheatingB
usually are preheated by steam before being startedC
are kept at a constant temperature and free from preheatingD
are kept at a low temperature to save energy
考题
单选题The power developed by a large slow-speed main propulsion diesel engine is dependent upon the （）A
quantity of air it takes in and retains in the cylinders during a given time periodB
proportion of trapped air that is utilized in the combustion processC
thermodynamic efficiency of the engine cycleD
all of the above
考题
单选题Why a gearbox is needed in a ship driven by a medium-speed diesel engine?（）A
To reduce the main engine speedB
To increase the main engine speedC
To govern the main engine speedD
To fix the propeller shaft
考题
单选题When ship navigating in rough sea, the first measure taken by the chief engineer to prevent the overload should be（）A
cleaning fuel oil, lubricating oil and seawater filterB
reducing fuel feeding of the main engine appropriately or reducing the pitch angle of propellerC
using low sea chestD
closing the skylight and the ventilation opening, which doesn’t affect the normal work of equipments
考题
单选题Whether a ship is sailing before the wind or sailing in the rough sea, we must reduce the fuel injection of the main engine.For the former one, it aims to prevent the main engine being（）, while for the later one, it aims to prevent the main engine being（）.A
overspeed；overloadB
overload；overspeedC
over torque；overspeedD
low mechanical efficiency；overload
考题
单选题The load limitation of governor should be reduced when ship navigating at sea, the main reason is to（）A
prevent the diesel engine surgingB
prevent governor from being damaged because of swingC
reduce the probability of the crank shaft being torsional vibrated and resonatedD
prevent the main engine being overload or overspeed
考题
单选题During maneuvering operations for a direct reversing large, low-speed, main propulsion diesel engine, which of the following actions is used to stop the shaft from turning prior to reversing the engine rotation?（）A
Flywheel inertiaB
Admission of starting airC
The way of the vesselD
securing of fuel to the cylinders
考题
单选题During the diesel engine running, the water level of FW expansion tank should normally kept in the （） level of glass tube.A
the highestB
above 3/4C
1/2-3/4D
the lowest
考题
单选题A large, low-speed, main propulsion diesel engine uses sea water to directly cool the （）.A
cylinder headsB
exhaust valvesC
scavenging airD
injectors
考题
单选题UMS are mainly unattended overnight and during this time （） should have control of the main engine.A
the chief engineerB
the engineer on cabin watchC
the bridge officer on watchD
the master
考题
单选题During the watch at sea （） should be logged or recorded in the engine log book.A
the running hours of the cooling water pumpB
chief engineer’s orderC
the main parameters of main and auxiliary equipmentD
the position of the vessel
考题
单选题After finished the engine, which of valves cannot be shut off by the duty engineer?（）A
fuel valveB
the starting air valveC
the sea chestD
the main sea pump inlet valve
考题
单选题During the diesel engine running, the water level of F.W expansion tank should normally kept in the （） level of glass tube.A
the highestB
above 3/4C
1/2 -3/4D
the lowest
考题
单选题Before "stand-by" is rung on the engine telegraph, it is usual to give the main engine （） ahead and astern.A
a brief trial with turning gearB
a brief trial on powerC
a long trial by steering gearD
one minutes trial with windlass
考题
单选题While sailing under normal weather and sea condition, the basic parameter which is used to restrict the fuel injection of main engine is （）A
power of main engineB
turbine rotation speedC
speed of main engineD
exhaust temperature
考题
单选题During the watch keeping at sea, at appropriate intervals inspection should be made of （）, auxiliary machinery and steering gear spaces by the duty engineer.A
the main propulsion plantB
lifesaving jacketsC
lifeboat engineD
state of emergency generator
考题
单选题During the dock repair, each sea valve must be disassembled, cleaned and ground well.Before it reassemble the sealing surface between the valve and the valve seat should be checked by （）A
chief engineerB
surveyorC
the engineerD
the technique personnel of the shipyard
考题
单选题During sea trial, the main engine well be kept run at load（）A
100%B
110%C
85%D
different
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