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单选题
In using reduction gears to obtain efficient propeller speeds, （）.
A
they must be located at the after end of the engine
B
they can only be used with one engine at a time
C
they eliminate the need for controllable pitch propellers
D
they are connected to the engine with a flexible coupling
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更多 “单选题In using reduction gears to obtain efficient propeller speeds, （）.A they must be located at the after end of the engineB they can only be used with one engine at a timeC they eliminate the need for controllable pitch propellersD they are connected to the engine with a flexible coupling” 相关考题
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()on a ship transmits power from the engine to the propeller.
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When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for workA.remains the sameB.is reducedC.is increasedD.is eliminated
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Propeller pitch speed minus ship speed divided by the propeller pitch speed is termed ___.A.apparent slipB.true slipC.pitchD.propulsive efficiency
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A controllable pitch propeller on a diesel driven vessel eliminates the need forA.friction clutchesB.disconnect clutchesC.reversing gearsD.reduction gears
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Lubrication for the main reduction gears used with diesel engines is usually supplied byA.oil from the main engine sumpB.an independent lube oil systemC.the stern bearing head tankD.the stem bearing sump tank
考题
In reducing engine speed to an efficient propeller speed by the use of reduction gears, _______.A.speed and torque are both reducedB.speed is reduced and torque remains unchangedC.speed is reduced and torque is increasedD.speed is sometimes unchanged while torque is increased
考题
单选题One major disadvantage of a low-speed diesel as compared to a steam main-propulsion system is（）.A
the extra weight required for the diesel reduction gearingB
a minimum speed for the engines that limits the minimum speed of the vesselC
the higher fuel consumption per SHPD
the low efficiency of the system when a controllable pitch propeller is used
考题
单选题A diesel engine is operating at 1800 RPM and driving a propeller at 600 RPMWhat is the speed reduction ratio?（）A
030 to 1B
300 to 1C
333 to 1D
330 to 1
考题
单选题What is the function of the thrust bearing?（）A
Prevents lateral movement of the slow speed gearB
Transmits propeller thrust to the hullC
Keeps spring bearings in lineD
Prevents main reduction gear axial movement
考题
单选题In any case the draught of the vessel at the（）shall not be less than that which is necessary to obtain full immersion of the propeller.A
forward perpendicularB
amidshipsC
longitudinal center of floatationD
after perpendicular
考题
单选题A reduction in load on a diesel engine results in （） of speed of the crankshaft.A
a reductionB
an increaseC
an outingD
a downwards
考题
单选题When transmitted by a reduction gear, diesel engine speed is reduced and the torque available for work （）A
remains the sameB
is reducedC
is increasedD
is eliminated
考题
单选题If keep the fuel injection of main engine unchanged when ship is fouled, that will causeⅠ.The speed of main engine to be reduced Ⅱ.Ship speed to be reduced Ⅲ.The resistance torque of propeller to be increased Ⅳ.Trim at stern to increase（）A
Ⅰ + ⅡB
Ⅰ ~ ⅢC
Ⅰ ~ ⅣD
Ⅰ + Ⅱ + Ⅳ
考题
单选题Misalignment of the drive shaft and propeller shaft flanges can be detected by using a dial indicator or （）.A
inside micrometerB
feeler gaugeC
adjustable trammelD
sighting device
考题
单选题（）is placed in the front of the ship under the water,which eases berthing or ma-noeuvering sideways at slow speed.A
The bulbous bowB
The anchorC
The bow thursterD
The propeller
考题
单选题Most often （） is attached to the engine-propeller shaft for efficient electric power generation.A
a variable-speed AC generatorB
a fixed-speed AC generatorC
an air blowerD
a DC generator
考题
单选题A propeller, in order to operate efficiently, must rotate at a relatively （） speed.A
highB
lowC
fastD
lowly
考题
单选题Propeller pitch speed minus ship speed divided by the propeller pitch speed is termed （）.A
apparent slipB
tree slipC
pitchD
propulsive efficiency
考题
单选题The reason why more and more of the large merchant vessels are being powered by medium-speed diesel engines is （）.A
they operate between 150 and 450 rpmB
they are connected to the propeller by gearingC
their smaller size and weightD
they can be connected directly to the propeller without gearing
考题
单选题Pitting in the area close to the pitch line and on the same end of each gear tooth of a reduction gear unit would be caused by （）A
corrosion on the gearsB
excessive gear speedC
dirt in the oilD
misalignment of the gears
考题
单选题Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）A
must churn the oil in the sumpB
is connected to the propeller shaftC
is driven at the highest RPMD
compensates for alignment variations between the engine and pinion gear
考题
单选题Compared to a constant pitch propeller, a controllable pitch propeller（）.A
more efficiently uses available engine powerB
operates at a lower efficiency at a fixed speedC
produces the same torque at lower engine powerD
develops its rated power at a lower speed
考题
单选题Propeller running at （） are generally efficient.A
high speedsB
medium speedC
low speedsD
the same speed with the engine
考题
单选题The four-stroke engine is used for （） and sometimes for main propulsion with a gearbox to provide a propeller speed of between 90 to 120 rev/min.A
alternatorB
turbo-chargerC
remote controllerD
windlass
考题
单选题When used with reversing reduction gears, medium-speed diesel engines should be bolted to their foundations with fitted bolts at the drive end and clearance(loosely fitted) bolts in other locations √This is done to （）A
maintain alignment when the ship’s hull is working in heavy seasB
ensure engine vibrations correspond to the natural frequency of the hullC
permit the engine to expand away from the driven equipment as the engine heats up and expandsD
maintain engine thrust bearing clearances
考题
单选题The linear motion of a diesel engine piston is converted to the rotary motion required to drive gears, propeller shafts, and generators by the （）.A
flywheelB
crankshaftC
journal bearingsD
camshaft
考题
单选题With（） the engine need not to be aligned with reduction gears or propeller shaft.A
Diesel engine propulsionB
Diesel electric propulsionC
Steam engine propulsionD
Gas turbine propulsion
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