Lube oil cannot be efficiently filtered if its （）.

单项选择题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

单项选择题Combustion knock occurring in a diesel engine can be caused by （）.

A.excessive fuel penetration
B.prolonged injection lag
C.reduced ignition lag
D.prolonged ignition lag

单项选择题A thrust bearing is used with a propulsion diesel engine to （）.

A.control axial movement of the crankshaft
B.transmit engine thrust to the propeller shaft
C.absorb vibrations in the propeller shafting
D.prevent propeller thrust from being transmitted to the hul

单项选择题Control of the main propulsion diesel engines can be shifted from the engine room to the wheelhouse from the （）.

A.wheelhouse control station
B.engine room control station
C.captains office
D.chief engineers office

单项选择题Combustion knock can occur in the cylinders of a diesel engine under any condition permitting （）.

A.a shortened ignition delay period
B.a lean fuel/air mixture
C.excess fuel in the combustion chamber
D.rapid vaporization of injected fuel droplets