单选题A reservoir, as used in hydraulic systems aboard ship, is used to store hydraulic oilAnother function is to（）A act as a shock absorberB maintain the stored oil under pressureC act as a base or foundation for the power unitD eliminate pressure surges in

Among the basic categories of equipment, which of the following are used to convert the hydraulic energy into linear motion?

A.hydraulic pumps

B.valves

C.hydraulic cylinders

D.hydraulic motors

______ play a very important part in hydraulic systems by preventing interaction between different parts of the hydraulic circuit.

A.Motors

B.Check valves

C.Safety valves

D.Reducing valves

Among the basic categories of equipment, which of the following are used to allow the hydraulic energy to be controlled?

A.hydraulic pumps

B.valves

C.hydraulic cylinders

D.hydraulic motors

Which of the following statements is TRUE regarding automatic identification systems（AIS）________．

A.AIS cannot be used to make passing arrangements because the system is not capable of this type of ship-to-ship communications

B.AIS cannot be used to make passing arrangements because the ship-to-ship text messaging feature is for emergency use only

C.AIS can be used to make passing arrangements via ship-to-ship text messaging but a vessel operator is not relieved from the requirement to sound whistle signals or make arrangements via bridge-to-bridge radiotelephone

D.AIS can be used to make passing arrangements via ship-to-ship text massaging thus relieving a vessel operator from making such arrangements via bridge-to-bridge radiotelephone or signaling intent to pass via whistle signals

Which statement is TRUE concerning buoyant work vests aboard tankers ________．

A.They may be worn while working on deck but not while working over the side

B.They must be used only under supervision of a designated ship's officer

C.They will be accepted for up to 10% of the required life preservers

D.They may be worn during drills

Among the basic categories of equipment, which of the following is used to convert hydraulic energy into continuous rotary motion?

A.hydraulic pumps

B.valves

C.hydraulic cylinders

D.hydraulic motors

______ is not usually used in liquid cargo systems．

A.Hydraulic drive systems

B.Electric drive systems

C.Steam drive systems

D.Man-powered drive systems

An electrical device which employs a stationary armature and a rotating electromagnetic field is used aboard as a

A.magnetic amplifier

B.ship's service alternator

C.three-wire DC generator

D.saturable core reactor

Which statement is TRUE concerning inert gas systems on tankers ________．

A.Flue gases from the ship's boilers are used in some systems

B.The gas is helium

C.Using the system accelerates the rusting of the tanks

D.All of the above

A hydraulic accumulator aboard a ship is designed to ______.

A.store fluid under pressure

B.act as a fluid reservoir

C.provide overpressure relief

D.replenish fluid to a system