单选题Under rotary pumps are the gear, （）, cam-and-piston and screw types.A reciprocatingB diffuserC turbineD vane

In case of your steering gear failed,________should be exhibited in shapes or lights.

A.no under command

B.restricted in her ability

C.restrained by her draught

D.underway

Dual electro-hydraulic steering units usually operate ______．

A.With both pumps on line at the same time

B.With one pump on standby

C.With the follow-up gear disconnected

D.Only when the rudder is moved amidships

Gear pumps are widely used to transfer any one of the following but .

A.fuel oil

B.lube oil

C.hydraulic oil

D.fresh water

In case of your steering gear failed, ______ should be exhibited in shapes or lights.

A.not under command

B.restricted in her ability to manoeuver

C.restrained by her draught

D.Underway

The Certificate of Inspection for a containership ______.

A.is issued by the Coast Guard and is usually valid for 2 years

B.must be posted under transparent material near the officers' licenses

C.lists all of the stability limitations and conditions imposed on the vessel

D.shows the due date of the quadrennial test of the cargo gear

When the helm is turned on the navigation bridge，which of the listed actions will be the FIRST response in the steering room on a ship equipped with an electro-hydraulic steering gear ________．

A.The pumps go to full stroke

B.The six-way valve aligns itself with the running pump

C.Both port and starboard cables are energized

D.The synchronous receiver turns，duplicating the helm motion

Which statement is NOT true?

A.In a simple vane pump, the rotor and cam ring are exactly concentric

B.Balanced vane pump has an elliptical cam ring

C.Liquid in both gear pump and vane pump are forced out to the outlet.

D.Balanced vane pumps can work at a higher pressure than the simple vane pump