The principal purpose of adjustment of the magnetic compass is to eliminate（）as far as possible.

单项选择题You are standing the wheelwatch on entering port and the master gives you a rudder command which conflicts with a rudder command from the pilot.What should you do?（）

A.obey the master‟s
B.obey the pilot‟s
C.bring the rudder to a position midway between the two conflicting orders
D.ask the pilot if he relinquishes control

单项选择题（）is used for lifting cargo.

A.A mooring winch
B.A windlass
C.A deck crane
D.A lifeboat

单项选择题The original equilibrium position is stable when（）.

A.metacentric height is positive
B.metacentric radius is positive
C.KG exceed maximum allowable limits
D.Free surfaces are excessive

单项选择题Emergency escape breathing device on board shall have a duration of service no less than（）.

A.20 minutes
B.15 minutes
C.10 minutes
D.5 minutes

单项选择题All engines in lifeboats and rescue boats shall be run for a total period of not less than（）in weekly inspections.

A.2 minutes
B.3 minutes
C.4 minutes
D.5 Minutes