Compass deviation is caused by（）.

单项选择题Compass error is equal to the（）.

A.deviation minus variation
B.variation plus compass course
C.combined variation and deviation
D.difference between true and magnetic heading

单项选择题Deviation in a compass is caused by the（）.

A.vessel's geographic position
B.vessel's heading
C.earth's magnetic field
D.influence of the magnetic materials of the vessel

单项选择题Deviation is the angle between the（）.

A.true meridian and the axis of the compass card
B.true meridian and the magnetic meridian
C.magnetic meridian and the axis of the compass card
D.axis of the compass card and the degaussing meridian

单项选择题Error may be introduced into a magnetic compass by（）.

A.making a structural change to the vessel
B.a short circuit near the compass
C.belt buckles
D.All of the above

单项选择题Gyrocompass repeaters reproduce the indications of the master gyrocompass. They are（）.

A.accurate only in the Polar regions
B.accurate electronic servomechanisms
C.hand operated
D.accurate only if the vessel is underway