单项选择题
A.compass error
B.true heading
C.variation
D.deviation
单项选择题 My gyro-compass()is two degrees east.
单项选择题 Your ship is steaming at night with the gyropilot engaged. You notice that the vessel’s course is slowly changing to the right. Which action should you take FIRST?().
单项选择题 The principal purpose of adjustment of the magnetic compass is to eliminate()as far as possible.