You swung ship and compared the magnetic compass against the gyro compass to find deviation. Gyro error is 2°E. The variation is 8°W. Find the deviation on a gyro heading of 166°.

Correct Answer: Option A — 1.0°W

Compass error is the algebraic sum of variation and deviation (Error = Variation + Deviation). With a gyro error of 2°E, true heading is 168°. Given variation is 8°W (-8°), deviation equals True minus Magnetic, resulting in 1.0°W per standard piloting procedures.