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 magnetic compass heading of 143°.

Correct Answer: Option A — 2.0°W

Using the formula Compass + Deviation = Magnetic, and Magnetic + Variation = True, we relate the gyro and magnetic compasses. With a gyro error of 2°E and variation of 8°W, the deviation is derived by comparing the compass heading to the true heading, resulting in 2.0°W.