Navigation Problems USCG Question #1663 (Set 49)

You swung ship and compared the magnetic compass against the gyro compass to find deviation. Gyro error is 2°W. The variation is 8°W. Find the deviation on a gyro heading of 039°. HEADING PSC-PGC 030.5°-024° 061.5°-054° 092.0°-084° 122.5°-114° 152.0°-144° 181.0°-174° 210.0°-204° 239.5°-234° 269.0°-264° 298.0°-294° 327.5°-324° 358.5°-354°

Official USCG Answer & Rule Citation

Correct Answer: Option D — 1.0°W

With a gyro error of 2° W, a gyro heading of 039° corresponds to a True heading of 037°. Given a variation of 8° W, the magnetic heading is 045°. Interpolating the provided table for a compass heading of 045°, the deviation is found to be 1.0° W.

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