On 17 June your 0815 zone time DR position is LAT 25°27.0'N, LONG 47°16.0'W. At that time, you observe the Sun bearing 079.5°psc. The chronometer reads 11h 15m 03s, and the chronometer error is 01m 15s fast. The variation is 3°E. What is the deviation of the standard magnetic compass?

Correct Answer: Option B — 3.5°W

Establish GMT using chronometer time and error, then look up Greenwich Hour Angle and declination in the Nautical Almanac. Solve the navigational triangle per Bowditch standards to obtain true bearing. Apply variation (3°E) and compare with the compass bearing to calculate the 3.5°W standard compass deviation.