On 11 December your 1816 ZT DR position is LAT 26°30.0'N, LONG 140°35.0'E. At that time, you observe Venus bearing 230°pgc. The chronometer reads 09h 14m 52s and the chronometer error is 01m 02s slow. The variation is 3.5°E. What is the gyro error?

Correct Answer: Option C — 3.3°E

Calculate the LHA of Venus using the corrected chronometer time and GHA/Dec from the Nautical Almanac. Determine the Zn using the sight reduction tables. Gyro error is the difference between the observed bearing (PGC) and the calculated true azimuth (Zn). Applying the variation confirms the 3.3°E gyro error.