On 23 July your 2100 ZT position is LAT 36°43.0'N, LONG 16°09.8'W, when you observed an azimuth of Polaris to determine the compass error. Polaris bears 359.0° per gyrocompass. At the time of the observation, the helmsman noted that he was heading 319.0° per gyrocompass and 331.0° per standard compass. Variation is 12.0°W. Which of the following statements is TRUE?

Question

Accepted Answer

Option A: The deviation is 1.7°E.. Polaris observation establishes gyro error by comparing true azimuth to gyro bearing. Applying westerly variation to magnetic heading and reconciling gyro, magnetic, and standard compass readings yields a deviation of 1.7°E, in accordance with Bowditch piloting and compass correction methods.