On 24 March your 0800 zone time fix gives you a position of LAT 22°16.0'N, LONG 31°45.0'W. Your vessel is steaming a course of 285°T at a speed of 16.5 knots. An observation of the Sun's upper limb is made at 0938 zone time, and the observed altitude (Ho) is 46°32.2'. The chronometer reads 11h 41m 01s, and the chronometer error is 02m 50s fast. Local apparent noon occurs at 1214 zone time, and a meridian altitude of the Sun's lower limb is made. The observed altitude (Ho) for this sight is 68°55.8'. Determine the vessel's 1200 zone time position.
Official USCG Answer & Rule Citation
Correct Answer: Option C — LAT 22°35.0'N, LONG 32°51.0'W
Applying the meridian passage formula from Bowditch, the latitude is derived from the observed altitude and declination. The longitude is determined by advancing the 0800 fix to the time of the sun sight and applying the intercept method, resulting in the final position of 22°35.0'N, 32°51.0'W.
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