On 15 November your 0813 zone time (ZT) fix gives you a position of LAT 22°30.0'N, LONG 67°28.0'W. Your vessel is on course 164°T, and your speed is 13.5 knots. Local apparent noon (LAN) occurs at 1215 ZT, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 49°46.0'. What is the latitude at 1200 ZT?
Official USCG Answer & Rule Citation
Correct Answer: Option D — 21°42.5'N
Update latitude from the 0813 fix to 1200 using dead reckoning run along course 164°T. At LAN, apply meridian altitude sight reduction formulas using declination and Ho to establish precise latitude at the time of transit.
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