On 13 October your 0515 zone time fix gives you a position of LAT 26°53.0'N, LONG 90°05.0'W. Your vessel is on course 068°T, and your speed is 7.8 knots. Local apparent noon (LAN) occurs at 1145 zone time, at which time a meridian altitude of the Sun's lower limb is observed. The observed altitude (Ho) for this sight is 54°51.5'. What is the latitude at 1200 ZT?

Question

Accepted Answer

Option B: 27°13.3'N. First, determine the latitude at LAN using the meridian altitude formula (L = 90° - Ho ± Dec). For 13 October, declination is 7°48.3'S. With Ho 54°51.5', the LAN latitude is 27°12.6'N at 1145 ZT. Advancing this position 15 minutes at 7.8 knots on course 068°T results in 27°13.3'N.