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

On 13 October your 0515 zone time fix gives you a position of LAT 26&deg;53.0'N, LONG 90&deg;05.0'W. Your vessel is on course 068&deg;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&deg;51.5'. What is the latitude at 1200 ZT?

Accepted Answer

Option A: 27&deg;13.3'N. Determine the latitude at LAN using the meridian altitude formula. Advance this position 15 minutes to 1200 ZT using the vessel's course of 068°T and speed of 7.8 knots. The resulting latitude of 27°13.3'N accounts for the northerly component of the vessel's movement during the interval.