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.

Question

On 24 March your 0800 zone time fix gives you a position of LAT 22&deg;16.0'N, LONG 31&deg;45.0'W. Your vessel is steaming a course of 285&deg;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&deg;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&deg;55.8'. Determine the vessel's 1200 zone time position.

Accepted Answer

Option B: LAT 22&deg;35.0'N, LONG 32&deg;51.0'W. Advance the 0800 fix to the 1200 position using the dead reckoning vector. Apply the meridian altitude observation at LAN to determine the precise latitude. Use the running fix method, combining the morning sun line and the noon latitude, to establish the final position at 1200 zone time.