On 7 November your 0830 zone time position was LAT 27°36.0'N, LONG 162°19.0'W. Your vessel was steaming on course 289°T at a speed of 19.0 knots. An observation of the Sun's lower limb was made at 0945 ZT. The chronometer read 08h 43m 11s and was slow 01m 51s. The observed altitude (Ho) was 38°21.1'. Local Apparent Noon (LAN) occurred at 1138 zone time. The observed altitude (Ho) was 45°35.0'. What was the longitude of your 1200 zone time running fix?

Question

On 7 November your 0830 zone time position was LAT 27&deg;36.0'N, LONG 162&deg;19.0'W. Your vessel was steaming on course 289&deg;T at a speed of 19.0 knots. An observation of the Sun's lower limb was made at 0945 ZT. The chronometer read 08h 43m 11s and was slow 01m 51s. The observed altitude (Ho) was 38&deg;21.1'. Local Apparent Noon (LAN) occurred at 1138 zone time. The observed altitude (Ho) was 45&deg;35.0'. What was the longitude of your 1200 zone time running fix?

Accepted Answer

Option A: 163&deg;38.8'W. Calculate the sun line of position using the intercept method and advance it to 1200 ZT. Combine this with the meridian altitude at LAN to establish the running fix. The intersection of the advanced LOP and the latitude at LAN provides the 1200 ZT longitude of 163°38.8'W.