On 20 November your 0612 zone time (ZT) position was LAT 25°38.0'N, LONG 166°54.0'W. Your vessel was steaming on course 126°T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 0854 ZT. The chronometer read 07h 51m 14s and was slow 02m 52s. The observed altitude (Ho) was 27°58.3'. LAN occurred at 1147 ZT. The observed altitude (Ho) was 45°35.0'. What was the longitude of your 1147 ZT running fix?

Question

Accepted Answer

Option B: 165°12.5'W. The 0612 position is advanced to the time of the LAN observation. By calculating the meridian altitude and applying the vessel's run, the longitude is corrected for the time interval between the initial fix and the meridian passage, yielding 165°12.5'W.