On 6 December your 0800 zone time DR position was LAT 21°48.0'N, LONG 124°30.0'E. Your vessel was steaming on course 045°T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 1012 ZT. The chronometer read 02h 10m 42s and was slow 01m 02s. The observed altitude (Ho) was 41°17.1'. LAN occurred at 1129 zone time. The observed altitude (Ho) was 44°53.7'. What was the longitude of your 1200 zone time running fix?

Question

On 6 December your 0800 zone time DR position was LAT 21&deg;48.0'N, LONG 124&deg;30.0'E. Your vessel was steaming on course 045&deg;T at a speed of 20.0 knots. An observation of the Sun's lower limb was made at 1012 ZT. The chronometer read 02h 10m 42s and was slow 01m 02s. The observed altitude (Ho) was 41&deg;17.1'. LAN occurred at 1129 zone time. The observed altitude (Ho) was 44&deg;53.7'. What was the longitude of your 1200 zone time running fix?

Accepted Answer

Option D: LONG 125&deg;35.2'E. Advance the 1012 ZT sun line to 1200 using the vessel's course and speed. Combine this with the meridian altitude observation at 1129 ZT to establish the latitude. The intersection of the advanced line and the meridian observation provides the longitude of the 1200 running fix.