Your vessel departs Yokohama from position LAT 35°27.0'N, LONG 139°39.0'E (ZD -9), at 1330 ZT on 23 July, bound for Seattle at position LAT 47°36.0'N, LONG 122°22.0'W (ZD +8). The distance by great circle is 4,245 miles, and you estimate that you will average 13.6 knots. What is your estimated ZT of arrival?

Question

Your vessel departs Yokohama from position LAT 35&deg;27.0'N, LONG 139&deg;39.0'E (ZD -9), at 1330 ZT on 23 July, bound for Seattle at position LAT 47&deg;36.0'N, LONG 122&deg;22.0'W (ZD +8). The distance by great circle is 4,245 miles, and you estimate that you will average 13.6 knots. What is your estimated ZT of arrival?

Accepted Answer

Option B: 2038, 4 August. Great circle distance of 4,245 miles at 13.6 knots requires 312.1 hours (13.0 days). Adjusting for zone time difference between Yokohama (ZD -9) and Seattle (ZD +8) spans 17 hours, resulting in an estimated arrival time of 2038 on 4 August.