12/02/2024
... 👌👇
Your vessel departs Yokohama from position Latitude 35º27.0’N, Longitude 139º39.0’E (Zone Description -9) at 1330 on 23 July, bound for Seattle at position Lat 47º36.0’N, Long 122º22.0’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 Zone Time of arrival?
Here is a format and step-by-step procedure to work any ETA that requires you to cross multiple time zones. These problems reward tidiness.
👉 01. Translate the Zone Time and Date of Departure Port to GMT and Date of Departure.
👉 02. Calculate the elapsed time of the voyage, including layovers, and apply it to GMT of Departure to find the GMT and Date of Arrival.
👉 03. Apply the reversed ZD (Zone Description) of the Arrival Port to GMT to find the ZT and Date of Arrival.
• Those steps applied to this problem work as follows:
01. Date & Zone Time of Departure Yokohama:
23 July. 1330
ZD Yokohama (-9)
GMT Departure:
👉 23 July 0430
02. Calculate elapsed time of voyage:
(Distance traveled is divided by the speed to find time in hours.)
4245 miles ÷ 13.6 knots = 312.1323529 hours
(Divide the hours by 24 to find the number of days.)
312.1323529 ÷ 24 = 13.00551471 days
(Subtract the whole number of days from the calculator screen and record them)
13.00551471 − 13 days = 0.00551471 days +13 (days)
(Multiply the percentage of an extra day by 24 to find how many hours it equals)
0.00551471 × 24 = 0.132352941 hours +0 (hours)
(If your calculator has a button that converts decimal parts of hours and minutes to hours and minutes described in time (or arc), press it now. If not, record the hours (in this case, 0) and subtract them from the screen and convert the percentage of an hour to minutes by multiplying by 60.)
0.132352941 × 60 = 8 minutes +08 (minutes)
👉 Total voyage: 13 days 00 hours 08 minutes
Added to GMT Departure: 5 August 0438
03. Apply the reversed ZD of Seattle -8
Date and Zone Time of Arrival in Seattle: 👉 04 August 20:38 👈
https://www.facebook.com/capt.haytham.nouni 👌