Navigation NAU 102 Lesson 13

Time Zones And, sometimes, Zulu Time Also, Coordinated Universal Time (UTC) Known as Greenwich Mean Time (GMT) ZD 0 – The starting point for world’s time system We must be able to convert between Time Zones

Time Zones E.g. When it is 0815 in Vallejo (ZD +8), what time is it GMT? add the ZD to local time. To convert from local time to GMT (+8) = 1615 GMT

Time Zones E.g. When it is 2230 in ZD +4, what time is it GMT? (+4) = 2630 GMT 2630 = 0230 the next day

Time Zones E.g. When it is 2230 in ZD -4, what time is it GMT? (-4) = 1830 GMT

Time Zones E.g. When it is 0230 on 07 Oct in ZD -4, what time is it GMT? (-4) = ? 0230 = 2630 on 06 Oct (-4)= 2230 on 06 Oct

Time Zones E.g. When it is 0815 GMT, what time is it in Vallejo (ZD +8)? subtract the ZD from GMT To convert from GMT to local time (+8) = 0015 Local Time

Time Zones E.g. When it is 0815 GMT, what time is it in ZD -8? subtract the ZD from GMT To convert from GMT to local time (-8) = 1615 Local Time

Time Zones E.g. DST in Vallejo (ZD +7) Zones keep the time of the next zone to the east. Daylight Saving Time Usually 2nd Sunday in March to first Sunday in November.

Time Zones Daylight Saving Time 2010: 2 nd Sunday in March (14 th) to first Sunday in November (7 th ). Note: some locations don’t keep daylight saving time (AZ, HI). Check Sailing Directions or the Nautical Almanac

Estimated Time of Arrival Step 2 – Determine transit time + delays Step 1 – Convert departure time to GMT What date & time will I get to my destination? Step 3 – Add transit time to GMT of departure Step 4 – Convert arrival GMT to local time

Estimated Time of Arrival E.g. You are on a voyage from San Diego to New York. The distance is 4860 nm. Your speed is 15 kts. You estimate a delay of 18 hours for bunkering & 14 hours for the Panama canal transit. If you depart at 0836 (ZD +7) on 04 July, what is your ETA at New York (ZD +4)?

Estimated Time of Arrival ETD San Diego 4 July 0836 ZD+7 ETD GMT4 July1536 GMT Step 1 – Convert departure time to GMT

Estimated Time of Arrival Step 2 – Determine transit time + delays Transit Time = Distance/Speed =4860 nm/15 kts. =324 hours 324 hours / 24 hours per day = 13.5 days 13.5 days = 13 days + (.5 days x 24 hours/day) Transit Time = 13 days 12 hours

Estimated Time of Arrival Transit Time13 days12 hours Bunkering18 hours Panama Canal +14 hours Total13 days44 hours Step 2 – Determine transit time + delays Voyage Time 14 days20 hours -24 hours

Estimated Time of Arrival Step 3 – Add transit time to GMT of departure ETD GMT 4 July 1536 Voyage time14 days20 hours ETA GMT18 July3536 GMT -24 hours ETA GMT 19 July1136 GMT

Estimated Time of Arrival Step 4 – Convert arrival GMT to local time ETA GMT19 July 1136 ZD -(+4) ETA NY19 July0736

Estimated Time of Arrival At 0915 zone time, on 7 November 1981, you depart Seattle, LAT 47°36.0'N, LONG 122°22.0'W (ZD +8). You are bound for Kobe, LAT 34°40.0'N, LONG 135°12.0'E, and you estimate your speed of advance at 18.5 knots. The distance is 4,527 miles. What is your estimated zone time of arrival at Kobe?

Introduction to Navigation Questions?