Sailing East to West - how to adjust ships time

[scotty123]

When, for example on a transatlantic, how is ships time adjusted?

Is it done each 15 degrees longitude perhaps, or on a regular daily adjustment?

 

[Cruiser2B]

Typically surface ships spread the hourly changes out over the passage (say 4 hour difference from Portsmouth to New York, 8-day passage, knock an hour off every second day). When turning the clock back, it's done during the day watches and when advancing the clock, it's done during the night watches. Submarines will often advance or retard their clocks to destination time on departure, as it doesn't really matter to them that sunset is at noon. That's the naval way - don't know what the commercial ships do.

 

[Richard10002]

Going back to 1977-1984, we used to do either hours or half hours, split between the 3 night watches only.

10 day trip, 8 hour time difference, no change on nights 1 and 10, 1 hour per night otherwise.

14 day trip, 8 hour difference, a mixture of hours and half hours, with an attempt to keep noon, (sun overhead), close to 1200hrs.

 

[snowleopard]

It is of course up to the individual. Normally best to do it in whole hours so you don't get complicated sums working out times for radio schedules. What we did was to change at the next noon after crossing a time zone boundary: 7.5°W, 22.5°W, 37.5 etc.

Best to change at noon rather than midnight, especially when heading west as it's a lot easier to do an extra hour's watch in daylight. Incidentally when heading west from the Canaries their clocks are an hour ahead of the time for their geographical zone so we reset the clock immediately on leaving port.

 

[TigaWave]

We never bothered, as local time is irrelevant if you don't have to be at work. Only need for time was navigation and taking sights, so clock was always GMT. Watch system was a rolling 3 on 3 off so alarm was set for 3 hours If you shift your local time someone ends up with a long or short watch which I've known to cause arguments...8-12 watch suddenly becomes a 5 hour watch if clocks are changed... mid day was always mid day for noon sights so lunch followed that...

 

[Guest]

[ QUOTE ]
When, for example on a transatlantic, how is ships time adjusted?

Is it done each 15 degrees longitude perhaps, or on a regular daily adjustment?

[/ QUOTE ]

During my time on Merch Ships ... it was done in whole hours ... corresponding to longitude change. Also it was usually done in the late afternoon / early evening ... about 1800. Reason being the 2nd Mate who is usually in charge of ships time wants to get some sleep before getting up for midnight watch ! So your 15 deg Long. is about correct... subject to nearest day .
The watches were increased or reduced by 20mins according to whether clocks went fwd or back.

 

[Guest]

[ QUOTE ]
We never bothered, as local time is irrelevant if you don't have to be at work. Only need for time was navigation and taking sights, so clock was always GMT. Watch system was a rolling 3 on 3 off so alarm was set for 3 hours If you shift your local time someone ends up with a long or short watch which I've known to cause arguments...8-12 watch suddenly becomes a 5 hour watch if clocks are changed... mid day was always mid day for noon sights so lunch followed that...

[/ QUOTE ]

Why should one carry the can ? I always split the hour over the three watches so no-one lost out or gained over others ...

 

[Bajansailor]

I would agree with TigaWave - just keep Ship Time as GMT and work your watches accordingly. Eg we were doing 3 on, 6 off on my last Atlantic passage, so everybody had a different watch each night, which was quite nice - this way everyone got to see sunrises on their watches.
And we would have lunch at local midday, and supper when it was getting dark - never mind that when we were approaching the Caribbean, we were having lunch at 1600 hrs and supper at 2200 hrs GMT - go by what your tummy tells you instead re mealtimes!