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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Changing Zone Descriptions at Sea
From: Jeremy C
Date: 2009 Nov 15, 15:12 EST
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From: Jeremy C
Date: 2009 Nov 15, 15:12 EST
I will add to Henry's description of how time is changed at
sea. He is correct, the MOST ships still maintain the three 20-minute
changes during the evening watches. I do have one captain who defies
tradition, as is his derogative, and changed it one hour at a time. The
trick was that he would switch watches that this was done on as we entered each
new time zone. For example, for the first change the 8x12 would do it at
2200 hours. For the next zone the 12x4 would do it at 0200, and finally
the 4x8 would do the third change at 0500. This makes all time
changes outside of the work hours of all but the two people on the bridge and
would not cause major confusion (usually).
The reason for the 20 minute changes is indeed to spread the pain or
sleep bonus among the three watches. The normal times are 2200, 0200, and
0600 so as not to interfere with people's work schedule. To be frank,
typically the watch officer hits the "advance" or "retard" button on the master
clock when he wants to. For example, when I do it on the 4x8 watch, i do
it soon after I arrive, so between 0400 and 0430. It doesn't really matter
at that point.
The navigational time it is COMPLETELY different. The DR's,
fixes, all of that, are retarded the WHOLE hour at 0200 on the 2nd Mate's watch
(he's the navigator.). He usually also does the bridge clocks (not hooked
up to the ship's master clock) at this time as well. So you will see
either no 0200 fix, or two 0200 fixes depending on what direction we are
traveling, as well as a note in the deck log book about advancing or retarding
the clock 1 hour to conform to a particular time zone.
I suspect that this may have been done on the 4x8 watches in times
past due to the fact that the 4x8 were traditionally the 2nd mate watches.
Perhaps Henry can weigh in on that point.
For some very fast ships, I have also heard of 2 hour changes in a
night. I have no personal knowledge on how that is done. I suspect
40 minutes per watch.
Jeremy
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