NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Interpolation to latitude
From: Bruce Hamilton
Date: 2009 Nov 15, 10:44 -0800
From: Bruce Hamilton
Date: 2009 Nov 15, 10:44 -0800
On the Canadian Merchant ships I worked on, our work life was governed by the time of the ship's home port, and log entries were in GMT. Bridge clock was GMT, and our wrist watches were EST.
We were home trade and only moved through 3 time zones. I can see time getting confusing with huge time zone changes as some crew are considered day workers, and meal times could get odd.
Captains and Chief engineers were traditionally day workers, but always on call, but I know of one shipping company where they stand a watch, and they carry only 2 mates and 2 engineers to keep the labour costs down.
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We were home trade and only moved through 3 time zones. I can see time getting confusing with huge time zone changes as some crew are considered day workers, and meal times could get odd.
Captains and Chief engineers were traditionally day workers, but always on call, but I know of one shipping company where they stand a watch, and they carry only 2 mates and 2 engineers to keep the labour costs down.
On Sun, Nov 15, 2009 at 1:05 AM, George Huxtable <george@hux.me.uk> wrote:
I had asked-
"I've noticed that Jeremy's interesting postings contain many references to
Zone Time, so it would be interesting to discover what US merchant vessel
practice is, and exactly what happens when they shift into a different time
zone. I can't say what the practice is in British merchant vessels; does
anyone know? My guess would be that two chartroom clocks are kept running,
one at GMT, one at Zone Time."
To which Henry Halboth replied, in [10615]-
"Did you really have to ask this one, or perhaps I have just misunderstood
your intent?? Regardless, I will answer - if just to show that I am still
alive."
===============
Well, it was worthwhile asking that question, if only to discover that Henry
was still going, and still sharp! Perhaps from one approaching fossildom
himself, he won't mind being described as our oldest living fossil, having
been at sea since 1936!
I had thought I knew how timing was done at sea, but Jeremy's frequent
references to Zone Time, which he has since explained, had rather surprised
me.
In another way, too, I'm glad I asked the question, because Henry's answer
contained something that was quite new to me, and it's always good to learn.
Henry wrote-
"The ship's daily activities and all clocks associated therewith were
regulated to Zone Time, generally advanced or retarded 20-minutes per night
watch when passing from one zone to another, so as to maintain some
semblance of normalcy in daily living and to be in coincidence with the time
being kept at the port of intended destination on arrival there."
That 20-minute business was quite new to me. Presumably, the aim was to
spread the benefit (or pain) of a Zone change equally between all three
watches.
Particularly in view of those 20-minute shifts, I wonder how bridge staff
would be aware what the adopted offset was, between GMT and ship time, at
any moment. Was it somehow posted up in the bridge (and in the radio room
also, when a ship had one, being the other place it needed to be known)? Or,
did it have to be deduced from the difference between a GMT clock and a
ship-time clock? Was there yet another clock, indicating zone time, where
that differed from ship time? Whose responsiblity was it to make the
necessary step-changes? Questions, questions...
Henry added-
"I did sail on one Panamanian Bark in the 1940s, from Panama City to Durban,
aboard which LMT was kept and all daily activity clocks were reset at LAN,
necessitating resetting to Zone Time on arrival at the port of destination.
GMT was, however, kept by Chronometer when it was running. This was an
unusual circumstance for the time."
I hadn't realised that he had actually made ocean passages under sail, if
that's what the reference to a "Panamanian Bark" implied. Indeed, that
practice, of resetting ship's time to local time each noon was a hangover
from the sailing ship era.
I wish we could persuade Henry to tell us some tales from those days, that
are still stowed away in his memory-locker.
George.
contact George Huxtable, at george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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