A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Henry Halboth
Date: 2017 Jan 4, 01:52 -0500
It was always my undrstaning that Zone Time was kept aboard ship in order to maintain a sense of normalcy about life in general, and as related to sleeing, mealtimes, etc., in relation to passage of the Sun; further in the Navy the ship’s position was officially logged at 0800. 1200, and 2000, while in the MM it was officially logged only at 1200 hours and certain statistical data relating to the day’s run calculated for record purposes I quite frankly cannot imagin the turmoil and confusion that would be created by keeping UT consistently on a long voyage. You could wind up eating breakfast and lunch in the dark and dinner in bright daylight, or for that matter all three in the dark, As for sight taking - I see no problem, you read the chronometer time in UT and calculate accordingly and simply note your LOP and/or position in Zone time. I never had or heard of a problem in relation to this until brought up on NavList/
Can't speak for the US Navy but in the US Merchant Marine prior to Y2K watches were 4 on 8 off. When clocks got advanced 1 hour to the next time zone going East (23 hour day) then evening and early morning watches stood 20 minutes less (3 hr. 40 min.). Going West watches stood 20 extra minutes after clocks were retarded one hour (25 hour day). On ocean going tugs watches were generally 6 on and 6 off. Some ships had clock systems that changed all the clocks onboard at the same time from the bridge. Fast ships in the days of cheap fuel were capable of crossing two time zones in day (SeaLand SL7 Container Ships).