[don1reed]

Ooops, Sri, minimax, I misunderstood.
I believe you're correct, however, about the "base time".
I'm making some tests currently to simplify and/or clearify it, i.e, lets say we're based at Pearl Harbor and given a mission to patrol off Honshu and we'll refit at Midway Island both ways.

Pearl Harbor, Oahu, H.I. ZD +10 William.

Midway Islands ZD -11 Love.

Honshu Island ZD -9 Item.

Note 1."Bowditch" tells us to convert Zone Time (ZT) to GMT by adding positive ZT and subtracting negative ZT; conversely converting GMT to ZT, a positive ZD is subtracted, and a negative one added.

Note 2."Bowditch" further tells us re Date Line:

E Longitude----> 180°----> W Longitude = Loose 1 day
1 January 1942--->|---> 31 December 1941
5 July 1944<------|<-----4 July 1944

Even as virtual navigators, we still have to deal with this...so, the first thing we must do before casting off is to calculate GMT.

As we travel westward toward our objective the clock in the sim is still adjusted to "base time", this is the reason sun/rise/set and Local Apparent Noon (LAN) are happening at weird hours of the day and night. In order to compensate, see Note 1. above, we convert GMT to ZT by adding a negative ZD to give us local time at our present location, then we can correctly calculate sunrise/sunset LAN for navigation purposes.

What I've yet to discover is when we refit at Midway Island, does the base time revert to Midway's local time. Anyone know?

Nations have created Standard time/Daylight saving time rules and regs for commercial purposes; but, the sun's place in the heavens obeys no human command.