What does it all mean?
It means the SH3 Gods Must Be Crazy. It seems that the developers created one time system for the sea and one for the sky. Hopefully I'm wrong and this is all just a terrible mistake.
There is no reason not to continue using the Screen Time as the GMT for all the usual time non celestial navigation duties. In fact, there is no way that the Screen Time could really be a local Zone Time because the Screen Time doesn't change when you cross Time Zone boundaries. It isn't realistic, but it seems to work for the observations of the sky above, and might hold up to more observations by interested Kaleuns. Those who do so should report their observations here. I am interested in hearing your experiences.
I will post links to the tools I used in this first voyage after U-13 returns to port.