NavList:

Older subs (second W11) or any diesel, is not like the true sub Nuclear, It can run underwater only hours on battery and then needs to build up the batters. The diesel uses the snorkel and poppet valves to run and charge the battery, when not on the surface. When the water or spillage hit the poppets, which is often the close the air running to the diesel and shut off the large amount of incoming air. It draws the air from inside the sub and your ears can burst. The crew is tested for this and many other physical abilities for living in this unusual condition . You must pass test of high pressure in a tank and coming up in a tank of water 50 feet or more. The diesel can’t run under water. The World War diesel along hostile waters needed to get fixes with out revealing to the enemy, it was risky to get stars with any light. So they did so at the dark night.
They got stasr against a dark night vision horizon, they stayed in the dark or under red light to adapt to very little light, they are low to the water, they use off center vision by not looking directly at the horizon, but up near 20 degrees from it. Someone else read the sextant and time under dim red light. I understand they did not use the periscope for sights, I don’t think they had one?. Any one got another answer? Not accurate but needed.

Byron:
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