Re: Why do submarine crewman work under red lights in submarines.

Well I did not knew it at all but since you aslked...
I asked a captain of the sea, and he told me: because of night vision. The 
captain of the submarine needs to look through the priscope. Its only light 
source is what ever light there is + his night vision. So - they use red 
light (or nowaday other lights better) to avoid loosing their night vision.

Now why that keeps night vision - think about rodopsin and its states of
exitation. Red light tends to push rodopsin to the resting state, while 
blue one push it to the activated state. This is part of the answer - 
though a big part of it. Read abouyt rodopsin and about night vision to get 
the full picture.