[jason210]

True - it's easier for your eyes to adjust from red light to dark than from white light to dark. In former USSR subs red light was constantly on at night and this was also an indicator for the crew that it was night.

Blue light is the most efficient colour for illumination in reduced light conditions. If you want to see with a dim light, make it blue, and you will see more. The eyes are most sensitive to blue and green light. Dim blue lights have been used on submarine for this reason. It's my guess that dim blue lights were used on U-boats when they wanted to save power, for example when running on batteries underwater.

I'm not sure if the blue lights were used on German U-boats, but if they were I'd guess it has more to do with day and night cycles than anything else.

In fact my guess would be that dim blue lights would be used when submerged in the daytime to save battery power.

You'd want as much light as possible in the U-boat before you go out on a daytime, watch so you aren't dazzled, so I guess that's where white lights would come in.

Be nice to have all this confirmed, but for now I'd be happy with rig for red and rig for white and rig for blue mods.