[Sailor Steve]

Surface ships always use red lights at night. White light blinds you to pretty much everything in the dark. Red light makes it much easier to see out and quicker for your eyes to adjust. Also it makes it easier for the interior to be dark but let the crew still see when they need to get from quarters to stations.

In a submarine there's not much need to dim the lights at night, except for the crew to sleep better because it's darker. When preparing for an attack the captain needs the lower lighting to help when he's looking out the periscope at night. If conducting a surface attack the bridge crew need to already be adjusted to the darkness, plus they want to keep the hatch open for emergencies, and the dim red light doesn't make a glow that the enemy can see.