This article has been around a long time: Night Vision - The Red Myth
without academic substantiation but seems credible.
This one is based on US Navy
studies: Red Light and Night Vision
My conclusion is that light level is more important than color, and that most people use light levels that are too high for good dark adaptation. From experience on many many deliveries crew often show up with red lights, particularly head
lamps, that are way too bright.
At sea, one should have your gear
organized so you don't need much if any light to get ready for watch. Black out the head
portlight so those coming off watch can use as much light as they like for ablutions before going to sleep.
On my boat, lights below at night are seven or eight red LEDs on the power panel, dim orange from the main VHF
, dim orange from the SSB
, and a dim blue glow from the panel of the entertainment radio
. I don't have any trouble negotiating the boat with that ambient light. In the head, in addition to the main boat lights, I have an inexpensive battery
powered LED "closet light" that is bright enough to shave with without the brilliance of the overhead halogen lights.
If you're aboard with me on Auspicious or on delivery
and turn to look at me coming up the companionway
with a head lamp turned on, regardless of the color of light, I'll be sorely tempted to rip it off your head and heave it over the side. Don't point lights in people's faces.