Just found this:
He reckons they are supposed to be orange and white (not red and green!) running lights - a holdover from old WW2 Navy procedures.
What's it look like on the other side of the fin? Two red...? That would be 1x nav light, 1x beacon/formation light. Green steady with red flashing would bear this out. Also, I would guess that in areas likely to be seen by the opposition they'd go dark anyway.Red and green on both sides is a sneaky way to fool the enemy at night. Switch over and they think you're going in the opposite direction.
I don't know why it is but a quick look at a few pictures would indicate this to be perfectly correct.
Possibly. If you look at the mast on a modern ship there's all sorts of lights that can be switched on in standard combinations - for example, when we're on DP and can't get out of the way of other vessels we'll show "restricted manoeuvrability" with a red over white over red masthead light stack at night.Sensible answer; possible lighting for different situations.