What is your most effective method to gathering ship nationality?

[Pisces]

Originally Posted by Captain Nemo

Are you sure of that? In real life at sea in the pitch black of night with no artificial lights whatsoever, you could make out the colours of a flag? I'm not sure either having never had to do it, but I don't think it would be that easy. During the war I think the rule of thumb was if the ship was blacked out it was a valid target no matter what the nationality, it was a risk the u-boat commander was willing to take.

Nemo

Actually, in the pitch blackness of the night, your color receptive cells in the center of your retina are much less sensitive than the cells on the outside of your retina (which isn't sensitive to any particular color). I don't quite remember exactly how these all are called, but I remember for sure, identifying colors in the night is extremely difficult. Most likely you'll identify it wrong. Be glad you see something at all.

I'm sure someone has links to pages/wikis on eye perception in the dark.