[seafarer]

Most neutrals I've seen had running lights on and search lights aimed at their flag.

If it's a darkened ship, and clearly trying to slip along in the night, it's likely fair game.

Oh, accept for those occasional German flagged ships traveling darkened (some other u-boat sank one of those off S. Norway when we were in the general area supporting the Norwegian campaign efforts, but it wasn't us - I swear - we was, err, somewheres else, yeah, yeah, that's it, we was somewheres else, wasn't us - I swear!).