Strange ships with lights
 

Ok I have GWX and I have come across this before, especially in early august of 1939. A ship with lights on the masts, flashing like a light house, with another ship close by. You sometimes see this in the channel. Any idea what it is?

Lightship, a floating lighthouse.
http://en.wikipedia.org/wiki/Lightvessel

They are environmental objects in the game, so you can't sink them. This also means the crew can't see them, which is why they always have a tug next to them so the crew will report them to you.