Why you are so easily spotted
 

Hi guys, I know about this problem of being spotted from miles away. Recently I was reading through some books on WWI and u-boats in particular, and I noticed that almost all the u-boats in the diagrams had two mast-like things on them, both sticking out way higher than the periscope.

http://www.subsim.com/radioroom/pict...pictureid=6909

I do not actually own this game, but as far as I know, the mast things aren't modeled in the game. However, it does seem to explain How you could be spotted from such a distance.