some would say there is nothing wrong with playing map contacts on. I wouldn't go that far, but i do agree that it's fine to have them on while 'training up'
Are you using karamozovnew's new interface for u-boats or not?
If not, have you identified the location of the TDC on the attack map page? Not the notepad feature on the periscope page. The notepad is flawed and best left alone. Try to use only the TDC on the attack map page.
the periscope notepad is a flawed copy of the sh3 system, and unfortunately is broken. For people coming from sh3 this is annoying but can be worked around, but for you it's probably just mystifying. basically, don't use it. only use the tdc on the attack map page.
this short thread goes into the details and has been found useful by some:
http://www.subsim.com/radioroom/show...iscope+notepad
Probably better to just use the new interface by karamozovnew and learn from scratch