Oh, one other thing: Make yourself a copy of Hitman's Kriegsmarine whiz-wheel:
http://www.subsim.com/radioroom/showthread.php?t=114351
Very useful for manual targeting, or even if you don't do manual targeting it is useful for figuring out intercept courses and such.
The front side is copied from an actual device used in u-boats, while the back side is an interpretation of what they might have used, based on the front.