I have played around a bit and I think torpedoes and sensors are bugged/nerfed big time... I'm cruising at 35 knots above layer about 1 nm from a torpedo and it doesn't pick me up (active sensor). Some subs don't even detect me even tho I'm driving around them under 5 miles away!! I got "locked on" only by one torpedo so far and I've been targeted by like 3 torps at once every time. They are totally blind/deaf. Neither does AI launch torps deep so it's easy to hide. The torp detection range is extremely bad and even with knowing the exact location of a ship, the torpedo misses...
edit: Surface ships are terrible at spotting me. I remember in stock game in this mission (
http://www.subguru.com/DW_missions/Malabar.zip) I got sunk many times by the destroyers but with this mod I'm never detected, let alone sunk. So what's wrong with this mod?