I'll just assume that my uboat was stuck without the new sonar system and had to make due with magical homing torpedoes.
I'm tempted to load the entire compliment with homing torpedoes and then approach a convoy and launch off all 6 bow tubes at the convoy broadside at 15 degree increments, reload and repeat, and sit back and watch the fireworks.
I'll either hit a lot of ships or whichever ship has the worst mechanic is going to be blown into very small pieces.
Steve