I couldn't help but notice while playing SH3, that my acoustic torpedoes usaully have a sucess rate of 70%. Upon reading some facts via uboat.net, it came to my attention that they really had a success rate of around 19%. Apparently they were largely unreliable. And mentioned further in the article it said that the allies had certain counter measures that involved dragging a box far behind a ship that emitted a loud noise to divert the homing torpedoes. I'm not asking anyone to create a mod, fix, or even consider this......I just merely thought it was interesting.
http://uboat.net/special/analysis.htm