In real life it was the magnetic pistol which caused the problems. In real life it was also almost impossible to disable the magnetic pistols. They were integral to the detonation system and it required a procedure of several hours to disable one, and that precluded having someone aboard who actually knew how they worked. Failure rates during the period reached as high as 40%.
The pistols were disabled in port and not used again until a new one was developed - in December 1942.
http://uboat.net/history/torpedo_crisis.htm
For a thorough evaluation read this:
http://www.google.com/url?sa=t&rct=j...vqraZALxEHcFBA