George
The demolition charges were permanently installed on U-505 while in the yards. It is my understanding that other IX-C boats were also rigged this way.The wiring went through the various bulkheads along with other wiring runs. They were not put in place during an action, probably because there would have been little time available to do so. The charges were distributed throughout the boat, placed so as to puncture the pressure hull and cause rapid flooding in all sections of the boat but I can't tell you exactly where each charge was located.
Don B