Bruce,

It's probably unlikely that she sank per se from the damage from the November 2 attack. Consider the evidence we have: pressure hull obviously intact, engines, and batteries operational, survived dive to rated maximum depth. That isn't a boat that's in immediate danger of foundering.

Now it is certainly possible that the damage contributed to her loss, say in a diving accident. It's also possible that U 56 simply hit a mine in the North Sea while homebound. Until the wreck is located -- not likely -- we won't know for sure.

I do thing that any additional action involving Russian forces is a long shot. The article makes clear the Russian navy didn't have much in the Arctic. In addition, U 56 had sailed on October 13 and was facing a week or so trip back to Germany. HSF U-series and UBIII boats didn't stay out for more than five weeks tops unless on an unusal assignment. Though she could have stayed on station for a few more days, I think it is likely that U 56 turned toward home after the November 2 action. The location were the Norwegian were dropped, which is west of where the attack took place, supports the notion. The more damage you presume, the more likely this is to have been the case.

Best wishes,

Michael