Last night I went to a talk in which an anecdote was related concerning the sinking of a U-boat, given as an example of self-sacrifice. However, somehow it didn't ring true to my ears, and I was wondering if anyone else has heard it and knows whether it happened, or if there was an incident which may have survived the story.

In essence, a damaged U-boat was in need of repairs and sought shelter in a French coastal village. The villagers made the crew very welcome, and willingly assisted with the repairs whilst the crew took some rest ashore. However, secretly the villagers helping with the repairs welded one of the torpedo tubes open so that the boat would sink as soon as it dived. Repairs complete, the boat prepared to set off; however, the Captain was so impressed with the welcome and assistance they had received that he offered to give the Mayor a quick trip in the boat. Fearing that the Germans would become suspicious if he refused, and thus discover the sabotage, the Mayor agreed - even though he realised it meant almost certain death. The boat set out, dived, and as planned sank with all hands - and the Mayor.

Several things seem wrong:
- Would a U-boat seek really refuge in a simple fishing village, which would not have the proper dockyard facilities?
- Would the crew really leave key repairs to a group of untrained, seemingly unsupervised Frenchmen who lacked any kind of security clearance?
- Wouldn't a welded-open torpedo tube be pretty obvious with even the most rudimentary of checks?
- I was under the impression that a U-boat's torpedo tubes were under the waterline even when on the surface, so wouldn't the boat have flooded pretty much immediately, rather than when it was out at sea and diving?
- Would a U-boat commander really waste time taking a minor French dignatory on a jolly when he evidently needed to complete a patrol and/or get his boat back to base to be properly repaired?

I just find it hard to swallow.