Explorers find downed German U-Boat off Mass.

[sarisataka]

5. Quite a mystery indeed

I think, why would they go so far inland? The only thing I can think of is some sort of intelligence or spy mission. You would think that there would have been some record of it...

Why it sank is another good question. The U-boats were fairly reliable and their crews were ingenious at repairing them and keeping them going. I cannot think of what malfunction would cause them to sink.

An entire crew defecting and never speaking of it? Remotely possible. Most of the German navy had no use for Nazis and tried to stay insulated from politics. Maybe the novel is a confession?