You've read stories about dead whales that wash up on shore and cause problems because they are too big to remove. This story is a little bit like that. Hastings Beach (where the Battle of Hastings took place in 1066) in England had a beached German U-boat wash up on April 15, 1919. There was no one aboard, because the crew had surrendered and the submarine was being towed to France when it got away. But now it was on the beach, right in front of the tourist hotels, too big and too far onto the beach to be towed back into the ocean. What to do? The citizens of Hastings decided to see the glass as half-full and make it a tourist attraction.
VIPs were shown inside U-118 by local coastguards, chief boatman William Heard and chief officer W. Moore, but tours stopped after both men grew sick and died several months later. The cause was initially attributed to rotting food which remained onboard following the U-boat’s surrender at Scapa Flow. But an inquest later determined that noxious gas released by the U-118’s damaged batteries was responsible for the men’s deaths.
So a submarine can rot and become noxious, kind of like a whale. Read the story of the U-boat that invaded Hastings without a single person aboard, at Urban Ghosts.