I've been reading the book Shadow Divers about deep sea scuba divers trying to identify the wreck of a German World War II U-boat off the New Jersey coast and it has me thinking about the parallels that a DM could draw.
Wrecks are often found by fishermen, who will sometimes trade the locations of the wrecks to charter boat captains.
The locations are jealously guarded and the wrecks themselves are dangerous locations that sometimes hide great treasures for those brave or stupid enough to dive them.
It' an easy comparison to make, but an interesting one too. I've already sketched an idea in my head of what it would look like in my home campaign. Perhaps I'll post that later...