I wonder how long it takes until a shipwreck leaves absolutely nothing remaining. Unless the ship was entirely wood, and everything on it biodegradable AND it didn't sink in deep water, it might last nearly forever.
I used to think that too. But now I doubt that. And I now think that only in exceptional circumstances would anything remain after a couple of hundred years. Especially with the iron ships.
Cold and anaerobic is what will preserve ships. And those conditions are not particularly common.
I’m sure I read something recently about there being a limited future for viewing the wreck of the Titanic before it degrades, and that’s under pretty deep water, over 2km down.
Correct - but there would still be parts and rust for quite awhile.