Whatever they think they can.
It's certainly NOT the OP's boat, but perhaps they'll think it was in his possession when it sank = theft. Since it's not his boat & he has possession of it after raising it = theft. Maybe it's got oil & gas trapped inside somewhere that starts to leak out once disturbed = toxic spill/EPA fines which if bad enough could get you detained by DNR/Fish & Wildlife.
I wouldn't take a car (or a boat) I found abandoned in a long forgotten field w/out LOTS of leg work first. Why is this any different?
Reminds me of the stupidity involved when someone doesn't want to fix a KNOWN rotten transom, and asks for info, or approval to do a band-aid faux repair. Someone who's never even seen the boat in person or put their hands on it always chimes in to agree it's safe to bolt on a steel plate or 2, then continue to use the boat 'just for the season' or 2.... It isn't.
We all know what typically happens, that boat gets sold to someone who usually has NO idea that the boat is unsafe, and then uses it.
It's bad enough that whoever asked about a band-aid fix is endangering themselves & those that board their boat. But for me the larger problem is that there is now a public record that reflects a bad decision that got someone's approval and who knows how many people will read that & think:
That guy online said it's OK, and it worked for the guy who asked the question, so it'll work for me too.
Why is it difficult to imagine (and suggest) that this recovery should be done correctly? In this instance, w/ a little effort, IMO, the OP could find out what is required of them prior to disturbing a sunken vessel and once recovered, legally gain ownership of it. That might even be possible prior to raising it since the HIN
IS clearly visible.
Rant over, my apologies to the OP for the thread drift ^^^
My original suggestion stands: I wouldn't touch it w/out doing some fact checking & asking lots of questions.