allthumbs,
I believe the rule of the water is something to the effect of.......
If the tower uses "there"
line to tow, salvage or other wise a boat, they then have rights to ownership.
Don't quote me on that one, but, that is the generally speaking right one has. There are some exceptions, such as some country's governments will claim ownership of boats that have sunk. Hence Spain with some of the gallions sunk in the 1800's as an example. Even then, it is hard for them to figure out if you found one, and brought the gold etc up with out them knowing.
Marty