I would suspect this has something to do with salvage laws. I have noticed from general reading that the captain of a sinking vessel was the last one off more due to the issue of salvage rights than chivalry. I would also point out that any wreck in a navigable waterway technically belongs to either the state or federal government, since the bottoms of the rivers are public lands, often to the high water mark.

Let us know what you find out.

Best,
Dale