His name is Duke Riley, and he has tattoos and a homemade replica of a wooden submerging vessel said to have been used (or not used) by the US in the Revolutionary War.
But there’s a problem. He’s an artist, not a scientist, so when he was reported to have been floating toward New York’s Queen Mary II, authorities could only imagine what sort of enormous bomb he must have hidden within the plywood/fiberglass structure. Riley was 200’ from the bow of the ship when he was detained.