I'd like to see how he modified his engine so it could run underwater. A periscope type device for air to enter the carburetor perhaps? And another for the exhaust pipe?
My car will happily "wade" through 70 cm of water which is over the wheels, Land Rover (I drive a Disco) tried to make it go through a metre of water, the whole system was waterproof but it floated in 80 cm.
Old pilots never die, they just run out of runway.