Thanks for the input so far.
Might be horribly inefficient but dont know. What about some type of thru hull magnetic drive like a stereo turn table or one of those stirring rods from chemistry class? could it be rigged for regen braking?
I've been thinking about amphibious vehicle design and it seems the greatest challenge is the land drive wheels.
Prior art seems to mostly consist of truck axles. Rudimentary and lots of places for water to penetrate and damage bearings, brakes and gears.
Later generations apear to be CV type...