Quote Originally Posted by niky View Post
Shroud and wire mesh... and if the mesh gets clogged up... stuff the drivetrain in reverse to unclog it.
The prop would have to be mounted away from the body and low enough to work properly in the water. But that would mean the prop would be sitting low and near the road as well. Potential damage if something big is run over by the vehicle, like a rock.

A jet drive keeps all the mechanism tucked away within the vehicle's chassis. The only thing exposed is the jet nozzle and that doesn't have to be underwater to work.