I read an article about searching for the earliest wheeled submarine [1] and the contender is the 1984 Argonaut Jr, a jury-rigged submersible using air hoses running to the surface to get air for its gasoline engine. This reminded me of the AquaSub [2], a DIY personal submersible where the cockpit is suspended between two articulated pontoons, so I combined the two designs.

By placing the generators and cable drums on the surface catamaran, the useful volume inside the submersible is increased and achievable depth is not limited by the rigidity of the air hoses. Nowadays this kind of hybrid vehicle would be replaced by an unmanned ROV, but the nuclear-powered wheeled submarine NR-1 [3] was built in the 1960s to conduct spy missions on the seafloor...

[1] https://jalopnik.com/cars-designed-.....are-1848340993
[2] https://rqriley.hostcentric.com/ima.....Sab004_lrg.jpg
[3] http://www.hisutton.com/NR-1.html