RX-7-powered rotary amphibious car hits auction

Car builder Mark Witt created a vehicle back in 2012 that he claimed was equally great for traversing land and water. It hit 210 km/h (130 mph) on the dried-up surface of Lake El Mirage in Arizona, running on a custom chassis and a Mazda RX-7 powertrain.

The amphibious vehicle, dubbed the Sea Lion by its creator, received an all-custom aluminum hull that was CNC-machined and TIG-welded for durability. Side tanks were added for buoyancy and a jet propeller was installed at the rear end for propulsion while in the water. A giant spoiler-like attachment at the front serves a dual purpose, deflecting waves and ensuring damage-free getting in and out of the water.

Once on dry land, the Sea Lion uses its wheels and handles like a normal street-legal car. The most impressive thing for us is that the steering wheel seamlessly switches between these two modes, acting like a normal steering wheel while on land and turning into a rudder for the jet propeller once amphibious. Not having two different sets of controls is handy, and must have been challenging to implement so seamlessly.

All power is sourced from a Mazda 13B rotary engine upgraded with a supercharger. The listing doesn’t reveal the output or the mileage. The cabin looks rather barebones and only fits the driver.

Mecum will attempt to find a new owner for the Sea Lion on September 20, 2025. If you happen to be interested, contact the seller for the details on where this weird one-off creation is legal to drive, because it doesn’t look like something you can take to the highway.