FOMM

An amphibious automobile is an automobile that is a means of transport viable on land as well as on or under water. They are unarmored for civilian use.
Amongst the smallest non air-cushioned amphibious vehicles are amphibious ATVs. These saw significant popularity in North America during the 1960s and early 1970s. Typically an amphibious ATV is a small, lightweight, off-highway vehicle, constructed from an integral hard plastic or fibreglass bodytub, fitted with six driven wheels, with low pressure, balloon tires. With no suspension and no steering wheels, directional control is accomplished through skid-steering – just as on a tracked vehicle – either by braking the wheels on the side where you want to turn, or by applying more throttle to the wheels on the opposite side. Most contemporary designs use garden tractor type engines, that will provide roughly 25 mph or 40 km/h top speed on land....