was manufactured from 1971 to 1981 Although many differing variants have been developed over the years, most amphibious ATVs share most of the following characteristics. In contrast to today's
ANSI definition of an ATV: "a vehicle that travels on low pressure tires, with a seat that is straddled by the (single) operator, and with handlebars for steering control", an AATV is intended for multiple riders, sitting inside, and will usually have two control sticks (and in some cases a steering wheel or joystick) rather than motorcycle-type handle bars as stipulated in the current definition. Typically constructed with a hard plastic or fiberglass watertight body "tub", AATVs usually have six or eight wheelsall drivenwith low pressure (around 3 PSI) balloon tires, no suspension (other than what the tires offer) and no steering wheels. Directional control is accomplished through
differential steeringjust as on a tracked vehicleeither by braking the wheels on the side of desired direction, 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 (40 km/h) top speed. AATVs typically do not meet
vehicle regulations in most countries, and are therefore strictly
Off Highway Vehicles (OHV). Though not as fast as a straddled ATV, the amphibious 6x6 and 8x8 can be operated with precision at slow speeds, carry more passengers and cargo, and has the ability to float. Although the spinning action of the tires is enough to propel the vehicle through the wateralbeit slowlyoutboard motors can be added for extended water use. On land the combination of a large number of wide wheels and tires, low tire pressure and low vehicle weight all result in exceptionally low ground pressure, high grip, and off-road ability. For further enhanced off-road, snow and mud performance, optional tracks can be mounted directly onto the wheels. == Vintage Manufacturers ==