The Cadillac Gage Commando, frequently denoted as the M706 in U.S. military service, is an American armored car designed to be amphibious. It was engineered by Cadillac Gage specifically for the United States Military Police Corps during the Vietnam War as an armed convoy escort vehicle. The Commando was one of the first vehicles to combine the traditionally separate roles of an armored personnel carrier and a conventional armored car, much like the Soviet BTR-40. Its notable height, amphibious capability, and waterproofed engine allowed American crews to fight effectively in the jungles of Vietnam by observing their opponents over thick vegetation and fording the country's deep rivers. The Commando was eventually produced in three distinct marks: the V-100, V-150, and V-200, all of which were modified for a number of diverse battlefield roles. An unlicensed copy of the Commando series, the Bravia Chaimite, was also manufactured in Portugal. After the American military disengagement from Vietnam, the Commando series was gradually retired from active U.S. service. It was superseded in the Military Police Corps by the derivative M1117 Armored Security Vehicle during the 1990s. Design and development The V-100 series of vehicles was developed in the early 1960s by the Terra-Space division of the Cadillac Gage company of Warren, Michigan. By 1962 a patent was filed and received by Terra-Space for a vehicle then only known as the Commando. The first prototype emerged in 1963, and the production variants entered service in 1964. The vehicle is equipped with four-wheel drive and uses axles similar to the ones used in the M34 series of trucks. The engine is a gasoline-powered 360-cubic-inch Chrysler V8, same as in the early gas models of the M113 armored personnel carriers. Its 5-speed manual transmission allows it to traverse relatively rough terrain. The M706 has a road speed of , and can travel across water at . A Commando's armor consists of high hardness alloy steel called Cadaloy, which protects against projectiles up to 7.62×51mm. Partly because of its armor, the M706 has an unloaded mass of over 7 tons. As a result, a common problem with the vehicle is rear axle failure caused by the extreme weight. However, because the armor also provides the monocoque structural framework, it can be lighter than a soft vehicle to which armor has been added, and the angle of the armor also helps protect against hits and mine blasts. The