that used by the World War II, amphibious DD Tanks. The front armor was overlain by a wooden "surfboard", actually three folded layers, hinged together. This could be opened up into a sloping vertical surface in front of the driver providing a bow of a boat hull, about level with the top of the turret. Fabric formed the rest of the water barrier, folding up from compartments lining the upper corner where the side met the top of the hull, and held up at the back with poles. The front of the "hull" was provided with a plastic window, but in practice it was found that water splashing onto it made it almost useless, and the driver instead usually had to take steering directions from the vehicle commander. The M2 Bradley adopted a similar solution, but dropped it with upgraded armor. In the Vietnam War, firing the gun often adversely affected the delicate electronics, which were at the early stages of the transition to solid state devices, so the missile and its guidance system was omitted from vehicles deployed to South Vietnam. The expensive missile was fired in anger only in the Persian Gulf War's Operation Desert Storm, despite a production run of 88,000 units. In 1971, Frankford Arsenal awarded Hughes Aircraft Corporation a contract to begin producing the AN/VVG-1 laser rangefinder for the M551A1 upgrade. Service history Vietnam War The U.S. Army staff in Washington had been recommending since 1966 to the commander of U.S. forces in South Vietnam, General Westmoreland, that the Sheridan should be used there. However, since the main gun ammunition was not available, he argued that it was simply a $300,000 machine gun platform. By 1968, the new, or soon to be, U.S. commander in South Vietnam, General Creighton Abrams, had been notified that the 152 mm shells were now available for the Sheridan. However, as General Abrams began to make preparations for the equipping of U.S. cavalry squadrons for the vehicle, the affected squadrons expressed their concerns that the new aluminum tanks were not only highly vulnerable to mines and anti-tank rocket fire, but they would not be as capable of "jungle busting" as the M48A3 medium tanks. In late 1968, General Abrams met with Colonel George S. Patton IV - the son of World War II General Patton - commander of the 11th Armored Cavalry Regiment (11th ACR), the only full regiment of