order to guard against every possible point of attack. Pyke's ideas were initially rejected, but in October 1941, Louis Mountbatten became Chief of Combined Operations and Pyke's ideas received a more sympathetic hearing. Mountbatten became convinced that Pyke's plan was worthwhile and adopted it. The scheme became Project Plough and many high-level conferences were dedicated to it. The problem of developing a suitable vehicle was passed to the Americans, and Pyke went to the US to oversee the development. However, Pyke, who could be very inflexible, fell out with various individuals on the project and the Americans moved on to design a more conventional tracked vehicle, the M29 Weasel. In 1944, Johannes Raedel, a soldier of the German Army and veteran of the Eastern Front invented his schraubenantrieb schneemaschine (screw-propelled snow machine). Raedel had seen the problems of operating tracked vehicles in the deep snows of Russia where a tank would dig out the snow under the tracks leaving the tank stuck on the snow compressed under the hull. According to Siegfried Raedel, son of Johannes: Amphibians The threaded cylinders are necessarily large to ensure a substantial area of contact and buoyancy. Being lightweight, the cylinders may conveniently serve as floats and the arrangement may be used in the design of an amphibious vehicle. During the Vietnam War, the American Waterways Experiment Station (WES) tested the Marsh Screw Amphibian, designed by the Chrysler Corporation. The vehicle's barge-like hull was built of aluminum. It was fitted with vertical supports at the four corners that supported the two rotating, bladed drums. The vehicle weighed under 2,500 pounds and could carry a 1,000 pound load. The Marsh Screw Amphibian proved fastest on packed snow, where it could exceed . It could move at in marshy conditions and in water. The vehicle "failed miserably on soil surfaces, especially sand" where it traveled only ." Despite such disappointing results, Chrysler produced a much larger vehicle, the Riverine Utility Craft (RUC) for the Navy in 1969. The RUC travelled on two aluminium rotors, in diameter. The RUC achieved impressive speeds of on water and nearly on marsh. Again, however, speeds on firm soils proved disappointing, reaching only and crossing dykes proved difficult – the vehicle would get stuck. It was powered with two Chrysler marine V-8 engines and pair of two-speed automatic transmissions. The Soviets built a screw-propelled vehicle, the ZIL-2906, specifically for the challenging task