Coast Machinery Marsh Master

The Marsh Master was designed in 1980 by Coast Machinery, who were asked to build an amphibious vehicle that could carry several men and their equipment over land, water, marsh and swamp. It was first used for surveying and repairing equipment in marshland where nothing else could go, and later for jobs such as fire control in southern California, mosquito control in Florida, and timber and safety work in frozen tundra.

Design

The vehicle has a welded aluminium monocoque body of 3/32 in plate and runs on two rubber belt tracks wrapped around buoyant pontoons, fitted with 3 x 24 in aluminium grousers. The tracks run on 8-inch high-impact rubber bogie wheels with stainless shafts and sealed, oil-bath bearings in aluminium housings, and each part can be replaced individually. Despite weighing just under 3,000 lb (about 1,360 kg), it exerts only about 1 psi on the ground.

Engines varied by model. The example described here had an air-cooled two-cylinder Onan petrol engine driving a Sundstrand M-25 hydrostatic transmission and twin hydraulic motors with reduction gears to the tracks, and could be steered with one hand. It reached 5 mph (8 km/h) on land and 2 mph (3 km/h) on water and could carry 1,000 lb afloat. A hydraulic winch was fitted at the front and a hydraulic tool outlet at the rear. It is 12 ft 1 in long, 7 ft 4 in wide and 7 ft 2 in high, with 24 in of ground clearance, and is small enough to be towed behind a 3/4-ton pickup.