Fowler Challenger III amphibious tractor

Fowler Challenger III is a continuous track amphibious launch tractor, which was specifically designed for the Royal National Lifeboat Institution (RNLI), to launch and recover carriage mounted lifeboats, from beach-launched lifeboat stations.



A total of 13 tractors were constructed over a seven-year period from 1953 to 1960. The tractor is a highly modified version of the standard 95 bhp Fowler Challenger III diesel crawler tractor, manufactured by John Fowler & Co. of Leeds.

A prototype was trialled successfully at Aberystwyth in 1952

The tractor developed a draw-bar pull of 21,100 Lbs, through its six-speed gearbox, and was fitted with a specially designed winch, allowing it to exert a maximum pull of 38,500 Lbs. at its lowest speed. Extended gear and clutch levers were fitted, to assist the driver when submerged.

The tractor has been made completely watertight, with the engine compartment sealed with watertight panels and doors. The engine was designed to run for long periods without overheating. Circular brass rubber-seated valves were fitted to the air intake and discharge ports, to be closed when submerged. To prevent damaged, an automatic stop device was also employed.

There were many requirements of the RNLI variant tractor:
 * Able to tow a life-boat and carriage weighing up to 14 tons over various types of terrain, including soft sand and deep shingle.
 * Able to pull the life-boat and carriage up gradients of 1 in 4 and to hold them by its brakes on these gradients.
 * Able to haul life-boat and carriage to the water, which at low water may be several miles at some stations.
 * Capable of operating continuously at full power, in water up to a depth of seven feet.