Talus MB-4H amphibious tractor

Clayton's design team developed a prototype at their facilities in Knighton which was tried and tested at several lifeboat station locations around the country to evaluate its performance at as many different working environments as possible. Once these trials had been completed successfully the first tractor was sent to New Brighton on the Wirral, Merseyside. Arriving in November 1990 the tractor and its carriage were used to launch the stations new Atlantic 21 inshore lifeboat.[4]

The MB-4H has been designed to work over varying beach environments and can easily launch and recover inshore lifeboats via an A85 DoDo (drive-on, drive-off) launch cradle/carriage. It will comfortably work at full power into up to 2 metres (6.6 ft) of calm water.[2] The tractor is divided into two sections with the front section housing the power unit, hydraulic oil tank for the front axle, hydraulic pumps, cooling systems and the fuel tank. The rear section houses the rear axle, hydraulic winch with 100 meters of cable, the operator and his/her controls, batteries, electronic control panel, and the drive gear. The driver's seat within the cockpit can face forward or rear, with duplicated controls front and back, allowing the operator flexibility during deployment or retrieval of the DoDo trailer and payload.[5] This allows the combination to drive to the launch site and then reverse round to launch the lifeboat into the sea. The rear-facing controls have the addition of a third foot pedal which is the dead-man control for the winch. The MB-4H has an automatic hydrostatic transmission which gives the tractor an ever-variable ground speed which corresponds to engine speed and ground/sea-bed conditions. To give the tractor excellent handling ability, the vehicle has a pivot steer type with all electrical, mechanical and hydraulic links passing through central wire-reinforced hose. The design allows the tractor to have a steering articulation of 40 degrees to the left or right and results in a turning circle of only ten metres.

The tractor's chassis and cockpit are water resistant and can be made water tight once the engine cooling side hatches have been closed on entering the water. The tractor will operate in broken water up to the depth of the air breather duct if required. The MB-4H's engine compartment is completely water tight. In the event of the tractor becoming in-operable whilst in the water, The operator can leave the cockpit via a roof hatch and the tractor can then be battened down and left on the sea bed in up to a depth of 4.0 metres (13.1 ft). In this situation the cab is designed to allow entry of sea water to prevent the tractor from floating away and causing only minimal damage to the vehicle, such as the wiper motors, exterior work lights etc. The tractor has been designed with extensive corrosion protection to protect from the very aggressive working environment of the sea water and beach conditions the tractor has to endure. The tractor, in most instances, is fully street legal with headlights, sidelights, brake lights and indicators. Work lights, blue flashing lights and a klaxon are also installed.