Terrapin (amphibious vehicle)

A column of 'Alligator' amphibious vehicles passing Terrepin amphibious vehicles on the Scheldt River near Terneuzen, October 13th, 1944.

The Terrapin "4-ton amphibian" was a British-manufactured, amphibious armoured transport vehicle of the Second World War. It was first used at Antwerp in 1944, and to great effect during the Battle of the Scheldt.

The Terrapin served with the assault teams of Royal Engineers as part of the 79th Armoured Division. They were used to carry infantry units (Canadian and British) over the rivers.


Development

Due to a shortage of US-manufactured DUKWs the British Ministry of Supply commissioned Thornycroft to design an amphibious vehicle capable of ferrying supplies and troops from ship to shore for the D-Day landings.

Some 500 Terrapin Mark 1 were built by Morris Commercial, the commercial vehicle side of the Morris Motor Company.

A Mark 2 Terrapin with a number of improvements reached the prototype stage but the war ended before it entered production.

The British Morris-Commercial Terrapin MkI.

Design of the Mark 1

Despite success in its first military action, the Terrapin was not an overall successful design, and had many significant defects which were never overcome in service.

Because of the size of the tyres, the Terrapin was a relatively high vehicle, and though open-topped, it was difficult to enter and exit. Any soldier attempting to exit over the side faced both prolonged exposure to enemy fire as well as possible injury from the fall.
More important, like the Medium Mark A Whippet tank of WWI, the Terrapin had drive to all eight wheels powered by two separate engines (both Ford V8), mounted side-by-side with each motor driving the wheels on one side, controlled by lever steering. This arrangement did not work on the Whippet, and failed on the Terrapin as well. If one engine broke down the Terrapin tended to swing around violently.
The two centrally located engines also split the cargo compartment in two, and though rated as a 4-ton vehicle, this prevented large loads such as heavy artillery or vehicles from being carried.
In use the vehicle was found to be rather slow, and was easily swamped in rough seas.
In addition, the driver had poor visibility as he was centrally located inside the middle of the vehicle. This was compounded by the installation of a canvas cover over the forward hold. As a result another crew member typically had to stand behind the driver and provide directions.
One interesting feature was that when being driven on a level surface the vehicle was supported on the four middle wheels, the front and rear wheels remaining clear of the surface (the front pair being raised significantly, the rear pair only slightly). The front and rear wheels provided support and traction on soft surfaces and when climbing slopes such as riverbanks. When driven in the water it was propelled by two rear-mounted propellers.

These failings quickly led to the abandonment of the design in favor of the development of the Mark 2, but the growing availability of large numbers of the much more successful American DUKW made further development unnecessary.


Design of the Mark 2

This was similar to the Mark 1 but had a forward driving position. It was a much longer vehicle, being 31 feet (9.4 m) long compared with the 23 feet (7.0 m) length of the Mark 1.

Survivors

Kevin Wheatcroft, a collector in Great Britain, is known as being the owner of an unrestored Terrapin Mk1. John Belfield, a collector in Australia, also owns a Terrapin wreck, which still carries the original Australian Registration Number (ARN) 149391.

Terrapin

Type Armoured personnel carrier
Place of origin United Kingdom
Production history
Manufacturer Morris Commercial
Number built 200


Specifications

Weight 7 tonnes
Length 7.01 m
Width 2.67 m
Height 2.92 m
Crew 2
Armour mm
Primary armament none
Secondary armament none
Engine 2 x Ford V8 190 hp ( kW) in total
Power/weight hp/tonne
Operational range 240 km
Speed 24 km/h, 5 mph in water