Mark VIII (tank)

Tank Mark VIII
Place of origin	United Kingdom, United States
Production history
Designed	1917
Manufacturer	UK: North British Locomotive Company US: Rock Island Arsenal
Produced	1918–1920
Number built	125
Specifications
Weight	37 long tons (38 t) (dry weight)
Length	34 ft 2 in (10.42 m)
Width	11 ft 8 in (3.56 m) 9 ft (2.7 m) sponsons in
Height	10 ft 3 in (3.13 m)
Crew	12 British tanks 10 US tanks
Armor	16 mm maximum
Main armament	two QF 6 pdr 6 cwt Hotchkiss (57 mm) guns
Secondary armament	seven 7.92 mm Hotchkiss machine guns or five M1917 Browning machine guns
Engine	V-12 Liberty or V-12 Ricardo 300 hp (220 kW)
Power/weight	7.89 hp/tonne (5.79 kW/t)
Suspension	unsprung
Operational range	50 mi (80 km)
Speed	5.25 mph (8.45 km/h) governed to 6.25 mph (10.06 km/h) maximum

The Tank Mark VIII also known as the Liberty or The International was an Anglo-American tank design of the First World War intended to overcome the limitations of the earlier British designs and be a collaborative effort to equip France, the UK and the US with a single heavy tank design.

Production at a site in France was expected to take advantage of US industrial capacity to produce the automotive elements, with the UK producing the armoured hulls and armament. The planned production levels would have equipped the Allied armies with a very large tank force that would have broken through the German defensive positions in the planned offensive for 1919. In practice manufacture was slow and only a few vehicles were produced before the end of the war in November 1918.

After the war, 100 vehicles assembled in the US were used by the US Army until more advanced designs replaced them in 1932. A few tanks that had not been scrapped by the start of World War II were provided to Canada for training purposes.

As the First World War progressed, the industrial production capacity of the Entente was taxed to the limit. Of the Allies, only Great Britain and France had been major industrial nations in 1914 and the latter had lost 70% of its heavy industry when the Germans overran that part of Lorraine that they had not already occupied in 1871. The output in Britain was limited by labour shortages due to the manpower demand of the armed forces and a rocketing national debt.

When the United States of America declared war on Germany on 6 April 1917, many in Britain hoped this event would solve all these problems. The two men directly responsible for British tank production, Eustace Tennyson d'Eyncourt and Lieutenant-Colonel Albert Gerald Stern, initially considered sending a delegation to the United States immediately, to convince the new ally to start production of a British tank design. After some reflection they decided it was best to leave the initiative to the Americans. Stern did contact the American Military Attaché in London immediately after war was declared. In June 1917 the first American approaches were made, but not by the US Army as they had expected. The US Navy wanted the most modern tanks for its US Marine Corps. At that moment the current British tank project was the Mark VI. It was designed with existing British industrial capacity in mind, posing limits that might be overcome by larger American production facilities. Stern therefore pretended that an even more advanced project had already been in existence which he called the Mark VIII (there was also a much more conventional Mark VII project). He invited the Americans to participate and contribute as much as they would like to its design. The Navy was on the brink of sending a team of engineers to Britain when the American Department of War was informed of developments by the US Military Attaché in London. It ordered the project to be shifted to the Army and selected Major H. W. Alden – in peacetime he had been an industrial expert – to go to the UK to work with the Mechanical Warfare Department design team at Dollis Hill on the first drawings of the new tank. He arrived in London on the 3 October, to discover that a lot of design work had already been done by Lieutenant G J Rackham, who had been sent to the Front to see for himself how the current designs performed in the dismal conditions then encountered at the battlefield in Flanders.