The Mark VIII tank also known as the Liberty or The International was a British-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 which had not been scrapped by the start of World War II were offered to Canada for training purposes.
Early development 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.Armour in Profile p3 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.
"International Tank"
The US Army had set up headquarters in France. In September it decided to form its own tank corps with 25 tank battalions including five heavy tank battalions. To equip the heavy units, Major James A. Drain – a staff officer to General Pershing and responsible for initial planning of the tank force – provisionally ordered 600 Mark VI tanks (then under development) from the British in October 1917.Armour in Profile p2 The Army tried to convince the Department of War to divert all available tanks to the Army, leading to a conflict with the Navy (the first of many to come over this issue). This posed serious problems for the British government. It now seemed that American involvement in the war would mean a lesser number of tanks available for the British forces. Also on 4 February 1917 binding agreements had been made with the French about tank production. These had to be renegotiated.
Winston Churchill, the new Minister of Munitions, had just been forced to fire Stern as director of the Mechanical Supply Department (Controller of the Mechanical Warfare Department) because of his mistakes in handling the Mark IV project, leading to enormous production delays. In pushing production through in the early days he had upset civil and military authorities. Stern was appointed in September to the new position of "Commissioner for Mechanical Warfare (Overseas and Allies Branch)" in order to coordinate tank production with the US and France. Stern went to France to meet the French Minister of Munitions, Louis Loucheur and the American commander-in-chief, John Pershing. Loucheur made it clear from the beginning that France had nothing to offer in terms of existing production facilities. This came as no surprise to Stern who had already prepared an "International Plan" of ten points (in fact a bilateral agreement between the US and Britain) that he now managed to get accepted by the Americans. He submitted this to Churchill on the 11 November. Its main points included (using the original terminology):
The incorporation of a partnership between the US and Great Britain for the production of 1,500 heavy tanks to be erected in France. The supply of a number of these tanks to France to further the higher purpose of Allied unity, should she require them. (Britain hoped France would produce its own Char 2C in sufficient numbers, Loucheur already knew this was unlikely to happen). France might supply an erecting shop, if convenient; in any case it might be wiser to build a new one (so a completely new factory would have to be built in France). A joint supply of components. Britain would supply guns, ammunition, and armour; the USA engines, transmissions, forgings, and chains (employing US car industry). The design would be based on British experience and American ideas and resources, and eliminate most of the faults in current tanks in power, loading, and trench crossing. Major Alden would collaborate to finish the working drawings before Christmas enjoying full cooperation of the British; the design was to be approved by both nations. Unskilled labour might be provided by imported Chinese; the French government ensured their local accommodation. Production would begin in April 1918 and finally reach 300 a month (so the number of 1,500 was only preliminary). The project would have high priority in regards raw materials, labour, factories, and transport. Management would be in the hands of two Commissioners, one British (Stern himself) and one American; but the French could appoint their own if their interests were concerned.
The plan already contained a specification: the tank should have a engine, weigh 38.8 tons (39.5 tonnes) and have a trench crossing capacity of . The 11 November briefing included the first use of the word "Liberty" for the tank which was taken from the engine chosen.
The first design conference took place on 4 December at GHQ in France and Churchill approved the plan soon afterwards. It was made into a formal treaty signed by the British Foreign Secretary Arthur Balfour and the US Ambassador Walter Hines Page on 19 January 1918. The treaty specified the programme in great detail. The first 1,500 tanks had to be made by the end of the year and the factory should be capable of expansion to 1,200 a month. Both goals were very ambitious given the fact there was neither a completed design nor a factory and that British tank production would in fact be 150 a month during 1918.
The United States would supply: the engine; radiator; fan; piping; silencer; lighting; dynamo; battery; propeller shaft; transmission, including gearbox; brakes; roller sprockets; gear shift and brake control; track links and pins; rear track sprockets, hub and shafts; front idler hub and shafts; track roller, track spindles and bushings.
Britain would supply: bullet and bomb-proof plates; structural members; track shoes and rollers; guns, machine guns and mountings; ammunition racks and ammunition.
The agreed price was to be £5,000 per vehicle. In December 1917 the Mark VI order was cancelled ensuring that the Mark VIII would be the new standard Allied weapon.
Description
The Mark VIII kept many of the general features of the Mark I-V series: it had their typical high track run and no revolving turret but two sponsons, one on each side of the tank, armed with a 6-pounder (57 mm) gun. But it also resembled the Mark VI-project in that it had more rounded and wider tracks and a large superstructure on top directly beneath the front of which the driver was seated. An innovative feature was the departure from the concept of the box tank with its single space into which all accessories were crammed. The Mark VIII was compartimentalised with a separate engine room at the back. This vastly improved fighting conditions as a bulkhead protected the crew against the deafening engine noise, noxious fumes and heat.
There were no machine guns in the sponsons, only the 6-pounders each manned by a gunner and loader. The side machine guns were to the rear of the sponsons mounted in the hull doors. Major Alden had designed the sponsons to be retractable (they could be swung in at the rear by the crew, being pivoted at the front), to reduce the width of the vehicle if enemy obstacles were encountered. Five more machine guns were in the superstructure: two at the front—left and right next to the driver—and one on each of the other sides. As there was no machine gun position covering the back of the tank there was a dead angle vulnerable to infantry attack. To solve this problem a triangular steel deflector plate was attached. The rear superstructure machine gunner could use it to deflect his fire down into that area behind the tank. The tank carried 208 shells and 13,848 machine gun rounds, mostly in a large ammunition locker in the centre which formed a platform on which the commander stood behind the driver observing the battlefield through a cupola with four vision slits. Later the side superstructure guns were removed on US tanks.
The twelfth crew member was the mechanic, seated next to the 300 hp Liberty V-12 (or in British tanks Ricardo V-12) petrol engine) cooled by a large horizontal radiator. Three armoured fuel tanks at the rear held 200 Imperial gallons (240 US gallons, or 909 litres) of fuel giving a range of 89 km. The transmission used a planetary gearbox giving two speeds in either forward or reverse. Top speed was .