M4 Sherman
US medium army tank

M4A3 Sherman (75mm)

M4 Sherman
Typ: US medium army tank
History: Design of the medium tank M3 Grant had been undertaken as a development of the M2A1 on the clear understanding that it was to be considered as an interim design to get a tank with 75mm gun armament into production and service as seen as possible. While design was carried out on the M3 the Armored Force Board drew up requirements for its successor with a 75mm gun in a fully traversing turret. Final M3 working drawings were completed in March 1941, and Rock Island Arsenal offered the Armored Force Board five suggested schemes for the M4 at a meeting the following month. The most straightforward scheme was selected, which entailed using the M3 medium chassis, suspension, power unit, transmission, and ether mechanical parts, unchanged, and providing a completely new hull top, either cast or welded, with a central turret mounting the 75mm gun. The 37mm gun was discarded and a machine gun cupola was to be retained on the new turret. Doors were provided in each side of the hull as in the M3. Designated Medium Tank T6, this vehicle was built in wooden mock-up form in May 1941 for Armored Force Board approval, and a pilot model, with cast hull and detail changes which included elimination of the cupola, was completed at Aberdeen Proving Ground on September 19, 1941. It is tempting to suggest that the T6 was influenced, if not copied to some extent, from the Canadian Ram (qv) in view of its similarity. Documentary evidence (and the chronology of events) disprove this, however. An early production Ram was sent from Montreal Locomotive works in July 1941 for tests at Aberdeen Proving Ground which lasted until October that year, hut APG's report on the Ram was concerned only with its comparison to the M3 and offered no comment on its relevance to the T6 design.

M4 Sherman tanks in manoeuvres in the American desert.

Meanwhile the German invasion of Russia in July 1941 indicated that American involvement in the war in Europe would increase in the year ahead. On President Roosevelt's personal orders tank production schedules for 1942, provisionally set at 1,000 medium tanks a month, were doubled. To achieve this, additional production facilities were required and Pacific Car & Foundry, Fisher, Ford, and Federal Machine & Welder were added to the list of plants earmarked to build the new medium tank. In October 1941, the T6 was standardised as the Medium Tank M4 and plans were made to introduce the M4 on to the production line, in these plants building M3s, at some convenient point early in 1942. This would mean that M4 medium tanks would be built at a total of 11 plants in 1942.

A Sherman tank of the RAC Tank Museum, Bovington Camp, Dorset (UK).

A major proposal was that a second purpose-built tank production plant be built on the Lines of Detroit Arsenal. In September 1941 Fisher were asked to erect and operate such a plant at Grand Blanc, Michigan. Building of Grand Blanc Tank Arsenal, designed from the start to turn out M4s, was started in January 1942 and tank production commenced the following July, though Fisher had, meantime, commenced building M4s in one of their existing plants.
The M4 pilot model was built by Lima Locomotive works in February 1942 differing from the T6 principally in the elimination of the hull side doors. Full production in three plants, Lima, Pressed Steel, and Pacific Car & Foundry started the follwoing month, all these initial production types being cast hull vehicles, designated M4A1. By the autumn of 1942 all other plants in the programme were in full production, and in October 1942, at the battle of Alamein, the first M4 mediums went into action with British forces.

The censor's marks the original contact print of this shot reveals the 1st Armd.Div. rhino above the unit serial '71' on the nearest trackguard - identifying a British Sherman II of HQ, 2nd Armd.Bde during the battle of Alamein.

The M4 series was the most widely produced, most widely used, and most important of all tanks in service with American, British, and allied forces in World War 2. While not necessarily the best Allied tank in qualitative terms, and certainly inferior in armour and hitting power to the best German (Panzer V Panther) and Soviet vehicles (T-34), the M4 medium tank (popularly known by its British name of M4 Sherman) had the virtues of simplicity of maintenance, reliability, speed, ruggedness, and an uncomplicated design. These were most important factors for a vehicle being mass-produced in commercial plants with no background of military experience in peace-time, for use largely by conscript troops with training time limited by the needs of war. In terms of cost­effectiveness, the M4 Sherman was supremely suited to the needs of the hour, a fact reflected in the total output of more than 40,000 tanks (and associated AFVs) based on the M4 chassis in the years 1942-46. Shermans were used by every allied nation in every armour role on every fighting front.

Shermans of the Red Army near Kharkov, 1943. Note the extra fuel tanks at the back of the hull.

The Medium Tank M4 had the same basic chassis as the M3 medium, with vertical volute, suspension, rear engine, and front drive. Apart from very early models, the bogies were altered, however, so that the return rollers were set behind, instead of on top of, the spring units. Hull was either welded, cast, or welded with cast/rolled nase, as detailed in descriptions of the different models, while the 75mm gun was set in a simple cast turret and provided with a gyro-stabiliser as in the M3. Initially the engine was a Continental R-975 air-cooled radial type, hut an ever­persistent shortage of this Wright-built power unit (which was essentially an aircraft engine and needed as such by the aero industry) forced the adoption of alternative engines, giving rise to the main production variants. The tank had a five man crew, could fire AP or HE shot, had a maximum arniour thickness of 50mm (more on reworked and late models) had controlled differential steering, weighed from 33 (short) tons, gross, and had a top speed of 24-30mph according to model. There were numerous detail changes and improvements in Sherman models during their production life.