Infantry tank

Background

The British tank arm was constrained by decisions about procurement made in the early 1930s. By 1931, experience with the Experimental Mechanized Force led to the report of the Kirke Committee and specifications for three types of tank, a medium tank with a small-calibre anti-tank gun and a machine-gun, a light tank with machine-guns for reconnaissance and to co-operation with the medium tanks by engaging anti-tank guns. A close support tank armed with a gun firing high explosive and smoke shells to give covering fire for tank attacks was also specified. The cost of experiments with tanks led in 1932 to the Director of Mechanisation to cancel work on a replacement for the medium tank, during the financial cuts imposed during the Great Depression. When work resumed in 1935, the army had Light Tank but no design bureau for a new medium tank and no engine powerful enough to move it. To avoid delay, the British chose not to attempt to design specialist tanks for close infantry support or for independent operational manoeuvres and in 1934, the Army Council decided that each infantry division should have a battalion of Infantry tanks (I tanks).

In May 1934, Lieutenant-General Hugh Elles was appointed Master-General of the Ordnance and Brigadier Percy Hobart, the Inspector, Royal Tank Corps, asked Vickers to design a tank for infantry co-operation, that could survive all existing anti-tank weapons and be cheap enough for mass production in peacetime and next year, Vickers had a two-man tank design, with a machine-gun and powered by a civilian Ford V8 engine of 70 hp (52 kW). The prototype of October 1936 weighted 10 long tons (10 t) had a maximum speed of only 8 mph (13 km/h) but carried 60–65 mm (2.4–2.6 in) of armour and was mechanically reliable. The A11, Infantry Tank Mk I, was the first Infantry tank (I tank) and the first practical expression of the decision to split design into I tanks and cruiser tanks, with different functions and tactics, supplied to separate units and formations.

The 1935 edition of the War Office publication, Field Service Regulations (FSR), containing the principles by which the army was to act to achieve objectives, was written by Major-General Archibald Wavell, made breakthrough the responsibility of infantry divisions with the support of Army Tank Battalions, equipped with specialised vehicles for infantry-artillery co-operation, the slow and heavy Infantry tanks. Once a breakthrough had been created, a Mobile Division containing a tank brigade with light and cruiser tanks, would advance through the gap and use the speed and range of its tanks to surprise the defender and attack flanks, headquarters and non-combatant units. By 1939, further amendments to FSR added counter-attacks on an enemy armoured breakthrough. (The codification of the difference between Infantry and cruiser tanks and their functions in FSR 1935, accidentally created an obstacle to all-arms co-operation that lasted long into the Second World War.) Defence against tanks could be achieved by troops finding physical obstacles and by controlling their own anti-tank guns. The obstacles could be woods and rivers or minefields as long as they were covered by fire from other weapons. In places lacking convenient terrain features, lines-of-communication troops would also need anti-tank guns and be trained to set up localities suitable for all-round defence

The need for economy in the design and production of the A11, which was too small for a radio, led to work on a successor, the A12, Infantry Tank Mk II in 1936. Capable of 15 mph (24 km/h), the A12 was still slow but had 60–70 mm (2.4–2.8 in) of armour, making it almost invulnerable to tank guns and standard foreign guns like the German 37 mm Pak 36 anti-tank gun. The tank had a four-man crew and a turret big enough for a radio and a Ordnance QF 2-pounder high-velocity gun, firing solid projectiles capable of penetrating all 1939–1940 German tanks. Vickers and government factories could not take on the work and it was farmed out to a civilian firm, which lacked experience, designers and draftsmen. It took until 1939 to bring the A12 into production as the "Matilda II" and it had not gone into service when the war began, only 67 A11s having been delivered. When the Matilda was supplied to Army Tank Battalions it was an effective tank in the Battle of France and in the Western Desert Campaign, where it outclassed Italian tanks and was effective against standard Italian and German anti-tank guns from 1940–1941 but was later found to be too slow for the fast tempo that German panzer units could achieve.

Other tank types

Using later terminology, the infantry tank has been compared to a heavy tank, while the cruisers were compared to mediums, lights, or even armoured cars. This comparison can be misleading: particularly as the infantry tank was never intended to have the same anti-tank capabilities as a heavy tank.

The infantry tank was distinctly different from either the "heavy tank" or "breakthrough tank" concepts, although some pre-war multi-turreted heavy machines such as the Soviet T-35 and the German Neubaufahrzeug (both taking some of their inspiration from the Vickers A1E1 Independent prototype - an idea which was abandoned by the War office in the late 1920s for lack of funding), which were similar, and with similar doctrines for their use. The Neubaufahrzeug was considered too slow for Blitzkrieg tactics and fell from favour. German (and to some extent Soviet) wartime doctrine shifted towards faster medium and heavy tanks fighting large multi-tank battles, with the role of the infantry tank in the assault taken by simpler Sturmgeschütz (self-propelled artillery).

An important difference, however, was that heavy tanks were generally very well armed, while infantry tanks were not necessarily better armed than other types. For example, the Soviet KV-1 heavy tank and British Matilda II infantry tank were deployed at about the same time in 1940. These two models had similar levels of armour protection and mobility, but the KV's 76.2 mm main gun was much larger than the Matilda's 2-pounder (40mm).

In British practice, the main armament of the infantry tank went in three phases. The pre-Dunkirk British Army Matilda I had only a single heavy Vickers machine gun, a compromise forced by the lightness of its chassis and the price it was built to. The Matilda II gained a capable anti-tank capacity for its time, with the 2-pounder, but these were only issued with solid-shot (i.e. non-explosive) for anti-tank use and had little effect as artillery when providing close support for the infantry. The ultimate evolution of the British infantry tank concept began with the Churchill Mk I, where a hull-mounted 3-inch howitzer could support infantry assaults with HE shells while the turret had a 2-pdr for use against other tanks. As the increasing size of tanks, and their turret ring diameters, allowed such a howitzer to be turret-mounted in vehicles such as the Crusader Close Support (CS) and Centaur CS cruiser tanks.

Britain and France

Since infantry tanks were to work at the pace of infantry units which would be attacking on foot, high speed was not a requirement and they were able to carry heavier armour. The first two purpose-designed infantry tanks, the A.11 Matilda Mark I armed with a heavy machine-gun and A.12 Matilda Mark II with a heavy machine gun and 2-pounder anti-tank gun. The Mark I had been ordered in 1938, but it had become clear that a better-armed tank would be needed and the Mark II, was already under design and would be ordered in mid-1938.

The two saw action in the Battle of France where in the Battle of Arras they caused a shock to the German panzer units. Losses of the Mark I in France were not replaced but the Mark II Matilda remained in production.

Infantry and cruiser tanks were expected to engage enemy tanks, hence the use of both the 2-pounder and then 6-pounder on both.

They were followed into service by the Infantry tank Mk III Valentine tank and A.22 Infantry Tank Mk IV Churchill designs. The Valentine proved to be difficult to develop further but the Churchill went through successive variants and served up to the end of the war.

As British cruiser tank designs developed into larger vehicles with more powerful engines, they could carry bigger guns and more armour and yet still achieve high speeds. At the end of the war the cruiser tank lineage led to the "universal tank" in the form of the Centurion.

In practice the British did not operate only infantry and cruiser tanks. Lack of production capacity meant the large scale adoption of US medium tanks.

During the inter-war years, the French Army adopted three light tanks in the infantry tank role. These were the Hotchkiss H35, the Renault R35 and the FCM 36. All three had two–man crews and were similar to the Matilda I in terms of size, weight and armour. However, they were better armed, having 37mm guns as well as co-axial machine guns.

In practice, although able to resist hits from other tanks and anti-tank guns, and designed for good, albeit slow, cross-country performance, the separation of tank functions into specialised areas such as infantry and cruiser types was not effective. Invariably the cruisers ended up meeting enemy tanks in combat, while the infantry tanks were the only ones present when a breakthrough was accomplished. The infantry tank idea faded as tank design progressed during the war. It was eventually replaced outright with the general acceptance of the 'universal tank' idea.

Soviet Union and Germany

The concept was also employed by the other big tank-producing nation of the 1930s: the Soviet Union, as exemplified by the T-26. The T-26 was a light tank assigned to infantry units and thus fulfilled the infantry tank role. It had the relatively thin armour of a light tank, but with a potent 45 mm gun. Their BT tanks were the fast cruiser types.

Germany had its separate Panzerwaffe; the German infantry used phased out Panzerkampfwagen Is in its Independent Tank Brigades. This is often seen as reflecting some explicit doctrine; in reality it was simply caused by a lack of funds, tank production not having any priority. When more money became available the Sturmgeschütz III was taken into use by the artillery, in its original role of an infantry close support vehicle—the counterpart of the Allied Infantry tanks.

US

The US disbanded its Tank Corps in 1919 and the National Defense Act 1920 defined tanks as an infantry responsibility and their purpose was to support the infantry. There were little funds available for tank development and only around two experimental tanks were produced a year. In the early 1930s, the promotion of mechanisation of the cavalry began. For political expediency and to avoid conflicting with the 1920 law, the tanks developed for the cavalry based on the infantry's light tanks were called "Combat Cars".

Medium tank designs produced were focused on infantry support. The M2 Medium Tank designed in the late 1930s had multiple machine guns to give all round fire and a 37 mm anti-tank gun. However before mass production could start the Battle of France had already shown that a 75 mm gun was needed.

Japan

The Japanese Imperial Army used tankettes as infantry support in the 1930s and into World War II. These small light tanks were also referred to as armoured cars (though they usually only held a crew of two and appeared like miniature tanks) and included the Type 92, Type 94, and Type 97 "TK" vehicles. Japanese troops would ride on the fast-moving tankettes, use them as tractors to pull equipment, or otherwise use them in support roles. Only later versions of the tankettes came equipped with anything other than machine guns. These vehicles were successful supporting infantry in campaigns against China in the 1930s but were not designed to engage other tanks with armour that was meant to repel only small arms fire.

Italy

The Fiat 3000 was the first tank to be produced in series in Italy. It was to be the standard tank of the emerging Italian armored units after World War I. The 3000 was based on the French Renault FT. The design was accepted with deliveries to begin in May 1919, but the end of the war caused the original order to be cancelled and only 100 were delivered. The first Fiat 3000s entered service in 1921 and were officially designated as the carro d'assalto Fiat 3000, Mod. 21. ("Fiat 3000 assault tank, Model 21").The up-gunned version of the Fiat 3000, armed with a 37/40 gun, was tested in 1929 and was officially adopted in 1930 with the designation of carro d'assalto Fiat 3000, Mod. 30. The Model 30, in addition to its improved armament, also differed from the Model 21 in that it had a more powerful engine, improved suspension, different engine compartment silhouette, and the external stores were stowed differently. Some Model 30s were also produced with two 6.5 mm machine guns as main armament, as on the Model 21, in lieu of the 37 mm gun. A limited number of Model 21 vehicles were exported to Albania, Latvia and Abyssinia (Ethiopia) prior to 1930.

Analysis

Despite the concept of splitting tanks into infantry and cruiser roles being an instance of the general economic principle of division of labour in mechanisation, during World War II, its application in mechanised warfare proved to be hugely inefficient in terms of technical development, production, maintenance, logistics and — worst of all — tactical flexibility. Therefore it was not surprising that during the war, it was progressively abandoned by all the major belligerent countries.