The cruiser tank–sometimes called the ‘cavalry tank’–was seen as a medium-weight, fast machine which could make reconnaissance forays deep into enemy territory, much as horse-mounted cavalry had in former conflicts.
Modern thinking on tank design demands that equal attention be paid to mobility, firepower and protection. These principles were not as well accepted in the mid-1930s when the concept of the cruiser tank was first mooted and the emphasis on the speed of the cruiser tank was generally at the expense of armoured protection and firepower–for the first years of the war, British cruisers were armed only with a 2-pounder (40mm) anti-tank gun.
As the Second World War progressed, the role of the cruiser tank, as originally envisaged, became less and less clear and battlefield experience showed that the cruisers were vulnerable to more powerful German anti-tank weapons–the fearsome 88mm KwK L/56 gun of the Tiger being an extreme case in point. The 2-pounder (40mm) gun was soon replaced by a 6-pounder (57mm) and then, in some cases, by 75mm, 77mm and 17-pounder (76.2mm) guns in an effort to engage German armour on equal terms. Of these, probably only the 17-pounder (76.2mm) and the related 77mm were superior to the German 88mm, particularly when firing armour-piercing discarding sabot (APDS) rounds.
Eleven cruiser tank designs were produced between 1934 and 1945. Some never saw enemy action at all and were retained for training purposes; others saw action but were no match for the German machines. Only two of the designs were really satisfactory–the Meteor-engined Cromwell and the up-gunned Comet variant.
Cruiser Tank Mk I (A9)
What became known as the A9 cruiser tank Mk I was originally conceived as a medium tank to replace the Vickers A6 medium tanks Mks I and II. Development work had started in 1934 under the direction of Sir John Carden of Vickers-Armstrongs, with a view to coming up with a cheaper and more effective design. The A9 was notable for being the first British tank to incorporate a ballistically designed hull, albeit that the maximum thickness of armour was not sufficient and the machine-gun turrets were vulnerable. It was also the first to be fitted with a centrally positioned hydraulically powered turret, and was the first to incorporate the Vickers-Gerlach tank periscope, rather than using direct-vision heavy glass blocks. The A9 was also a pioneer in deep wading and, in 1939, one example was successfully driven completely submerged.
The tank was relatively small: the low hull had a length of just 231in and a width of 100in. Riveted construction was used throughout, with a maximum thickness of armour of 14mm, giving a combat weight of around 12 tons. There was no separation of the driving and fighting compartments and the hull must have been a tight fit for the standard six-man crew. Vickers had proposed that a Rolls-Royce Phantom II engine be used, but production vehicles were powered by a rear-mounted AEC A179 six-cylinder petrol engine, producing 150bhp from 9,630cc, and driving the rear sprockets through a five-speed manual gearbox. Utilising the Vickers ‘slow motion’ suspension, the road wheels were arranged in threes on a pair of bogies, the front and rear wheels on each side being of larger diameter. A large single spring was provided for each bogie, together with a Newton and Bennett telescopic hydraulic shock absorber. Top speed was in the order of 25mph on the road and 15mph across country, with a range of 100–145 miles.
For the prototype, the main gun was a 3-pounder (47mm) but all production vehicles were armed with the standard 2-pounder (40mm), together with three Vickers .303in water-cooled machine guns: one coaxial with the main gun, the other two in auxiliary turrets on either side of the hull. A fan was fitted in the hull to clear the gun fumes. There was also a close-support variant–cruiser tank Mk I CS–which mounted a 3.7in howitzer in place of the standard 2-pounder (40mm) gun.
A total of just 125 vehicles were constructed: fifty by Vickers-Armstrongs and seventy-five by Harland and Wolff in Belfast. The Mk I cruisers saw service in France in 1940 and in the Middle East the following year; however, although the main gun was effective against the Italian tanks, it was no match for the more sophisticated German machines. The crews also complained that the design was unreliable and was prone to shedding tracks.
Cruiser Tank Mk II (A10)
Three months after starting work on the A9, Sir John Carden’s team at Vickers-Armstrongs began designing an infantry version, designated A10. However, despite the armour being increased to a maximum of 30mm using bolt-on plates, the design was felt to be inadequately protected for the infantry-support role and it was reclassified as a heavy cruiser, becoming the cruiser tank Mk II. Even as a cruiser it was not successful, however, and despite the suspension being found to work well in the desert, the War Office criticised the machine for being slow and underpowered, with a poor cross-country performance.
In design the hull was similar to the A9, although the auxiliary machine-gun turrets were omitted, which allowed the crew to be reduced to five. The Vickers ‘slow motion’ suspension was retained, as was the AEC A179 petrol engine and the five-speed transmission. Measuring 217in in length, making it slightly shorter than the A9, but with the width identical at 100in, the additional armour put the weight up to 13.75 tons, having the effect of bringing the top speed down to 16mph on hard surfaces and 8mph off the road.
The main gun was the 2-pounder (40mm); there was also a single coaxial Vickers .303in water-cooled machine gun, and a 7.92mm Besa machine gun in a barbette to the right of the hull, making it the first British tank to be fitted with an air-cooled machine gun. On the Mk IIA there was an armoured radio housing and a redesigned mount for the main gun; the Vickers machine gun was also omitted in favour of a second 7.92mm Besa machine gun. As with the A9, there was also a close-support variant (cruiser tank Mk II CS) mounting a 3.7in howitzer.
Production started in 1938, and the type was built by Vickers-Armstrongs (ten), Metropolitan-Cammell Carriage and Wagon Company (forty-five) and the Birmingham Railway Carriage and Wagon Company (120). Like the A9, the A10 was never considered to be more than a stop-gap measure whilst the A13 was developed.
Cruiser Tank Mk III (A13)
The cruiser tank Mk III was probably the most significant British tank of the interwar period and made much of what had gone before redundant. Developed by Morris Commercial Cars and constructed in small numbers by the company’s newly established munitions subsidiary, Nuffield Mechanizations and Aero, it was the first British tank to incorporate the suspension that had been designed by the American J. Walter Christie. Using a combination of short swinging arms bearing against long coil springs, the suspension gave the tank a standard of off-road performance that was far in advance of anything previously seen in a British tank and the Christie suspension went on to be used on all subsequent British cruiser tanks.
Although Morris Commercial had been supplied with two Christie tanks from the USA during 1936, the hull of these machines was considered to be too small to accept the typical British turret and the decision was made to incorporate the suspension into a completely new hull. The opportunity was also taken to incorporate Newton and Bennett telescopic hydraulic shock absorbers. The A13 was powered by a rear-mounted Nuffield Liberty V12 tank engine, the origins of which went back to an aero engine designed in 1917. With a power output of 340bhp from a capacity of 27,022cc, the engine was coupled to the rear sprockets via a four-speed manual gearbox. In prototype form, the vehicle was capable of a maximum speed on the road of more than 35mph, with 25mph achievable across country–this led to various mechanical problems. Eventually the road speed was governed to 30mph; in conjunction, the transmission was modified and the tracks redesigned, with a shorter pitch between links.
With an overall height of 100in, and an overall length of 237in, the A13 seemed long and low, an illusion reinforced by the large-diameter road wheels that also served as track-return rollers. The turret was similar to that fitted to the A9 and A10, and the main gun was the familiar 2-pounder (40mm), together with a coaxial Vickers .303in water-cooled machine gun. The maximum thickness of armour was just 14mm, giving a battle weight of 14 tons.
Trials began in October 1937; in January 1938, even before the trials were completed, sixty-five vehicles were ordered, with deliveries scheduled to begin in early 1939.
Cruiser Tank Mk IV (A13 Mk II)
With the design redesignated as A13 Mk II, the cruiser tank Mk IV was fitted with a new style of turret that incorporated distinctive V-section side plates to give a spaced armour configuration. At the same time, new minimum requirements for the armoured protection of cruiser tanks resulted in the maximum thickness of armour on the hull being increased to 30mm, raising the total weight of the vehicle to 14.75 tons. Some examples were built with additional armour covering the gun mantlet. Whilst the turret may have been redesigned, the main gun was still the 2-pounder (40mm), and there was also a coaxial Vickers .303in water-cooled machine gun, which, on the Mk IVA, was replaced by a Besa 7.92mm machine gun. A close-support variant was also produced, mounting a 3.7in howitzer and designated cruiser tank Mk IV CS. The engine, transmission and running gear were unchanged and, despite the increase in overall weight, the maximum road speed remained 30mph.
Some sources suggest that the total production amounted to 655 vehicles, of which 455 were produced by Nuffield Mechanizations and Aero, and a further 200 by the London Midland and Scottish Railway (LMS) workshops, English Electric and Leyland; others suggest that the figure was 240. The A13 Mk II was withdrawn from active service at the end of 1941, but remained in use as a training vehicle.