Cromwell tank
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The Cromwell tank, officially Tank, Cruiser, Mk VIII, Cromwell (A27M), was one of the series of cruiser tanks fielded by Britain in the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. Named after the
English Civil War The English Civil War (1642–1651) was a series of civil wars and political machinations between Parliamentarians (" Roundheads") and Royalists led by Charles I ("Cavaliers"), mainly over the manner of England's governance and issues of re ...
-era military leader
Oliver Cromwell Oliver Cromwell (25 April 15993 September 1658) was an English politician and military officer who is widely regarded as one of the most important statesmen in English history. He came to prominence during the 1639 to 1651 Wars of the Three Ki ...
, the Cromwell was the first tank put into service by the British to combine high speed from a powerful, reliable engine (the
Rolls-Royce Meteor The Rolls-Royce Meteor later renamed the Rover Meteor is a British tank engine that was developed during the Second World War. It was used in British tanks up to 1964. It was a result of co-operation between Leyland Motors and Rolls-Royce who bet ...
) and reasonable
armour Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...
. The intended dual-purpose high velocity gun could not be fitted in the turret, so a medium velocity dual purpose gun was fitted instead. Further development of the Cromwell combined with a high velocity gun led to the
Comet tank The Comet tank or Tank, Cruiser, Comet I (A34) was a British cruiser tank that first saw use near the end of the Second World War, during the Western Allied invasion of Germany. The Comet was developed from the earlier Cromwell tank and mounted ...
. The name "Cromwell" was initially applied to three vehicles during development. Early Cromwell development led to the creation of the A24 Cavalier. Later Cromwell development led to the creation of the competing Tank, Cruiser, Mk VIII, Centaur (A27L) design. The Centaur tank was closely related to the Cromwell, both vehicles being externally similar. The Cromwell and Centaur tanks differed in the engine used; the Centaur had the 410 hp
Liberty engine The Liberty L-12 is an American water-cooled 45° V-12 aircraft engine displacing and making designed for a high power-to-weight ratio and ease of mass production. It saw wide use in aero applications, and, once marinized, in marine use both ...
, the Cromwell had the significantly more powerful 600 hp Meteor; Centaur hulls were converted to Cromwells by changing the engine. The Cromwell first saw action in the
Battle of Normandy Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful invasion of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 (D-Day) with the Norm ...
in June 1944. The tank equipped the armoured reconnaissance regiments of the
Royal Armoured Corps The Royal Armoured Corps is the component of the British Army, that together with the Household Cavalry provides its armour capability, with vehicles such as the Challenger 2 Tank and the Scimitar Reconnaissance Vehicle. It includes most of the A ...
, in the 7th Armoured Division, 11th Armoured Division and the
Guards Armoured Division The Guards Armoured Division was an armoured division of the British Army during the Second World War. The division was created in the United Kingdom on 17 June 1941 during the Second World War from elements of the Guards units, the Grenadier ...
. While the armoured regiments of the latter two divisions were equipped with
M4 Sherman } The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the Military history of the United States during World War II, United States and Allies of World War II, Western Allies in World War II. The M4 Sherman prove ...
s, the armoured regiments of the 7th Armoured Division were equipped with Cromwells. The Centaurs were not used in combat except for those fitted with a 95 mm howitzer, which were used in support of the
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during the amphibious invasion of Normandy.


Development


Initial designs: A23, A24

Development of the Cromwell and Centaur dates to 1940, as the
Crusader tank Crusader, in full "Tank, Cruiser Mk VI, Crusader", also known by its General Staff number A.15, was one of the primary British cruiser tanks during the early part of the Second World War. Over 5,000 tanks were manufactured and they made imp ...
was being readied for service. The
General Staff A military staff or general staff (also referred to as army staff, navy staff, or air staff within the individual services) is a group of officers, enlisted and civilian staff who serve the commander of a division or other large military un ...
was aware that the Crusader would become obsolete, and in late 1940 they set out the specifications for a replacement tank, expected to enter service in 1942, fitted with the
QF 6 pounder 6-pounder gun or 6-pdr, usually denotes a gun firing a projectile weighing approximately . Guns of this type include: *QF 6 pounder Hotchkiss, a 57 mm naval gun of the 1880s; a similar weapon was designed by Driggs-Schroeder for the US Navy ...
gun.
Vauxhall Vauxhall ( ) is a district in South West London, part of the London Borough of Lambeth, England. Vauxhall was part of Surrey until 1889 when the County of London was created. Named after a medieval manor, "Fox Hall", it became well known for ...
responded with the A23, a scaled down version of their A22 Churchill infantry tank. This would have had 75 mm of frontal armour, used a 12-cylinder Bedford engine, carried a crew of five and would have had the same suspension as the A22. Nuffield submitted the A24, heavily based on its Crusader design and powered by its version of the
Liberty engine The Liberty L-12 is an American water-cooled 45° V-12 aircraft engine displacing and making designed for a high power-to-weight ratio and ease of mass production. It saw wide use in aero applications, and, once marinized, in marine use both ...
, a V-12 design dating the late days of
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
and now thoroughly outdated. Nevertheless, as the design was based on the Crusader, it was expected it could be put into production rapidly. The final entry was from Leyland and Birmingham Railway Carriage & Wagon (BRC&W). Their design was similar to the Nuffield, but with different suspension and tracks. The designs were received and examined in January 1941, with Nuffield's A24 being declared the winner on 17 January. Six prototypes of the Cromwell were ordered for the spring of 1942. These arrived four months late, and by this time the design was already outdated. It was put into production anyway, but in service it proved underpowered. Only a small number were built. Delays in the A24 program led to demands to get the
QF 6 pounder 6-pounder gun or 6-pdr, usually denotes a gun firing a projectile weighing approximately . Guns of this type include: *QF 6 pounder Hotchkiss, a 57 mm naval gun of the 1880s; a similar weapon was designed by Driggs-Schroeder for the US Navy ...
into service earlier. This led to a series of up-gunned Crusaders mounting the 6-pounder.


Creation of the Meteor engine

With the start of the war,
Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...
ended car production and set up a design team looking for other ways to use their design capability. The team formed under the direction of
W. A. Robotham William Arthur Robotham (26 November 1899 - 1980) was a Rolls-Royce executive involved in the development of Rolls-Royce cars, during World War II of tanks and tank engines, and post-war of Rolls-Royce and Bentley cars complete with bodies and th ...
at Clan Foundry in
Belper Belper is a town and civil parish in the local government district of Amber Valley in Derbyshire, England, located about north of Derby on the River Derwent. As well as Belper itself, the parish also includes the village of Milford and the ha ...
, north of
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. They began recovering and refurbishing parts from crashed Merlin engines with the intention of using them for non-aviation purposes. In October 1940, Robotham met Henry Spurrier of Leyland Motors to discuss British tank design. The Tank Board desperately needed a more powerful tank engine to replace the aging Liberty. Robotham and Spurrier decided to attempt to fit a refurbished and re-worked
Rolls-Royce Merlin The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litres (1,650  cu in) capacity. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Initially known as the PV-12, it was later ...
engine to a Leyland tank for testing. Design had three priorities:Silver Ghosts and Silver Dawn; W A Robotham; Constable, London * To remove the supercharger and make the engine operate on standard fuel; * To fit the engine into a current
Crusader tank Crusader, in full "Tank, Cruiser Mk VI, Crusader", also known by its General Staff number A.15, was one of the primary British cruiser tanks during the early part of the Second World War. Over 5,000 tanks were manufactured and they made imp ...
so the engine, and the remaining elements of the tank could be tested under greater load; * To improve the cooling system such that the larger output engine could be cooled in the same space. They removed the supercharger from a Merlin Mk. III to downgrade the performance to a suitable level for tank use, reversed the direction of engine rotation to match tank transmissions, and fitted the resulting engine to a Leyland-built Crusader. Delivered to
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on 6 April 1941, the test team had trouble timing its runs because it was so fast, estimating it reached . Leyland arranged to start production of 1,000 examples of the engine as the Meteor. With engine power doubled, it soon became apparent that the additional stresses placed on the Crusader components required significant re-work to increase reliability. Leyland had no spare capacity, and re-work commenced with the help of BRC&W. It was planned to fit this to BRC&W-built versions of their original A24 submission.


Design splits, and production commences: A24, A27L, A27M

Refitting the design of the A24 Cromwell for the Meteor engine was not acceptable to Nuffield, and hence a new specification of tank was created working with Leyland, the A27 Cromwell. In mid-1941, Leyland changed its mind, concerned about cooling problems. This was a major concern for the Tank Board, as cooling issues had been a major problem for the previous generation of Crusader and Covenanter tanks. The Tank board was still committed to the Meteor, but to avoid dedicating all resources into a potentially flawed design, the design was split into three separate vehicles: * A24 Cromwell I under Nuffield, later known as Cavalier. This was based on the existing specification of Liberty engine and Wilson steering, working from experience learned with the Crusader. * A27L Cromwell II initially under
English Electric N.º UIC: 9094 110 1449-3 (Takargo Rail) The English Electric Company Limited (EE) was a British industrial manufacturer formed after the Armistice of 11 November 1918, armistice of World War I by amalgamating five businesses which, during th ...
, but design taken over by Leyland, later known as Centaur. This was to be based on a revised and upgraded Liberty engine and the newly available Merrit-Brown gearbox as used on the Churchill tank. * A27M Cromwell III under BRC&W, which carried the Cromwell name through to production and service. This was to be based on the new Meteor engine and the Merrit-Brown gearbox, but was also to be designed such that the Liberty engine could be fitted if problems arose. These early design designations of Cromwell I, II, and III are not to be confused with the later production designations of Cromwell I, II, etc. which were production variants of the A27M. While Leyland continued with the Liberty under A27L, the Tank Board continued with the Meteor engine by placing an order directly with Rolls-Royce. Leyland also suggested using a diesel engine of their own design, although this was later abandoned. Cromwell's cooling system was a new design and put through over nine months of testing in a variety of configurations. This included the development of new fan drives and inlet louvres, which can be seen on the Cromwell engine deck. The resulting system for a Meteor-powered tank delivered both the necessary cooling performance, and reduced the power lost in driving the cooling system from 90 hp to 30 hp.Development of Cromwell Series, FVDE This made the performance improvement of the Meteor over the Liberty even more pronounced and left room for expected development of the A27. The first (mild steel) prototype of a Meteor-powered A27M Cromwell was delivered to the Army for trials in March 1942, several months before the A24 that was supposed to precede it, and also prior to the A27L Centaur pilot vehicle. With nearly it proved to be exceptionally mobile when tested. Orders were placed for both A27L and A27M versions as there were concerns about the production rate of the Meteor. Design also commenced on a 17-pounder armed version under specification A30, leading to parallel development of the A30 Challenger. As all of Rolls-Royce's production capacity was engaged in producing the Merlin engine for aircraft, production of the Meteor version was initially based solely on parts recovered from crashed aircraft, with many engines still showing crash damage. Additional sources for manufacturing the Meteor engine were investigated. Even when assigned reduced production quotas, BRC&W proved unable to meet the demand for Cromwell, and Leyland became the design and production parent of both the A27L and A27M versions including subcontracted work.


Rover engine production

Rolls was at this time having trouble meeting demand for the Merlin, let alone the Meteor. Meanwhile,
Rover Rover may refer to: People * Constance Rover (1910–2005), English historian * Jolanda de Rover (born 1963), Dutch swimmer * Rover Thomas (c. 1920–1998), Indigenous Australian artist Places * Rover, Arkansas, US * Rover, Missouri, US ...
was having troubles developing
Frank Whittle Air Commodore Sir Frank Whittle, (1 June 1907 – 8 August 1996) was an English engineer, inventor and Royal Air Force (RAF) air officer. He is credited with inventing the turbojet engine. A patent was submitted by Maxime Guillaume in 1921 for ...
's Power Jets W.2 jet engine design due to increasing animosity between the engineers at
Power Jets Power Jets was a British company set up by Frank Whittle for the purpose of designing and manufacturing jet engines. The company was nationalised in 1944, and evolved into the National Gas Turbine Establishment. History Founded on 27 Januar ...
and Rover. Things became particularly heated when Whittle learned that Rover had set up a secret lab to develop their own versions of the design. Whittle had, during the same period, contacted Rolls for help delivering some of the required parts that Rover proved unable to produce. A solution to both their problems was offered by
Ernest Hives Ernest Walter Hives, 1st Baron Hives (21 April 1886 – 24 April 1965), was the one-time head of the Rolls-Royce Aero Engine division and chairman of Rolls-Royce Ltd. Hives was born in Reading, Berkshire to John and Mary Hives, living at 31 C ...
, a Rolls board member, who had met Whittle and was fascinated by the jet engine (Rolls-Royce's major product was piston aero engines). Hives called a meeting with his counterpart at Rover,
Spencer Wilks Spencer Bernau Wilks (26 May 189110 March 1971) was a British manager and administrator in the motor manufacturing industry. He served variously in positions including Managing Director, Chairman, and President of the Rover Company from 1929 unt ...
, and the two met late in 1942 at the Swan and Royal pub in
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. Hives offered to trade the Meteor for the W.2, an offer Wilks jumped at. Rover set up production at their Tyseley factory, and an additional line was set up by
Morris Motors Morris Motors Limited was a British privately owned motor vehicle manufacturing company formed in 1919 to take over the assets of William Morris's WRM Motors Limited and continue production of the same vehicles. By 1926 its production represent ...
in Coventry. Production began in November 1942. That month, new names were given to all three designs; the original A24 Cromwell I became the
Cavalier The term Cavalier () was first used by Roundheads as a term of abuse for the wealthier royalist supporters of King Charles I and his son Charles II of England during the English Civil War, the Interregnum, and the Restoration (1642 – ). It ...
, the Liberty powered A27L Cromwell II became Centaur, and the Meteor powered A27M kept the name Cromwell. It would take considerable time for Rover to make ready production lines for the Meteor, and it was not until a few months later, in January 1943, that sufficient Meteor engines were available and the A27M Cromwell began production. The official handover of the Meteor and W.2 took place on 1 January 1943.


Possible cancellation, and armaments trouble

To increase production of Meteor engines Rover and Morris required machine tools from the US, which took time to arrive. In the interim, Centaur production continued, to avoid closing Cromwell tank production lines. The Cromwell had originally been intended to mount the high velocity QF 6-pounder tank gun as primary armour piercing (AP) armament with a few mounting the
Ordnance QF 95 mm howitzer The Ordnance QF 95-mm howitzer was a British howitzer built in two versions during the Second World War. The tank howitzer version was accepted for service use, but the infantry version was not. Design and development The Ordnance QF 95-mm tank ...
to fire high explosive and smoke shells as close support tanks. The earlier introduction of US M3 Grant and
M4 Sherman } The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the Military history of the United States during World War II, United States and Allies of World War II, Western Allies in World War II. The M4 Sherman prove ...
tanks placed a dual purpose 75 mm gun into British and Commonwealth service. The 75 mm could fire a more effective HE shell than the 6-pounder at the cost of a reduction in armour-piercing performance. The 6-pounder firing solely AP shells was a retrograde step. Once the Vickers 75 mm HV gun was seen to be too big for the Cromwell turret, work was begun in December 1942 on the
Ordnance QF 75 mm The Ordnance QF 75 mm, abbreviated to OQF 75 mm, was a British tank gun of the Second World War. It was obtained by boring out the Ordnance QF 6-pounder ("6 pdr") 57 mm anti-tank gun to 75 mm, to give better performance against infantry ...
(a development of the 6-pounder that fired US ammunition) for fitting to British tanks. Mark IV Cromwells were delivered with 75 mm guns from November 1943. To maintain the capability to take on Axis tanks, production was to be split: * 10 percent fitted with
Ordnance QF 95 mm howitzer The Ordnance QF 95-mm howitzer was a British howitzer built in two versions during the Second World War. The tank howitzer version was accepted for service use, but the infantry version was not. Design and development The Ordnance QF 95-mm tank ...
; * 30 percent with a high velocity weapon: either 6-pounder or under the A30 development the 76mm 17-pounder; * 60 percent with a ''dual purpose weapon''. Noting the problems with the medium velocity 75 mm dual purpose weapon, Vickers had already commenced development of a high velocity 75 mm gun that would fire American 75 mm ammunition but at a much higher velocity. A complete move to Sherman tanks was not acceptable to British forces who would then be dependent on the US for tank production. At the same time, Cromwell with the Meteor engine and a HV weapon was shown to have superior power ''and'' armament, while US efforts to produce the Sherman replacement, the T20 Medium Tank, were not receiving sufficient attention. A compromise was achieved with a reduction in British tank production during 1943 and 1944, with an increase in consumption of Sherman tanks, the remainder being delivered in parts as spares. Centaur production bore the brunt of this reduction, having only been continued to maintain factories producing Cromwell hulls while the number of Meteor engines was inadequate. It had already been arranged that Centaur production would be phased out when Meteor engine production increased. The list of machine tools required for the increase in Meteor output was also agreed, allowing Cromwell manufacture to scale. At the same time as negotiations with the US, problems were being encountered with the use of the Vickers 75 mm HV gun in the Cromwell, with a larger turret ring being required. This was now expected to be introduced in mid 1944, leaving the majority of Cromwells with the medium velocity gun similar to the Sherman. Design of the high velocity variant was split to a separate specification. Intended as just another version of Cromwell, the new A34 version eventually needed significant re-engineering leading to production of the A34 Comet, which used a high velocity gun firing 17-pounder ammunition from a gun by a smaller cartridge down a shorter barrel. In the interim, the A27M version started.


Early trials

The first real field test of the design was carried out in August–September 1943, when examples of the Centaur and Cromwell were tested against Shermans (the diesel-engined M4A2 and multibank petrol-engined M4A4) in Exercise Dracula, a long trip around Britain. The Shermans proved to be the most reliable by far, requiring 420 hours of specialist fitter attention over a total distance travelled of with 199 defects. This corresponds to 0.03 hours per mile. In comparison, the Cromwells drove with 367 defects and required 814 hours, or 0.07 hours per mile. The Centaur managed only with 297 defects, due to constant breakdown, and required 742 hours, or 0.087 hours per mile. The Cromwell and Centaur were given additional time to work out these problems. The Cromwell problems were mostly related to oil leaks and brake and clutch failures, an observer noting that these were well-known and should already have been corrected. The crews expressed their love for the design and especially its speed and handling. The Centaur was largely dismissed, with one observer expressing his hope that units were being equipped with it only for training purposes. The same reviewers unanimously supported the Sherman. A similar test in November demonstrated the Cromwell was improving, while the underpowered Centaur fared no better than in the first test. Alongside Cromwell production, Centaur production design also allowed for the later conversion to the Meteor engine. A small number were retro-fitted for trials as Cromwell III and Cromwell X. As the Cromwell proved itself, larger numbers were fitted with the Meteor engine on the production line as Cromwell III and IV (not to be confused with the earlier Cromwell III design project).


Final specification

The production model design was finalised on 2 February 1944 when Leyland released specifications for what they called the "Battle Cromwell". This included a number of minor changes to the basic design, including of extra armour below the crew compartment, the introduction of an all-round vision cupola for the commander,
seam welding Electric resistance welding (ERW) is a welding process where metal parts in contact are permanently joined by heating them with an electric current, melting the metal at the joint. Electric resistance welding is widely used, for example, in manufa ...
all joints to waterproof and strengthen the tank, and standardising on the A27M version with Meteor engine and Merritt-Brown transmission. The Cromwell Final Specification was applied part way through the production of Cromwell III and IV, changing the appearance and specification of both vehicles. The specification was later improved toward the end of the war with the Cromwell VII, resulting in an upgrade programme. Centaur and Cavalier never met the requirements to enter front-line service. Most were used for training, although a few notable exceptions were used in action.


Production

Total A27 production consisted of 4,016 tanks, 950 of which were Centaurs and 3,066 Cromwells. In addition, 375 Centaur hulls were built to be fitted with an anti-aircraft gun turret; only 95 of these were completed. Production was led by
Leyland Motors Leyland Motors Limited (later known as the Leyland Motor Corporation) was a British vehicle manufacturer of lorries, buses and trolleybuses. The company diversified into car manufacturing with its acquisitions of Triumph and Rover in 1960 and 1 ...
on Centaur, and
Birmingham Railway Carriage and Wagon Company The Birmingham Railway Carriage and Wagon Company (BRC&W) was a railway locomotive and carriage builder, founded in Birmingham, England and, for most of its existence, located at nearby Smethwick, with the factory divided by the boundary be ...
(BRC&W) on Cromwell. Several other British firms also built Centaur and Cromwell tanks, however, as the numbers required were greater than any one company could deliver. Companies contracted to build the tanks included
English Electric N.º UIC: 9094 110 1449-3 (Takargo Rail) The English Electric Company Limited (EE) was a British industrial manufacturer formed after the Armistice of 11 November 1918, armistice of World War I by amalgamating five businesses which, during th ...
,
Harland and Wolff Harland & Wolff is a British shipbuilding company based in Belfast, Northern Ireland. It specialises in ship repair, shipbuilding and offshore construction. Harland & Wolff is famous for having built the majority of the ocean liners for the W ...
, John Fowler & Co.,
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,
Metro-Cammell Metro-Cammell, formally the Metropolitan Cammell Carriage and Wagon Company (MCCW), was an English manufacturer of railway carriages, locomotives and railway wagons, based in Saltley, and subsequently Washwood Heath, in Birmingham. Purchased ...
,
Morris Motors Morris Motors Limited was a British privately owned motor vehicle manufacturing company formed in 1919 to take over the assets of William Morris's WRM Motors Limited and continue production of the same vehicles. By 1926 its production represent ...
and
Ruston-Bucyrus Ruston-Bucyrus Ltd was an engineering company established in 1930 and jointly owned by Ruston and Hornsby based in Lincoln, England and Bucyrus-Erie based in South Milwaukee, Wisconsin, the latter of which had operational controlThe Amazing ...
. Production of Cromwell and Centaur was split into two different groups. Cromwell was to be built by BRC&W and Metro-Cammell while Centaur was to be built by Leyland, English-Electric, Harland & Wolf, John Fowler & Co., LMS, Morris, Ruston-Bucyrus. Nuffield also switched production to Centaur when Cavalier completed. To increase Cromwell production capacity, English Electric switched from manufacturing Centaur to Cromwell, but remained tooled for Centaur. This resulted in a number of Cromwells being built with Centaur hulls. By January 1943, when production started, Leyland had become the production and design lead for A27 series including subcontractors producing components. Records show that John Fowler & Co. also produced both varieties. Vauxhall produced two Cromwell pilot models—with a turret similar to that of the
Churchill Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from 1 ...
—in the expectation that they would build Cromwells once production of Churchill was terminated in 1943, but Churchill production was extended and Vauxhall withdrew from the Cromwell programme.


Design


Hull

The frame was of riveted construction, though welding was used later. The armour plate was then bolted to the frame; large bosses on the outside of the plate were used on the turret. The suspension was of the Christie type, with long helical springs (in tension) angled back to keep the hull sides low. Of the five road wheels each side, four had shock absorbers. The tracks were driven by sprocketed wheels at the rear and tension adjusted at the front idler, this being standard British practice. Some variants were produced with tracks; later, 15.5-inch tracks were used. As with previous Christie-suspension cruiser tanks, there were no track return rollers, the track being supported instead on the tops of the road wheels, known as the "slack-track" design. The side of the hull was made up of two spaced plates, the suspension units between them, and the outer plate having cutouts for the movement of the road-wheel axles. The gearbox had five forward and one reverse gears. The first gear was for "confined spaces, on steep inclines or...sharp turns". The transmission was the new Merrit-Brown Z.5, which offered differential steering without clutching or braking, a major advance on previous designs. It gave the Cromwell superb manoeuvrability. The Meteor engine delivered 540 hp at 2,250 rpm giving the Cromwell speed as well as manoeuvrability. This was the maximum rpm, which was limited by governors built into the magnetos. Fuel consumption on "pool" petrol (67
octane Octane is a hydrocarbon and an alkane with the chemical formula , and the condensed structural formula . Octane has many structural isomers that differ by the amount and location of branching in the carbon chain. One of these isomers, 2,2,4-Tri ...
) was between 0.5 and 1.5 miles per gallon depending on terrain. The driver sat on the right in the front of the hull, with the hull gunner on the left, separated by a bulkhead. The driver had two periscopes and a visor in the hull front. The visor could be opened fully or a small "gate" in it opened; in the latter case, a thick glass block protected the driver. A bulkhead with access holes separated the driver and hull gunner from the fighting compartment. A further bulkhead separated the fighting compartment from the engine and transmission bay. The engine compartment drew cooling air in through the top of each side and the roof and exhausted it to the rear. To allow fording through up to deep water, a flap could be moved to cover the lowermost air outlet. Air for the engine could be drawn from the fighting compartment or the exterior; it was then passed through oil bath cleaners. It was modified so that the exhaust fumes were redirected so that they were not drawn into the fighting compartment, a problem found when tanks were drawn up together, preparing to advance. In June 1944, the Cromwell saw action during
Operation Overlord Operation Overlord was the codename for the Battle of Normandy, the Allies of World War II, Allied operation that launched the successful invasion of German-occupied Western Front (World War II), Western Europe during World War II. The operat ...
, the
Allied An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...
invasion of Normandy. It had a mixed reception by crews, being faster, and with a lower profile than the
Sherman tank } The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. It w ...
, but also being smaller and more cramped. Cromwell had of frontal armour, compared with on the glacis of the early Shermans, though it was unsloped and hence less effective in practice. 123 Cromwells were later produced with applique armour on the hull front that reached .


Turret and armament

Following British tank doctrine of the time, the vehicle was designed to fire on the move. The turret offered hydraulically powered turret traverse motors with proportional speed control. Later vehicles fitted an all-round view cupola for the commander to identify and track targets. Both gunner and commander had rotating and pivoting Vickers Gundlach tank periscopes, while fixed episcopes were fitted in the cupola. There was a 7.92 mm
Besa machine gun The Besa machine gun was a British version of the Czechoslovak ZB-53 air-cooled, belt-fed machine gun (called the TK vz. 37 in the Czechoslovak army"TK" from ''těžký kulomet'' "heavy machine gun"; "vz" from ''vzor'' "Model"). The name came ...
mounted co-axially to the main armament, operated by the gunner. A second was gimbal mounted in the front of the hull, with 45 degrees horizontal and 25 degrees vertical movement. Sighting was by a No. 35 telescope, which was connected through a linkage to the mounting. In the top of the turret was a 2-inch "bombthrower" angled to fire forward. Thirty
smoke grenade Smoke grenades used at demonstrations in Paris, 2008 upBritish L83A1 Smoke Grenade manufactured in May 2008. This grenade has already been used. A smoke grenade is a canister-type grenade used as a signaling device, target or landing zone mark ...
s were carried for it. Early models of the Cromwell were equipped with the QF 6-pounder (57 mm). Using the new
armour-piercing discarding sabot Armour-piercing discarding sabot (APDS) is a type of spin-stabilized kinetic energy projectile for anti-armour warfare. Each projectile consists of a sub-calibre round fitted with a sabot. The combination of a lighter sub-calibre projectile wit ...
round, which became available in quantity in early 1944, this gun could penetrate over 100 mm of steel armour at ranges on the order of , making it effective against all but the most heavily armoured tanks. However, British tankers had long complained about this weapon's lack of a useful
high explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
(HE) round for attacking soft targets like trucks, anti-tank guns and infantry defences. A HE shell had been introduced for the 6-pounder, but it was described as being largely useless—the calibre of the gun was simply too small to carry a useful load of explosive. This was not entirely accidental; British tank policy of the time suggested that different models of the same tank, carrying different specialised weapons, was a better solution to this problem than a single weapon that attempted to do all things. Experience with the US M3 75 mm gun suggested this thinking was wrong, that a single gun could be used in a "dual purpose" role against both tanks and softer targets. This led Vickers to begin development of a 75 mm weapon of 50 calibres in length, which would fire the same HE shell as the US gun, but with a higher propellant load that would make its anti-tank rounds more effective. However, as examples of this weapon began to arrive in May 1943, it was clear it would not fit into any turret that could be mated to the Cromwell's turret ring. This problem was eventually solved by the realisation that the 6-pounder could be bored out to 75 mm and fire unmodified US ammunition. While this would lead to less anti-tank performance, this was considered a reasonable trade-off in exchange for the rapid introduction of the HE rounds. The resulting ROQF 75 mm could be easily swapped out with the 6-pounder, and newly built models mounting the gun were known as the Mark V. The ROQF 75 mm would be the primary weapon for the majority of Cromwells produced. A close support version of the Cromwell was fitted with the QF 95 mm howitzer in place of the 75 mm. This too fired HE, though its primary role was delivering smoke shells, covering the other tanks in the unit. Some command or OP tanks had the armament removed, leaving space in the turret for further radios. These were fitted with a dummy wooden gun, so as not to appear different to the enemy and attract hostile fire.


Cromwell and Centaur differences

Aside from the engine and its ancillaries (fans, radiator, clutch, etc.), both vehicles are very similar designs. While similar however, there were a number of minor variations between Cromwell and Centaur caused by the divergence of design and production. Increases in Cromwell's design weight from 24 to 27 tons resulted in a reworking of the suspension during the design process, which was not reflected on Centaur. Cromwell had heavier grade suspension with longer suspension arms. Cromwell's shock absorbers and springs were improved against Cavalier, and increased to four (compared with Centaur's three). The method of track tensioning is a commonly noted difference. Initially, the design based on A24 Cavalier used a worm drive for tensioning. This was noted as being slow to operate, and trapped dirt. BRC&W developed an alternative ratchet mechanism based on the
Valentine tank The Tank, Infantry, Mk III, Valentine was an infantry tank produced in the United Kingdom during World War II. More than 8,000 of the type were produced in eleven marks, plus various specialised variants, accounting for approximately a quarter ...
, and this was incorporated into the A27M Cromwell design, also enabling the tank to accept wider tracks. Centaur under Leyland continued without this development. Some of these differences can be seen in Cromwells built with Centaur hulls, although many were removed with the introduction of the Cromwell Final Specification. This included the Cromwell method of track tensioning. By comparison, Cavalier can easily be identified by the vehicle's rear armour plate, which incorporates Crusader style horizontal angled exhaust louvres. Cromwell and Centaur both have a flat rear armour plate, with exhaust venting to the top immediately behind the engine deck. For this reason, many Cromwell and Centaur vehicles had a cowl fitted to direct the exhaust gases back where they could not re-enter the tank fighting compartment.


Further developments

An earlier requirement for a 17-pounder armed tank became more important when the Vickers HV 50 calibre 75mm gun failed to fit on Cromwell. A version of Cromwell mounting the more powerful Ordnance QF 17-pounder (76.2 mm) had been commenced by BRC&W early in the development process. This required a much larger turret ring, which in turn required the hull to be lengthened (with an additional road wheel added to each side for a total of six) and the centre hull section widened. The result was the A30
Cruiser Mk VIII Challenger The Tank, Cruiser, Challenger (A30) was a British tank of World War II. It mounted the QF 17-pounder anti-tank gun on a chassis derived from the Cromwell tank to add anti-tank firepower to the cruiser tank units. The design compromises made ...
, but had its limitations and only 200 were produced. While successful, production ceased in favour of the much easier conversion of
Sherman Firefly The Sherman Firefly was a tank used by the United Kingdom and some armoured formations of other Allies in the Second World War. It was based on the US M4 Sherman, but was fitted with the more powerful 3-inch (76.2 mm) calibre British 17- ...
, originally developed as a safeguard for the A30 programme, allowing greater numbers to be fielded. However, development of the Vickers HV 50 calibre 75mm gun continued, with the bore increasing to fire modified versions of the 17-pounder ammunition. This gun and its ammunition were designed specifically to fit in a turret that a reworked Cromwell-sized design could carry. This became the 77 mm HV with only slightly lower performance than the base 17-pounder. By the time this weapon was ready, a number of other changes had been worked into the tank design, producing the
Comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
, which replaced both the Cromwell and Challenger.


Performance

The A24 design specification had originally been constrained by the available tank engines of the time, delivering only 300 hp and limiting the weight. The evolution to A27M increased the weight slightly, but fitting a 600 hp engine almost doubled the power-to-weight ratio and created a very fast tank. This was combined with the Merrit-Brown gearbox that allowed the tank to steer while still powering both tracks, allowing it to maintain speed while manoeuvring, while tanks like the Sherman or T-34 lost power while turning and necessarily slowed down. Cromwell was the fastest British tank to serve in the Second World War, with a top speed of . This speed was extremely beneficial in both attack and defence, outmanoeuvring opponents. At least one case is known of vehicle commanders using the vehicle's fast speed to jump large gaps. In the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
, a troop of three Cromwells was able to leap a wide canal when surprised by enemy forces. This speed proved too much for even the Christie suspension and in later models the final drive ratio was changed to lower the top speed to , which was still fast for its time. The Cromwell's armament was changed from the 6-pounder to the dual purpose 75mm. This gave a significant reduction in armour penetration compared to newer 6-pounder
Armour-piercing discarding sabot Armour-piercing discarding sabot (APDS) is a type of spin-stabilized kinetic energy projectile for anti-armour warfare. Each projectile consists of a sub-calibre round fitted with a sabot. The combination of a lighter sub-calibre projectile wit ...
ammunition, which was becoming available, but added the ability to fire High Explosive shells, which were more capable against other targets, such as
anti-tank gun An anti-tank gun is a form of artillery designed to destroy tanks and other armored fighting vehicles, normally from a static defensive position. The development of specialized anti-tank munitions and anti-tank guns was prompted by the appearance ...
s. The High Velocity 75mm gun was developed in an attempt to give both good anti-tank and HE performance, but in May 1943 proved too big to be fitted to the Cromwell. This issue led to the development of the A34 Comet, while the gun bore was increased to 76.2mm to gain compatibility with the 17-pounder ammunition albeit with smaller shell casings with less propellant. The lack of a high-velocity weapon proved to be a significant limitation against opponents such as the Tiger, and Cromwell had to rely on mobility. The dual-purpose 75 mm main gun fired the same ammunition as the US 75 mm gun as used on the Sherman, and was also fitted to the Churchill and other British tanks later in the war, it had around the same HE and armour-piercing capabilities as the 75 mm equipped Sherman tank. The Cromwell's speed and low profile gave an advantage over the Sherman however, giving the tank the element of surprise and making return fire more difficult. Cromwell crews in North-West Europe succeeded in outflanking the heavier and more sluggish German tanks with superior speed, manoeuvrability and reliability. The armour on the Cromwell ranged from up to thick overall. On all-welded vehicles built by BRC&W, the weight saved by the welding allowed for the fitting of additional
appliqué armour Military vehicles are commonly armoured (or armored; see spelling differences) to withstand the impact of shrapnel, bullets, shells, rockets, and missiles, protecting the personnel inside from enemy fire. Such vehicles include armoured fightin ...
plates on the nose, vertical driver's plate and turret front, increasing the maximum thickness there to . These vehicles are identified by their War Department numbers carrying the suffix W, e.g. T121710W. The armour compared well with that of the Sherman, although the Cromwell did not share the Sherman's sloped glacis plate. While the Cromwell was a match for the majority of Axis tanks in use, it was not a match for the armour and armament of the latest German heavy vehicles developed at the same time. British tank design would go through another stage, the
Comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
cruiser, before developing the Centurion tank.


Combat service


World War II

The Cromwell tank entered front-line service with the Allied invasion of Normandy in June 1944. Cromwells landed with the following forces on D+1. They saw extensive action with the British Army, forming part of the
6th Airborne Division The 6th Airborne Division was an airborne infantry division of the British Army during the Second World War. Despite its name, the 6th was actually the second of two airborne divisions raised by the British Army during the war, the other being t ...
, 7th Armoured Division, 11th Armoured Division,
Guards Armoured Division The Guards Armoured Division was an armoured division of the British Army during the Second World War. The division was created in the United Kingdom on 17 June 1941 during the Second World War from elements of the Guards units, the Grenadier ...
, and 1st (Polish) Armoured Division. The tank was also used by the 1st (Czechoslovakian) Independent Armoured Brigade Group as part of the First Canadian Army in Dunkirk. Cromwells were used as the main tank in the armoured brigades of the 7th Armoured Division, while being used in the armoured reconnaissance regiments of the other British armoured divisions, Guards Armoured Division and 11th Armoured Division, in North-west Europe. It excelled at this task because of its speed and low profile. The tank was praised for its speed and reliability, while its low profile made it harder to spot. The standard 75mm gun could tackle the majority of German armoured vehicles, and the HE shell was effective, but could not penetrate the front of heavier German tanks such as the
Tiger The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...
or
Panther Panther may refer to: Large cats *Pantherinae, the cat subfamily that contains the genera ''Panthera'' and ''Neofelis'' **'' Panthera'', the cat genus that contains tigers, lions, jaguars and leopards. *** Jaguar (''Panthera onca''), found in So ...
. Although a rare occurrence on the battlefield, during the Battle of Normandy it was in the British sector where the majority of these German machines were encountered. The issue with the 75mm gun was perhaps most pronounced during the
Battle of Villers-Bocage The Battle of Villers-Bocage took place during the Second World War on 13 June 1944, one week after the Normandy Landings, which had begun the Western Allies' conquest of German-occupied France. The battle was the result of a British attempt to ...
in which the Cromwells were unable to engage German Tiger tanks frontally with any reasonable chance of success. Several Tigers were knocked out by British forces in the battle nonetheless. The 75mm HV had been intended to rectify this, but prior to entering service it was found to be too large to fit in the Cromwell turret. Instead Cromwells fought alongside the 17pdr armed
Sherman Firefly The Sherman Firefly was a tank used by the United Kingdom and some armoured formations of other Allies in the Second World War. It was based on the US M4 Sherman, but was fitted with the more powerful 3-inch (76.2 mm) calibre British 17- ...
or Challenger, both of which could destroy Panthers and Tigers at standard combat distances. Cromwells (and 75mm armed Shermans) were supplemented by these vehicles at varying ratios per troop of 1/2 to 1/3. Though this provided a good solution to the issue of heavy German tanks, it added an additional level of complexity for battlefield commanders in having to place the 17pdr armed vehicles tactically within a formation. However this complication was not unique to the British Army, the US employed similar methods and faced the same issue with their 75mm armed Sherman tanks. This situation persisted until the development of the A34 Comet was concluded, mounting the new 77mm HV gun and removing the need for mixed units. In contrast, the Centaur was chiefly used for training; only those in specialist roles saw action. The Centaur IV Close Support version with a 95 mm howitzer saw service in small numbers as part of the Royal Marine Armoured Support Group on
D-Day The Normandy landings were the landing operations and associated airborne operations on Tuesday, 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during World War II. Codenamed Operation Neptune and often referred to as D ...
. Originally intended to be used from landing craft and serve as static pillboxes, these examples retained the engine allowing the Marines to advance the tank inland. A number of Centaurs were also re-purposed as combat engineering vehicles, such as an armoured bulldozer. The Sherman remained the most common tank in British and other Commonwealth armoured units in Europe. The Cromwell, in turn, was succeeded by small numbers of the Comet tank. This was based on the Cromwell and shared many components but had been designed from the outset to mount a superior gun, the 77 mm tank gun (a version of the 17 pounder with different ammunition). Only the 11th Armoured Division was fully re-equipped with the Comet before the war ended.


Units equipped

* 2nd Battalion
Welsh Guards The Welsh Guards (WG; cy, Gwarchodlu Cymreig), part of the Guards Division, is one of the Foot Guards regiments of the British Army. It was founded in 1915 as a single-battalion regiment, during the First World War, by Royal Warrant of George V. ...
*
8th King's Royal Irish Hussars The 8th King's Royal Irish Hussars was a cavalry regiment in the British Army, first raised in 1693. It saw service for three centuries including the First and Second World Wars. The regiment survived the immediate post-war reduction in forces ...
* 1st Royal Tank Regiment * 5th Royal Tank Regiment * 4th County of London Yeomanry (Sharpshooters) * 5th Royal Inniskilling Dragoon Guards * 2nd Northamptonshire Yeomanry * 15th/19th King's Royal Hussars * 6th Airborne Reconnaissance Regiment, RAC * 16th Independent Armoured Brigade (Polish) * 10th Mounted Rifle Regiment (Polish) *
Royal Marines Armoured Support Group The current Royal Marines Armoured Support Group (RMASG) is an element of the Royal Marines that operates the Viking BvS 10 All Terrain Vehicle. It is based at Bovington in Dorset. The original RMASG was formed in the Second World War to give Bri ...
(Centaur IV)


Post war

During the
Korean War , date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
, the British had a total of 14 Cromwell tanks, including six of the
8th King's Royal Irish Hussars The 8th King's Royal Irish Hussars was a cavalry regiment in the British Army, first raised in 1693. It saw service for three centuries including the First and Second World Wars. The regiment survived the immediate post-war reduction in forces ...
Regiment and eight of the 45th Field Regiment, Royal Artillery. Among them, the Cromwell tanks belonging to the Royal Artillery were artillery observation tanks, which removed the main gun and expanded observation and communication equipment. In December 1950, 14 tanks were organized into a ''Cooper Force'' led by Captain Donald Ashley-Cooper, and were deployed to Jangheung,
Yangju Yangju () is a city in Gyeonggi Province, South Korea. Yangju is located south of Dongducheon and north of Uijeongbu, not far from Seoul. History * 1395 - Renamed to Yangju. * January 1, 1963 - Uijeongbu is separated and becomes a city. * Apr ...
to support the 1st Battalion,
Royal Ulster Rifles The Royal Irish Rifles (became the Royal Ulster Rifles from 1 January 1921) was an infantry rifle regiment of the British Army, first created in 1881 by the amalgamation of the 83rd (County of Dublin) Regiment of Foot and the 86th (Royal County D ...
Regiment, whose duty was to defend northwest of Seoul. On the night of 3 January 1951, the 1st Battalion of the Royal Ulster Rifles and ''Cooper Force'' retreated under orders to withdraw from superior command. During the process, 157 soldiers were killed and all tanks were destroyed or abandoned as they escaped along the gorge without protection provided by friendly units. One of the captured Cromwells operated by the Communist Party was destroyed by a British Centurion tank near Hangang Railway Bridge on February 1. Another captured tank deployed to Wolmido near
Incheon Incheon (; ; or Inch'ŏn; literally "kind river"), formerly Jemulpo or Chemulp'o (제물포) until the period after 1910, officially the Incheon Metropolitan City (인천광역시, 仁川廣域市), is a city located in northwestern South Kore ...
by the communists was recaptured by South Korean marines on February 10. American marines helped South Korean marines to repair the recaptured Cromwell for usage. However, the ''Marine Cromwell'' only rolled for a few days until it was handed back to its original owner, the British. Cromwell Tanks were used by Czechoslovakia and Israel. Fifty-two Centaur I tanks were donated in early 1946 to the
Greek Army The Hellenic Army ( el, Ελληνικός Στρατός, Ellinikós Stratós, sometimes abbreviated as ΕΣ), formed in 1828, is the land force of Greece. The term ''Hellenic'' is the endogenous synonym for ''Greek''. The Hellenic Army is the ...
, during the opening stages of the
Greek Civil War The Greek Civil War ( el, ο Eμφύλιος όλεμος ''o Emfýlios'' 'Pólemos'' "the Civil War") took place from 1946 to 1949. It was mainly fought against the established Kingdom of Greece, which was supported by the United Kingdom ...
but they were kept in storage due to the lack of trained personnel. In 1947, the first Greek officers returned from training courses in the United Kingdom and training of tank crews began. In April 1948, the Centaurs were organised in three Centaur tank companies initially numbered II, IX and XI, but a year later were renumbered 381, 382, 383 and temporarily attached to Reconnaissance Regiments 391, 392, and 393. The Centaurs saw limited service in the war because battles were fought mainly on mountainous areas, but proved useful in supporting infantry units and in defence of inhabited areas. After the end of the war, in October 1949, the three Centaur companies were organised into the 391 Tank Regiment. The Centaurs were replaced by US built M47s and in 1962 were sold and scrapped. One Centaur is preserved in the Greek Army Tank Museum. The British army, Austria and Jordan used the upgraded Charioteer version of the Cromwell post-war. Jordanian vehicles saw action in conflicts in the Middle-East.


Operators

* * * * : Handful captured from the British ''Cooper Force'' during the Korean War. * : 1 recaptured from North Korea then returned to the United Kingdom. * * *


Variants

Development of hull types and armaments occurred independently. Hull types applied to all variants. A single mark could cover up to four types, and a type up to six marks making classification complex. Combinations of mark and type were applied by different manufacturers.


Cromwell

;Cromwell I: Early vehicles armed with the Royal
Ordnance QF 6 pounder The Ordnance Quick-Firing 6-pounder 7 cwt,British forces traditionally denoted smaller ordnance by the weight of its standard projectile, in this case approximately . The approximate weight of the gun barrel and breech, "7 cwt" (cwt = hundredwe ...
(57 mm) gun (with 64 rounds of ammunition). Only 357 produced due to the switch from the 6 pounder (57 mm) to the 75 mm gun. ;Cromwell II: Pilot vehicle built by Vauxhall with cast turret similar to Churchill VII. This did not enter production. ;Cromwell III: Centaur I hull fitted with Meteor V12 engine to A27M standard. Turret houses Royal
Ordnance QF 6 pounder The Ordnance Quick-Firing 6-pounder 7 cwt,British forces traditionally denoted smaller ordnance by the weight of its standard projectile, in this case approximately . The approximate weight of the gun barrel and breech, "7 cwt" (cwt = hundredwe ...
. Only ~ 200 produced due to scarcity of Centaur I's. ;Cromwell IV: Centaur III hull re-engined with Meteor engine. Turret houses 75 mm ROQF Mk V gun. Later Cromwell IV's saw the introduction of the Final Specification, changing some features (such as track-adjuster) to normal Cromwell standard. The most numerous variant with over 1,935 units produced. ;Cromwell V: Cromwell built to Final Specification and armed with the 75 mm gun. ;Cromwell VI: Cromwell built to Final Specification and armed with 95 mm howitzer. 341 produced. ;Cromwell VII: Upgrade to Cromwell IV, V, and VI armed with the 75 mm gun. Some hulls were upgraded with features from later hull types. Wider (15.5 inch) tracks, and upgraded suspension (where not fitted earlier in the production programme). These were introduced very late in the war and did not see much in the way of combat. ~ 1,500 produced, Some saw combat in the
Korean War , date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
and many were later converted to FV4101 Tank, Medium Gun, Charioteer. ;Cromwell VIII: Cromwell VI reworked with same upgrades as VII but retaining the 95 mm howitzer.


Centaur

;Centaur I: Armed with the Royal
Ordnance QF 6 pounder The Ordnance Quick-Firing 6-pounder 7 cwt,British forces traditionally denoted smaller ordnance by the weight of its standard projectile, in this case approximately . The approximate weight of the gun barrel and breech, "7 cwt" (cwt = hundredwe ...
(57 mm) gun (with 64 rounds of ammunition). It was used only for training. 1,059 produced. ;Centaur II: Mark I with wider tracks and no hull machine gun. Experimental only. ;Centaur III: Centaur armed with the 75 mm ROQF Mk V gun. In 1943, most Centaur I were converted to IIIs, but a few remained as such. 233 produced. ;Centaur IV: Centaur armed with a 95 mm howitzer (with 51 rounds of ammunition). This is the only version of the Centaur known to have seen combat, in service with the
Royal Marines Armoured Support Group The current Royal Marines Armoured Support Group (RMASG) is an element of the Royal Marines that operates the Viking BvS 10 All Terrain Vehicle. It is based at Bovington in Dorset. The original RMASG was formed in the Second World War to give Bri ...
. The vehicles were fitted with wading gear to get them ashore. Trunking waterproofed the engine inlets and covers were fitted to the guns. 114 produced. ;Centaur Bulldozer: A Centaur tank with the turret removed and installed a simple winch-operated bulldozer blade. Used as armoured obstacle-clearing vehicle. Issued to the 79th Armoured Division in Belgium during the latter part of 1944.


Hull variants

Hull types ranged from Type A to Type F. Each type applied a different package of changes to the hull design to different marks of tank. Changing the vehicle type allowed the introduction of changes without changing the overall offensive capability.


Vehicles based on chassis


Conversions

A number of further vehicles were based on the Cromwell tank hull, either re-working existing vehicles or built from scratch with the Cromwell as the basis: ;Cromwell Command :The main gun was removed and it carried one each of the No. 19 (Low Power) and No. 19 (High Power) wireless sets. These were used by brigade and divisional headquarters. ;Cromwell Observation Post : Cromwell IV, Cromwell VI, or Cromwell VIII fitted with extra radio equipment; 2 x No. 19 and 2 x No. 38 (portable) radios. The main gun was retained. ;Cromwell Control :Two No. 19 Low Power radio. Main armament kept. Used by regimental headquarters ;Centaur, AA Mk I: Used a Crusader III, Anti-Aircraft Mk II turret fitted with twin 20 mm Polsten guns instead of Oerlikon. Were originally deployed in Normandy, but withdrawn as unnecessary due to Allied air superiority. 95 were produced. ;Centaur, AA Mk II: Same turret as Crusader III, AA Mk III but with twin 20 mm Polsten AA guns. ;Centaur Dozer: A Centaur with the turret removed and given a simple dozer blade operated by a winch. Since the winch passed over the top of the hull it was not possible to retain the turret. Issued one per Cromwell squadron and to RE. One of "
Hobart's Funnies Hobart's Funnies is the nickname given to a number of specialist armoured fighting vehicles derived from tanks operated during the Second World War by units of the 79th Armoured Division of the British Army or by specialists from the Royal En ...
". 250 produced. ;Centaur Observation Post (OP): A Centaur with a dummy main gun, and extra radio communications. ;Centaur
Kangaroo Kangaroos are four marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern gre ...
: A Centaur with turret removed to make space for passengers. (few produced) ;Centaur
Armoured Recovery Vehicle An armoured recovery vehicle (ARV) is typically a powerful tank or armoured personnel carrier (APC) chassis modified for use during combat for military vehicle recovery (towing) or repair of battle-damaged, stuck, and/or inoperable armoured f ...
(ARV): A Centaur with turret removed, and replaced with
winch A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attache ...
fitted instead, and an optional
A-frame An A-frame is a basic structure designed to bear a load in a lightweight economical manner. The simplest form of an A-frame is two similarly sized beams, arranged in an angle of 45 degrees or less, attached at the top, like an uppercase lette ...
. Post-war, a number of Cromwells were upgraded to meet the new
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
threat: ; FV 4101 Charioteer: Cromwell hull with a QF 20 pounder gun in a tall turret, designed in the 1950s to give more fire support. 200 produced.


Designs based on the Cromwell

The Cromwell tank design was also used as the basis for the design of following vehicles: ; A30 Challenger :The design combined a lengthened Cromwell chassis with widened superstructure to mount the 17-pounder gun in a new turret. ;A30 Avenger SP 17pdr :A version of the Challenger using a lighter open-topped turret in a gun-carrier role. ;
A33 Excelsior A33, A 33 or A-33 may refer to : * Douglas A-33, a 1941 American ground-attack fighter aircraft * Excelsior tank, A33 Excelsior British heavy tank prototype * HLA-A33, a human serotype * Samsung Galaxy A33 5G, an Android smartphone and also : * On ...
:An experimental design with elements of
Infantry tank The infantry tank was a concept developed by the United Kingdom and France in the years leading up to World War II. Infantry tanks were designed to support infantrymen in an attack. To achieve this, the vehicles were generally heavily vehicle armo ...
as a possible replacement for
Churchill tank The Tank, Infantry, Mk IV (A22) Churchill was a British infantry tank used in the Second World War, best known for its heavy armour, large longitudinal chassis with all-around tracks with multiple bogies, its ability to climb steep slopes, a ...
. When the Churchill continued to meet requirements, development was halted. ; A34 Comet :A tank based on lessons learned from the Cromwell development, incorporating a larger turret ring, now enabling this class of tank to utilise the latest gun available. This tank reflects much of what was intended for the Cromwell. The majority of following British tank designs utilised the Meteor engine and Merritt-Brown steering & gearbox combination initially developed for the Cromwell, lasting all the way through
Centurion A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 ...
. This proved to be one of the primary elements in the development of the
main battle tank A main battle tank (MBT), also known as a battle tank or universal tank, is a tank that fills the role of armor-protected direct fire and maneuver in many modern armies. Cold War-era development of more powerful engines, better suspension sys ...
.


Surviving vehicles

Around 56 Centaur and Cromwell tanks survive, ranging from scrapyard wrecks to fully restored museum vehicles.


Cromwell tanks

Around 26 Cromwell tanks exist in various states. * Cromwell I.
Royal Australian Armoured Corps Memorial and Army Tank Museum The Royal Australian Armoured Corps Memorial and Army Tank Museum is located at Puckapunyal, an Australian Army training facility and base 10 km west of Seymour, in central Victoria, south-eastern Australia. The base is the home of the R ...
, Puckapunyal, Victoria, Australia. Cromwell MkI shipped to
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
to assist with the up gunning of the Australian Cruiser tanks but did not arrive before that programme had been terminated. Repainted with the markings it arrived in Australia with, it is now under cover on display at the museum. * Cromwell IV.
The Tank Museum The Tank Museum (previously The Bovington Tank Museum) is a collection of armoured fighting vehicles at Bovington Camp in Dorset, South West England. It is about north of the village of Wool and west of the major port of Poole. The collection ...
, Bovington,
Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...
, England. * Cromwell IV Command Tank ''T187617''.
Imperial War Museum Duxford Imperial War Museum Duxford is a branch of the Imperial War Museum near Duxford in Cambridgeshire, England. Britain's largest aviation museum, Duxford houses the museum's large exhibits, including nearly 200 aircraft, military vehicles, artill ...
,
Cambridgeshire Cambridgeshire (abbreviated Cambs.) is a Counties of England, county in the East of England, bordering Lincolnshire to the north, Norfolk to the north-east, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and North ...
, England. * Cromwell IV on
A1065 road The A1065 is a main road in the English region of East Anglia. It provides the principal road connection to parts of the west and north of the county of Norfolk from Newmarket and points south of there, including London. It runs from a juncti ...
Thetford Forest Thetford Forest is the largest lowland pine forest in Britain and is located in a region straddling the north of Suffolk and the south of Norfolk in England. It covers over in the form of a Site of Special Scientific Interest. History The ...
,
Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...
, England, as part of a memorial to 7th Armoured Division ("Desert Rats") whose armoured regiments had trained there prior to embarking for Normandy. * Cromwell IV Rick Wedlock Collection, UK. In running condition. * Cromwell IV. National War and Resistance Museum, Overloon, Netherlands. Recovered after the
Battle of Overloon The Battle of Overloon was a battle fought in the Second World War battle between Allied forces and the German Army which took place in and around the village of Overloon in the south-east of the Netherlands between 30 September and 18 October ...
in October 1944. * Cromwell IV. Heintz Barracks,
Bastogne Bastogne (; nl, Bastenaken, ; german: Bastnach/Bastenach; lb, Baaschtnech) is a city and municipality of Wallonia located in the province of Luxembourg in the Ardennes, Belgium. The municipality consists of the following districts: Bastogn ...
, Belgium. In running condition. * Cromwell IV Wilrijk, Antwerp, Belgium. This was unveiled in September 2014 for the 70th anniversary of the liberation of the city in 1944. * Cromwell IV. Army Technical Museum, Lesany, Czech Republic. In running condition. * Cromwell IV "Faust". Private collection, Czech Republic. In running condition. * Cromwell IV.
Kubinka Tank Museum The Kubinka Tank Museum (Центральный музей бронетанкового вооружения и техники - Tsentral'nyy Muzey Bronetankovogo Vooruzheniya I Tekhniki -Central Museum of Armored Arms and Technology) is a larg ...
, Russia. * Cromwell IV. Museum of Zadorozhniy Tec, Russia. * Cromwell IV and a Cromwell III.
Yad la-Shiryon Yad La-Shiryon (officially: The Armored Corps Memorial Site and Museum at Latrun; he, יד לשריון) is Israel's official memorial site for fallen soldiers from the Israeli Armor Corps, armored corps, as well as one of the most diverse tank ...
Museum, Latrun, Israel. Were used by the
IDF IDF or idf may refer to: Defence forces * Irish Defence Forces * Israel Defense Forces *Iceland Defense Force, of the US Armed Forces, 1951-2006 * Indian Defence Force, a part-time force, 1917 Organizations * Israeli Diving Federation * Interac ...
in War of Independence (1948–1949). * Cromwell IV "Blenheim".
American Heritage Museum The American Heritage Museum is a military history museum located on the grounds of the Collings Foundation in the town of Stow, Massachusetts, west of Boston. The collection consists of over 100 artifacts, most of which were formerly part of ...
,
Stow, Massachusetts Stow is a town in Middlesex County, Massachusetts, United States. The town is located west of Boston, in the MetroWest region of Massachusetts. The population was 7,174 at the 2020 United States Census. Stow was officially incorporated in 1683 ...
, USA. In running condition. * Cromwell IV. Private Collection, St. Louis, Missouri, USA. * Cromwell IV.
The Wheatcroft Collection The Wheatcroft Collection in the United Kingdom is a large and important collection of historical softskin and armoured military vehicles. It is located in Leicestershire, England, and is one of the largest private collections of military vehicles ...
, UK. Unrestored wreck. * Cromwell IV(A27M). Adrian Barrell Collection, UK. Currently just a restored hull with no turret. * Cromwell IV. Rex & Rod Cadman Collection, UK. Unrestored wreck. * Cromwell IV. Heintz Barracks, Bastogne, Belgium. A wreck and not restored. * Cromwell IV. Army Technical Museum, Lesany, Czech Republic. A wreck with no turret. * Cromwell IV. Handmet Military, Gostyń, Poland. A wreck with no turret. * Cromwell IV. Vojenské Museum, Králíky, Czech Republic. A wreck with no turret. * Cromwell IV. Smržovka private tank museum, Czech Republic. Currently a wreck and not restored. * Cromwell IV. Smržovka private tank museum, Czech Republic. A wreck with no turret. * Cromwell IV.
The Wheatcroft Collection The Wheatcroft Collection in the United Kingdom is a large and important collection of historical softskin and armoured military vehicles. It is located in Leicestershire, England, and is one of the largest private collections of military vehicles ...
, UK. * Cromwell IV. Private collection, Czech Republic. This Cromwell hull was a spare parts donor for the restoration of the Cromwell nicknamed "Faust"


Centaur tanks

Around 17 Centaurs and 9 Centaur Dozers exist in various states. * Centaur I. Muzeum Broni Pancernej Centrum Szkolenia Wojsk Lądowych, Poznań, Poland. Being restored to running condition (as of March 2015). * Centaur I. Hellenic Army Armor Museum, Athens, Greece. The Greek Army received 52 Centaur I tanks from the British in 1946. * Centaur IV T215477. Cobbaton Combat Collection, Devon, England. In running condition. * Centaur IV.
Musée des Blindés The ''Musée des Blindés'' ("Museum of Armoured Vehicles") or ''Musée Général Estienne'' is a tank museum located in the Loire Valley of France, in the town of Saumur. It is now one of the world's largest tank museums. It began in 1977 un ...
, Saumur, France. * Centaur IV T185102 ''Vidette'' 95mm. Memorial Pegasus Bridge Museum,
Ranville Ranville () is a commune in the Calvados department in the Normandy region in northwestern France. Ranville was the first French village liberated on D-Day. The village was liberated by the British 13th Parachute Battalion, commanded by Lieute ...
, France. * Centaur IV ''T185075'' . La Brèche d’Hermanville (Sword Beach), France. A Cromwell dozer with Cavalier turret to resemble Centaur support tank. * Centaur IV. Calcada da Ajuda, Lisboa, Portugal. About 24 tanks were sold to Portugal. * Centaur IV. Portuguese Army Cavalry School Museum, Santarém, Portugal. Mounted on a plinth in the town * Centaur IV. Portuguese Army Cavalry School Museum, Santarém, Portugal. * Centaur IV. Santa Margarida da Coutada, Portugal. * Centaur IV. Two found 8 miles offshore in
Bracklesham Bay Bracklesham Bay is a biological and geological Site of Special Scientific Interest in West Sussex. It is a Geological Conservation Review site. It is a coastal bay on the west side of the Manhood Peninsula in West Sussex, England. The bay lo ...
, West Sussex, England. Discovered in a good state of preservation in the
Solent The Solent ( ) is a strait between the Isle of Wight and Great Britain. It is about long and varies in width between , although the Hurst Spit which projects into the Solent narrows the sea crossing between Hurst Castle and Colwell Bay t ...
, but are unlikely to be recovered. * Centaur IV. Dennis Roberts Collection, UK. In running condition. * Centaur VII. Rex & Rod Cadman Collection, Kent, England. Wreck of a Mark VII. * Centaur VII T217875. Kevin Powles Collection. Vehicle under restoration. * Centaur VII.
Salisbury Plain Salisbury Plain is a chalk plateau in the south western part of central southern England covering . It is part of a system of chalk downlands throughout eastern and southern England formed by the rocks of the Chalk Group and largely lies wi ...
firing range, England. Used as live fire target. * Centaur VII. Oberhoffen-sur-Moder, France. Wreck of Centaur VII stored outside with other tank wrecks. * Centaur Dozer. Private Collection, UK. Tank restored to working order. * Centaur Dozer ''T186642''.
The Tank Museum The Tank Museum (previously The Bovington Tank Museum) is a collection of armoured fighting vehicles at Bovington Camp in Dorset, South West England. It is about north of the village of Wool and west of the major port of Poole. The collection ...
,
Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...
, England. Restored. * Centaur Dozer. Isle of Wight Military Museum, Hampshire, England. Restored, 79th Armoured Division insignia painted on hull front. * Centaur Dozer. formerly of Isle of Wight Military Museum, Hampshire, England. Not restored in bad condition. * Centaur Dozer T185462. Ian Galliers Collection UK. Unrestored in bad condition. * Centaur Dozer. Armoured Corps Museum,
Ahmednagar Ahmednagar (), is a city located in the Ahmednagar district in the state of Maharashtra, India, about 120 km northeast of Pune and 114 km from Aurangabad. Ahmednagar takes its name from Ahmad Nizam Shah I, who founded the town in 1494 ...
, Maharashtra, India. * Centaur Dozer ''T185484''. Armoured Corps Museum, Ahmednagar, Maharashtra, India. * Centaur Dozer. Rex & Rod Cadman Collection, UK. Unrestored in bad condition. * Centaur Dozer. Rex & Rod Cadman Collection, UK. Unrestored in bad condition.


Others

There are also a few chassis of indeterminate origin which might be either Centaur or Cromwells. * Two hulls at The Tank Museum, Dorset, England. * A hull in the Rex & Rod Cadman Collection, UK * A hull and a dozer hull owned by Staman International Trading, Nijverdal, Netherlands. * A dozer hull, Defence Services Museum, Myanmar Image:Centaur front.jpg, Centaur IV behind Sword Beach, Normandy, France Image:Puckapunyal-Cromwell-2.jpg, A Cromwell Mk. 1 displayed at the Royal Australian Armoured Corps Tank Museum, Puckapunyal, Australia (2007). The white writing on the turret is to inform cargo handlers that it is not to be transported by sea as deck cargo. Image:Centaur Dozer at the Tank Museum 02.JPG, Centaur Dozer at the Tank Museum Image:Tank Mark VIII Centaur in the Musée des Blindés, France, pic-5.JPG, Tank Mark VIII Centaur in the Musée des Blindés, France


See also

*
Vickers Tank Periscope MK.IV The Gundlach Periscope, usually known under its British designation as Vickers Tank Periscope MK.IV, was a revolutionary invention by Polish engineer Rudolf Gundlach, manufactured for Polish 7TP tanks from the end of 1935 and patented in 1936 as ...
*
Rhino tank "Rhino tank" (initially called "Rhinoceros") was the American nickname for Allied tanks fitted with "tusks", or bocage cutting devices, during World War II. The British designation for the modifications was Prongs. In the summer of 1944, during t ...


Tanks of comparable role, performance, and era

* Australia
Thunderbolt A thunderbolt or lightning bolt is a symbolic representation of lightning when accompanied by a loud thunderclap. In Indo-European mythology, the thunderbolt was identified with the 'Sky Father'; this association is also found in later Hell ...
* Canadian Grizzly I * German
Panzer IV The ''Panzerkampfwagen'' IV (Pz.Kpfw. IV), commonly known as the ''Panzer'' IV, was a German medium tank developed in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz. 161. The Panze ...
* Hungarian Turán III * Italian
Carro Armato P 40 The P 26/40 was an Italian World War II heavy tank. It was armed with a 75 mm gun and an 8 mm Breda machine gun, plus another optional machine gun in an anti-aircraft mount. Design had started in 1940 but very few had been built by the ...
* Italian P43 (proposal) * Japanese
Type 3 Chi-Nu was a medium tank of the Imperial Japanese Army in World War II. Like the Type 1 Chi-He, this tank was an improved version of the Type 97 Chi-Ha. It incorporated a Type 3 75 mm tank gun, one of the largest Japanese tank guns during the war. Th ...
* Romanian 1942 medium tank (proposal) * Soviet
T-34 The T-34 is a Soviet medium tank introduced in 1940. When introduced its 76.2 mm (3 in) tank gun was less powerful than its contemporaries while its 60-degree sloped armour provided good protection against Anti-tank warfare, anti-tan ...
* Swedish Stridsvagn m/42 * United States
M4 Sherman } The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the Military history of the United States during World War II, United States and Allies of World War II, Western Allies in World War II. The M4 Sherman prove ...


Notes


Notes

;Citations


References

* * * * * * * * * * *


External links

* OnWar specifications
Cromwell I


* * * * {{Authority control Cruiser tanks of the United Kingdom World War II tanks of the United Kingdom Military vehicles introduced from 1940 to 1944