Crusader, in full "Tank, Cruiser Mk VI, Crusader", also known by its General Staff number A15, was a British cruiser tank during the early part of the Second World War. Over 5,000 tanks were manufactured and they made important contributions to the British victories during the North African campaign. The Crusader saw active service in Africa but the chassis of the tank was modified to create anti-aircraft, fire support, observation, communication, bulldozer and recovery vehicle variants.
The first Crusader Mark I tanks entered service in 1941 and, though manoeuvrable, they were relatively lightly armoured and under-armed. The following Crusader Mark II had a maximum armour of . The main armament for the Crusader Mark I and IIs was a 40 mm Ordnance QF 2-pounder gun; the following Crusader Mark III was fitted with a 57 mm Ordnance QF 6-pounder gun at the expense of one member of the crew in the turret. This variant was more than a match for the mid-generation German Panzer III and Panzer IV medium tanks that it faced in combat. As part of the 1st Armoured Brigade, the Crusader was to prove vital during the Second Battle of El Alamein, at the siege of Tobruk and in the Tunisia campaign.
Retained in service because of delays with its replacement, by late 1942, the lack of armament upgrades, plus reliability problems in the harsh desert conditions and the appearance of uparmoured and upgunned German tanks in the Afrika Korps, saw the Crusader replaced as the main tank by US-supplied M3 Grant and then by the M4 Sherman medium tanks but it was retained in combat use until the end of the war in North Africa and after that for training in Britain.
Design and development In 1938, Nuffield Mechanizations and Aero Limited produced their A16 design for a heavy cruiser tank based on Christie suspension. Looking for a lighter and cheaper tank to build, the General Staff requested alternatives from British industry. To this end, the A13 Mk III cruiser tank, which was to enter service as the "Tank, Cruiser Mk V" (known as the Covenanter), was designed by London Midland and Scottish. Nuffield was, in 1939, offered the opportunity to take part in the production of the Covenanter.
Nuffield preferred to work on its own version of the A13, though it still provided design work for the Covenanter's turret. This new tank was adopted as "Tank, Cruiser, Mk VI Crusader", under General Staff specification A15. Although Crusader is often referred to as an improved version of the Covenanter, it was a parallel design. Both tanks were ordered "off the drawing board" without prototypes. Despite a later start, the pilot model of the Crusader was ready six weeks before the first Covenanter.
Unlike earlier "Christie cruisers" (the A13 Mark III and Mark IV tanks and the Mark V Covenanter) that were built with four road wheels, Crusader had five road wheels each side to improve weight distribution in a tank that weighed almost instead of the of the previous cruisers. The -diameter wheels were of pressed steel with solid rubber tyres. The hull sides were built up of two separated plates, with the suspension arms between them.
It had a different engine from the Covenanter, different steering system and a conventional cooling system with radiators in the engine compartment. Covenanter used a new engine design and Crusader adapted the readily available Liberty engine to fit into a lower profile engine compartment. At the left side of the front hull—a place occupied by the engine radiator in the Covenanter—was mounted a small hand-traversed auxiliary turret armed with a Besa machine gun. The auxiliary turret was awkward to use and was often removed in the field or remained unoccupied.
The A13 Mk III Covenanter and the A15 Crusader designs used the same main turret. The turret was polygonal—with sides that sloped out then in again—to give maximum space on the limited turret ring diameter. Early production vehicles had a "semi-internal" cast gun mantlet, which was quickly replaced in production by a better protected larger cast mantlet with three vertical slits for the main gun, a coaxial Besa machine gun, and the sighting telescope. There was no cupola for the commander, who instead had a flat hatch with the periscope mounted through it.
The main armament, as in other British tanks of the period, was balanced so that the gunner could control its elevation through a padded shaft against his right shoulder rather than using a geared mechanism. This fitted well with the British doctrine of firing accurately on the move.
Further development Crusader III
When it was understood that there would be delays in the introduction of successor heavy cruiser tanks (the Cavalier, Centaur and Cromwell) and the need for cruiser tanks, the Crusader was up-gunned with the 57 mm 6-pounder, the first British tank to mount this gun. Design work for a new turret started in March 1941, but Nuffield was not involved until late in the year, when they adapted the existing turret with a new mantlet and hatch.
The turret also received an extractor fan to clear fumes from the firing of the gun. The larger gun restricted turret space, so the crew was reduced to three, with the commander also acting as gun loader, a role previously performed by the wireless operator. The auxiliary turret space was given over to ammunition stowage.
Crusader III also saw the introduction of the Mk. IV Liberty engine, fixing many of the reliability issues previously encountered. This featured the Mk. III engine's later updated water pumps along with a shaft drive replacing chain drive for the cooling fans.
Production started in May 1942 and 144 were complete by July. The Crusader III first saw action, with about 100 participating, at the Second Battle of El Alamein in October 1942.
The Crusader was converted to a mobile armoured observation post for direction of artillery. The turret was fixed in place, the gun was removed and a dummy barrel fitted to give it the same outward appearance of a regular tank. With no requirement for ammunition, the interior was given over to the radios, two No. 19 radios and No. 18 radio, map boards and related equipment. The Royal Artillery could then operate the OP tank up front among the fighting units directing artillery fire in their support.
Crusader AA tanks The Crusader III was also used to create self propelled anti-aircraft guns. First was the Crusader III, AA Mk I which replaced the 6-pounder in the enclosed turret with a Bofors 40 mm anti-aircraft gun with an autoloader and powered mounting in an open-topped turret. The crew numbered four: gun commander, gun layer, loader, and driver. It was intended for use by organic AA units in armoured formations.
After trials, it was superseded by the Crusader III, AA Mk II, which was armed with twin Oerlikon 20 mm guns for anti-aircraft use. The prototype appeared from Morris Motors in the summer of 1943, the pilot model being issued for testing in June. The armor thickness in the turret was 30 mm at the front and 14 mm on the sides and 17 mm on the rear. The guns were housed in a small, multi-sided polygonal turret with heavy armour, but poor situational visibility for spotting approaching aircraft. The crew numbered four: the commander/gunner, two loaders, and driver. The tank carried 600 rounds of ammunition, in 60-round magazines.
After evaluations, the tank was urgently redesigned as the Crusader III, AA Mk III. The Mk III differed from the Mk II: An improved turret with raised "lips" in the turret aperture, and a narrower aiming frame. An additional single .303 (7.7 mm) Vickers K machine gun in an armoured jacket, between the 20mm guns. The position of the radio, which was moved to the hull in order to free some space inside the turret. The driver now also acted as the radio operator, instead of the commander.
After the failure of the Crusader AA Mk I, the Royal Artillery created a new project based on the Crusader chassis, officially called 40 mm SP AA Gun (Tracked). The design was a 40 mm Bofors gun mounted directly on a Crusader III hull top with its standard shield. Another similar project was the 20 mm SP AA Gun (Tracked), which mounted three 20 mm Oerlikons instead of the Bofors. Both were produced in very limited quantities, and were for used by LAA (SP) regiments. They were intended as a stop gap to ensure AA cover in the immediate landings of D-day but were retained in the beach head until late 1944. After the Crusader chassis had worn out, the AA mountings were transferred to trucks.
Gun Tractor
The Crusader gun tractor came out of a need for a tracked vehicle that could tow the heavy 76.2 mm QF 17-pounder anti-tank gun, which resulted in the Crusader II, Gun Tractor Mk I. It was a Crusader tank hull with a simple boxy superstructure replacing that of the gun tank. The thick structure protected the driver and the gun crew of six. The tractor also carried ammunition on the rear and within the crew area.
Although nearly as heavy as the gun tank, it was still capable of high speed and was officially limited to . This was still hard on the towed 17-pdr guns. They were used in northwest Europe from the Normandy landings of 1944 to the end of the war in 1945.
Other developments Crusader tanks could be fitted with an Anti-Mine Roller Attachment (AMRA) Mk Id, a mine clearing device consisting of four heavy rollers suspended from a frame. Weight of the rollers could be increased by filling them with water, sand etc.
Crusaders were used for experimentation such as a flotation kit, consisting of two pontoons attached to hull sides, special blades attached to tracks to propel the vehicle in water and a cowl over engine air intakes and cooling louvres.
Performance Initial performance of the Crusader was found to be better than the comparable M3 Stuart light tanks. Despite reliability problems, the tanks formed the primary unit for British cruiser tank armoured regiments, while the Stuart was used for reconnaissance.
The Crusader suffered from chronic reliability problems in desert use. Tanks arriving in North Africa were missing many of the essential tools and servicing manuals needed to maintain operation; these had been stolen or lost in transit. As tanks broke down, the lack of spare parts meant that many components were replaced with worn parts recovered from other tanks. When the tanks were returned to the base workshops upon reaching service intervals, many were serviced with components that had already reached their design lifespan. A rapid increase in manufacturing output caused quality problems as inexperienced workers began assembling tanks. This placed further pressure on the receiving base workshops that had to carry out overhauls.
The new tanks also had a number of design flaws that needed to be worked out. The reconfiguration of the Mk. III Liberty engine into a flatter format to fit into the Crusader engine compartment had badly affected the tank's water pumps and cooling fan arrangements, both of which were critical in the hot desert temperatures. Several official and unofficial local modifications were applied to improve reliability and conserve water, which otherwise had to be prioritised on keeping the vehicles running. Rectification of these issues took a very long time, by which time confidence in the Crusader had been lost. Calls were made at various points for the vehicles to be replaced with the Valentine infantry tank or US-made M3 Grant tank.
More and more Crusaders were returned to base workshops, leading to a shortage of battle-ready tanks and a massive backlog of repair works to be completed. The number of operational vehicles dwindled, and US-made replacements were brought in.