Chapter Seven

Specials, Engineers’ Tanks and ‘Funnies’

So-called ‘special tanks’ started to appear as early as 1917 when the British Army modified Mk IV heavy tanks, equipping them with fascine bundles or hollow timber cylinders to allow ditches to be crossed. Both Mk IV and Mk V tanks were also fitted with hinged ramps which provided a means of crossing other obstacles–thus, creating the first bridging tanks. Others had their armaments removed and were adapted for use as supply vehicles or gun carriers, whilst the armoured recovery vehicle was developed by the simple expedient of attaching a jib and pulley block or powered crane to the front of an obsolete tank. Flame-thrower tanks were discussed, although never produced in the First World War.

In 1918, after the Armistice, the development impetus was lost and few special tanks saw service during the interwar years. The outbreak of the Second World War saw a resurgence of interest in using armoured vehicles for specialised roles, including anti-aircraft defence, mine clearing, bridging, etc.; in the lead-up to the D-Day landings, a range of so-called ‘funnies’ was developed, each tasked with overcoming a particular problem. These vehicles made an enormous contribution to the success of the landings.

Anti-Aircraft Tanks

In the immediate pre-war years, the British Army had tended to favour mounting anti-aircraft weapons on 15cwt trucks, initially using the portée method in which the gun was intended to be dismounted before use, but latterly using gun carriers from which the gun could be fired without dismounting.

From mid-1943, the Germans had started to mount heavier anti-aircraft guns on the chassis of the PzKpfw III and PzKpfw IV tanks, and the British soon followed suit, with the Crusader III adapted to mount either a single Bofors 40mm anti-aircraft gun in a tall, square turret (Crusader III, AA, Mk I), or latterly, twin Oerlikon 20mm cannon (Crusader III, AA, Mk II) in a lower-profile turret. A Mk III variant had the radio equipment moved from the turret into the hull, and a few vehicles were also equipped with triple Oerlikon cannon in an open mount, for training purposes. Centaur chassis were also fitted for anti-aircraft use, initially using Polsten cannon (Centaur, AA, Mk I), but subsequently with the same turret as the Crusader, mounting two Oerlikon 20mm cannon (Centaur, AA, Mk II).

Although intended for use during the Normandy landings, Allied air superiority was such that the vehicles were not required and the anti-aircraft units were disbanded shortly after June 1944.

Armoured Recovery Vehicles

Given the size and weight of even the average tank of the period, compared to the average wheeled heavy recovery vehicle, it should have been self-evident that the most suitable vehicle for recovering a disabled tank was another tank. Yet it was not until February 1942 that the British Army began to look into the question of converting tanks to the role of armoured recovery vehicles (ARV). The Royal Electrical and Mechanical Engineers (REME) workshops at Arborfield produced experimental ARVs based on the Covenanter, Crusader, Churchill and Grant chassis, largely by the simple expedient of removing the turret and gun and equipping the hull with basic recovery equipment.

The Crusader and Covenanter were both rejected as being unsuitable, but, with their comparatively roomy hulls, the Churchill and Grant were both considered for further development, appearing as the Churchill ARV Mk I, and the Grant ARV Mk I. A 3-ton jib was stowed on the rear of the hull: it was designed to be erected at the front or rear as required, and could be used to remove and replace a tank engine and/or gearbox. The jib could similarly recover a disabled or bogged-down tank. Cavalier, Centaur and Sherman hulls were also adapted in much the same way.

In 1943, the British Army started to receive the US Army’s T2 tank recovery vehicle. Based on the M3 Lee hull, the T2 was equipped with a high-lift jib and a heavy winch, and led to the development of a similarly equipped British vehicle, designed by the REME workshops and constructed using both Sherman and Churchill hulls. Known as the ARV Mk II, a fixed turret was installed, mounting a dummy gun, and providing space for a Croft 60-ton winch. There was a detachable 3.5-ton winch at the front, and a fixed 9.5-ton winch at the rear, as well as a substantial earth anchor. The British Army also used the Sherman-based M32 tank recovery vehicle, describing it as the ARV Mk III.

Mention should also be made of the beach armoured recovery vehicles (BARV) developed specifically for recovering drowned or disabled tanks from the D-Day beaches. Designed by REME, and constructed using both Churchill and Sherman hulls, the BARV had the turret and gun removed and the hull sides raised to allow the vehicle to wade in up to eight feet of water. The Churchill version never progressed beyond the prototype stage.

Assault Vehicle, Royal Engineers

After the unsuccessful assault at Dieppe in August 1942, Lieutenant-Colonel J. J. Donovan of the Royal Canadian Engineers suggested that such operations might have a greater degree of success if a form of tank could be developed that would carry the sappers and their equipment, as well as providing a sufficient degree of protection to allow working under fire. By December 1942, a prototype had been constructed and successfully demonstrated by the Royal Canadian Engineers, using a Churchill II. The interior of the hull was cleared of unnecessary fittings, and stowage compartments were provided for the engineers’ equipment. A 290mm Pétard spigot mortar was installed in the turret, capable of firing a 40lb ‘dustbin’ charge 230 yards. A second prototype was constructed soon afterwards using a Churchill III, although lacking the mortar.

Designated assault vehicle, Royal Engineers (AVRE), the first 108 vehicles were constructed by the workshops of the Royal Electrical and Mechanical Engineers (REME). Although not all were equipped with the mortar, the AVRE was used to equip 1st Assault Brigade of the 79th Armoured Division in time for use on the D-Day beaches. MG Cars Limited was subsequently given a contract for adapting a further 574 Churchill III and IV tanks to AVRE configuration.

The AVRE was a very adaptable vehicle, with brackets on the front and sides of the hull to accept all kinds of attachments. These included the 30-foot-span small box-girder bridge (SBG); various hessian and canvas mat-laying devices, including the tank landing craft (TLC) laying devices–the Bobbin Carpet, Twin Bobbin Carpet, Roly Poly, and Log Carpet, all designed to prevent tanks from becoming bogged down in soft ground; the Onion and Goat demolition-charge placing devices, although only the Goat was produced in quantity; and the fascine, a bundle of 8-foot long wooden stakes, which was used as an aid to crossing ditches and trenches. AVREs were also used to push ‘skid’ Bailey bridges into position.

There were also experiments with improving the firepower of the mortar. The Woodpecker mounted four 290mm mortars on the hull sides, whilst Ardeer Aggie was fitted with a recoilless mortar, which fired a 54lb projectile 450 yards. Experiments with Shermans as the basis for an AVRE were subsequently abandoned, although the Canadian Army did convert the M3-based Ram tank.


Following the end of the First World War there had been experiments using Mk V** heavy tanks as bridging vehicles. During the interwar years, there were further experiments with Dragon Mk I field artillery tractors as bridge carriers. By 1925, a 16-foot-span light-girder bridge had been designed for use with the Vickers medium tank–although fine in principle, it was found that the span was too short to be of practical use. Subsequently, Matilda infantry tanks were used to push bridge sections across gaps of up to 80 feet, and Churchills were similarly used with ‘skid’ Bailey bridges during the Second World War.

However, most bridgelayers of the period were designed actually to carry the bridge and to launch it across the gap. Work on bridgelaying tanks had started in the mid-1930s, when Covenanters and Valentines were converted to the bridgelayer role using a hydraulically deployed scissors bridge known as ‘scissors bridge, 30 foot, number 1’.

With the introduction of the much heavier Churchill tank, the original scissors bridge was no longer adequate and a new rigid-span 30-foot bridge was developed–described as ‘bridge, tank, 30 foot, number 2’–to be carried on the hull of the Churchill IV. The bridge was launched from the hull of the tank but lacked the central pivot, simply needing to be rotated through 180 degrees. Churchill bridgelayers were used in Italy and in northwest Europe.

Churchill and Sherman tanks were also used as the basis of the armoured ramp carrier–generally known as Ark. Ramps were attached to either end of the hull, and a trackway was fitted to the top of the hull: in operation, the tank was driven into the centre of the ditch or trench, or up against a sea wall, and the ramps were folded out at either end to form a continuous bridge, with the tank remaining in the ditch during use. The Churchill Ark I had a span of 28 feet, whilst the Ark II had a span of 48 to 54 feet, according to the types of ramp fitted. Arks were used in Italy and northwest Europe.

CDL Searchlight Tanks

Some experiments with searchlight-equipped tanks had taken place during the closing months of the First World War, presumably in an effort to allow combat to continue into the hours of darkness, but it was not until the years leading up to the Second World War that anyone came up with the idea of using powerful searchlights as a weapon, effectively to paralyse the opposition. In 1937, a searchlight weapon was demonstrated to the War Office, with further trials at the Royal Armoured Corps Gunnery School at Lulworth in Dorset, in June 1940.

Following the success of these trials, the Vulcan Foundry and the Ashford works of the Southern Railway Company were given a contract for 300 turrets, each equipped with a 12.75 million-candela carbon-arc searchlight powered by a generator driven by the tank’s engine. Described as the canal defence light (CDL), these turrets were mounted on the Matilda infantry tank. The light was reflected from a huge parabolic mirror and focused through a lens, emerging through a vertical slit, covered by a movable shutter, on the turret front. The slit could be rapidly opened and closed, creating a stroboscopic effect designed to dazzle, disorientate and temporarily blind the enemy. It was proposed that CDL tanks could be used in pairs, deployed at some distance apart, with their searchlight beams focused on an enemy stronghold, which would allow infantry to advance, unseen in the darkness between the two vehicles.

Three British regiments were equipped with CDL Matildas and Churchills, and latterly with M3 Lee/Grants, where a separate engine was provided to drive the generator. The US Army also raised a number of CDL battalions, three of which went to France some time after D-Day. During the Rhine crossing in March 1945, both British and American CDL tanks were stationed on the riverbank, scanning the water with their searchlights to illuminate possible enemy sabotage teams attempting to blow the bridge.

Duplex-Drive Amphibious Tanks

Amphibious tanks had been tested during the First World War, but none had worked well enough to be used in combat. Nevertheless, development continued during the interwar years, with small tanks that had natural buoyancy, or with conventional vehicles carrying flotation devices. In June 1941, the prolific Hungarian inventor, Nicholas Straussler, finally solved the problem of making tanks float by using a folding canvas screen attached to a frame welded around the top of the hull. The screen was raised by compressed air–a process that took around fifteen minutes–and was secured by stays. By increasing the displacement of the hull, this allowed the tank to float. A second drive system, which diverted power from the tracks to rear-mounted propellers, allowed the tanks to ‘swim’ from landing craft to beach–and also gave them their name of duplex drive, or DD, the name having been chosen to obscure the role of the vehicle. In the water, the tanks were steered by means of a rudder and by swivelling the propellers on a horizontal axis.

Major General Percy Hobart of the 79th Armoured Division took the principle of Straussler’s folding screen and carried out trials in Portsmouth Harbour using a modified Tetrarch. At the same time, a Crusader was fitted with inflatable pontoons for comparison. The success of the Tetrarch led to the selection of the Valentine as the basis for the development of the duplex-drive tank, with the development work given to the Metropolitan-Cammell. Plans were also put in hand to convert Sherman, and even Cromwell and Churchill tanks, for the amphibious role.

Deliveries of the Valentines were completed by the beginning of 1944. By this time, the DD tanks had already been issued to units for training purposes, and the majority of the American, British and Canadian DD tank crews did their preliminary training using Valentines. However, it soon became clear that the Sherman was more suitable for amphibious use, and the conversion was carried out using Sherman III and Sherman V variants. The modifications were similar to those made to the Valentine, but the increased weight of the Sherman dictated an increase in the height of the canvas screen. Drive to the propellers was taken from the rear sprockets using bevel gears, with the advantage that the tracks were running as soon as the tank touched the beach. The propellers were designed to hinge upwards when not in use.

DD Shermans were used very effectively on D-Day, although rough seas could, and did, drive the vehicles off course. The Shermans were also used during the Rhine crossing in 1945 and a small number of Valentine DDs were used in Italy in 1945.

Flame-Thrower Tanks

In July 1940, Lagonda Motors constructed and demonstrated a portable flamethrower device, with a range of little more than 100 feet, to the Department of Miscellaneous Weapons Development (DMWD). The weapon came to the attention of Major General Sir Donald Banks, Director-General of the Petroleum Warfare Department, and he asked Lagonda if a larger mobile unit could be designed with a range of 150 feet or more. Eventually, Lagonda managed to produce a unit that could pump burning petroleum fuel 350 feet.

Although indisputably a fearsome weapon, at the time it seems that it had no clear application until it was suggested that there might be a role in the protection of shipping against low-level attack, and that it could be equally effective in defending airfields. An initial order was placed by the Admiralty, for what was described as the Mk I vertical flame-thrower, intended to be used from the decks of ships.

However, the flame-thrower became better known as a vehicle-mounted weapon following Lagonda’s development of an experimental armoured vehicle using a Commer truck chassis. This led to the production of what was known as the Cockatrice. The first of these, the ‘light Cockatrice’, used a Bedford QL 3-ton 4x4 chassis, whilst the ‘heavy Cockatrice’ was mounted on the 6x6 AEC Model O854 chassis. The equipment fitted to the Cockatrice was subsequently adapted by the Canadian Army for use on the universal carrier, in which form it was described as the ‘Ronson’ flame-thrower, and this, in turn, led to the development of the Wasp. At the end of July 1942 work started on adapting the Wasp to allow it to be fitted to tanks.

Early development work was carried out on a pair of Valentines, one using a projector ignited by cordite charges, the other operated by gas pressure. The fuel was carried in a trailer and the flame projector was mounted on the hull front. Trials showed that the gas-operated system was better and this led to the development of what became known as the Churchill Crocodile.

A dozen pilot models were ordered before the War Office decided that the Churchill lacked sufficient protection for what would, inevitably, be combat at close quarters, and that a smaller, more mobile vehicle might be better. Nevertheless, work on the Crocodile continued, under the direction of R. P. Fraser of Lagonda, and a prototype towing a special gas-pressurised 400-gallon fuel trailer was demonstrated in January 1943. The fuel was passed to the towing vehicle under pressure through a special articulated coupling, and was ejected through a projector nozzle fitted into the front of the hull. Early examples used the original long-barrelled Wasp Mk I projector, but this was subsequently superseded by the Wasp Mk II, which was capable of emitting burning fuel at a rate of more than six gallons a second. The major advantage was that the flamer-thrower equipment did not require the main gun to be removed and, although the trailer impaired the mobility of the tank to some degree, it could be jettisoned once empty and the vehicle could resume its previous role as a gun tank.

Lagonda became the parent firm of a group of companies described as the ‘Crocodile Production Group’ and some 800 (out of a contracted 1,000) Crocodiles were constructed. Initial work concentrated on the Churchill IV, but production vehicles used the Churchill VII chassis.

The Matilda Frog was similarly equipped, and there were examples of experimental flame-thrower Shermans under the names Salamander and Adder. Canadian Ram tanks were also equipped as flame-throwers, when they were known as the Ram Badger.

The Crocodile proved enormously effective against pillboxes and strong points and was deployed in Italy and then, in quantity, from D-Day onwards.

Mine-clearing Tanks

During the Second World War, huge numbers of anti-tank mines were laid by the opposing armies, as well as even greater numbers of anti-personnel, or land mines. Although many were laid in the Soviet Union, there was, nevertheless, considerable concern amongst those planning the invasion of north-west Europe regarding the dangers that the mines presented to the advancing armies. All kinds of solutions to the problem were proposed, including explosive devices, flails, rollers and ploughs–all of them attached to modified tank hulls. Many were immediately dismissed as being impractical, but others were developed to the point where they became quite successful.

Explosive devices

Various attempts were made to develop devices that could clear a lane through a minefield by exploding the mines ahead of an advancing tank. Two such devices, dubbed Snake and Conger, consisted of a long hosepipe or cylinder of explosive that could be pushed across a minefield and detonated remotely. It was found that the Snake could clear a path about 30in wide, certainly sufficient to allow infantry to pass through safely. Subsequently there were trials with rocket-propelled Snakes fired from multiple tubes mounted on the hull of a Churchill, but, despite some limited production, the rocket-propelled Snakes were never deployed in anger.

A similar device was dubbed Tapeworm. Designed to be towed across the minefield by a flail tank, Tapeworm consisted of a flexible hosepipe that could be filled with liquid explosive once in position and then detonated.


Development of the flail tank dates back to 1939 when the Mechanization Board proposed that anti-tank mines could be exploded by weights attached to the ends of spring-steel strips on a revolving drum carried ahead of a tank. However, it was not until the summer of 1941, when the problem of anti-tank mines in North Africa had become acute, that serious consideration was given to the deployment of a flail tank. Major Du Toit of the South African Forces suggested replacing the spring-steel strips and weights with revolving chains and, by November 1941, Du Toit was with AEC at Southall working on the development of a practical flail.

Initially described as the ‘tank winch’, but retrospectively known as the Baron Mk I, the first prototype mounted the flail onto a Matilda II, still with its turret and gun. A cross-shaft, fitted with two rows of chains, was carried on arms at the front of the tank about six feet above the ground. The shaft could be raised or lowered hydraulically, and was driven at about 80rpm by a Chrysler petrol engine. The device was intended to flail mines, cut through barbed wire, and destroy anti-tank earthworks, but trials showed that the engine was not sufficiently powerful, nor could the rotor be held at a constant height. The Baron Mk II appeared in April 1942, using a six-cylinder Bedford engine to power the rotor and the hydraulic raising and lowering system. The length and arrangement of the chains was varied to give a consistent beat pattern whilst minimising damage to the chains. It was found that barbed wire became entangled around the flail rotor, occasionally jamming it solid, and the rotor was eventually fitted with circular saw blades and V-notch wire cutters.

Clearly, the device had considerable potential, but more power was required to drive the chains at a higher speed. Earlier experiments with a ‘perambulator’ device that used a Matilda tank to push a flail were abandoned, and work started on the Baron Mk IIIA.

The turret and gun of the Matilda were replaced by an armoured operator’s cab, housing two Bedford engines to drive the rotor, which carried thirty-nine chains, arranged in three rows. Mine-detonating efficiency was in the order of 90–100 per cent, but the mines tended to damage the chains, and the radius of action was only about 440 yards before the chains were unserviceable. However, the device could successfully cut through two German Dannert wire fences, and dig a 12-foot wide path through an earth bank in six minutes. An order for sixty flails was placed with Curran Brothers in January 1943, and the first production vehicle underwent acceptance trials in May 1943.

Meanwhile, a simpler flail device had been developed in the Middle East during 1942. Dubbed the Scorpion, it was mounted on both Matilda II and the M3 Lee/Grant vehicles, although in the former case the main gun was removed. The rotor was carried about four feet above the ground and some seven feet ahead of the tank, with steel rope flails operating at about 115rpm. Unfortunately, the device was mechanically unreliable and was also too wide for the doors of a landing craft. Nevertheless, it was felt to be promising and, in March 1943, twenty-five Scorpion flail sets were ordered for delivery by the end of May. A production prototype was attached to a Valentine, but the trials were far from satisfactory and the device was destroyed by a mine exploding under its belly. Further production was halted pending work on a second prototype which incorporated additional belly protection and on which the flails, now of cable chain, rotated in the opposite direction. On two occasions mines were thrown onto the driver’s visor; to counter this, wire netting was fitted to the cross framework. By the end of July 1943, the Scorpion was issued for user trials, but it was eventually abandoned. A proposed ‘perambulator’ Scorpion was constructed and trialled, but performed so poorly that further development was similarly abandoned, as was work on the Matilda-based Baron and the Sherman-based Marquis.

By the middle of June 1943, there had been sufficient progress with mounting a modified version of the Scorpion flail on a Sherman tank–known as the Crab–and this became the most successful of the flails. Developed by AEC following the unsuccessful trials of the Scorpion ‘pram’, the Crab differed from other such devices by using the engine of the tank–in this case the Chrysler multi-bank engine of the Sherman V–to drive the flail. The first Crab was inspected in August 1943, with an order for six prototypes rapidly following. One of these was built by AEC, the other five were constructed by T. C. Jones, and in September 1943 the first prototype was ready for trials. The flails were attached to a drum carried six feet ahead of the tank at a constant 51in above the ground; forty-three flails were arranged on the drum in seven spiral rows. With the tank in first gear the drum rotated at 184rpm, giving a mine-detonating efficiency of 91 per cent. An auxiliary gearbox was later used to allow the engine power to be better matched to the flailing speed. Following trials, the design was ‘frozen’ and work started on the first production vehicle, which included a hydraulic system for raising and lowering the drum.

User trials started at the end of October 1943 and the system proved effective at destroying mines and cutting barbed wire. The hydraulic system allowed the flail to rise at each detonation but, nevertheless, approximately twenty-five chain links were lost each time a mine was detonated and the chains needed to be replaced after seven or eight mines. In fact, the drum was so damaged after detonating twenty-seven German Tellermines that it needed to be returned to AEC for repair; nevertheless, work started immediately on building 300 Crabs, for completion by the end of March 1944.

Trials were subsequently conducted with a Crab flail incorporating a Baron rotor and flail layout. Known by the code name Lobster, this project was abandoned in June 1944.

In use, flail tanks were operated in echelon, each vehicle slightly overlapping the path of its predecessor. No practical solution was found to the problems of forward visibility when flailing and a direction gyro and binnacle compass system was fitted to the lead tank, coupled with a speed and distance indicator; battery-operated marker lights were dropped from chutes on the rear tank(s) in the echelon to indicate the cleared area. In April 1944, this system was replaced by the Whyman lane marker, which used flagged stakes fired into the ground by ballistic cartridges.


The first plough for anti-tank mines, developed by John Fowler & Company, was fitted experimentally to a Dragon medium Mk IIIC gun tractor. Consisting of a frame pushed ahead of the vehicle to which were fitted five coulter plough blades in a V arrangement, it was sufficiently successful that, by 1939, it had been adapted to suit the infantry tank Mk I.

In April 1943, Samuel Butler of Leeds developed this idea further to produce the Farmer Front device, which was fitted to a Churchill tank. The number of plough blades was increased to nineteen, arranged in an arrow formation, but the frame was insufficiently strong and tended to buckle in use, leading to the trials being abandoned. The subsequent Farmer Track was also abandoned. The Ipswich-based agricultural engineers, Ransomes, Sims & Jeffries, took the idea a stage further with the Farmer Deck, in which there were two large plough blades together with skids or rollers to provide additional support. Despite a series of promising trials, and a production run of 200, the idea was abandoned in 1944.

Other types of plough were developed and tested by the 79th Armoured Division, with the most successful known as the Bullshorn, but, again, all were eventually abandoned in favour of the flail.


Anti-mine rollers had already been developed in the years immediately following the First World War and, in 1937, John Fowler & Company had trialled such a device on a Dragon medium Mk III gun tractor. Described as the anti-mine roller attachment (AMRA)–consisting of a girder frame projecting ahead of the tank carrying four heavy rollers–variants of this device were developed for use with cruiser tank Mks I to IV, the Matilda, Valentine, Covenanter, Crusader and Churchill. This idea was also adapted for the anti-mine reconnaissance castor roller (AMRCR), which proved useful against anti-personnel mines although, like all of the roller devices, it was subsequently superseded by the flails.

Rollers with projecting spikes were tested experimentally in the Middle East. One such device, dubbed Porcupine, was tested in Britain in conjunction with a Sherman, but it was destroyed after dealing with just two German Tellermines. The Humber Motor Company proposed a device that used a huge single roller, ten feet in diameter and twelve feet wide, driven by an integral electric motor and designed to be towed behind a tank. The colossal weight of the roller, which was known as Katok, consigned this idea to the scrap heap.

The most successful roller device was devised by General Worthington, Commander of the 4th Canadian Division. In June 1943, he proposed using resiliently mounted heavy rollers on an infantry tank and, by October 1943, a prototype of the Canadian indestructible roller device (CIRD) had been constructed at the Canadian Army workshops at Borden, Hampshire. In conjunction with the Obstacle Assault Centre at Aldershot, the device was attached to a Churchill infantry tank. Following a series of trials, the CIRD was deemed to be sufficiently promising to warrant further investigation and possible production and, in December, arrangements were made to fit the device to a Sherman.

Design parentage was vested in the Deputy Director, Fighting Vehicles (DDFV), with the main contractors being Edwin Danks, a boiler-making company based in Oldbury, Birmingham, Henry Simon of Cheadle Heath, and C. & W. Walker, gas engineers of Donnington, Shropshire. The first production device was trialled in April 1944, and the designs for both Churchill and Sherman tanks were standardised in May 1945. The CIRD consisted of two huge rollers of solid forged armour-quality steel, 16in wide and 26in in diameter, each weighing one ton. The rollers were carried on long arms, arranged to pivot about eight feet ahead of the tank in front of each track, and were suspended on a substantial cross-shaft, with helical springs provided to position the trailing arms.

Curiously, the device appeared to have little effect on the manoeuvrability of the tank; however, unlike the flail, which cleared a broad path, the CIRD cleared mines only in the tracks of the tank–in order to clear a wide path it was necessary to run a number of tanks in a staggered line abreast. One major advantage that the CIRD had over other devices was that there were no mechanical moving parts and thus no need for a vulnerable drive system. It could also be quickly attached to any suitable tank–in the field, if necessary–and similarly jettisoned without too much difficulty. Perhaps most importantly, the fighting abilities of the tank remained unimpaired.

As the trials proceeded, it became apparent that repeated detonations caused the edges of the rollers to spread and to jam in the saddle so that they could not rotate. This was overcome by reducing the width of the rollers by half an inch. Other defects included drooping of the side arms and a tendency for the rollers to seize on the axles. The average life of a roller was seven detonations (of a British Mk IV mine). In an effort to overcome some of the shortcomings, the diameter of the rollers was increased to 28in, and the width to 18in, whilst still maintaining the side clearance, resulting in each of these enlarged rollers now weighing 3,000lb–unfortunately, the increase in weight was too much for the Sherman and the hull bracket attachments failed.

The Churchill proved itself to be made of sterner stuff and, with the improved device fitted the mine-detonating efficiency was increased to 93 per cent and 71 per cent for mines at depths of two inches and four inches respectively. It required 19 detonations in succession of the German Tellermine 42 to split one of the larger rollers. Subsequent rollers were able to withstand the detonation of 20 double British Mk IV mines, and one actually withstood the successive detonation of double, triple and quadruple Tellermine 42s. There were unsuccessful trials in late 1944 with laminated rollers, consisting of alternate layers of either copper and steel, or rubber and steel, and both were eventually abandoned.

By November 1944, the Sherman-mounted device had also been satisfactorily redesigned to permit the use of 18-inch wide rollers with new side arms. At the same time, design parentage was passed to Edwin Danks. Trials with an even heavier, 21-inch-wide roller showed that there was little to be gained by further increases in size or weight, but a new type of attachment for the trailing arms and the cross-shaft was developed which reduced the amount by which the roller could wander on the shaft.

In May 1944, the CIRD was also adapted for use with the Cromwell and Comet tanks. Changes were made to the shape and method of attachment of the side arms to allow them to be fixed to the front of the hull, reducing the overall mine-detonating efficiency to 77 per cent. The device was passed to the Assault Training and Development Centre in June 1944 for user trials but, not long after this, the War Office concluded that land mines were not presenting a particular problem and the project was cancelled.

Rollers continued to be used for mine clearance, with devices such as Rodent, Lulu and Centipede used with some degree of success. The Lulu system was particularly interesting since the device attempted to adapt the successful Polish electro-magnetic mine-detection system for use with a tank.

Tank ‘Dozers

Redundant Valentine, Matilda, Crusader, Alecto and Centaur tanks were all converted to the ‘dozer role, generally by removing the turret and fitting a structure to the sides of the hull which could support a steel bulldozer blade. The blade was raised and lowered by a winch in the fighting compartment using a cable running over a tripod structure at the front of the hull. The Churchill AVRE could also be fitted with a ‘dozer blade. Of these, only the Matilda and the Churchill AVRE retained the main gun.

These tanks proved themselves to be invaluable in clearing streets of the rubble of shelled buildings during the advance across Europe.


In May 1940, in an attempt to counter German massed air strikes in France, the British Army hastily adapted the Vickers Mk V light tank for the anti-aircraft role, typically fitting two or four 15mm Besa machine guns in a special turret. (Warehouse Collection)


Exterior stowage diagram for the light anti-aircraft tank. (Warehouse Collection)


Crusader II equipped for the anti-aircraft role. (Warehouse Collection)


In the Churchill ARV Mk I, seen here towing a Churchill II on a tracked trailer, the turret opening was covered by a roof plate that included escape hatches, and twin Bren guns were provided for antiaircraft defence. (Tank Museum)


Designed by REME workshops, the Churchill ARV Mk II was fitted with a fixed turret, mounting a dummy gun and housing a Croft 60-ton winch. (Tank Museum)


Similar to the Churchill-based ARV Mk II, the Sherman version had a dummy gun and was fitted with a 60-ton winch. (Warehouse Collection)


Photographed at the REME Museum, this M32B1 Sherman ARV is based on the cast-hull of the M4A1. (Warehouse Collection)


On the Sherman BARV, the engine air inlet and exhaust outlets were raised above the waterline, and a substantial timber pusher pad was attached to the nose. The BARV was very successful during the landing stages of the invasion of Europe in 1944. (IWM, B5578)


This privately owned Sherman BARV was recovered from a Portsmouth scrapyard and painstakingly restored. (Simon Thomson)


The Churchill AVRE was fitted with a 290mm Pétard spigot mortar. (Tank Museum)


The Churchill AVRE remained in service into the post-war years. This version was photographed in 1949. (Warehouse Collection)


Churchill AVRE with the Bobbin Carpet Mk II canvas mat. (Warehouse Collection)


On the Covenanter bridgelayer, the turret was removed and the scissor bridge was carried across the hull in a folded position ready to be launched from the nose. (Warehouse Collection)


When the folded sections of the Covenanter bridge reached the vertical position, the two components began to separate, opening out to the full width; once the bridge sections were horizontal, they could be laid across the gap and the tank could be disengaged. (Tank Museum)


The Covenanter bridgelayer lacked reliability and tended to be reserved for training, but the Valentine saw some service in north-west Europe following the D-Day landings. (Warehouse Collection)


Valentine bridgelayer with the bridge in the travelling position. (Warehouse Collection)


Churchill bridgelayer with the bridge laid across the hull for travelling. (Warehouse Collection)


Archer self-propelled gun demonstrating the Churchill 30-foot bridge (bridge, tank, 30ft, no 2). (Warehouse Collection)


Churchill Ark Mk II, Italian pattern. In this design, there were no trackways across the hull itself. (Warehouse Collection)


Although it never got beyond the prototype stage, the Churchill Great Eastern was a more sophisticated development of the ramp carrier with a span of 60 feet; rocket power was used to launch the ramp sections across the opening. (Warehouse Collection)


The Churchill Lakeman Ark had trackways elevated above the turret, with a ramp at the rear. (Warehouse Collection)


Valentine DD with the wading screen in the collapsed position. Three prototypes were constructed by July 1942, and Metropolitan-Cammell was commissioned to start to convert 450 Valentine V, IX and XI variants. The number was later increased to 625. (Simon Thomson)


Preserved Valentine DD tank with the wading screen erected. Although the canvas screen prevented the driver from seeing where he was going, thus making the commander’s role indispensable, once ashore, it could be quickly lowered and the tank could assume its fighting role. The Valentine could only swim with the turret traversed to the rear. (Simon Thomson)


Most DD tanks were constructed using the Sherman hull. The Sherman was readily available and, perhaps most importantly, the position of the turret allowed the tank to swim with its gun forward which meant that it was ready to fire as soon as land was reached and the screen was collapsed. (IWM, B5897)


Sherman DD photographed in the water with the wading screen erected. The screens were manufactured by the Firestone Tyre Company. (Warehouse Collection)


Churchill Crocodile in action–there is little doubt that the flame-thrower inspired a greater dread on the part of those that came into contact with it than any other weapon. A captured German general told British interrogators that ‘of all the weapons at your disposal, my men most feared your flame-throwers.’ (Warehouse Collection)


Churchill Crocodile showing the gas-pressurised two-wheeled trailer, which carried 400 gallons of petroleum-based fuel. The trailer could be jettisoned once the fuel had been consumed. (Warehouse Collection)


Driver’s compartment stowage diagram for the Churchill Crocodile. (Warehouse Collection)


The first production mine flails, known as the Scorpion, were attached to the Valentine III, but were abandoned following user trials. (Warehouse Collection)


When the Octopus flail was attached to the Sherman it became known as the Marquis, but it was eventually abandoned in favour of the Crab. (Warehouse Collection)


By the middle of June 1943, a modified version of the Scorpion flail had been mounted on a Sherman tank. Known as the Crab, the tank retained both turret and gun, and the Crab became the most successful of the flails. (Warehouse Collection)


German prisoners of war stand knee-deep in the sea watching a Jeep being towed ashore. Behind them is a Sherman Crab belonging to the Westminster Dragoons. (IWM, B5089)


Developed by Samuel Butler, the Farmer Track plough used a pair of five-foot-diameter wheels to support the six spring tines which were intended to lift the buried mines. The device became clogged in use and further development was abandoned in December 1943. (Warehouse Collection)


The CIRD was designed to be driven through an area believed to contain mines, where pressure from the heavy roller would detonate any mines immediately under the roller. Mine-detonating efficiency was 83 per cent for mines laid at a depth of two inches, reducing to 65 per cent when the depth was increased to four inches. The device was used in conjunction with Cromwell, Comet and Sherman (seen here) tanks. (Warehouse Collection)


The upward blast from an exploding mine caused the roller of the CIRD, and its trailing arm, to rotate around the cross-shaft and come to rest upside down, with a spade on the cross-shaft digging into the ground. As the tank moved forward, the spade would cause the roller and its trailing arm to return to its normal position. (Warehouse Collection)


The Polish-designed Lulu detector mechanism used non-metallic rollers on arms positioned ahead of the vehicle. When the roller passed over a mine, or a similar piece of metal, the electrical balance between two coils was disturbed and a signal was sent to the vehicle. Prototypes were built but it was never tried in combat. (Warehouse Collection)


The Centaur ‘dozer tank was converted by Foden from the standard gun tank and was allocated to regiments equipped with the Cromwell. (Warehouse Collection)

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