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Tank Infantry Mark II A12, Matilda CDL (E1949.353)
DescriptionNight fighting always presents problems but searchlights had been tested on tanks as early as 1919. The idea of turning them into an offensive weapon is credited to a Mr A V M Mitzakis from Greece who lived and worked in Britain. Mitzakis interested General Fuller and the Duke of Westminster in his scheme before the war but the British authorities did not take it up until about 1940. The idea was to use a light of such power that it would dazzle the opposition, leaving them temporarily blind and disorientated. Using a carbon arc light the CDL could generate up to 13 million candle power which was made to flicker. This causes the pupil to dilate and contract rapidly, temporarily blinding the viewer.
Churchill, Grant and Matilda tanks were converted to the CDL role. This involved replacing the original turret with the type shown here, which has a vertical slit in the front through which the light shines, covered by a mechanical shutter. The operator sits in the left side of the turret and is provided with asbestos gloves to change the carbons in the lamp. He directs the light onto its target and controls the machine-gun.
Training in Britain was carried out at Lowther Castle near Penrith. Five British and two American battalions were trained on CDL and two of the British units went out to Egypt. In fact the CDL was never employed as intended. A few tanks were used to cover the Rhine Crossing and there were incidents in India after the war but that is all. The term Canal Defence Light is often explained as a disguise but it may well have something to do with arrangements to defend the Suez Canal.
THE NAME DOVER
According to a Mr Deacon he served in C Squadron, 49th RTR when the regiment was stationed in Kent and the names Dover, Deal and Derne (?) were chosen for his troop (they were previously named with M words and Dover is believed to have been Mastiff). At this time the Matilda was a gun tank but the regiment subsequently converted to CDL but retained the names.
During a visit to the Tank Museum Mr Deacon appears to have convinced the Curator at the time, probably General Duncan, that this exhibit was his actual tank and it seems that Dover corporation was asked to supply suitable transfers of the town's crest to flank the name on each side. Nobody in Dover council at present has any recollection of this.
Precise Name: Tank, Infantry Mark II, Matilda I, CDL
Other Name: A12
Night fighting has always posed major problems for armies; it is hard enough to identify the enemy and navigate across the battlefield in the confusion of battle in daytime. Darkness makes everything immeasurably more difficult.
The CDL or Canal Defence Light was an early attempt to exploit darkness by using a very bright, flickering light as an offensive weapon. It was the brainchild of Mr. A.V.M. Mitzakis, a Greek citizen. His idea was to use a 13 million candle power light. This would dazzle, disorient, and possibly temporarily blind any one that looked at it. Furthermore by making the light flicker at a particular frequency the pupils of the eyes of anyone looking at it would expand and contract very rapidly, reinforcing the effect.
Mr. Mitzakis interested General Fuller, the tank pioneer, and also the Duke of Westminster in his idea in 1937 and the device was demonstrated to the Army. The War Office expressed no interest until 1940 when it was decided to build prototypes mounted on the Matilda II chassis. They were given the cover name of Canal Defence Lights, (CDL), possibly suggestive of a project to defend the Suez Canal. The work was conducted in great secrecy. The light source, a carbon arc lamp, was housed in a new armoured turret. There was a vertical slit down the front of the turret. A mechanical shutter that opened and closed over the slit created the flickering effect. The light operator sat on the left side of the turret was provided with asbestos gloves so that he could change the hot carbon arcs when they burned out. He was also provided with a machine gun in the turret front.
Eventually CDL turrets were fitted to 300 Matilda II and V tank chassis, enough to equip one tank brigade in Britain and one in the Middle East. Initial training was carried out at Lowther Castle near Penrith in Cumbria. A total of five British Battalions were trained, two of which were sent to the Middle East, forming the First Tank Brigade in 1942. They were never used in their intended role. Early in 1943 it was decided to convert some M3 Grant medium tanks to CDLs after M4 Shermans superseded them as gun tanks. The CDL turret replaced the Grants’ 37mm turret, but they retained their hull mounted 75mm guns. These tanks were sent to North West Europe following the Normandy invasion. They were never deployed in an offensive role but some of them were used to provide illumination when the Rhine was crossed in 1945. Other CDL tanks were sent to the Far East but were not used against the Japanese. The CDL turret was also mounted on the chassis of the Churchill tank.
The US Army adopted the CDL in 1943 and 335 M3 tanks, mostly the M3A1 model, were converted. Eventually six battalions were trained as CDL units for operations in NW Europe. The US Army called the CDL tanks ‘T10 Shop Tractors’ as a disguise. The vehicles were never used in combat.
The CDL is an early example of an incapacitating or non-lethal weapon, a type of weapon that some modern armies are very interested in.
Summary text by Mike Garth
Main utility typeLight
Country of UseU.K. (1942)
|Manufactured||1942||Ruston and Hornsby Ltd.||United Kingdom||Grantham, Lincolnshire|
EraWorld War 2
Current LocationBOVTM - B18 - WW2 Hall - Britain at Bay
|Armament - Main Weapon Type||Arc Light Weapon - Carbon Arc Spotlight|
|Armament - Secondary Weapon Type||7.62 mm Besa Machine Gun|
|Engine||2 x AEC, 6 Cylinder, water cooled|
|Transmission||6 Forward, 1 Reverse|
|Suspension||Horizontal coil spring|
|Fuel||Volume||181.8||ltr||plus 163.6 litres in auxiliary tank|
|Speed - Road||Maximum||24||kph|
|Armour Thickness - Hull||Maximum||78||mm|
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