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Oscillating Turrets

Oscillating turrets were one of the latest trends in tank design in the early years of the Cold War, in the 1950s. The original intention of this type of turret was to make it easier to employ an automatic gun loader in the turret of a tank.
As well as the ability to fit an autoloader, there were other benefits. These included the ability to mount a big gun on a small chassis, have fewer crew members by the omission of the Loader crew member, and have a smaller turret. It also generally allows for a better front profile ballistically.

An AMX-13 90. The AMX-13s is perhaps the most famous and most successful tanks to use oscillating turrets. Photo: The Modeling News.

Design

Oscillating turrets consist of two parts that move on a separate axis. These are the top ‘roof’ section which holds the rigidly mounted main armament which moves up and down. In a conventional turret, the gun moves separately from the turret body, on its own trunnions.
The bottom ‘collar’ part is attached to the ‘roof’ via pivot joints and is fixed directly to the turret ring, allowing conventional 360-degree traverse.

History

Though it seems a relatively modern idea, the oscillating turret design actually goes back as far as the First World War, to a designer by the name of Arnold H. S. Landor. Landor, a British inventor living in Italy, who designed a new armored car in 1915. It featured possibly the first ever oscillating turret, which was armed with 65 or 75mm gun (specifics unknown) mounted on the vehicle’s roof. This was closely followed by an Armored car designed by Joseph Gonsior, Friedrich Opp, and William Frank. A joint project between the USA and Austro-Hungary from 1916, it had a machine gun in an oscillating turret. The elevation/depression was controlled via hand-cranks.
The next time such a component would appear would be in the early 1940s on the French armored car prototype, the Panhard 201. After the German invasion of France, the prototype was evacuated to northern Africa. This armored car was topped off with an oscillating turret that was manually operated and armed with an SA35 25mm gun.

The Panhard 201 with a simple oscillating turret. Photo: SOURCE
Late in the in the Second World War, the turret type was used again, this time as part of the German prototype Self-Propelled Anti-Aircraft Gun, the Flakpanzer IV Kugelblitz. This prototype was named after its turret; the name translates to “Lightning Ball”. It consisted of an armored ball mounted on an armored collar connected to the turret ring. The ball, mounting dual 30mm MK 103 cannons, moved independently in elevation, allowing it to target aircraft.
Post Second World War and during the early stages of the Cold War, the French began to lead the way in the development of this type of turret. They invested a great deal of time and money in designing such turrets for light tanks like the AMX-13 and armored cars such as the Panhard EBR (descendant of the 201). The French became the leaders in this technology and was the first (also one of the few) nation to employ this type of turret on a vehicle that saw active service.
Though they were never used on a serial production vehicle, the United States of America also began experimenting with oscillating turret designs in the late 1950s. Such turrets were developed for Light, Medium, and Heavy Tanks. Several prototypes were built to test these turrets, but they were never adopted. This was largely due to the fact that the Americans found no real advantage in using these turrets over the conventional format.

A scale model of the Kugelblitz produced by the designers. Photo: panzernet.net

Advantages

The major advantage of this type of turret was that it made the addition of an autoloader far easier becasue the loading system moves with the gun. In a conventional, rotating turret, an autoloader would have to follow the gun in elevation and depression to align the shell with the breech, and then ram it in. This method was used in the T37, an experimental American light tank. In other cases, such as with the Soviet IS-7 heavy tank, the gun had to be brought back to a neutral elevation after every shot, making engaging a target with multiple shots much slower. This is called the ‘index position’ and its an issue that remains to this day.
Oscillating turrets eliminated the hassle of both of these methods. As the gun was rigidly placed in the upper part of the turret, the autoloader, attached to the upper ‘roof’ section was free to ram shells in whatever the elevation angle the gun. Not only does this system speed up reloading but it allows the gun to stay on target during reloading which improves the speed of second and subsequent shots on target.
In a conventional turret, the breech of the gun sinks into the basket when elevated, meaning that the turret ring has to be of large enough diameter to accommodate this motion. With an oscillating design, the breach remains above the turret ring whatever the angle, meaning that the turret ring can be smaller, ergo, the hull can be smaller allowing for a bigger gun proportionally on a smaller vehicle. However, in this case, the maximum elevation angle is defined by the space between the rear of the turret and the deck of the hull, which may be less than the angles possible in a conventional design where the breach can fall into the hull.

Disadvantages

In this type of turret, the gun is often mounted high-up to grant as much room for elevation and depression as possible. Angles of fire though, were still rather limited when compared to traditional gun mounts. In elevation, the turret bustle would often be mere inches above the engine deck. Mounting the gun high in the turret gives a larger silhouette and easier to spot at distance than the lower-profile conventional turret. This is somewhat offset, however, due to the fact that in a hull-down position less of the turret would be exposed due the height of the gun mount and the improved ballistic shape of the turret
One of the biggest issues with oscillating turrets is that they could not be made safe against NBC (Nuclear, Biological, Chemical) attacks. Due to the to their design, there was a gap between the two moving sections of the turret. This was usually covered by waterproof canvas or rubber bellows that shrank and extended with the motion of the turret, but it was not an air-tight seal.

Outcome

The complexity of their design was the downfall of the oscillating turret, with most work on such designs coming to an end in the mid-1980s. To most military bodies, the opinion was shared that the turrets provided ‘no real advantage’ over the traditional format.
Autoloader technology had improved to the point of being compatible with a regular gun and turret layouts, removing the need for such turrets and the disadvantage of not being able to be sealed against NBC had remained a major and unresolved problem.
In 2013, however, a new vehicle with an oscillating turret entered service with the US Military. This is the M1128 Mobile Gun System (MGS). It consists of an unmanned, remote-controlled turret on the hull of the Stryker ICV (Infantry Combat Vehicle). The vehicle is armed with a 105mm M68A2 rifled gun, and is fed by an 8-round autoloader. It is currently one of the only vehicles with an Oscillating turret serving in an active Military.

The M1128 MGS with turret eleveated. Photo: WBS


French AMX-13 75.

Austrian SK-105 Kürassier

American 90mm Gun Tank T69

American Stryker based M1128 Mobile Gun System
Illustrations by Tank Encyclopedia’s own David Bocquelet

Tanks & AFVs with Oscillating Turrets

France

Panhard EBR: Armored car. In 1940, one of the pilot vehicles, the Panhard 201, was used in testing one of the earliest examples of an oscillating turret. Later models shared turret types and weaponry with the AMX-13. 1954, in service in France until 1981
AMX-13: A series of light tanks. Started out with a cylindrical oscillating turret with non-autoloading 75mm. This progressed to a longer, squarer turret with an autoloading system known as the FL-10. It is perhaps the most successful type of oscillating turret. Armaments progressed from a 75mm gun, to a 90mm and finally a 105mm gun. Entered service in 1952, in service with France until the 1970s, also in the arsenal of countries like Israel, Mexico and Singapore. Singapore only began to retire the tank in 2012.
Char Leger De 12 Tons: Competing design for a light tank, utilising a similar (if not the same) turret as the AMX-13. The major difference was with the running gear based on the classic German interleaved design. Early 1950s, no serial production.
AMX ELC EVEN series: A series of light tanks with various weapons including 30mm, 90mm and 120mm guns. The oscillating turret , consisted of a flat upper part on top of a ‘neck’ joint which was protected behind a truncated material cover. The weapons were often mounted off the center line at the extreme right or left of the turret. 1955, no serial production.
Batignolles-Châtillon Char 25t: Medium tank prototype designed along the same lines as the AMX-13s. It was armed with a 90mm gun and auto-loader. 1954, no serial production.
Lorraine 40t: Medium tank prototype with a unique suspension consisting of pneumatic road-wheels. It was armed with a powerful 100mm gun and autoloader. 1952, no serial production
AMX-50: A series of heavy tank prototypes. The earliest version borrowed much from the Lorraine 40t using a similar turret and the same 100mm gun and autoloading system. The later version incorporated a newer, larger turret design similar to that of the AMX-13’s known as the ‘Tourelle D’ and was armed with a 120mm gun. The AMX-50s borrowed the German style suspension with interleaved road-wheels. Early 1950s, no serial production.
Somua SM: A heavy tank design that competed with the AMX-50. It featured the same turret as the early AMX-50 prototype, armed with a 100mm gun fed by an autoloader. The hull design was heavily inspired by the Tiger II, but used a different individual wheel suspension instead of the famous interleaved type. Early 1950s, no serial production
Medium Tank M4 with FL-10: A number of surplus Sherman tanks were updated by adding the AMX-13’s 75mm armed FL-10 turret. Various models of Sherman were updated, including M4A1s and M4A2s. M4A2s with the turret were used by the Egyptian army in the Six-Day War. Mid-1950s, limited production.
Light Tank M24 with FL-10: A project to modernize M24s in France’s inventory by replacing the standard turret with the 75mm armed FL-10 of the AMX-13. 1956, no serial production

United States of America

Gonsior, Opp, and Frank War Automobile: A joint armored car project designed by Joseph Gonsior, Friedrich Opp, and William Frank. A joint project between the USA and Austro-Hungary from 1916, it had a machine gun in an oscillating turret. The elevation/depression was controlled via hand-cranks. Never left blueprint stages. 1916, no serial production.
76mm Gun Tank T71: A light tank design by two competitors. These were Detroit Arsenal (DA) and Cadillac Motor Car Division (CMCD). DA’s design utilised an oscillating turret and autoloader feeding a 76mm gun. The vehicle was never built and never left blueprint stages. Early-1950s, no serial production
90mm Gun Tank T69: Medium Tank prototype with an oscillating turret mounted on the hull of the failed T42 medium tank project. The turret contained an 8-shot cylinder, not unlike a giant version of one you would find on a handgun. Only one was ever built as the turret was not thought to provide “any real advantage” over the traditional type. Mid-1950s, no serial production.
105mm Gun Tank T54E1: Medium tank prototype produced for series of trials to find the best way to mount a 105mm gun on the hull of the M48 Patton III. An autoloader system was also utilised inside the turret. Mid-1950s, no serial production.
155mm Gun Tank T58: A heavy tank design utilising an oscillating turret with autoloader, mounted on the hull of the T43/M103 hull. Had the tank left the drawing board, it would’ve been armed with a 155mm gun, the largest gun to be mounted in an oscillating turret. Mid-1950s, no serial production.
120mm Gun Tank T57: A heavy tank design similar to the T58 but armed instead with a 120mm gun. Mid-1950s, no serial production.
120mm Gun Tank T77: A heavy tank project to mounting the T57’s turret on the hull of the M48 Patton III. Mid-1950s, no serial production.
M1128 Mobile Gun System: The latest American vehicle to use this turret type. It consists of an unmanned, remote turret on the hull of the Stryker ICV (Infantry Combat Vehicle). The vehicle is armed with a 105mm M68A2 rifled gun, and is fed by an 8-round autoloader. 2013, currently serving.

Austria

SK-105 Kürassier: Austrian light tank. The hull was an indigenous design, but it utilized the turret of the AMX-13 bought from France. They were armed with 105mm guns. Early 1970s, in service with Austria until the 1990s, remains in service countries such as Argentina and Botswana.

Sweden

EMIL Project: A series of heavy tank designs with heavily armored oscillating turrets. They were designed with autoloaders and guns from 105mm to 150mm. Two chassis, codenamed “Kranvagn” (English: Crane vehicle) were constructed before the project’s cancellation. Early 1950s, no serial production.
Strv m/42-57 Alt. A.2.
In an effort to up-gun their already vastly outdated Stridsvagn m/42. A meeting was held on February 15th, 1952 on possible improvements. One solution was to mount a new oscillating turret design on to the m/42’s hull. This idea never came to fruition, however.

Germany

Flakpanzer IV Kugelblitz: Anti-aircraft tank built on the chassis of the Panzer IV. The tank was named after its turret, the name meaning “Ball Lightning”. It was armed with two 30mm MK 103 auto-cannons. 1943, no serial production.
DF 105 Combat Tank: A cooperative project between France and Germany combining the Marder I chassis with an updated AMX-13 turret with a 105 mm main gun. It was called the DF 105 Combat Tank. Early-mid 1980s, not serialized. Mid-1980s, no serial production.
CLOVIS, FL-20, 105mm: A follow up project of the DF 105. The Marder chassis remained the basis, but a completely new oscillating turret was added. It was possibly one of the last turrets of the type to be developed. 1985, no serial production.

Great Britain

COBRA: A design for a 30-ton tank to carrying a 120mm gun. It was extremely lightweight for a tank with such a gun, but retained excellent armor protection over the entire frontal arc. Side and rear armor were sacrificed, however. 1954, no serial production.

Italy

AMX-13/60: An update program that replaced the existing gun of the French Light Tanks with a high-velocity 60mm gun.

Links, Resources & Further Reading

www.chars-francais.net
www.armchairgeneral.com
Panzer Tracts issue 12–1: Flakpanzerkampfwagen IV and other Flakpanzer projects development and production from 1942 to 1945, Thomas Jentz & Hilary L. Doyle.
Presidio Press, Patton: A History of the American Main Battle Tank, Volume 1, R. P. Hunnicutt
Presidio Press, Firepower: A History of the American Heavy Tank, R. P. Hunnicutt
Rock Publications, the AMX-13 Light Tank. Volume 2: Turret, Peter Lau
The Tank Museum, Bovington, UK
The National Armor and Cavalry Museum (NACM), USA
Musée des Blindés, Saumur, France

Categories
Tech WW2 British Funnies WW2 US Other Vehicles

Canal Defence Light (CDL) Tanks

United Kingdom/USA (1942)
Infantry Support Tank

At the time of its conception, the Canal Defence Light, or CDL, was a Top Secret project. This ‘Secret Weapon’ was based around the use of a powerful Carbon-Arc lamp and would be used to illuminate enemy positions in night attacks as well as disorient the enemy troops.
A number of vehicles were converted to CDLs, such as the Matilda II, the Churchill, and the M3 Lee. In keeping with the highly secret nature of the project, Americans designated vehicles carrying the CDL as “T10 Shop Tractors.” In fact, the designation “Canal Defence Light” was intended as a code name to draw as little attention to the project as possible.

Development

Looking at the CDL tanks, one would be forgiven for thinking that they were one of the famous ‘Hobart’s Funnies.’ but in fact, the man credited with the creation of the Canal Defence Light was Albert Victor Marcel Mitzakis. Mitzakis designed the contraption with Oscar De Thoren, a naval commander who, like Mitzakis, had served in the First World War. De Thoren had long championed the idea of armored searchlights for use in night attacks and the project continued under the supervision of the venerable British Major General, J. F. C. “Boney” Fuller. Fuller was a noted Military historian and strategist, credited as one the earliest theorists of modern armored warfare. With Major General Fuller’s backing, and even the financial support of the Second Duke of Westminster, Hugh Grosvenor, the first CDL prototype was demonstrated to the French Military in 1934. The French were not keen, thinking the system was too fragile.
The British War Office had refused to test the device until January 1937 when Fuller contacted Cyril Deverell, the newly appointed Chief of the Imperial General Staff (C.I.G.S.). Three systems were demonstrated on Salisbury Plain in January and February 1937. Following the demonstration which took place on Salisbury Plain, three more of the devices were ordered for tests. There were delays, however, and the War Office took over the project in 1940. Tests finally began and orders were placed for 300 devices that could be mounted to tanks. A prototype was soon constructed using a spare Matilda II hull. A number of Churchills and even Valentines were also supplied for the tests.
The turrets were manufactured at the Vulcan Foundry Locomotive Works in Newton-le-Willows, Lancashire. Components were also produced at the Southern Railway workshops in Ashford, Kent. The Ministry of Supply delivered the Matilda hulls. The turrets were identified by Type, eg. Type A, B & C. The Ministry of Supply also established an assembly and training site known as the CDL School at Lowther Castle, near Penrith, Cumbria.

American Tests

The CDL was demonstrated to United States officials in 1942. Generals Eisenhower and Clark were present for the demonstrations. The American’s became intrigued by the CDL, and decided to develop their own version of the device. Designers chose the then outdated and plentiful M3 Lee Medium tank as a mount for the light.
For the purposes of extreme secrecy, production stages were split between three locations. The Arc-Lamps being provided by the US Army Corps of Engineers, the American Locomotive Company, New York, worked on modifying the M3 Lee to accept the CDL turret and the Pressed Steel Car Company, New Jersey, constructed the turret as “Coastal Defence Turrets.” Finally, the components were united at the Rock Island Arsenal, Illinois. 497 Canal Defence Light equipped tanks had been produced by 1944.
Crews were trained at Fort Knox, Kentucky, and in the huge Arizona/California maneuver area. Crews training with the vehicles – codename “Leaflet – went under the codename “Cassock.” Six Battalions were formed and would later join British CDL tank regiments, covertly stationed in Wales.
American crews came to call the CDL Tanks “Gizmos”. Tests would later begin to mount the CDL on the newer M4 Sherman chassis, developing their own unique turret for it, which will be explored in a subsequent section.

Let There Be Light

The Carbon-Arc searchlight would produce a light as bright as 13 Million candle-power (12.8 million candela). Arc-Lamps produce light via an arc of electricity suspended in air between two carbon electrodes. To ignite the lamp, the rods are touched together, forming an arc, and then slowly drawn apart, maintaining an arc. The carbon in the rods vaporizes, and the vapor produced is extremely luminous, which produces the bright light. This light is then focussed by a large concave mirror.

Using a series of mirrors to reflect it, the intensely bright beam of light passes through a very small vertical slit on the left of the turret face. The slit was 24 inches (61cm) tall, and 2 inches (5.1cm) wide and had a built in shutter that would open and close two times per second, giving the light a flickering effect. The theory was that this would dazzle enemy troops, but also had the added bonus of protecting the lamp from small-arms fire. Another tool to dazzle troops was the ability to attach an amber or blue filter to the lamp. Coupled with the flashing, this would increase the dazzling effect and could still illuminate targets areas effectively. The system also allows for the use of an infra-red illumination bulb so that IR vision systems can see at night. The field covered by the beam was a 34 x 340 yards (31 x 311 m) area at a range of 1000 yards (910 m). The lamp could also elevate and depress 10 degrees.

“…a source of light placed at the focus of a parabolic-elliptical mirror reflector [made from aluminium] is thrown by this reflector near the back of the turret which directs the directs the beam forwardly again to focus at or about an aperture in the wall of the turret through which the light beam is to be projected…”

An excerpt from Mitzakis’ patent application.

The device was housed in a special one-man cylindrical turret that was squared off on the left, and rounded on the right. The turret could not rotate 360 degrees as the cabling would snag so could only rotate 180 degrees left or 180 degrees right but not all the way around. The turret featured 65 mm of armor (2.5 in). The operator inside, listed in the vehicle design as “observer”, was positioned on the left side of the turret, partitioned off from the lamp system. The commander was issued with a pair of Asbestos gloves which were used when the carbon electrodes that power the light burned out and needed changing. He also had the role of operation the tank’s only weapon, a BESA 7.92 mm (0.31 in) machine gun, which was positioned on the left of the beam slit in a ball mount. The device was also designed to be employed on small naval vessels.

CDL Tanks

Matilda II

The faithful “Queen of the Desert,” the Matilda II, was now a largely considered outdated and outclassed in the European theatre, and as such there was a surplus of these vehicles. The Matilda II was the first tank to be equipped with the CDL Arc-Lamp turret, identified as the Type B turret. The Matildas were as reliable as ever with reasonable armor, however they were still extremely slow, especially compared to the more modern tanks entering service. As such, the Matilda hull gave way to that of the M3 Grant, which could at least keep up with the majority of Allied vehicles as well as sharing a lot of component parts with other Allied vehicles, making supply easier.
Another variant of the Matilda came out of this project, the Matilda Crane. This involved a Matilda using a specially designed crane attachment, that could lift off the CDL or standard turret as required. This allowed an easy conversion, meaning that the subject Matilda could be used as a gun tank, or a CDL tank.

Churchill

The Churchill is the rarest of the CDLs, with no pictorial records whatsoever, barring a cartoon from a newspaper. The 35th Tank Brigade, as well as being issued with Matildas, were also issued with Churchills, forming the 152nd Royal Armored Corps. It is unclear whether these Churchills were ever equipped with the CDL. The turret ring for the Churchill was only 52″ (1321mm) compared to 54″ (1373mm) on the Matilda and the later M3 Grant. The turrets, therefore, were not interchangeable from Matilda or M3 CDLs. Armor on the turret was also increased to 85mm.
There is a written record for the existence of the Churchill CDL in the form of a report by a member of the 86th Field Regiment, Royal Artillery, stating that he witnessed Churchills equipped with CDLs deployed on the 9th February 1945 near Kranenburg, Germany.
An excerpt from his report:
“A Churchill tank carrying a searchlight took up position at the rear of our position and at night floodlit the area, pointing its beam over the town. They turned night into day and our gunners working on the guns were silhouetted against the night sky.”

M3 Lee

In the long run, the M3 Grant was always the intended mount for the Canal Defence Light. It was quicker, able to keep up with its compatriots, and retained its 75mm tank gun allowing it to defend itself much more effectively. Like the Matilda, the M3 Grant was largely considered obsolete, so there was quite a surplus of the tanks.
The CDL replaced the secondary armament turret atop the M3. The M3s, originally, were also fitted with the Type B turret of the Matilda. Later, the turret was changed to the Type D. This welded up some of the ports and openings, but also saw the addition of a dummy gun next to the beam slit to give it the appearance of a normal gun tank. The Americans also tested the M3, known as the Lee in their service, as a CDL tank. The tanks used were mostly of the M3A1 type with the cast super-structure. The turret was mostly identical to the British pattern, the major differences being a ball mount for a Browning M1919 .30 Cal. as opposed to the British BESA.

M3A1 CDL

M4 Sherman

After the M3 CDL, the M4A1 Sherman was the next logical choice for a variant. The turret used for the M4 was much different than the British original, designated the Type E. It consisted of a large round cylinder, that featured two shuttered slits in the front, for two Arc-Lamps. The lamps were powered by a 20-kilowatt generator, driven by a power takeoff from the tank’s engine. The commander/operator sat in the middle of the lamps, in a central sectioned off compartment. In the middle of the two beam slits, there was a ball mount for a Browning M1919 .30 Cal. machine gun. There was a hatch in the middle of the turret roof for the commander. A few were also trialed using the M4A4 (Sherman V) hull. The use of the M4 did not get past prototype stages, however.

The Prototype M4 CDL

Matilda CDL of the 49th RTR
Matilda CDL of the 49th RTR – 35th Tank Brigade, north-eastern France, September 1944.
Churchill CDL, western Rhine bank, December 1944.
M3 Lee/Grant CDL, other wise known as a “Gizmo”.

Medium Tank M4A1 CDL prototype.
All illustrations are by Tank Encyclopedia’s own David Bocquelet

Service

As it would happen, the Canal Defence Lights saw extremely limited action and did not operate in their intended roles. Due to the secret nature of the CDL project, very few armored commanders were actually aware of its existence. As such, they were often forgotten and not drawn into strategic plans. The operational plan for the CDLs was that the tanks would line up 100 yards apart, crossing their beams at 300 yards (274.3 meters). This would create triangles of darkness for attacking troops to move forward in while illuminating and blinding enemy positions.
The first CDL equipped unit was the 11th Royal Tank Regiment, formed early in 1941. The regiment was based at Brougham Hall, Cumberland. They trained at Lowther Castle near Penrith at the specially established ‘CDL School’, set up by the Ministry of Supply. The Regiment was supplied with both Matilda and Churchill hulls, with a total of 300 vehicles. British CDL equipped units stationed in the United Kingdom could later be found as part of the British 79th Armored Division and 35th Tank Brigade, they were joined by the American 9th Armored Group. This group trained in their M3 CDLs at Camp Bouse, Arizona, before being stationed in the United Kingdom. They were then stationed in Wales, in the Preseli Hills of Pembrokeshire where they would also train.

A Grant CDL testing its beam at Lowther Castle
In June 1942, the battalion left the UK, bound for Egypt. Equipped with 58 CDLs, they came under the command of the 1st Tank Brigade. The 11th RTR set up their own ‘CDL School’ here, where they trained the 42nd Battalion from December 1942 to January 1943. In 1943, Major E.R. Hunt of the 49th RTR was detailed in late 1943 to lay on a special demonstration for the Prime Minister and op Generals. Major Hunt recalled the following experience:

“I was detailed to lay on a special demonstration with 6 CDL tanks for him (Churchill). A stand was erected on a bleak hillside in the training area at Penrith and in due course, the great man arrived accompanied by others. I controlled the various maneuvers of the tanks by wireless from the stands, ending the demo with the CDLs advancing towards the spectators with their lights on halting just 50 yards in front of them. The lights were switched off and I awaited further instructions. After a brief interval, the Brigadier (Lipscomb of the 35th Tank Brigade) rushed up to me and ordered me to switch on the lights as Mr. Churchill was just leaving. I immediately ordered the 6 CDL tanks to switch on: 6 beams each of 13 million candlepower came on to illuminate the great man quietly relieving himself against a bush! I immediately had the lights extinguished!”

Back in the UK at Lowther, two more tank battalions had converted to CDL units. These were the 49th Battalion, RTR, and 155th Battalion, Royal Armoured Corps, and were equipped with Matilda CDLs. The third battalion to arrive was the 152nd Regiment, RAC, who were equipped with Churchill CDLs. The 79th Armored Division was the first Canal Defence Light force to see deployment in Europe in August 1944, the other units were retained in the UK. Rather than let the remaining crews sit idle, they were assigned to other roles, such as mine clearance or assigned to regular tank units.
In November 1944, Canal Defense Lights of the 357th Searchlight Battery, Royal Artillery provided light for the mine-clearing flail tanks clearing a path for Allied armor and infantry during in Operation Clipper. This was one of the CDLs first uses in the field.

An M3 CDl on the Bank of the Rhine, 1945. The device is concealed under a tarp. Photo: Panzerserra Bunker
The Canal Defence Lights only real action, however, was at the hands of United States forces during the Battle of Remagen, specifically at the Ludendorff Bridge where they assisted in its defense after the Allies captured it. The CDLs were 13 M3 “Gizmos,”, from the 738th Tank Battalion. The tanks were perfect for the task, as they were sufficiently armored to stand up to the defensive fire coming for the German controlled East Bank of the Rhine. Standard searchlights would have been destroyed in seconds but the CDLs were successfully used to illuminate every angle to deter surprise attacks. This included being shone into the Rhine itself (fitting the vehicle’s name), which helped reveal German frogmen trying to sabotage the bridge. After the action, without the need to defend against incoming fire, captured German spotlights took over the role.
After the action, a captured German officer reported in questioning:
“We wondered what those lights were as we got the hell shot out of us as we tried to destroy the bridge…”
British M3 Grant CDLs were used as their forces crossed the Rhine at Rees. The CDLs drew heavy fire with one of the tanks being knocked out. More were used to cover British and US forces as they crossed the Elbe River Laurenburg and Bleckede.
Some Canal Defence Lights were ordered for the Pacific Campaign in 1945 by the US 10th Army for the attack on Okinawa, but the invasion was over by the time the vehicles arrived. Some British M3 CDLs did make it to India under the 43rd RTR and were stationed here for the planned invasion of Malaya in February 1946, the war with Japan came to an end before this of course. The CDLs did see a form of action however, by assisting the Calcutta Police in the riots of 1946 with great success.

Surviving CDLs

To no surprise, CDL survivors are rare today. There are only two on public display in the world. A Matilda CDL can be found in The Tank Museum, Bovington, England and an M3 Grant CDL can be found at the Cavalry Tank Museum, Ahmednagar in India.

The Matilda CDL as it sits today in The Tank Museum, Bovington, England. Photo: Author’s Photo

The surviving M3 Grant CDL at the Cavalary Tank Museum, Ahmednagar, India.

An article by Mark Nash with research assistance from Andrew Hills


Links, Resources & Further Reading

Mitzakis Patent application: Improvements Relating to Light Projection and Viewing Equipment for Turrets of Tanks and Other Vehicles or Ships. Patent Number: 17725/50.
David Fletcher, Vanguard of Victory: The 79th Armoured Division, Her Majesty’s Stationery Office
Pen & Sword, Churchill’s Secret Weapons: The Story of Hobart’s Funnies, Patrick Delaforce
Osprey Publishing, New Vanguard #7: Churchill Infantry Tank 1941-51
Osprey Publishing, New Vanguard #8: Matilda Infantry Tank 1938-45
Osprey Publishing, New Vanguard #113: M3 Lee/Grant Medium Tank 1941–45
Patton’s Desert Training Area by Lynch, Kennedy, and Wooley (READ HERE)
Panzerserra Bunker
The CDL on The Tank Museum’s website