Wednesday, 31 May 2023

Landships Left In Port

Fosters of Lincoln Ltd. built tanks during the First World War, but returned to peaceful products after its conclusion, as the military no longer needed new tanks. When the situation began to change and the Mechanical Warfare Board was established in 1928, Sir William Tritton offered his help, but was rudely rejected. The reverse took place a few years later: when approached for help, Tritton refused. Fosters was doing fine without the army. Its factories were loaded with orders for consumer goods, and it was not worth his time to deal with the military for miserly contracts. However, peace did not last forever. 1939 came and with it, war.

A colossus from yesterday’s war

Talk of bringing seasoned tank designers out of retirement began in the summer of 1939. Words became actions in the fall. On September 5th, the Director of Mechanization Major General Davidson invited Sir Albert Stern, the designer of the famous British rhomboid tanks, to develop a “special tank”. On October 12th, 1939, the Minister of Supply Leslie Burgin created the Special Vehicle Design Committee within his fledgling ministry. The committee included Tritton, Ricardo (the developer of WWI era tank engines), and Major General Sir Ernest Swinton, among other engineers and soldiers. As many of these men had experience in designing tanks during the First World War, the committee was nicknamed TOG (The Old Group or The Old Gang).

The committee’s task was to develop a tank that could cross a 16 foot (4.9 meter) wide trench, climb 7 foot (2.1 m) tall wall, and have enough armour around the perimeter to protect from 37 and 47 mm anti-tank guns and 105 mm howitzers at 100 yards (91 m). The estimated mass of such a vehicle was 70-75 tons. This colossus would be armed with 2-pounder guns in sponsons and a field gun in the front of the hull capable of penetrating up to 7 feet (2.1 meters) of reinforced concrete as well as machine guns and smoke bomb launchers. The crew was composed of “just” 8 men. According to Sir Edmund Ironside, the Chief of the Imperial General Staff, this tank would be needed at least a year from now, but work on it should start immediately. This project was designated “superheavy tank - land battleship”.

The tank was not created in an information vacuum. Members of the SVDC spent November 24th-30th in Paris, familiarizing themselves with the latest advances in French tank technology. Representatives of the British General Staff and others from the military were also present. The draft project of the new tank was ready soon after, on December 19th, 1939. Stern expected his tank to require 2.5-4“ (63-102 mm) of cemented armour and inquired at the admiralty about producing it.

The designers presented a model of their new tank to a military commission on December 21st. The tank was quite original for a group of old men, although not entirely satisfactory. The tank had a fairly large turret that could fit a 3” AA gun or 25-pounder. The tracks passed through an armoured conduit, which protected them from damage. The tank was rejected. The military requested a more conservative vehicle closer to old “rhombus” tanks. The new tank needed tracks that wrapped around the whole hull. No turret was needed; all armament would be installed in sponsons. The requirement for a field gun was removed, and no effort would be taken to equip the tank with a more powerful gun.

The designers began working on a new tank on January 11th. A model of the new vehicle was ready on February 29th. This is when the tank received a name: TOG 1. This tank weighed 55-60 tons with 2-4”(51-102 mm) thick armour. The armour was attached to a mild steel skin ⅜” (9.5 mm) thick. The committee estimated that such a tank could be built by June. Since the SDVC presented itself as a group of designers rather than manufacturers, there was no plan to build this tank at Fosters. The SVDC estimated that production of these tanks could reach 40 per month by November and a sufficient amount would be available “for the 1941 campaign”. No mention was made of what factory or factories was supposed to build them.

The TOG 1 was quite archaic. A 75 mm cannon was located in the front and 2-pounder guns in sponsons. The turret was not required by the customer.

These calculations were for naught. The TOG 1 was rejected on March 1st, 1940, as requirements changed again. The new tank needed a turret that could fit a gun larger than a 2-pounder instead of tiny sponsons. Tracks that wrapped around the entire hull were judged too vulnerable. This decision gave the initially proposed tank a green light. That tank was given the name TOG 2. The SVDC decided to build the TOG 1 anyway in order to test certain design elements.

The TOG 1 prototype on trials. Sponsons are not installed. This tank would have never gone into production, but it was still built to test design elements.

Burgin did not last in the War Cabinet too long. On May 12th, 1940, he was replaced by Herbert Morrison. However, Burgin’s committee lived a life of its own. The SVDC soon produced its first tank. The TOG 1 set out for trials near the city of Lincoln.

The tank received a colossal engine: a 600 hp Paxman diesel designed to power emergency generators at power plants. Since no mechanical transmission had been developed for such a powerful engine, a heavy and bulky electrical transmission was used (even the initial estimates put its weight at 6-7 tons) and hydraulic clutch. The 33 foot (10 meter) long tank weighed 65 tons. Like the tanks of the First World War, the running gear was unsprung.

Trials showed that the electric motors chosen for this tank were too weak and could not make full use of the generator’s output. The tank’s top speed was just 7 mph (11 kph). There was no point in submitting this tank for government approval, although Fosters proved that a tank with an electric transmission could be built.

The TOG 1 did not remain in its initial form. A new SSS (Synchro self-shifting) gearbox was installed by August of 1941. According to Harold Sinclair, the head of the company that developed it, driving a tank with such a gearbox did not require any special skills. It was also much easier to use than an unsynchronized gearbox. Well timed changing of gears would prolong motor and clutch life.

The tank also used a new Wrennie turning mechanism, described as “analogous to the Merrit-Brown”. This mechanism allowed the vehicle to turn easily even when climbing hills. The hydraulic clutch also made the tank easier to drive than a traditional friction clutch.

Anti-tank bureaucracy

The TOG 2 chassis was ready by early 1941. This tank was lighter than the TOG 1 and had more powerful motors, as a result of which its top speed grew to 9 mph (14.5 kph). This was where development came to a stop. The military was expected to change requirements yet again. It was not clear if the tank was going to be transported by rail (in which case it was too wide for the gauge), what kind of gun it was supposed to have, whether 76 mm of armour would be enough, and would it be possible to make the vehicle shorter if the requirement for trench crossing was rescinded. The SDVC could not continue its work until these questions were answered.

A possible armament layout for the TOG 2. A triple mounting with a 2-pounder gun, 3” howitzer, and BESA machine gun is installed in the turret. A more powerful gun is installed in the hull. Machine guns are installed in sponsons.

The issue of armament was indeed a tough one. The Churchill, the most modern British infantry tank, had the same armament as existing infantry tanks but at a much higher weight. The British already had more powerful guns than the 40 mm 2-pounder available. Work on the 57 mm 6-pounder began in 1938, but this gun could not fit in the Churchill’s turret.

By May of 1941 the 6-pounder was only the minimum required gun for new tanks. The military demanded more powerful weapons. Theoretically, such a gun already existed. Work on the “super-powerful” 76 mm 17-pounder began by the summer of 1941, but there was no tank to put it in. The 6-pounder gun was eventually installed into Churchill, Valentine, and Crusader turrets, but nothing larger could fit.

The TOG 2 had no issue with carrying either gun, and installing such a powerful weapon would have made it much more competitive. However, the 17-pounder gun would not be ready until the distant future, and a more powerful gun was needed now. There was one such option. Old 3” 20 cwt AA guns that were capable of destroying any known tank at the time were kept in storage. A massive 72” (1829 mm) turret ring was required to install this gun. It barely fit into the casemate of the Churchill Gun Carrier, but it would fit into a TOG 2 without radical changes.

Calculations showed that the heavy turret would gain another 9-10 tons of weight as a result of this conversion. The SVDC had to create a new type of turret traverse mechanism. The turret ring was located not atop the turret platform, but on the floor of the tank.

The turning mechanism underneath the fighting compartment floor.

The TOG continued to pop up in correspondence here and there, but the military did not rush with its conclusions. Morrison, Burgin’s replacement as the Minister of Supply, did not hold his position for long. Morrison was replaced by Andrew Duncan in October of 1940, who himself was dethroned by Lord Beaverbrook in June of 1941. No progress was achieved by November 3rd, 1941, and so Sir Albert Stern decided to send him an enraged letter. Stern complained that there was no stability in British tank building. In just 26 months of war Stern worked with 4 Ministers of Supply and 5 Directors of Mechanization, only one of which had any military experience at all. In this chaos, every company involved in tank building made their decisions on their own, while the impressive tank building experience of the Fosters company went unused.

The TOG 2 tank with a 3” 20 cwt gun. The tank could also fit the more powerful 17-pounder in the turret.

The letter had an effect, but not the kind that Stern hoped for. Oliver Lucas, the Director of Mechanization whose abilities Stern so thoroughly criticized, decided to dismiss the SVDC on November 4th, 1941. Stern resigned in protest. In his letter to his patron Lord Hankey, he wrote: “and so the chaos continues, now with only amateurs at the helm”.

The end of the SVDC did not mean the end of the TOG tanks. Assembly of the TOG 2 was nearing completion and blueprints of the improved TOG 2R were expected in mid-November.

Lord Hankey tried to support his tank. In a letter written on January 8th, 1942, he tried to persuade Sir John Anderson, member of the War Cabinet and President of the Privy Council, that the tank was quite good and could be sped up to 12 mph (19 kph) with further work. Hankey also attached a note from Fosters recommending the creation of a new tank committee within the Ministry of Supply that also praised the TOG 2. On January 21st Hankey handed yet another letter signed by former SVDC members to Lord Beaverbrook. The letter stated that their tank could be modified to take a 17-pounder gun. No other tank that could mount even a 6-pounder existed in metal. Stern predicted that it would take two years before a tank mounting a 17-pounder could be built. Beaverbrook’s answer was short: “The work of Stern’s committee will be reviewed without prejudice”.

In the Churchill’s shadow

Trials of the TOG 2 began before Stern’s scandal. A test turret was shot up on the proving grounds at Shoeburyness on October 2nd and 3rd, 1941. The tests were performed to establish the toughness of various methods of attaching the armour plates to the skin and resistance of the new turret traverse mechanism under fire. The turret was placed in a structural steel frame that imitated the hull. A triple gun mounting for the 2-pounder, 3” howitzer, and BESA machine gun was installed in the turret. The weapons themselves were absent.

A triple gun mount on the TOG 2 tank. The mount fell off when the turret was shot at.

The armour of the turret was quite interesting. Plates of different thicknesses (nominally 76 and 60 mm of surface hardened armour) were attached to a ½” (12.7 mm) thick mild steel skin. The turret roof was made from 25 mm thick homogeneous armour. The methods of attaching the armour to the skin varied, as finding the optimal solution was a part of the trials.

Small arms fire showed that the triple gun mount resisted bullets well, but it could not stand up to more powerful weapons. One hit with 25-pounder proof shot was enough to deform the pinions and knock off the gun mount.

A few methods of attaching the armour to the mild steel skin. Every one of them weakened the armour locally and fell apart when hit.

Further trials showed that armour bolted to a mild steel skin was enough to protect from 2-pounder fire if the shell hit in the center of the plate, but not if it hit close to a bolt. The bolts would burst if the shell landed close enough to them, after which either the shell penetrated the weakened armour or the bolt head came off and turned into a projectile inside the tank. Either way, the crew and tank would be put out of action. 2-pounder and 25-pounder shot could also deform the main plates if they hit in the right places. The frame that carried the turret deformed when the turret was struck and eventually jammed the traverse mechanism. Trials showed that the mechanism was easily damaged, as it took on too much shock when the turret was hit.

Firing the 6-pounder showed that the 73 mm thick sides (60 mm surface hardened plate plus 12.7 mm thick skin) could be penetrated fairly easily: from 1250 yards (1143) at an angle of up to 17 degrees from normal. The turret plates cracked when hit with 6-pounder shot, but the testers still considered it a good result after such heavy attack. Testers also remarked on the utility of the mild steel skin as a spall liner. The steel protected the crew from spalling and could even stop AP shot, provided it deformed or lost enough energy going through the main armour. Despite the jamming during trials, the idea of placing the turret ring on the hull floor was considered promising.

Diagram of the experimental turret.

The TOG 2 was sent to Farnborough for trials in early January of 1942. Former members of the SDVC were banned from attending. The tank finished trials and was returned to Lincoln by March 21st. Trials were ended prematurely as road wheels broke from vibration. Attempts to reduce the pressure on the road wheels by lengthening the chassis failed. In addition, the tank became harder to drive.

There were some positive conclusions that came from the trials. The electric transmission worked well. Driving the tank with a steering wheel and two pedals was easy and did not require any special training. According to trial reports, even General Richardson’s driver from the women’s Mechanized Transport Corps with no tank driving experience could drive the TOG 2. Testers suggested using such a solution in modern tanks.

Fosters did not give up and attempted to improve their tank, but work went slowly. A torsion bar suspension for the TOG 2 was ready only by March of 1943. The suspension was placed underneath the tank, which reduced its clearance. On March 11th the tank was demonstrated in Grantham, Lincolnshire.

It was no longer possible to put the TOG 2 into production, but The Old Gang did not give up. Sirs Stern and Tritton proposed a new tank on a 45 ton chassis capable of carrying up to 20 tons of armour up to 6” (152 mm) thick. The former SVDC also proposed using their solutions on lighter vehicles. Stern also proposed a shortened version of the TOG 2. Since the requirement for crossing trenches was no longer relevant, the tank could be shortened by 6 feet (1.83 meters), which reduced the mass by 20 tons. The difference could be used to thicken the armour.

A sketch of the TOG 2 tank’s final form made by a representative of the Canadian General Staff. The sketch shows the turret ring, special conduit for the track, and locations of components.

Even though personal relationships played a role in the tank’s death, Fosters doomed the TOG from the start by declining to produce it. There were also glaring issues with the design, especially from a production standpoint. British industry struggled with the fairly conventional 40 ton Churchill tank, and production of the 70 ton TOG 2 with no shortage of previously untried mechanisms would be a daunting task.

The TOG 2 was no longer needed by 1943. The Churchill had proven itself in battle and was now fighting on two fronts. Stern’s prediction did not come to pass. The Archer SPG and Challenger tank carrying 17-pounder guns were ready by March of 1943. These vehicles were far from perfect, but they were quite combat capable. There was also a new compact 600 hp tank engine, more reliable ways of joining thick armour plates, and better ways to protect a tank’s tracks from damage. The SVDC’s tank ended up without a purpose.

  • Archive of the Canadian Military Headquarters, London (1939–1947) RG 24 C 2
  • The National Archives, Kew
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