Early Paper British Amphibious Tanks

Artist’s impression of the colossal WLT Type 1, drawn from the plans submitted by Mr Cargin. The unique pads on the tracks are extended on the leading edge of the tracks, and are changing their aspect on the top rear of the track unit that has the soldier standing next to it.

From the Johnson Light infantry tank in the early 1920s through to the Duplex Drive tanks of the Second World War it would appear that there was no development work on amphibious tanks in the UK. Vickers did design a couple of two-man amphibious tanks in the 1930s, but these were not effective combat machines, being almost unarmoured and armed only with a machine gun. Yet the machine did find some overseas sales, most notably to Russia, who developed the tank into the T-37A. The British did develop some wooden floats that could be attached to a Vickers light tank to enable it to cross bodies of water but, apart from that, the common misconception is that Britain did not carry out any research or development into amphibious tanks.

During the first years of the Second World War Britain devoted some time and effort to designs and studies into operating tanks across water. By sheer coincidence, some private individuals were also thinking of this problem and came up with some ideas on the subject.

The first tank to receive a mention in the historical record was just such a private venture. On 2 July 1940 William Train Gray, of Altrincham, Chester, filed a patent for an amphibious tank but no plans or drawings were included with the application. Mr Gray’s novel idea was termed a ‘longitudinal’ tank with a series of sections rotating around a single axis. One section held the tank’s fighting compartment and crew, and remained the same way up at all times, while the others had tracks on the bottom and boat-like elements, such as propellers, hull and rudders on the top. When entering the water the front section would rotate through 180 degrees, leaving the tracks on the top and the boat on the bottom. The same would happen when the rear section entered the water. The process was reversed when leaving the water. For obvious reasons, the idea does not seem to have even been looked at by the government’s scientific bodies.

The government itself was alive to the idea of amphibious tanks. Throughout 1940 there was some thought going into the concept of amphibious tanks, their design and operation. Although some experiments had been carried out on submersible tanks, including a cruiser Mk I being modified to drive along under water and managing to operate in water ten-feet deep. Initially thoughts were of infantry tanks being submersible for river crossings and the like, and cruiser tanks being supported by flotation devices. For landings from the sea, submersible designs were less favoured, and the development moved away from submersion. One idea put forward was the concept of building ‘the battle landships of the Army’. These were seen more as boats with tracks and were in the 800-850-ton range. Lord William Douglas Weir, the man behind these ideas, pointed out that tracked machines of 1,200 tons already existed. With a warship’s level of armour they would be able to ignore field artillery and would crush any known obstacle.

This idea was seen as too outlandish and the task of designing an amphibious tank and defining the requirements of the tank were handed to the Department of Naval Land Engineering (DNLE), which had previously designed the ‘Nellie’ trench-digging machine. The general staff requirement envisioned that the landings would consist of about 100 tanks in the first wave, launched from about 200 yards offshore. After landing, the tanks would need to fight and be able to secure a bridgehead about three to five miles in depth to cover follow-on waves. The War Office wanted the tanks in production by 1 April 1941. The short timescale meant that some of the more difficult propositions, such as submersion, were again dismissed which upset some parts of the development team as they had designed and were working on a submersible tank. The new DNLE tank was known simply as the AT-1, with the ‘AT’ standing for Amphibious tank. The design included track propulsion when in the water, which had some bearing on the next design we will study.

On 28 August 1940 an envelope with some plans and a covering letter landed on a desk in London in the Department for Scientific Research (DSR), and was then passed onto the DNLE for comment as they were working on amphibious tanks. The letter was from Matthew Cargin, of Wolley Avenue, New Farnley, Leeds, and in it he proposed a pair of new amphibious vehicles, both called the WLT. One stood for ‘Water and Land Tank’, the other ‘Water and Land Transport’. These monsters were just over 49 feet in length and 17 feet in width, and weighed between 235 and 265 tons. The ground pressure for the ‘WLT’ tank was a surprisingly low 1.25kg/cm2. In comparison, Germany’s super-heavy Maus was 1.45kg/cm2. Mr Cargin helpfully gave options for the tanks and transports. The Types 1 and 2 were both tanks with conical revolving turrets, the only difference between the two being the arrangement of their tracks. Type 1 had four tracks mounted on two independent turntables while Type 2 had its four tracks mounted directly to the hull in a much more conventional method. Most had four engines in the 225bhp range, although the Transport Type 2 had twin 375bhp engines. Endurance was about eight days of continuous use with land speeds ranging from 38mph to 60mph. Maximum water speed for all was about 11 knots. The transports could carry eleven men as well as supplies to keep them fed and watered for the tank’s full endurance.

One of Cargin’s proposals was to increase either the armour thickness or firepower of the WLT tanks, although he did warn that increasing either meant that the vehicles would no longer be amphibious. Cargin did not list the armament but the WLT tank plans show what looks like a 9.2-inch gun, and the weapon’s dimensions on the plan match those of the BL 9.2-inch gun Mk X.

The tracks themselves, for all four types, had pads that flipped out to help propel the vehicle through the water. The tracks would always turn in the same direction but a control could be set for forward or astern. When in ‘forward gear’, the pads on the bottom of the track would flip out, and the pads on the top part of the track run would close; for ‘astern’ the opposite was the case. This created paddles pushing in the desired direction. On land the pads on the tracks were all closed up. This particular feature was praised, along with the ingenuity of Mr Cargin in working out the idea. However, nearly every other element of his design, including ventilation and armour thickness, came in for some condemnation. The track design, while ingenious, was considered too complex for use and most of Cargin’s calculations were also considered suspect. As a final point, the DNLE, who were working on track propulsion, were concerned about where Cargin had got the idea, and asked for MI5 to investigate him. At the time, due to the level of ingenuity Cargin had shown, the Department for Scientific Research was considering offering him a job. In a few short weeks over Christmas 1940 MI5 were able to put a complete dossier together on Mr Cargin:

Age 42. Married. Born in Newcastle of Scottish parents. Ship engineer by trade. Was apprenticed at Newcastle-upon-Tyne and subsequently worked on the ships of many firms. In 1925 he went to Canada where he worked as a Draughtsman in various employments until he returned to this country in 1932. Believed since 1932 to have had one period of employment only, namely for some three months in 1939 as a Draughtsman with John Fowler (Leeds) Ltd. There was routine work at a wage averaging £3 10. 0. a week and he was not a very efficient workman. Absent sick on many occasions and eventually left of his own accord. Present source of income believed to be from property owned by his wife. No criminal records in Leeds district known and no observations arise under S.A.55.

This less than glowing reference caused him to be dropped from the DSR’s recruitment list, and a letter of rejection for the WLT project was sent out.

Things went quiet for a period before, in late 1940, Mr Cargin reappeared. He had spent the intervening months drawing up detailed plans of the ventilators and other components to prove that his ideas were correct. He then started bombarding government departments with letters, sometimes at a rate of one a day. His letters went varyingly to the Ministry of Supply, the DSR and the Prime Minister’s office and were mostly identical. At one point he sent in a letter demanding to know when his plan would be taken up by the British. Another he wrote to the DSR asked if they had received his letter, which he had sent to the Prime Minister’s office only a couple of days before.

In his letters to the Prime Minister’s office, Cargin answered the DNLE’s complaint about the armour thickness of the tanks. He also laid out how these were war-winning weapons. On the armour thickness, he pointed out the armour plate was made of chromium-steel which, unfortunately, Cargin seemed to think would offer protection far in advance of normal armour. He may well have been right in the First World War but, by 1940, armour technology had moved on. Several times Mr Cargin took great pains to point out this perceived advantage in armour.

The second point he raised was how his WLTs would win the war, and the peace afterwards. First, just 500 WLT tanks and a similar number of WLT transports would be needed. This force would land directly into Germany from the mouth of the Rhine to the Kiel Canal. As follow-on forces held the coast and pushed slowly inland, the WLTs would charge along the Kiel Canal to the Baltic and down the Rhine. Then, with the flank secure, the force, again led by the WLTs, would push on into the heart of Berlin. Cargin also offered an alternative plan – landing in the area of Rotterdam to Dunkirk, then pushing on to the Baltic and Frankfurt and thence to Berlin. To defeat the Japanese, he forecast the same number of WLTs would be needed, although he failed to mention how they should be used.

Having won the war with just 1,000 tanks, Cargin turned his prowess towards the peace. The WLT transport, he predicted, would be able to handle heavy goods transport and so eliminate the need for expensive ports. A factory could just load its goods onto a waiting WLT which would then drive to the coast and sail to the nearest coast to the destination before driving the last leg overland. There followed a list of countries where the WLT transport would sell well as a guaranteed commercial success. This list included pretty much every land mass in the world apart from Russia and Europe. Mr Cargin closes his letter with the following line about his scheme: ‘would require £20,000,000 capital for initial success.’ That is nearly £1.2 billion today.