16 January 1942. London, England.
On a visit to London, Carden had lunch with the American Colonel George Green. Green was one of the Americans in the Harriman Mission sent by the President to coordinate with the British regarding Lend-Lease and other matters. Green had been invited to sit on the Tank Board and act as Liaison Officer regarding design and production issues on Armoured Fighting Vehicles.
Carden had been told that the American was an Army Reserve Officer, but had been Vice-President in one of General Motors subsidiaries (Yellow Truck and Coach Manufacturing). Green had also been vice-chairman of the Advisory Committee of the Ordnance Department, and Carden had been impressed by him. Green wanted to know more about Carden’s work and was particularly interested in the Birch Gun. Green had been spending some time with 6th Armoured Division, who were the first to be equipped with both the Birch Self-Propelled Gun and also the Vanguard SPAAG.
The American army were experimenting with a ‘Howitzer Motor Carriage’ based on the hull of an M3 Medium tank carrying the standard M1A2 105mm howitzer. Green had thanked Carden as a Birch SPG had been sent over to America for evaluation and had helped those working on the T32 project a great deal. The Vanguard SPAAG had also been evaluated by the Americans and was provoking a lot of interest.
The fact of the matter was that, with the run down of Valiant II production about to begin, moving over to Victor tanks, the Birch and Vanguard SPGs were being redesigned using the Crusader hull built by the Nuffield Group of companies. It was possible that some of the Valiant I hulls might be used for the Birch and Vanguard once their use as tanks was no longer needed. In Carden’s opinion the Nuffield designs for a SPG and SPAAG weren’t quite as good as his own, but the War Office had to have its way.
Colonel Green had seen some of the design work and thought that the American M7 was probably the better choice than Nuffield’s. He had to admit that as the M7 was using the American 105mm gun, rather than the British 25-pdr, he didn’t believe that the War Office would want it. Carden accepted that that was the probability, with things going the way they were in North Africa, production of British built AFVs was just about meeting War Office needs.
The Canadians were making progress with their Ram tank, and since it would likely be armed with the 25-pdr as standard, there was the possibility that some of their Valiant I production would be turned over onto Birch and Vanguard SPGs. Carden also knew that the Canadian production of the Valiant II was likely to be allocated to Russia on completion of their own army’s needs. It certainly made some kind of sense to load up a ship in Halifax, then sail it via two convoys to Murmansk, rather than unload it in Liverpool, then load another ship in Liverpool with British made Valiant IIs and then sail to Murmansk.
Colonel Green asked Carden what he thought about the Tank Destroyer idea that the T12 had developed into the M3 Gun Motor Carriage. Carden smiled as he realised the M3 Gun Motor Carriage had nothing to do with the M3 Light or Medium tanks, but was a half-track with a 75mm gun on it. The old British system of tanks with names like A10, A11, A12 etc seemed child’s play compared to the American desire to call all sorts of things the same M-something. As to the concept of the tank destroyer he noted Leslie Little’s idea to mount a 6-pdr gun in a low profile hull based on the Tetrarch. So far, as far as Carden could see from German developments, they were using armoured hulls to carry infantry support weapons, though there had been a couple of panzerjägers captured which had some merit for anti-tank regiments being mobile enough to keep up with an armoured division.
The idea of a dedicated ‘tank destroyer’ was, as far as Carden was concerned, unnecessary because the best destroyer of other tanks was a tank. Having a good tank with a good gun that could take on enemy tanks, and support the infantry with HE shells, was all that was necessary. He called it the ‘universal tank’. One tank with good speed, armour and gun would be enough to win the war. By all means, have a family of Armoured Fighting Vehicles based on the same hull/engine for the various SPGs, Engineering tasks, the kind of things Percy Hobart was working on, but one kind of tank would do. The Infantry vs Cruiser idea would be obsolete with a universal tank.
Carden told Green that that was why he liked what he’d seen of the new M4 Medium tank. It wasn’t perfect, but its speed and gun were fine, he did think it could do with a bit more armour. He could also see that it had room for development, the turret ring size meant that it could take a bigger gun if that became necessary. He could see it taking its place in both Armoured Divisions and Tank Brigades (to use the British distinction). Carden was surprised that its designers had organised the engine driving the forward sprocket which made the hull much taller than it had to be. The British tended to like a lower profile, the Victor would be about a foot lower than the M4. Carden suggested that was why the M3 Grants were going to the Australians and Indians who’d probably be up against the Japanese whose tanks weren’t up to much.