This heavy assault tank developed for the British Army specifically for World War II by Nuffield Mechanizations. Weighing in at 78 tons, this mammoth was not easily transported, but this was accepted as it had been designed for clearing fortifications with powerful weaponry and heavy armor.
In attacking the Siegfried line, a border of heavily fortified strongholds and vehicle defenses protecting the French side of the German territory, Allied Forces correctly assumed that serious land based firepower would be needed to achieve victory over Nazi forces. The Tortoise was one of many responses from Allied forcing in taking on such fierce defenses. So powerful this drive for large, heavy tanks had been that the Tank Board of the British Army decided to take one of the models proposed, the AT16, directly from a mockup to production without the need for time consuming trials. With an order of 25 tanks quickly placed.
Design work on the Tortoise had begun early in 1944 with emphasis being placed on heavy armor and firepower. This design, in aiming for maximum armor coverage, merged the turret and the hull superstructure as one, giving the armament a solid structure to fire from.
Specifications and Construction
This tank, was not actually a tank and technically should have been classified as a self-propelled gun, however the British Army not see the need for such a classification. The US Military went one step ahead and actually classed this type of vehicles in their own category, the super heavy tank such as the T-28.
The Tortoise was split into three compartments. The rear compartment housed the engine, with the crew being protected in the middle compartment offering easy of access to the weapon systems and maximum armor coverage. The frontal section housed the tank’s transmission.
The suspension of this heavy tank consisted of a torsion bar system and the drive train consisted of a Merrit-Brown transmission. Fitted with a system allowing the same gear ration for backward and forward motion, this tank could effortlessly back up out of any situation it got itself stuck into. With this being a heavy tank designed to break enemy defense lines, this was a crucial addition to the drivetrain.
Powering this tank was a Rolls-Royce Meteor V12 engine. To simply operation and usage in tanks, the Merlin which was an aviation engine, had its supercharger removed while the engine was also de-rated down to 600 bhp to run on ordinary pool petrol. The Merlin also had some of its more expensive alloys replaced with ordinary steel components to thus become the Meteor engine. The design philosophy was to use the use of high performance Merlin parts that landed up in the reject bin as Meteor spares.
This slow tank only had a top speed of 12 mph and with being such a heavy tank, only a range of 87 miles. It measured in at an overall size of 33 feet long by 12.8 feet wide and 9.84 feet high. Armor thickness measured between from 7 to 9 inches.
The weapon system of the tank consisted of a large main gun and three Besa machine guns. The main gun was an Ordnance QF-32 Pounder with a caliber of 94 mm using a separate charge and shell system. The shell weighed 32 pounds and was able to piece armor. One Besa was installed on an armored coaxial mounting platform directly to the left of the main gun, while the other two had been mounted inside a turret to the top right of the hull.
Movement of the main gun was also not only limited to a vertical movement like ordinary tanks which relied on turret movement for traversing the gun. Since the hull and superstructure of this tank were fused as one, a limited transverse, power assisted system had been installed. The main gun therefore utilized an armored ball mount to make targeting adjustments.
The Tortoise had a crew of seven which consisted of a commander a driver and a gunner. Two loaders operated the ammunition with an additional two soldiers operating each of the other two machine guns.
One of the tortoise tanks was sent to Germany to be battle tested, where it successfully destroyed a German Panzer tank at a distance of 1000 feet. The war was soon over with Japan and Germany capitulating to the Allies.
End of an Era
With the war having ended, a lot of these experimental projects was cancelled. With peacetime came peacetime projects and budget cuts led to the cancellation of many military projects, with some even being completely abandoned, left to rust.