¹⁄35

A39 Tortoise

Introduction

The A39 Tortoise traces its heritage back to 1943 when plans were drawn up in response to a requirement for an Assault Tank that it was anticipated would be necessary for the destruction of enemy fortifications during the closing, siege-like, stages of the war. In all, eighteen separate designs were submitted, with the Tortoise being the only one built, and although it went straight to production with no prototype, it failed to be ready before World War Two ended; such is the story of the Tortoise. It was armed with a modified 3.7 inch Heavy Anti-Aircraft gun fitted in a ball mount, instead of the more usual trunnions. The gun was more than a match for any armoured vehicle in German service, and for that matter anything in Soviet service at the time as well.

Two of the six Tortoises did make it to Germany in 1948, where they demonstrated the same design weaknesses as the German King Tiger: it wrecked roads and very few bridges could handle the weight or width, which made it extremely difficult to get it to where it was wanted. The main gun did however prove to be extremely accurate and powerful, although the two-part ammunition storage was an issue, with a complete round weighing 45lb.

The Tortoise shared its layout with the German STuGs which would have been on its target list had it made its debut in time. The six examples were manufactured by Nuffield Mechanisations Ltd, who had originally landed the contract for 25 tanks in February 1944. With the war’s end, the order was reduced to twelve, the first vehicle not being finished until 1946, and the order was then cancelled with only six vehicles having been completed.

The following information comes from Bovington Tank Museum.
The design that was actually produced by Nuffield Mechanisations Ltd, AT17, was submitted in February 1944. It mounted a 3.7in (93.4mm) gun carried in a ball mount or gimbal in the hull front. This gun fired an Armour Piercing Discarding Sabot projectile at 3,600 feet/sec and proved to be very accurate and destructive. The gun was capable of penetrating all the German tanks of the late war period and would probably have been a match for contemporary Soviet tanks. The tank rode on 36in wide tracks and had a double torsion bar suspension. The superstructure was a massive single casting. The armour had a maximum thickness of nearly 9 inches (225mm) and the tank weighed a massive 78 tons. It seems that all the physical constraints that British tank designers had laboured under were discarded for this project! These included the limits due to the railway loading gauge, the strength of Bailey Bridges and the width of landing craft ramps. In practice the Tortoise proved to be too slow and unwieldy for the conditions of modern warfare and was a nightmare to transport.