Tortoise: The Heaviest British Tank of World War II (And It Failed)

World War II History

Tortoise: The Heaviest British Tank of World War II (And It Failed)

This impressive tanks was massive, but was a failure despite the amount of damage it could both take and dish out.

Despite having one of the most powerful main guns of the war, and an impressive amount of armor protection, the Tortoise heavy tank design was a failure. Here’s why.

British World War II-era armored vehicles are an odd bunch. From the decidedly terrible Covenanter or the not-so-great but actually somewhat innovative Valiant, some British tanks were rather small and under-gunned, while some others were enormous behemoths. One of the heaviest of them all was Britain’s Tortoise tank.

The British Army designed the Tortoise as an answer to Germany’s Westwall, the long line of defensive fortifications along Germany’s western border and stretching northward to their border with the Netherlands, all the way south to their border with Switzerland. Nazi Germany touted the wall as impenetrable, and though it was not, it certainly represented a tough nut to crack—one that the Tortoise was intended to smash.

The Tortoise was massive: standing nearly ten feet tall and about thirty-three feet long, it weighed nearly eighty tons. For perspective, the M1 Abrams tank, one of the heaviest main battle tanks today, weighs less than seventy-five tons. Part of the reason for this incredibly high weight was the tank’s intended role as an assault gun. In order to smash through and destroy Nazi German bunkers and other fortifications, the tank would have had to withstand an incredible amount of firepower. And it would have.

The Tortoise opted for a turret-less casemate design. Though this made the main gun less maneuverable, it eliminated any armor weak spots where the turret is mated to the hull. At its thickest point, the Tortoise’s armor was fully nine inches thick—and the Tortoise’s main gun was no slouch either. This video explains more about the Tortoise and gives a good all-round impression of its size.

The 32-pounder gun on the Tortoise was adapted from a 94mm anti-aircraft gun and modified to fit inside the Tortoise’s casemate thanks to an interesting ball mount which gave the gun some mobility, despite the turretless design. The cartridge was a two-part design, with shell and powder charge packed separately into the gun. As its name implies, if fired an approximately 32-pound shell up to 5,000 meters per second, and arguable could have been one of the most effective anti-tank guns of the war.

The Tortoise was actually rushed into production and put through initial tank trials by the British Army, which noted that despite the tank’s enormous size, it appeared to be rather reliable, if very underpowered. The Tortoise’s main gun was also noted for excellent penetration even from extreme distances.

Despite the Tortoise’s superior armor protection and the impressive main gun, the large tank was never actually a success. The tanks had been designed and ordered too late in the war to rush into production and arrive at the front lines. Furthermore, the Allies smashed through the German Westfall before the Tortoise could be pressed into service, eliminated what would have been the Tortoise’s primary objective. And lastly, the end of World War II in 1945 spelled an end to the Tortoise project after only six prototypes had been built.

Caleb Larson is a defense writer with the National Interest. He holds a Master of Public Policy and covers U.S. and Russian security, European defense issues, and German politics and culture.

Image: Wikimedia.