The ‘Thundering’ British Sherman That Beat The Ground With 43 Chains To Clear German Minefields

June 1943, approving ground somewhere in southern England.

British engineers bolted a spinning drum carrying 43 heavy chains to the front of a Sherman tank, started the engine, and drove it into a live minefield.

The chains whipped the earth at 142 revolutions per minute.

Each steel ball struck the ground with over 150 kg of force.

Mines detonated in sequence, hurling geysers of dirt and shrapnel skyward.

The tank kept moving.

When it reached the far side, a path 10 ft wide had been beaten clean through ground that would have killed every man who tried to cross it on foot.

Everyone who watched the demonstration thought the same thing.

It looked completely absurd.

It also worked.

The Sherman crab would become the most effective mechanical mine clearing device of World War II, and its absence on one particular beach would become one of the war’s most costly lessons.

To understand why the crab mattered, consider what it was built to defeat.

By May 1944, Germany had laid 6,58,330 mines across the western defenses alone.

That figure had quadrupled in just 7 months, driven by field marshal RML’s obsession with fortifying the Atlantic wall.

RML wanted between 50 and 100 million mines as his first line of defense.

At Elamagne 2 years earlier, mine density had reached nearly 7,000 anti-tank mines per kilometer in what the Germans called their devil’s gardens.

The mines themselves came in devastating variety.

The Teller mine packed 5 1/2 kg of TNT, enough to rip the tracks off any tank.

The S mine, which Allied soldiers called the bouncing Betty, was arguably the most feared anti-personnel weapon of the entire war.

When triggered, a propellant charge launched it 1 m into the air before detonating 360 steel balls across a lethal radius of 65 ft.

Germany produced over 1.93 million of them.

The shoe mine 42 was a simple wooden box containing 200 g of explosive, cheap to build and virtually invisible to metal mine detectors.

The glass mine 43 used a glass body for the same reason.

Perhaps most ingeniously, the top mine was constructed from compressed wood pulp and painted with a mildly radioactive substance called tarnand allowing German Geiger counter detectors to locate their own mines while Allied equipment found nothing.

This was only discovered after the war.

Before the flail, clearing a minefield meant soldiers crawling on their hands and knees, proddding the earth with bayonets angled at 30°, feeling for resistance every few centimeters.

The Polish mine detector, invented by Lieutenant Joseph Kasaki, who donated the patent for free and received only a thank you letter from King George V 6th, roughly doubled clearance speed, but that still meant about 200 square meters, and it could not detect wooden or glass-cased mines at all.

Across the entire war, landmines killed an estimated 375,000 soldiers and caused over 20% of all American tank losses in Europe.

The mine flail concept emerged from three independent sources that converged.

The British Mechanization Board first proposed the idea in 1939, attaching weights on spring steel strips to a spinning drum carried ahead of a tank.

Chains quickly proved superior to strips.

Independently in Ptoria in 1941, Captain Abraham Duty, a South African motor engineer serving as a sergeant in the artillery, built a test rig on a truck and demonstrated it on film.

General Archin saw the footage and dispatched Duty to England under strict secrecy.

Meanwhile, in North Africa, Captain Norman Bry conducted separate flail experiments along the Gazala line in the spring of 1942.

That same summer, Lieutenant Colonel Mil Coleman independently conceived the idea after watching wire tangled in a vehicle’s sprocket strike the ground with each rotation.

A prototype nicknamed the Durban Mark1 was assembled in 24 hours, completed by the 6th of August, 1942.

5 weeks later, generals Alexander Montgomery and Mohead watched a demonstration.

A brigadier named Ry noted the device looked like a scorpion, and the name stuck.

Montgomery demanded 25 units for his coming offensive.

According to accounts from those present, his exact words were, “Do not belly ache.

Order two dozen.” The resulting Matilda Scorpion carried 24 flails driven by an external 105 horsepower Ford V8 engine bolted to the tank’s right side.

25 were rushed into service for Alamagne in October 1942.

They proved the concept, but exposed crippling floors.

The external engine broke down constantly.

Dust clouds choked air filters and blinded drivers, forcing crews to wear gas masks.

The vehicles were too wide for Bailey Bridges, and the exposed auxiliary engine operator had no protection whatsoever.

One unexpected benefit did emerge, however.

According to veteran accounts, the noise and terrifying appearance of the flails caused several Axis units to surrender without resistance.

The breakthrough came when engineers at AEC Limited realized the M4 A4 Sherman’s Chrysler multi-bank engine, producing roughly 425 horsepower could power both the tank and the flail through a single power takeoff from the main transmission.

This eliminated the external engine entirely.

A drive shaft ran down the right side of the hull, and an additional gearbox maintained the correct rotation speed regardless of how fast the tank was moving.

The first Sherman Crab prototype completed trials in September 1943.

It solved every major Scorpion problem, no external engine.

It retained its turret and 75 mm gun for conventional combat.

Wire cutters on the drum ends prevented chain tangling and sophisticated lane marking systems, including bins of powdered chalk, smoke grenade dispensers, and illuminated poles fired into the ground, ensured infantry could follow the cleared path even in darkness.

The crab could not fire its gun while flailing because the turret had to face rearward to clear the boom arms and the dust cloud eliminated all visibility.

But the moment flailing stopped, it fought as a standard Sherman.

Earlier designs had the gun removed entirely.

In 1948, Due to received £13,000 from the Royal Commission on awards to inventors for his foundational work on the concept.

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Right back to D-Day.

Approximately 70 Sherman crabs were prepared for the Normandy assault operated by three regiments of 30th Armored Brigade within the 79th Armored Division.

The Westminster Draons landed on Gold Beach.

The 22nd Draons went to Sword and Juno.

The first Lotheians and Border Horse came ashore as reinforcements on D plus11.

Crabs were among the very first vehicles to touch the beach on all three British and Canadian sectors, landing between 0725 and 0750 on the 6th of June 1944.

The most vivid surviving account comes from Private Martin of the German 726th Infantry Regiment defending Larry on Gold Beach.

He described the drum revolving with chains crashing onto the earth with deafening noise, raising clouds of dust and soil, the pounding felt beneath their position.

He recalled a Panzer Foust rocket fired at the spinning chains being knocked harmlessly into the air when a PAK gun struck one crab’s drum.

The cylinder separated from the vehicle while still spinning at full speed, careening through the dunes and scattering chain fragments.

At that same position, Captain Roger Bell of the Westminster Draons deliberately placed his crab in the line of fire of an 88 millimeter gun that had already knocked out two AVREs, engaging it with high explosive and armor-piercing shells until it fell silent.

His lane was the only successful gap on the left brigade’s front.

Bel received the military cross from Montgomery personally.

A post-action report noted that crabs cleared more than 50% of the required beach exit lanes and used their main guns to considerable effect.

The contrast with Omaha Beach became the crab’s most powerful argument.

On the British and Canadian beaches, the full complement of specialist armor supported the landings.

On Omaha, American forces had only DD tanks, most of which sank in rough seas, some bulldozers, and no specialist armor.

Casualties at Omaha reached between 2400 and 3600.

Gold Beach saw roughly 400.

Juno and Sword each saw around a thousand with comparable troop numbers.

General Bradley had requested 25 flail tanks after a February 1944 demonstration, but the Churchill based vehicles would have required retraining and a separate logistics chain.

Bradley later acknowledged that had the specialist vehicles been adapted to Sherman tanks earlier, his forces likely would have used them.

Eisenhower’s postwar verdict was unequivocal.

He credited the novel mechanical contrivances with the comparatively light casualties on every beach except Omaha, adding that it was doubtful the assault forces could have established themselves without these weapons.

Germany never fielded an effective equivalent.

Their experimental Panther Dres flaggel flail broke its own chains during its only demonstration in January 1945.

At Kursk, the 653rd heavy Panseryaga battalion lost 37 of 49 Ferdinands to mines before 5 in the afternoon on the first day.

The Americans experimented with over 15 designs, but never officially adopted a mine flail during the war.

The Soviets relied on PT34 mine rollers and massive manual clearance by combat engineers.

After Normandy, the three Crab Regiments were parcled out across British, Canadian, and sometimes American divisions for every major operation.

During Operation Goodwood in July 1944, crabs cleared British minefields ahead of the armored corridor from the Orn Bridge Head.

Operation Stonia, the battle for La Harour in September 1944 was catastrophic with 34 crabs destroyed in a single engagement, the heaviest loss of the entire campaign.

In the Netherlands, the Westminster Draons cleared minefields during the brutal fighting at Overoon and Venray.

Lieutenant Sam Hall’s crab, knocked out by a panzer Foust at Brookhusen, now sits in the Overoon War Museum.

Operation Veritable, the assault through the Reichkes in February 1945, saw crabs create lanes through extensive German minefields for both the 153rd Brigade and the Fifth Canadian Brigade in appalling conditions of mud, flooding, and determined resistance.

For the Rine crossing the following month, most crabs had their flails removed and fought as conventional gun tanks in the final advance toward Hamburg.

When it was proposed to convert all surviving crabs back to standard Shermans, crews bitterly resisted.

They considered themselves a specialist elite.

The conversion never happened.

None of this would have occurred without Major General Sir Percy Hobart, known as Hobo, one of the most brilliant and difficult officers in British military history.

a Royal Engineers officer who earned a DSO and MC in the First World War.

Hobart transferred to the Royal Tank Corps in 1923 and became one of the earliest advocates of independent armored warfare.

His published writings were followed so closely in Germany that Hines Gderion paid from his own pocket to have every Hobart article translated.

In Egypt, Hobart transformed a ragtag unit mocked as the mobile farce into the seventh armored division, the desert rats.

But his combative personality made powerful enemies.

In 1940, General Wavel dismissed him into retirement.

Hobart joined the local defense volunteers as a lance corporal assigned to defend Chipping in the Cotswwells.

Churchill intervened directly, writing to the chief of the imperial general staff that the high commands of the army are not a club and that exceptionally able men must not be prevented from serving.

Recalled to duty, Hobart was given command of the 79th Armored Division in March 1943 and assembled the remarkable family of specialist vehicles known as Hobart’s Funnies.

By war’s end, his division fielded nearly 7,000 vehicles and 21,000 personnel.

Approximately 689 Sherman crabs were ordered for conversion with total production across all marks reaching roughly a thousand units.

The crab’s direct modern descendant is the Arvar JSFU.

Developed from 1982 in Abodinia, Scotland.

Carrying 72 chains in a blast resistant cab, a single Arvar cleared 308 mines in one day at Bram Air Base in Afghanistan.

The principle remains identical to what those engineers demonstrated in 1943.

Armor protected chains, beating the Earth so that human beings do not have to.

The Sherman crab was loud.

It was slow.

It left its crew blind and unable to fire during the very act they were designed to perform.

It threw up clouds of dust visible for miles.

It looked, by any conventional standard, ridiculous.

But the soldiers who walked through the lanes it cleared are the ones who came home.

That was not luck.

That was British engineering solving a problem no one else could solve.

With 43 chains and the stubborn conviction that there had to be a better way than sending men to crawl through minefields on their hands and knees, there was and it worked.