World War Photos

British M4 Sherman Crab Flail Tank Explodes Mines in Normandy 1944

The Crab Flail Mine-Clearing Tank was a vital innovation in clearing mines during World War II, particularly during the Normandy invasion. It represented an evolution in the British Army’s approach to mine-clearing, building on earlier designs such as the Scorpion flail tank, which had been used in the North African campaign.

Development and Design

1. Origins:

   • The earlier Scorpion mine flail tank had proven effective but had limitations, including the need for a separate engine to power the flail system, which added complexity and made it difficult to transport, particularly on narrow LCT (Landing Craft, Tank) ramps. These limitations spurred the development of a more efficient design.

2. The Crab Design:

   • The Crab flail tank was developed in 1943 as a more advanced and practical solution. Unlike the Scorpion, the Crab’s flail system was powered directly by the tank’s main engine, simplifying the design and improving reliability.
   • The Crab was based on the Sherman V tank chassis, and a prototype was completed in August 1943. After further testing and refinements, the design was accepted for production later that year. The British Army ordered 689 Sherman V Crabs for conversion, a significant number reflecting the anticipated demand for mine-clearing tanks in future operations.

3. Deployment:

   • By the time of Operation Neptune (the codename for the naval component of Operation Overlord), about 70 Crab flail tanks had been prepared for deployment. These tanks were assigned to the initial assault waves on British and Canadian beaches during the D-Day landings.
   • Despite their deployment, the Crab tanks were not considered ideal for beach mine-clearing operations. Detonating mines in the soft sand often resulted in large craters, which then became obstacles for following vehicles. This limitation highlighted the challenges of using flail tanks in certain environments.

Alternatives and Challenges

1. The Bullshorn Device:

   • As an alternative to the flail system, the British also developed the Bullshorn device, a mine plough designed to clear mines by using prongs to push them aside, creating a clear path.
   • Ten Bullshorn devices were assembled and mounted on Churchill AVREs in time for D-Day, but only two were actually deployed in the initial assault waves. This limited deployment reflected both logistical challenges and the experimental nature of the device.

2. American Mine-Clearing Efforts:

   • The US Army also explored mine-clearing technology, producing 41 copies of the Scorpion as the T3 mine exploder. However, all these were committed to the Italian theater by early 1944 and were not available for Operation Neptune.
   • Two new American mine-clearing tanks, the T1E1 and T1E3, were developed in early 1944. These used massive steel rollers to detonate mines but were unsuited for amphibious operations due to their excessive weight and the high ground pressure they exerted on the tank, which significantly hampered mobility.

Outcome and Legacy

1. Production and Supply Issues:

   • The ETOUSA (European Theater of Operations, United States Army) recognized the need for mine-clearing tanks and established a requirement for 25 Crab flail tanks and 40 Bullshorn mine ploughs in early 1944. However, British industry struggled to meet these demands, and by the time of the Normandy invasion, only 180 Crabs were in service with the British 79th Armoured Division, with 45 more in reserve.
   • After D-Day, the First US Army received nine Crab tanks in mid-July 1944, but no Bullshorn ploughs were delivered, highlighting ongoing supply challenges.

2. Impact on Normandy and Beyond:

   • Despite their limitations, the Crab tanks played a crucial role in the early stages of the Normandy invasion. Their ability to clear minefields, even imperfectly, was vital in allowing armored units to advance and secure the beaches.
   • The development and use of the Crab flail tank underscored the importance of specialized engineering vehicles in modern warfare and laid the groundwork for further innovations in mine-clearing technology.