Contributor: Alan Chanter
ww2dbaseThe formidable and extensive defences built by the Germans in France on the English Channel coast presented a serious challenge to any attempt by the Western Allies to open a second front. In March 1943 the Chief of the Imperial General Staff, General Alan Brooke, decided that what would be needed, if the dreadful slaughter of the Somme and Passchendaele were not to be repeated, was a Twentieth-Century equivalent of a medieval siege train, constructed to substitute machines for manpower and thus restore mobile armoured dominance at every stage in the assault, even where the defences were their strongest.
ww2dbaseFortunately there were already in existence several specialist devices (the ideas for some dating from the First World War) with others in the process of experiment or development which could be suitable. But first Brooke needed a man to head the project. It soon became evident to him that there was really only one officer with the necessary experience of armour warfare in all its aspects, together with a ruthless energy capable of accomplishing so enormous a task: The fifty-eight-year-old Major-General Percy Hobart.
ww2dbaseHobart's task was indeed a daunting one. He would need to decide what needed to be accepted or rejected, developed or improved, and put into quantity production. He would also need to drill ordinary tank crews in a spirit that recognized no insuperable obstacle, and devise methods to allow the crews to act in the elimination of every possible obstacle combination. Finally he would need to persuade or bulldoze the various military and industrial organisations to build his specialist equipment to his specifications (including stipulating that each vehicle should retain the ability to fight on its own should this be necessary), and to have them available for employment within the fourteen months prior to the planned date of invasion.
ww2dbaseHobart's 79th (Experimental) Armoured Division would be required to land in the van of the assault; to open gaps on their own before the first waves of infantry got ashore, and then dominate the defences without exposing more than a few unarmoured men to direct the aimed fire against the German defences. They would have to overcome the beach minefields, break down the artificial barriers, demolish or bridge the next row of sea walls, concrete blocks and deep ditches, then dispose of more minefields, subjugate the remaining pill boxes, and then, if that was enough, accompany the next wave of assault infantry and armour as they moved deep inland. Speed would be essential in performing these complex operations, particularly in the British sectors, where the nature of the ground would aid a German armoured counterattack. The need to quickly gain depth and space inland in which to fight a mobile battle, took precedence over almost every other requirement once a lodgement ashore had been made.
ww2dbaseAgainst all sorts of odds Hobart succeeded in his task and was ready, by early 1944, to demonstrate a wide range of armoured hardware to General Dwight Eisenhower, and to his own brother-in-law, General Bernard Montgomery, when they came home to take charge of the invasion forces. There was a brigade each of Sherman DD amphibious tanks, Crab mine clearing tanks and Churchill AVREs assault Engineer tanks. One regiment had Crocodile flame-throwing tanks, and another brigade was equipped with the Grant Canal Defence Light (CDL). Other devices with animal names - "Hobo's Menagerie" or "The Funnies" as they came to be known - followed in the months to come. These included various Churchill tanks carrying a selection of bridges or fascines (invented appropriately by a Canadian named Donovan after Dieppe) and other devices for crossing walls, ditches and areas of soft sand. The combination of DD, Crab, and AVRE were, however, the basic elements of the beach assault teams which worked ahead of the infantry on the 6 June 1944.assault.
ww2dbaseMontgomery grasped the purpose and significance of specialised armour at once, insisting that the maximum amount be made available for the forthcoming invasion of North-West Europe (Operation Overlord). Simultaneously, he insisted that the Americans should be offered a half share of everything the British had made, getting Hobart to demonstrate each device to his Allies. Eisenhower fell heavily for the DDs, and demanded a brigade's worth, but left the choice of the other items to General Omar Bradley, who, in turn, left the decision process to members of his staff. They, for various reasons, mostly thin, rejected the specialist armour vehicles. The consequences of this would be felt most disastrously by the American assault infantry when they were forced to land in the face of deadly fire on their appointed invasion beaches.
ww2dbaseCanal Defence Light was the coded name given to a modified Grant tank fitted with a powerful flickering searchlight whose purpose was to dazzle the defenders and thereby spoil their ability to judge distances. In the event, the CDLs were not used on D-Day, although some would later be employed during the Rhine River crossings to illuminate the battlefield, thus allowing the advance to continue after dark.
ww2dbaseThe amphibious duplex drive tanks, invented by Nicholas Strausler, were designed to be capable of swimming ashore from landing craft in order to provide immediate armoured support to the first wave of assault infantry. Floatation was by means of a simple arrangement whereby a canvas screen, temporarily erected around the vehicle, displaced the tank's weight in the water. Propulsion in the water was provided by two propellers driven by the tank's engine.
ww2dbaseDeveloped specifically for the 79th Armoured Division, the Sherman Crab mine clearance tank employed the revolving drum and hanging chain system that had been developed by Major A. S. du Toit of the South African Engineers for the earlier Scorpion mine clearing tank used with some success in the Western Desert campaign. Some 43 chains were mounted on a revolving drum powered by the main tank engine and connected through a series of Carden shafts and reduction gear from the tank's propeller shaft to the off-side end of the rotating drum. Further developments included the addition of barbed wire-cutting disks and a contour-following device that allowed the flails to operate effectively over rough ground. The Crab carried the normal Sherman armament which allowed it to be used in a combat role if necessary. As the speed whilst flailing mines was very slow (about 2-3 miles per hour) and the crew were effectively blinded by the amount of dust thrown up by the flailing chains, it was normal in action for the Crab to be accompanied by other tanks such as the flame-throwing Crocodiles to provide protection from any enemy interference.
ww2dbaseThe Churchill Assault Vehicle Royal Engineers (AVRE) was borne out of a lesson learnt during the 1942 Dieppe raid where Engineers had been effectively prevented from clearing beach obstacles by enemy fire. Thus this vehicle was specifically designed to transport demolition teams to the required spot and there give protection to them whilst they carried out their assigned task. The AVRE had a stripped down interior and was armed with the Petard demolition mortar that could fire a heavy demolition bomb against concrete emplacements. AVREs could also be fitted with a range of other devices to become bridge-layers, Fascine-carriers, Matting-layers or Log-carriers; all able to assist the assault on the enemy's defences by providing means for assault troops and other vehicles to cross ditches, barbed wire or areas of soft ground. The AVRE proved to be so useful in these tasks that their descendants are still in regular use with today's modern mechanised Armed Forces.
ww2dbaseTo deal with enemy pill-boxes and other similar fortifications, the British Army had demanded a flame-throwing tank as early as 1938. After testing several different designs it was decided, in 1942, to develop one utilising the Churchill infantry tank as the basis, and specifying that the flame projector should have a minimum range of 73 meters (80 yards) and a duration of fire of not less than one minute. Since this requirement demanded a large quantity of fuel and pressure cylinders, the pressurised fuel needed to be in an armoured trailer rather than aboard the tank.
D-Day Invasion of Hitler's Europe (Purnell's History of the World Wars Special, Phoebus Publishing, 1968/75)
Ian V. Hogg & John Weeks, The Illustrated Encyclopedia of Military Vehicles (Hamlyn, 1980)
Philip Trewbitt, Armoured Fighting Vehicles (Dempsey-Parr, 1999)
A. J. Smithers, Rude Mechanicals (Grafton Books, 1989)
Last Major Revision: May 2012
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Thomas Dodd, late 1945