After trials with flame fuel carried in trailers and tested on Valentines (qv) in 1942, the General Staff decided to standardise on a flame-throwing system actuated by gas (nitrogen) pressure. Design was finalised in 1943 with an initial order for 250 units featuring armour protection for the fuel trailer, and the Churchill IV was selected as operating vehicle. In October 1943 the Mk VII was chosen instead. Fuel passed along the belly via a "link" with the trailer, and the projector replaced the hull machine gun. Late production Churchill VIIs were all built for speedy adaptation to the Crocodile role as required. Vehicle's main armament could still be used, of course. Range of the Crocodile was 80-120 yards in 80 one-second bursts from a full trailer. When empty or hit the trailer could be jettisoned. Trailer weighed 6t (long) tons. Used in NW Europe 1944-45, total production was 800 Crocodile units by May 1945, 250 earmarked for the Far East.
Churchill AVRE: (AVRE : Armoured Vehicle, Royal Engineers)
Though the Dieppe raid was unsuccessful it proved that specialised types of armour were needed to assist assault forces in landing on and taking fortified open beaches. Urgently shown to be necessary was a heavily armoured vehicle to carry and support assault engineers charged with breaching heavy defences. Lt. Donovan of the Royal Canadian Engineers proposed adapting an existing tank. Both the Ram and Sherman were evaluated for the role, but the choice fell on the Churchill which had a roomier hull plus side escape doors which were useful for egress under fire. A spigot mortar, called a Petard, of 29cm calibre and firing a 40lb bomb 80 yards, was developed, tested in a Covenanter tank, and modified for fitting on the 6pdr mount of the Churchill III or IV. 180 Churchills of these marks were converted to AVREs by D-Day, June 6, 1944, and equipped the 1st Assault Brigade of 79th Armoured Division at this time. Subsequently another 574 vehicles were converted and AVREs played an important part in the NW Europe campaign. AVREs were fitted to carry and drop fascines (brushwood bundles), the CIRD (Canadian Indestructible Roller Device) for mine-clearing, and SBG (Small Box Girder) bridges, attachment points being incorporated for all these to be handled as required. A few AVREs were unarmed or lacked the usual AVRE fittings, these being used mainly for training. Also produced for use with the AVRE was a sledge for towing stores, fascines, or explosives. Further AVRE development took place post-war, again with the Churchill as a basis, though this is beyond the scope of the present volume.
Sherman Crab I and II
A further refinement from the Lobster, this was developed in June 1943 and put into production and a complete brigade of 79th Armoured Division was equipped with these vehicles for the Normandy landings. The Crab rotor had 43 flailing chains which beat the ground ahead of the vehicle, drive for the rotor coming via a power take-off from the engine. Beneath the rotor arms were wire-cutters for clearing barbed wire. There was a screen across the hull front and covers over the driver's and assistant driver's periscopes to offer protection against dust and earth thrown up by the flails. Crabs were organised in troops of five and were allocated for mine clearing operations as required by local commanders. Crabs were fitted with lane-marking equipment (to indicate "swept" lanes) and station-keeping lights for following vehicles. The Mk II version differed from the Mk I in having a contouring device to give better coverage of rough or irregular ground. A Sherman BARV was also fitted experimentally with Crab equipment, but used only for trials.