It was dropped into trenches to allow the tank to cross over more easily.
A large number of these tanks were also used for development work.
Other experimental versions tested radios, mortars placed between the rear horns, and recovery cranes.
Some of these devices were later used on operational tanks.
Mark IVs were also the first tanks fitted with unditching beams by field workshops.
A large wooden beam, reinforced with sheet metal, was stored across the top of the tank on a set of parallel rails.
If the tank became stuck, the beam was attached to the tracks (often under fire) and then dragged beneath the vehicle, providing grip.
– and a QF 6 pdr 6 cwt gun in each sponson, with its barrel shortened as it had been found that the longer original was apt to strike obstacles or dig into the ground.Nearly 460 Mark IV tanks were used during the Battle of Cambrai in November 1917, showing that a large concentration of tanks could quickly overcome even the most sophisticated trench systems.In the aftermath of the German Spring Offensive on the western front, the first tank-to-tank battle was between Mk IV tanks and German A7Vs in the Second Battle of Villers-Bretonneux in April 1918.The last Mark IV to see service was Excellent, a Mark IV male retained by the naval gunnery school on Whale Island, Hampshire, HMS Excellent.In the early years of the Second World War it was restored to operational status and driven to the mainland, where its new career was allegedly brought to an early end after a number of cars were damaged.