The origins of what are generally called ‘engineers’ tanks’ date back to the earliest days of tank warfare, when in 1917 the British Army modified a number of their Mk IV heavy tanks to facilitate the crossing of deep ditches or trenches. The tanks were adapted to carry fascine bundles or hollow timber cylinders that could be dropped into the ditch in such a way that the tank could drive across it. Mk IV and Mk V tanks were also equipped as bridging tanks by being fitted with hinged ramps to provide a means of crossing other obstacles. Others had their armaments removed and were adapted for use as supply vehicles or gun carriers, while the armoured recovery vehicle was developed by the simple expedient of attaching a jib and pulley block, or a powered crane, to the front of an older or obsolete tank. After the Armistice was signed in 1918 development of the machines generally came to a halt, with few special tanks produced during the interwar years. The outbreak of the Second World War brought a resurgence of interest in using what were essentially modified tanks for specialised roles, particularly for recovering disabled armoured vehicles, a task that was often beyond the capabilities of existing wheeled heavy tractors.
Engineers’ tanks really came into their own during the D-Day landings. In the months preceding the invasion a range of so-called ‘funnies’ was developed, each tasked with overcoming a particular problem, and these vehicles made an enormous contribution to the success of the landings. The fact that the Sherman was plentiful, simple in construction and above all reliable made it the ideal choice for producing a whole range of these specialised vehicles, for example flail tanks, mine-clearing devices, rocket-launchers and flame-throwers. Most of the conversions were ‘official’, but others, including the mounting of a double-track assault bridge on the Sherman nose, were field modifications made in response to the changing situation on the ground … and the US authorities did not necessarily always agree with what the British were doing to ‘their’ tanks.
The US Army’s M32 tank recovery vehicle was the only Sherman engineer tank variant to be produced in significant volume, and the pilot model, built by Lima Locomotive in 1943, was constructed on the hull of a standard M4 from which the gun and turret had been removed. It was originally designated TRV (tank recovery vehicle) T5, and changes from the standard gun tank specification included the addition of a large, fixed superstructure mounted in place of the turret, and an 81mm smoke-laying mortar fitted to the top of the hull. A 60,000lb winch was installed in the fighting compartment, and there was a pivoting A-frame jib on the hull, mounted in such a way that it could be used in conjunction with the winch. Additional tow points and equipment stowage facilities were also provided. The design was standardised as the M32 in September 1943. Later variants included the M32B1, based on the hull of the M4A1; the M32B2, which used the M4A2 hull; the M32B3, using the hull of the M4A3, including some examples with HVSS suspension; and the M32B4, which used the M4A4 hull, but never made it into production. As well as Lima Locomotive, M32 recovery vehicles were constructed by the Baldwin Locomotive Works, Federal Machine & Welder, International Harvester and Pressed Steel Car.
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