Description As there was no time for a completely new design, the Mark IX was based on the Mark V, with the hull lengthened to . The 150 hp Ricardo engine was moved to the front, the gearbox to the back and the suspension girders left out entirely. This created an inner space long and wide, enough room for thirty (officially even fifty) soldiers or ten tons of cargo. To ensure sufficient stiffness for the chassis, the floor was reinforced by heavy transverse girders. The infantry inside had to contend with the control rods for the gears running along the roof and the drive shaft through the middle. Unfortunately for the infantrymen, no seats were built in for them in the tank. The crew proper consisted of a driver sitting on the left and a commander sitting to the right of him (the first time in a British tank making this concession to the prevailing traffic conditions in France), a mechanic, and a machine gunner who could man a gun in a hatch at the rear. A second machine gun was fitted in the front. Designed as an armoured personnel carrier, the type had elements of an infantry fighting vehicle, as along each side of the hull there were eight loopholes, through which the soldiers could fire their rifles. Four of the total of sixteen loopholes were in the four oval doors (two to each side) through which soldiers could embark and disembark. Despite the use of thinner——armour, the operational weight was still and the speed only . The tank could also carry supplies in a tray on the roof behind the commander's armoured observation turret (being the highest point at ), while towing up to three loaded sledges. Rackham tried to improve internal conditions by putting a large silencer on the roof together with ventilation fans; but there was still no separate engine compartment and it is, therefore, questionable whether the project achieved the goal of a vehicle capable of delivering a squad of infantry in fighting condition, even given the severely limited operational range of the Mark IX. Operational history and project The Mark IXs were used for some years after the war. Pictures exist of vehicles carrying the designation "IC" painted on their hulls, probably indicating they were indeed used as "Infantry Carriers". The type – named The Pig after the low front track silhouette that gave