The Germans dug wider trenches to thwart the new British Mk IV Male and Female tanks 4001 & 4002. In 1917 trail modifications to improve trench crossing ability began. The tadpole tail extended the raer of the tank by about 9 feet. Problems with the conversion were not overcome by the end war and therefore the tank saw no action. The length of the tank was 35'5" (10.8m), height 8'2" (2.49M) and the width was 13'6" (4.11m). It was powered by a daimler 6 cylinder engine and had a maximium speed of 3.7 Mph (6kph). It carried 2 6 Pounder guns and 3 machine guns.