Simonds devised the "Kangaroo", an early armoured personnel carrier converted from non-operational armoured vehicles "defrocked Priests". Granatstein characterizes the plan as "brilliant if too complicated", in that it did not account for the inexperience of the troops. The two commanders of the armored divisions tasked with leading the assault, George Kitching and Stanisław Maczek both objected to Simonds's plans for a "mailed fist" assault on narrow fronts as allowing the Germans to concentrate their forces for counter-attack, but Simonds argued the planned heavy bombing attack by American bombers would disorganize the Germans enough to allow a breakthrough. As Maczek's English was very poor and Simonds spoke no Polish, the two generals spoke in French, in which Maczek was fluent. Simonds insisted that his French was not that good and so Kitching translated for him. Kitching later accused Simonds of being better at French than what he pretended as the interval for translations gave him more room to develop arguments to dismiss Maczek's concerns. During Operation Totalize, the American bombers who were supposed to hit the German lines instead carpet-bombed the II Canadian Corps's artillery and assembling areas, badly disorganizing the offensive. While the offensive was derailed by the American "friendly fire", the aggressive Meyer took advantage of the pause to stop the advances of both the 1st Polish Armored Division at St. Aignan and the 4th Canadian Armored Division at Langannerie. Simonds's plan for Totalize had called for Canadian heavy and medium artillery to support the Canadian and Polish tanks as they advanced, but the accidental American bombing of the Canadian artillery had robbed the Allied armor of the expected fire support. Simonds, knowing of the weakness of the Sherman tanks, which were both under-armored and under-gunned, had planned for his artillery to knock out Meyer's Tigers and Panthers, and expected the Germans to counter-attack at once with their armor. The next day, Simonds sent the Worthington Force, comprising a battlegroup of the British Columbia regiment and the Algonquin regiment, which however took a wrong turn, and was annihilated by Meyer who sent his Tiger and Panther tanks against the Shermans. Tractable, on August 14, used a smoke screen in an attempt to shield armour from German anti-tank weaponry. The Canadian historian Desmond Morton wrote that Operation Tractable should have been a disaster as the Wehrmacht had captured a copy of the Canadian operations plan the night before, but despite