The US Army was experimenting at the same time as the Soviets and Germans as was the French and British. The British had a Model of Tank in 1918 that not only could be used as a carrier of supplies and Infantry but had successfully been tested in Amphibious tests. The Mark IX could carry 10 tonnes of supplies, or 30 armed Infantrymen and on 11 November 1918 successfully showed its amphibious capability in Welsh Harp Reservoir.
Read George S. Patton III, Adna R. Chaffee Jr., Charles De Gaulle, Hugh Elles, JFC Fuller, Basil Liddell Hart......