Nicknamed Sherman and the name stuck. Major deliveries were of the M4A4.
Duplex Drive (DD)
Nicholas Straussler designed a way for a tank to be converted into an amphibious vehicle. By 1943 the first of the Shermans were modified to have a collapsible screen that used 36 air tubes to hold it up. There was a boat shaped platform welded to the exterior of the hull that the the screen was attached to.
It took about 15 minutes for a crew to put up the screen and be ready to go into the water.
There were two propellers that moved the Sherman through the water. The main steering was done by moving the propellers and there was a rudder that the commander could control.