Here with images of American WW2 armor, amphibious and what was termed deep-wader. Click on all images to see an enlarged view.
A Sherman duplex drive [DD] tank. That skirt inflatable and allowing the tank to swim. Able to "swim" ONLY under the most suitable and ideal of circumstances. At Normandy the conditions far less than ideal, almost all of the DD tanks being swamped and sunk!! An entire battalion of such tanks attempted to "swim" ashore at Omaha beach, only five tanks of thirty-two able to do so successfully, and three of those landed directly at the beach.
A Sherman deep wading tank. has the two manifolds. One for air intake and one for exhaust. That tank can wade in water hull-deep up to the bottom of the turret. NOT a "swimmer" but a "wader".
One of those deep wading Sherman tanks. Made it ashore but became stuck in the mud
A deep fording Sherman tank has made it ashore at Tinian. A tank belonging to a Marine unit in the Pacific theater.
That Sherman DD the idea sound but ONLY DURING THAT MOST IDEAL OF CONDITIONS?
IDEAL conditions as being non-existent at Normandy, 6 June 1944.