Why 27 of 29 Sherman DD Tanks Sank at Omaha Beach
Rough seas sank 27 of 29 Sherman DD tanks at Omaha Beach because their flotation skirts assumed one-foot waves, but D-Day surf reached six feet.
On D-Day, the 741st Tank Battalion’s Sherman DD amphibious tanks were intended to cross the surf and support the infantry at Omaha Beach. Instead, 27 of the 29 tanks deployed that morning sank.
The cause was the sea itself. The tanks relied on canvas skirts to create a buoyant envelope, but that flotation system was designed to operate in waves about one foot high. At Omaha Beach, the waves reached six feet, quickly swamping the tanks before they could reach the shore.
The episode shows how a small mismatch between engineering assumptions and battlefield conditions can undermine a carefully planned amphibious assault. The tanks did not fail because they were poorly built, but because the environment was far more hostile than the design had anticipated.