From the modern signage for Landing Ship – Tank:
These giant flat-bottomed boats were designed based on requests from the British Admiralty for a craft that could carry large payloads of troops, tanks and other materiel across the ocean and land them on a foreign beach ready to fight. While these Landing Ship Tanks weren’t particularly quick or nimble (those aboard referred to them as Large Slow Targets), they were workhorses and were a key component in the successful D-Day invasions at Normandy in France, at landings in North Africa and beaches throughout the Pacific. U.S. engineers designed these vessels for rapid construction, and it took just four short months for the first LSTs to be floated out of their Hingham building docks in the fall of 1943. As important a vessel as they were, their size and cruising speed of 9 knots made LSTs extremely vulnerable, with over 40 being lost to enemy fire during the war.
If you’ve ever seen old war footage of the D-Day invasion at Normandy during World War II, you would immediately recognize the LSTs beached along the coastline. It is easily the best known and most influential of all landing craft.
With their flat-bottomed design, LSTs literally beached themselves on shore. Then, using a special anchor, it could winch itself off the beach back into deeper water.
Displacement: 4,080 tons (full load)
Draft: 8′ fwd; 144″ aft (full load)
Speed: 12 knots
Complement: 7 officers, 204 enlisted