The British evacuation from Dunkirk in 1940 demonstrated to the Admiralty that the Allies needed relatively large, ocean-going ships that could handle shore-to-shore delivery of tanks and other vehicles in amphibious assaults upon the continent of Europe. As an interim measure, three 4,000- to 4,800-GRT tankers, built to pass over the restrictive bars of Lake Maracaibo, Venezuela, were selected for conversion because of their shallow draft. Bow doors and ramps were added to these ships, which became the first tank landing ships, LST (1): , and . They later proved their worth during the invasion of Algeria in 1942, but their bluff bows made for inadequate speed and pointed out the need for an all-new design incorporating a sleeker hull.