High-speed transport

High-speed transports were converted destroyers and destroyer escorts used in US Navy amphibious operations in World War II and afterward. They received the US Hull classification symbol APD; "AP" for transport and "D" for destroyer.

APDs were intended to deliver small units such as Marine Raiders, Underwater Demolition Teams, and United States Army Rangers onto hostile shores. An APD could carry up to 200 troops - a company-size unit. It could also provide gunfire support if needed. USS Manley was officially designated the Navy's first high-speed transport on 2 August 1940 when she became APD-1.

Before United States entered World War II, as newer and more modern destroyers joined the fleet, some older destroyers were refitted for other duties: as seaplane tenders, destroyer minelayers, or destroyer minesweepers, and in an innovation, as fast transports carrying fully equipped troops for assault landings. During the war, newly built or unfinished destroyer escorts were converted to APDs.

The first group of APDs (APD-1 through APD-36) were converted from one Caldwell-class, 17 Wickes-class, and 14 Clemson-class "flush-deck" destroyers built during and after World War I. Some of these had been previously converted to aircraft tenders or other uses.

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