The Tacoma class of patrol frigates served in the United States Navy during World War II and the Korean War. Originally classified as gunboats (PG), they were reclassified as patrol frigates (PF) on 15 April 1943. The class is named for its lead ship, , a Maritime Commission (MARCOM) S2-S2-AQ1 design, which in turn was named for the city of Tacoma, Washington. Twenty-one ships were transferred to the British Royal Navy, in which they were known as Colony-class frigates, and twenty-eight ships were transferred under Lend-Lease to the Soviet Navy, where they were designated as storozhevoi korabl ("escort ships"), during World War II. All Tacoma-class ships in US service during World War II were manned by United States Coast Guard crews. Tacoma-class ships were transferred to the United States Coast Guard and various navies post-World War II. Design In 1942, the success of German submarines against Allied shipping and the shortage of escorts with which to protect Allied sea lines of communication convinced US President Franklin D. Roosevelt of a need to engage mercantile shipbuilders in the construction of warships for escort duty. The United States Maritime Commission (MARCOM), which oversaw the wartime merchant shipbuilding program, proposed to meet this requirement by building a version of the British River-class frigate, a Royal Navy ship type based on a mercantile design in British shipyards experienced in building commercial ships. Two River-class ships under construction in Montreal, Quebec, Canada, as (for the Royal Navy) and (for the Royal Canadian Navy), were transferred to the US Navy in 1942, prior to completion, as prototypes for the Tacoma class and became the and , respectively. The naval architecture firm of Gibbs & Cox, designed the Tacoma class by modifying the River class to American requirements. The Tacoma-class units were designed and armed to serve mostly as anti-submarine warfare (ASW) ships. They were distinguished from the River class primarily by their pole (instead of the British tripod) foremast and lighter main guns, /50 caliber gun instead of the British /40 caliber gun, and they had an American rather than British powerplant. The Tacoma-class was designed to take advantage of American construction techniques employing prefabrication. Unlike most other types of warship, the Tacomas, like the Rivers, were built to mercantile standards. With the proven effectiveness of the River class on escort duty, MARCOM's goal was to allow commercial shipyards without prior experience of naval construction standards