High Quality Content by WIKIPEDIA articles! USS APc-21 was a United States Navy APc-1 class small coastal transport vessel in World War II. Laid down on 24 May 1942 as Coastal Minesweeper AMc-173 at Hodgdon Brothers, Goudy and Stevens, East Boothbay, Maine, she was launched on 2 September 1942 and commissioned as APc-21 on 27 February 1943.