High Quality Content by WIKIPEDIA articles! The Type C4 class ship were the largest cargo ships built by the United States Maritime Commission (MARCOM) during World War II. The design was originally developed for the American-Hawaiian Lines in 1941, but in late 1941 the plans were taken over by the MARCOM. Seventy-five ships were built as cargo and troopships in three shipyards: Kaiser Richmond, CA (35 ships), Kaiser Vancouver, WA (20 ships) and Sun SB & DD in Chester PA (20 ships). All ships were capable of 17 knots, driven by a single screw steam turbine generating 9,900 shp. Among the variations of the design were the Haven class hospital ship. They were followed post-war by thirty-seven of the larger C4-S-1 class, also known as the Mariner class.