Type C3 ships were the third type of cargo ship designed by the United States Maritime Commission (MARCOM) in the late 1930s. As it had done with the Type C1 ships and Type C2 ships, MARCOM circulated preliminary plans for comment. The design presented was not specific to any service or trade route, but was a general purpose ship that could be modified for specific uses.
The C3 was larger and faster than the C1 and C2 contemporaries, measuring 492 feet (150 m) from stem to stern (vs. 459 feet (140 m) for the C2), and designed to make 16.5 knots (30.6 km/h; 19.0 mph) (vs. 15.5 kn (28.7 km/h; 17.8 mph) for the C2). Like the C2, it had five cargo holds. A total of 465 of these ships were built between 1940 and 1947.