Liberty ship
Liberty ships were a class of cargo ship built in the United States during World War II under the Emergency Shipbuilding Program. Although British in concept, the design was adopted by the United States for its simple, low-cost construction. Mass-produced on an unprecedented scale, the Liberty ship came to symbolize U.S. wartime industrial output.
SS John W. Brown, one of four surviving Liberty ships, photographed in 2000 | |
| Class overview | |
|---|---|
| Name | Liberty ship |
| Builders | 18 shipyards in the United States |
| Cost | US$2 million ($42 million in 2024) per ship |
| Planned | 2,751 |
| Completed | 2,710 |
| Active | 2 (Traveling museum ships) |
| Preserved | 4 |
| General characteristics | |
| Class and type | Cargo ship |
| Tonnage | 7,176 GRT, 10,865 DWT |
| Displacement | 14,245 long tons (14,474 t) |
| Length | 441 ft 6 in (134.57 m) |
| Beam | 56 ft 10.75 in (17.3 m) |
| Draft | 27 ft 9.25 in (8.5 m) |
| Propulsion |
|
| Speed | 11–11.5 knots (20.4–21.3 km/h; 12.7–13.2 mph) |
| Range | 20,000 nmi (37,000 km; 23,000 mi) |
| Complement | |
| Armament | Stern-mounted 4-in (102 mm) deck gun for use against surfaced submarines, variety of anti-aircraft guns |
The class was developed to meet British orders for transports to replace ships that had been lost. Eighteen American shipyards built 2,710 Liberty ships between 1941 and 1945 (an average of three ships every two days), easily the largest number of ships ever produced to a single design.
Their production mirrored (albeit on a much larger scale) the manufacture of "Hog Islander" and similar standardized ship types during World War I. The immensity of the effort, the number of ships built, the role of female workers in their construction, and the survival of some far longer than their original five-year design life combine to make them the subject of much continued interest.