Liberty ship

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 ($43 million in 2024) per ship[1]
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[2]
Displacement	14,245 long tons (14,474 t)[2]
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	Two oil-fired boilers triple-expansion steam engine single screw, 2,500 hp (1,900 kW)
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	38–62 USMM 21–40 USNAG[citation needed]
Armament	Stern-mounted 4-in (102 mm) deck gun for use against surfaced submarines, variety of anti-aircraft guns

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,^[3] 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.^[4]

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),^[5] 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.