Liberty ship

SS John W. Brown, one of four surviving Liberty ships, photographed in 2000
Class overview
NameLiberty ship
Builders18 shipyards in the United States
CostUS$2 million ($43 million in 2024) per ship[1]
Planned2,751
Completed2,710
Active2 (Traveling museum ships)
Preserved4
General characteristics
Class and typeCargo ship
Tonnage7,176 GRT, 10,865 DWT[2]
Displacement14,245 long tons (14,474 t)[2]
Length441 ft 6 in (134.57 m)
Beam56 ft 10.75 in (17.3 m)
Draft27 ft 9.25 in (8.5 m)
Propulsion
  • Two oil-fired boilers
  • triple-expansion steam engine
  • single screw, 2,500 hp (1,900 kW)
Speed11–11.5 knots (20.4–21.3 km/h; 12.7–13.2 mph)
Range20,000 nmi (37,000 km; 23,000 mi)
Complement
ArmamentStern-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.

  1. ^ Wise & Baron 2004, p. 140
  2. ^ a b Sawyer & Mitchell 1985, p. 39.
  3. ^ Wardlow, Chester (1999). The Technical Services – The Transportation Corps: Responsibilities, Organization, and Operations. United States Army in World War II. Washington, D.C.: Center of Military History, United States Army. p. 156. LCCN 99490905.
  4. ^ Flippen, J. B. (April 2018). Speaker Jim Wright. Austin, Texas: University of Texas Press. p. 60. ISBN 9781477315149. Archived from the original on 17 June 2022. Retrieved 29 November 2021. mass-produced during the war, the Liberty Ship had become a symbol of the miracle of American production
  5. ^ "Liberty Ships built by the United States Maritime Commission in World War II". usmm.org. American Merchant Marine at War. Archived from the original on 9 May 2008. Retrieved 28 November 2021. (2,710 ships were completed, as one burned at the dock.)