The British Dorington Court of 1939 was the basis for the Liberty ship design, adapted for welded construction and with improved crew accommodation. Liberties were 441'6" in overall length and 57' in beam, and they registered 7,176 tons gross and 10,865 tons deadweight. Two oil-fired boilers provided steam for a three-cylinder, triple-expansion engine of 2,500 indicated hp that drove the vessel at 11 knots. The commission was criticized for specifying such old-fashioned machinery. However, as it worked out, there was a critical shortage of more modern turbine machinery because of the demands of other wartime expansion programs; moreover, the engines themselves were thoroughly reliable, and there was a substantial force of engine room crewmen who were very familiar with this type of plant.
Speedy construction and delivery was central to the Liberties' contribution to the war effort. An overwhelming majority of the yards in which they were constructed were newly created facilities purpose-built either by the Maritime Commission or by the contractors. Initially, the vessels required around 250 days for completion, but within a year, this was reduced to less than 50 days. The Richmond Shipbuilding Corporation, a subsidiary of Henry J. Kaiser's Permanente Metals Corporation, broke all records by assembling the Robert E. Peary in just over four days between 8 and 12 November 1942 and delivering the ship three days later. More important, American shipyards delivered 93 new ships in September 1942, totaling more than 1 million deadweight tons, of which 67 were Liberties.
Liberty ships proved to be very adaptable. Although intended to operate as freighters, they were modified for service as troop transports, tankers, aircraft transports, depot ships, and an array of naval auxiliaries.
Liberty ships were tough, even though they were classified as expendable war materials. Some problems were encountered with unexpected stress fatigue, but the ships often survived considerable combat damage and served successfully throughout the world in all types of weather. Many continued in postwar commercial service for 25 years or more. Two are preserved as tributes to the type's crucial contribution to the Allied victory: the John W. Brown at Baltimore, Maryland, and the Jeremiah O'Brien at San Francisco. Paul E. Fontenoy
Bunker, John. Liberty Ships: The Ugly Ducklings of World War II. Annapolis, MD: Naval Institute Press, 1972.; Bunker, John. Heroes in Dungarees: The Story of the American Merchant Marine in World War II. Annapolis, MD: Naval Institute Press, 1995.; Cooper, Sherod. Liberty Ship: The Voyages of the "John W. Brown," 1942–1946. Annapolis, MD: Naval Institute Press, 1997.; Sawyer, L. A., and W. H. Mitchell. The Liberty Ships: The History of the "Emergency" Type Cargo Ships Constructed in the United States during World War II. Newton Abbot, UK: David and Charles, 1970.
Paul E. Fontenoy