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Liberty ship
SS John W. Brown is one of only two surviving operational Liberty ships.
SS John W. Brown, one of two surviving operational Liberty ships, photographed in 2000
Class overview
Name: Liberty ship
Builders: 18 shipyards in the USA
Planned: 2,751
Completed: 2,710
Preserved: 2
General characteristics
Class & type: Cargo ship
Displacement: 14,245 long tons (14,474 t)[1]
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)
Capacity: 10,856 t (10,685 long tons) deadweight (DWT)[1]
Complement: 38–62 USMM
21–40 UGNAG[2]
Armament: Stern-mounted 4-in (102 mm) deck gun for use against surfaced submarines, variety of anti-aircraft guns

Liberty ships were cargo ships built in the United States during World War II. Though British in conception, they were adapted by the U.S. as they were cheap and quick to build,[3] and came to symbolize U.S. wartime industrial output. Based on vessels ordered by Britain to replace ships torpedoed by German U-boats, they were purchased for the U.S. fleet and for lend-lease deliveries of war materiel to Britain and to the Soviet Union via deliveries through Iran. Eighteen American shipyards built 2,710 Libertys between 1941 and 1945, easily the largest number of ships produced to a single design.

The production of these vessels mirrored on a much larger scale the manufacture of the Hog Islander ship and similar standardized types during World War I. The immense effort to build Liberty ships, the sheer number of ships built, and the fact that some of the ships survived far longer than the original design life of five years, make them the subject of much interest.

History and service

Profile plan of a Liberty Ship

In 1936, the American Merchant Marine Act was passed to subsidize the annual construction of 50 commercial merchant vessels to be used in wartime by the United States Navy as naval auxiliaries. The number was doubled in 1939 and again in 1940 to 200 ships a year. Ship types included a tanker and three types of merchant vessel, all to be powered by steam turbines. Limited industrial capacity, especially for reduction gears, meant that relatively few of these ships were built.

In 1940, the British government ordered 60 tramp steamships from American yards to replace war losses and boost the merchant fleet. These Ocean-class ships were simple but fairly large (for the time) with a single 2,500 hp (1,860 kW) reciprocating steam engine of obsolescent but reliable design. Britain specified coal-fired plants because it had extensive coal mines but did not at the time have significant domestic oil fields (the major North Sea field had yet to be discovered).

140-ton vertical triple expansion steam engine of the type used to power World War II Liberty ships, assembled for testing prior to delivery.

The predecessor designs, including the Northeast Coast, Open Shelter Deck Steamer, were based on a simple ship originally produced in Sunderland by J.L. Thompson & Sons (see Silver Line) from 1879, and widely manufactured up to the SS Dorrington Court, which was built in 1938. The order specified an 18-inch (0.5 m) increase in draft to boost displacement by 800 long tons (810 t) to 10,100 long tons (10,300 t). The accommodation, bridge and main engine of these vessels were located amidships, with a long tunnel to connect the main engine shaft to its aft extension to the propeller. The first Ocean-class ship, SS Ocean Vanguard, was launched on 16 August 1941.

The design was modified by the United States Maritime Commission to conform more, but not entirely, to American construction practices, but more important, to make it even quicker and cheaper to build. The US version was designated 'EC2-S-C1': 'EC' for Emergency Cargo, '2' for a ship between 400 and 450 feet (120 and 140 m) long (Load Waterline Length), 'S' for steam engines, and 'C1' for design C1. The new design replaced much riveting, which accounted for one-third of the labor costs, with welding, and had oil-fired boilers. The order was given to a conglomerate of West Coast engineering and construction companies known as the Six Companies, headed by Henry J. Kaiser, and was also adopted as the Merchant Marine Act design. Liberty ships were designed to carry 10,000 tons of cargo, usually one type per ship, but, during wartime, generally carried loads far exceeding this.[4]

By 1941, the steam turbine had become the preferred marine steam engine because of its greater efficiency when compared to earlier reciprocating compound steam engines. However, steam turbine engines required very precise manufacturing techniques and balancing and a complicated reduction gear, and the companies capable of manufacturing them already were committed to the large construction program for warships. Therefore, a 140-ton[5] vertical triple expansion compound steam engine of obsolete design was selected to power Liberty ships because it was cheaper and easier to build in the numbers required for the Liberty ship program and because more companies could manufacture it; eighteen different companies eventually built the engine. It had the additional advantage of ruggedness and simplicity; parts manufactured by one company were interchangeable with those made by another, and the openness of its design made most of its moving parts easy to see, access, and oil. The engine – 21 feet (6.4 meters) long and 19 feet (5.8 meters) tall – was designed to operate at 76 rpm and propel a Liberty ship at about 11 knots (12.7 mph; 20.4 km/hr).[6]

On 27 March 1941, the number of lend-lease ships was increased to 200 by the Defense Aid Supplemental Appropriations Act, and increased again in April to 306, of which 117 would be Liberty ships.

The ships were constructed of sections that were welded together. This is similar to the technique used by Palmer's at Jarrow, northeast England, but substitutes welding for riveting. Riveted ships took several months to construct. The work force was newly trained – no one had previously built welded ships. As America entered the war, the shipbuilding yards employed women, to replace men who were enlisting in the armed forces.

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The ships initially had a poor public image due to their appearance. In a speech announcing the emergency shipbuilding program, President Franklin D. Roosevelt had referred to the ship as "a dreadful looking object", and Time magazine called it an "Ugly Duckling". To try to assuage public opinion, 27 September 1941 was dubbed Liberty Fleet Day, as the first 14 "Emergency" vessels were launched that day. The first of these was SS Patrick Henry, launched by President Roosevelt. In remarks at the launch ceremony, FDR cited Patrick Henry's 1775 speech that finished "Give me liberty or give me death". Roosevelt said that this new class of ships would bring liberty to Europe, which gave rise to the name Liberty ship.

Aerial photograph of the Liberty ship SS John W. Brown outbound from the United States carrying a large deck cargo after her conversion to a "Limited Capacity Troopship." It probably was taken in the summer of 1943 during her second voyage.

Eastine Cowner, a former waitress, at work on the Liberty ship SS George Washington Carver at the Kaiser shipyards, Richmond, California, in 1943. One of a series taken by E. F. Joseph on behalf of the Office of War Information documenting the work of African-Americans in the war effort.

The first ships required about 230 days to build (Patrick Henry took 244 days), but the average eventually dropped to 42 days. The record was set by SS Robert E. Peary, which was launched 4 days and 15½ hours after the keel was laid, although this publicity stunt was not repeated: in fact much fitting-out and other work remained to be done after the Peary was launched. The ships were made assembly-line style, from prefabricated sections. In 1943, three Liberty ships were completed daily. They were usually named after famous Americans, starting with the signatories of the Declaration of Independence.

Any group which raised war bonds worth $2 million could propose a name. Most bore the names of deceased people. The only living namesake was Francis J. O'Gara, the purser of the SS Jean Nicolet, who was thought to have been killed in a submarine attack, but, in fact, survived the war in a Japanese prisoner of war camp. Other exceptions to the naming rule were the SS Stage Door Canteen, named for the USO club in New York, and the SS U.S.O., named after the organization itself.[7]

Another notable Liberty ship was SS Stephen Hopkins, which sank the German commerce raider Stier in a ship-to-ship gun battle in 1942 and became the first American ship to sink a German surface combatant.

SS Richard Montgomery is also notable, though in a less positive way: the wreck of the ship lies off the coast of Kent with 1,500 tons[vague]

of explosives still on board, enough to match a small nuclear weapon should they ever go off. One Liberty ship that did explode was the SS E. A. Bryan which detonated with the energy of 2,000 tons of TNT (8,400 GJ) in July 1944 as it was being loaded, killing 320 sailors and civilians in what was called the Port Chicago disaster. Another infamous Liberty ship that exploded was the rechristened SS Grandcamp, which caused the Texas City Disaster on 16 April 1947, killing at least 581 people.

Six Liberty ships were converted at Point Clear, Alabama, by the United States Army Air Forces into floating aircraft repair depots, operated by the Army Transport Service, starting in April 1944. The secret project, dubbed "Project Ivory Soap", provided mobile depot support for B-29 Superfortress bombers and P-51 Mustang fighters based on Guam, Iwo Jima, and Okinawa beginning in December 1944. The six ARU(F)s (Aircraft Repair Unit, Floating), however, were also fitted with landing platforms to accommodate four Sikorsky R-4 helicopters, where they provided medical evacuation of combat casualties in both the Philippine Islands and Okinawa.[8]

The last new-build Liberty ship constructed was the SS Albert M. Boe, launched on 26 September 1945 and delivered on 30 October 1945. She was named after the chief engineer of a United States Army freighter who had stayed below decks to shut down his engines after a 13 April 1945 explosion, an act that won him a posthumous Merchant Marine Distinguished Service Medal.[9] In 1950, a "new" liberty ship was constructed by Industriale Maritime SpA, Genoa, Italy by using the bow section of Bert Williams and the stern section of Nathaniel Bacon, both of which had been wrecked. The new ship was named SS Boccadasse, and served until scrapped in 1962.[10][11]


SS Jeremiah O'Brien

Early Liberty ships suffered hull and deck cracks, and a few were lost to such structural defects. During World War II, there were nearly 1,500 instances of significant brittle fractures. Twelve ships, including three of the 2,710 Liberties built, broke in half without warning, including the SS John P. Gaines,[12][13] which sank on 24 November 1943 with the loss of 10 lives. Suspicion fell on the shipyards which had often used inexperienced workers and new welding techniques to produce large numbers of ships in great haste.[14] The Ministry of War Transport lent the British-built Empire Duke for testing purposes.[15] Constance Tipper of Cambridge University demonstrated that the fractures were not initiated by welding, but instead by the grade of steel used, which suffered from embrittlement.[14] She discovered that the ships in the North Atlantic were exposed to temperatures that could fall below a critical point when the mechanism of failure changed from ductile to brittle, and thus the hull could fracture rather easily. The predominantly welded (as opposed to riveted) hull construction then allowed cracks to run for large distances unimpeded. One common type of crack nucleated at the square corner of a hatch which coincided with a welded seam, both the corner and the weld acting as stress concentrators. Furthermore, the ships were frequently grossly overloaded and some of the problems occurred during or after severe storms at sea that would have placed any ship at risk. Various reinforcements were applied to the Liberty ships to arrest the crack problems, and the successor design, the Victory ship, was stronger and less stiff to better deal with fatigue.

Several designs of mass-produced petroleum tankers were also produced, the most numerous being the T2 tanker series, with about 490 built between 1942 and the end of 1945.

After the war

SS Jeremiah O'Brien

More than 2,400 Liberty ships survived the war. Of these, 835 made up the postwar cargo fleet. Greek entrepreneurs bought 526 ships and Italians bought 98. Shipping magnates like John Fredriksen, John Theodoracopoulos,[16] Aristotle Onassis,[17] Stavros Niarchos,[17] Stavros George Livanos, the Goulandris brothers,[17] and the Andreadis, Tsavliris, Achille Lauro, Grimaldi and Bottiglieri families were known to have started their fleets by buying Liberty ships. Weyerhaeuser operated a fleet of six Liberty Ships (which were later extensively refurbished and modernized) carrying lumber, newsprint, and general cargo for years after the end of the war.

The term "Liberty-size cargo" for 10,000 long tons (10,000 t) may still be heard in the shipping business.

Some Liberty ships were lost after the war to naval mines that were inadequately cleared. Pierre Gibault was scrapped after hitting a mine in a previously cleared area off the Greek island of Kythira in June 1945,[18] and the same month saw Colin P. Kelly Jnr take mortal damage from a mine hit off the Belgian port of Ostend.[19] In August 1945, William J. Palmer was carrying horses from New York to Trieste when she rolled over and sank 15 minutes after hitting a mine a few miles from destination. All crew members and six horses were saved.[20] Nathaniel Bacon ran into a minefield off Civitavecchia, Italy in December 1945, caught fire, was beached, and broke in two; the larger section was welded onto another Liberty half hull to make a new ship 30 feet longer, named Boccadasse.[21]

As late as December 1947, Robert Dale Owen, renamed Kalliopi and sailing under the Greek flag, broke in three and sank in the northern Adriatic Sea after hitting a mine.[22] Other Libertys lost postwar to mines include John Woolman, Calvin Coolidge, Cyrus Adler, and Lord Delaware.[23]

In the 1960s, three Liberty ships were reactivated and converted to technical research ships with the hull classification symbol AGTR (auxiliary, technical research) and used to gather electronic intelligence and for radar picket duties by the United States Navy. SS Samuel R. Ailken became USS Oxford (AGTR-1), SS Robert W. Hart became USS Georgetown (AGTR-2), and SS J. Howland Gardner became USS Jamestown (AGTR-3). All of these ships were decommissioned and stricken from the Naval Vessel Register in 1969 and 1970.

SS Hellas Liberty (ex-SS Arthur M. Huddell) in June 2010

Only two operational Liberty ships, SS John W. Brown and SS Jeremiah O'Brien, remain. Brown has had a long career as a school ship and many internal modifications, while O'Brien remains largely in her original condition. Both are museum ships that still put out to sea regularly. In 1994, O'Brien steamed from San Francisco to England and France for the 50th anniversary of D-Day, the only large ship from the original Overlord fleet to participate in the anniversary. In 2008, SS Arthur M. Huddell was transferred to Greece and converted to a floating museum dedicated to the history of the Greek merchant marine;[24] however, while missing major components were restored, this ship is no longer operational.

Liberty ships continue to serve in a "less than whole" function many decades after their launching. In Portland, Oregon, the hulls of Richard Henry Dana and Jane Addams serve as the basis of floating docks.[25] SS Albert M. Boe survives as the Star of Kodiak, a landlocked cannery, in Kodiak Harbor at 57°47′12″N 152°24′18″W / 57.78667°N 152.405°W / 57.78667; -152.405.

SS Charles H. Cugle was converted into MH-1A (otherwise known as USS Sturgis). MH-1A was a floating nuclear power plant and the first ever built. MH-1A was used to generate electricity at the Panama Canal Zone from 1968–1975. She was also used as a fresh water generating plant. She is currently anchored in the James River Reserve Fleet.[26]

Fifty-eight Liberty ships were lengthened by 70 feet (21 m) starting in 1958.[27] This gave the ships an additional 640 long tons (650 t) of carrying capacity at a small additional cost.[28][citation needed] The bridges of most of these were also enclosed in the mid-1960s in accordance with a design by naval architect Ion Livas.

In 2011, the United States Postal Service issued a postage stamp featuring the Liberty ship as part of a set on the U.S. Merchant Marine.[29]

U.S. shipyards

Liberty ships were built at eighteen shipyards located along the Atlantic, Pacific and Gulf coasts:[30]

  • Alabama Drydock and Shipbuilding, Mobile, Alabama
  • Bethlehem-Fairfield Shipyard, Baltimore, Maryland
  • California Shipbuilding Corp., Los Angeles
  • Delta Shipbuilding Corp., New Orleans, Louisiana
  • J.A. Jones Construction Company
    • Panama City, Florida
    • Brunswick, Georgia
  • Kaiser Company, Vancouver, Washington
  • Marinship, Sausalito, California
  • New England Shipbuilding Corporation, South Portland, Maine The East and West Yards were both on the same 60 acres (240,000 m2) of shipyard. However, the two yards commenced operations under different titles and until early 1942 were separated by rigid legal conditions.
    • East Yard
    • West Yard
  • North Carolina Shipbuilding Company, Wilmington, North Carolina
  • Oregon Shipbuilding Corporation, Portland, Oregon
  • Permanente Metals Corporation, Richmond, California (a Kaiser facility)
    • Yard No. 1
    • Yard No. 2
  • St. Johns River Shipbuilding, Jacksonville, Florida
  • Southeastern Shipbuilding Corporation, Savannah, Georgia
  • Todd Houston Shipbuilding, Houston, Texas
  • Walsh-Kaiser Co., Inc., Providence, Rhode Island

In popular culture

  • A Liberty ship was featured in the Quantum Leap episode "Ghost Ship".
  • A Liberty ship, converted to a hospital ship, is the eponymous subject and setting of Alistair MacLean's mystery thriller San Andreas (1984) The prologue to this novel, also by MacLean, is an essay on Liberty ships and the conditions, character and behavior of the British Merchant Marine owners that used them, and sailors that sailed them.
  • A Liberty ship is featured in the Humphrey Bogart 1943 film Action in the North Atlantic. Its deck gun is described as being 5" rather than 4", probably for wartime propaganda reasons. Called the Seawitch in the film, its dedication plaque describes it as "Built for/ U.S. Maritime Commission/ Hull No. 628B/ by/ Atlas Shipbulding Corporation/ Kearny, New Jersey/ April 1943".
  • In Clive Cussler's book Deep Six, the prologue details a Liberty ship that disappears in the 1960s and becomes a recurring ghost ship in The Flying Dutchman vein. It is later found by Dirk Pitt, leading to further adventures.
  • Most of the engine room scenes of the 1997 film Titanic were shot aboard the museum Liberty Ship SS Jeremiah O'Brien in San Francisco Bay. Scott Sigler's book Nocturnal also has several scenes that take place on the Jeremiah O'Brien.
  • The wreck of the SS Richard Montgomery is central to the plot of Stephen Barlay's 1977 novel Blockbuster, in which an extortionist threatens to blow it up, thereby causing serious flooding in central London, if his demands are not met.
  • The 3 May 1942 episode of the radio comedy The Great Gildersleeve revolves around a trip to the Richmond Shipyards where Gildersleeve's niece Marjorie christens a Liberty Ship the Throckmorton P. Gildersleeve.

See also


  1. 1.0 1.1 Davies, 2004, page 23.
  2. "Liberty Ships Design". 2012. Retrieved 7 May 2012. 
  3. "Video: America Reports On Aid To Allies Etc. (1942)". Universal Newsreel. 1942. Retrieved February 21, 2012. 
  4. [1]- cite: American Merchant Marine at War; retrieved 2012-07-20
  5. Live (the program of Project Liberty Ship provided for cruises of the Liberty ship SS John W. Brown, 2013 edition, claims both that the engine weighed 135 tons (p. 10) fully assembled and that it weighed 140 tons (p. 11).
  6. Live (program of Project Liberty Ship provided for cruises of the Liberty ship SS John W. Brown, 2013 edition, p. 10.
  7. Reading 1: Liberty Ships National Park Service Cultural Resources.
  8. The Hoverfly in CBI, Carl Warren Weidenburner
  9. "SS Albert M. Boe". 2004. Retrieved 7 May 2012. 
  10. "Liberty Ships - B". Mariners. Retrieved 6 January 2012. 
  11. "Liberty Ships - N - O". Mariners. Retrieved 6 January 2012. 
  12. Wreck of the SS John P Gaines
  13. Fracture – some maritime examples. Mechanical Engineering Department, University of Western Australia.
  14. 14.0 14.1 Constance Tipper (researcher into Liberty ship fracture)
  15. Hedley-Whyte, John; Milamed, Debra R. "Asbestos and Ship-Building: Fatal Consequences". Ulster Medical Society. pp. 191–200. PMC 2604477. PMID 18956802. 
  16. The Shipping World and Shipbuilding & Marine Engineering News, 1952, p. 148.
  17. 17.0 17.1 17.2 Elphick, Peter. Liberty, p. 401.
  18. Elphick, Liberty, p. 309.
  19. Elphick, Liberty, p. 166.
  20. Elphick, Liberty, p. 271.
  21. Elphick, Liberty, p. 108.
  22. Elphick, Liberty, p. 402.
  23. Elphick, Liberty, p. 325.
  24. The Hellas Liberty Project
  25. Did You Know: Liberty Ships Still Afloat in Portland
  26. Adams, Rod (November 1, 1995). "Army Nuclear Power Plants". Retrieved 7 May 2012. 
  27. Modern Ship History[dead link]
  28. The History of Modern Shipping[dead link]
  29. "Postal Service Salutes U.S. Merchant Marine on Forever Stamps". Press Release. USPS. 28 July 2011. Retrieved 25 May 2012. 
  30. "WWII Construction Records, Private-Sector Shipyards that Built Ships for the U.S. Maritime Commission". Colton Company. Archived from the original on 13 November 2007. Retrieved 1 December 2007. 

Further reading

External links

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