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{{Short description|US cargo ship class of WWII}}
{{about|the class of US cargo ship|ships named "Liberty"|Liberty (ship)}}
{{Use American English|date=October 2013}}
{{Use dmy dates|date=July 2019}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=Jeremiah_O.Brien_2022-c.jpg
|Ship caption={{SS|Jeremiah O'Brien}}, one of four surviving Liberty ships, photographed in 2022
}}
{{Infobox ship class overview
|Name=Liberty ship
|Builders=18 shipyards in the United States
|Operators=
|Class before=
|Class after=
|Subclasses=
|Cost= [[United States dollar|US$]]2&nbsp;million (${{formatnum:{{Inflation|US|2|1940|r=0}}}}&nbsp;million in {{CURRENTYEAR}}) per ship<ref name= "Wise-Baron p. 140">{{harvnb|Wise|Baron|2004| p=140}}</ref>
|Built range=
|In service range=  
|In commission range= 
|Total ships building=
|Total ships planned=2,751
|Total ships completed=2,710
|Total ships cancelled=
|Total ships active=2 (Traveling [[museum ship]]s)
|Total ships laid up=
|Total ships lost=
|Total ships retired=
|Total ships preserved=4
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship class=[[Cargo ship]]
|Ship type=
|Ship tonnage={{GRT|7176}}, {{DWT|10865}}{{sfn|Sawyer|Mitchell|1985|p=39}}
|Ship displacement={{convert|14245|LT|MT}}{{sfn|Sawyer|Mitchell|1985|p=39}}
|Ship length={{Convert|441|ft|6|in|abbr=on}}
|Ship beam={{Convert|56|ft|10.75|in|1|abbr=on}}
|Ship height=
|Ship draft={{Convert|27|ft|9.25|in|1|abbr=on}}
|Ship depth=
|Ship hold depth=
|Ship decks=
|Ship deck clearance=
|Ship ramps=
|Ship ice class=
|Ship power=
|Ship propulsion=*Two oil-fired boilers
* triple-expansion steam engine
* single screw, {{Convert|2500|hp|abbr=on}}
|Ship speed= {{Convert|11|-|11.5|kn|lk=in}}
|Ship range={{Convert|20000|nmi|abbr=on}}
|Ship endurance=
|Ship boats=
|Ship capacity=
|Ship troops=
|Ship complement=*38–62 [[United States Merchant Marine|USMM]]
* 21–40 [[United States Navy Armed Guard|USNAG]]{{citation needed|date=September 2023}}
|Ship crew=
|Ship time to activate=
|Ship sensors=
|Ship EW=
|Ship armament=Stern-mounted 4-in (102 mm) deck gun for use against surfaced submarines, variety of [[anti-aircraft guns]]
|Ship armor=
|Ship aircraft=
|Ship aircraft facilities=
|Ship notes=
}}
|}
'''Liberty ships''' were a [[ship class|class]] of [[cargo ship]] built in the United States during [[World War II]] under the [[Emergency Shipbuilding Program]]. Although British in concept,<ref name=Wardlow>{{cite book |last1=Wardlow |first1=Chester |year=1999 |title=The Technical Services – The Transportation Corps: Responsibilities, Organization, and Operations |series=United States Army in World War II |location=Washington, D.C. |publisher=[[United States Army Center of Military History|Center of Military History, United States Army]] |lccn=99490905 |page=156}}</ref> 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.<ref name=Flip60>{{cite book |last= Flippen |first= J. B. |date= April 2018 |title= Speaker Jim Wright |url= https://utpress.utexas.edu/books/flippen-speaker-jim-wright |location= Austin, Texas |publisher= [[University of Texas Press]] |page= 60 |isbn= 9781477315149 |quote= mass-produced during the war, the Liberty Ship had become a symbol of the miracle of American production |access-date= 29 November 2021 |archive-date= 17 June 2022 |archive-url= https://web.archive.org/web/20220617010700/https://utpress.utexas.edu/books/flippen-speaker-jim-wright |url-status= dead }}</ref>

The class was developed to meet British orders for transports to replace ships that had been lost. Eighteen American [[shipyard]]s built 2,710 Liberty ships between 1941 and 1945 (an average of three ships every two days),<ref name=usmmburn>{{cite web |url= http://www.usmm.org/libertyships.html |title= Liberty Ships built by the United States Maritime Commission in World War II |website= usmm.org |publisher= American Merchant Marine at War |access-date= 2021-11-28 |quote= (2,710 ships were completed, as one burned at the dock.) |archive-date= 9 May 2008 |archive-url= https://web.archive.org/web/20080509091805/http://www.usmm.org/libertyships.html |url-status= dead }}</ref> easily the largest number of ships ever produced to a single design.

The Liberty ship was effectively superseded by the [[Victory ship]], a somewhat larger, materially faster, more modern-powered vessel of generally similar design. Over 500 were built between 1943 and 1945.

Liberty ship 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 [[Rosie the Riveter|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.

==History==

===Design===
[[File:Libertyship linedrawing en.jpg|right|thumb|upright=1.5|Profile plan of a Liberty ship]]
[[File:Planlibertyship.jpg|thumb|upright=1.5|alt=A colored diagram of compartments on a ship|A colored diagram of compartments on a Liberty ship, from the right side, front to the right
{{Div col|colwidth=10em}}
{{legend|#44ce35|Machinery spaces}}
{{legend|#fcfd1d|Command and control}}
{{legend|#f8632e|Liquid stores}}
{{legend|#a2fffe|Dry cargo}}
{{legend|#163098|Engine room}}
{{legend|#cbcbcb|Misc}}
{{legend|#cbfc82|Dry stores}}
{{legend|#9991fe|Habitation}}
{{Div col end}}]]
In 1936, the American [[Merchant Marine Act of 1936|Merchant Marine Act]] was passed to subsidize the annual construction of 50 commercial merchant vessels which could be used in wartime by the [[United States Navy]] as naval auxiliaries, crewed by [[United States Merchant Marine|U.S. Merchant Mariners]]. The number was doubled in 1939 and again in 1940 to 200 ships a year. Ship types included two tankers and three types of merchant vessel, all to be powered by [[steam turbine]]s. Limited industrial capacity, especially for reduction gears, meant that relatively few of these designs of ships were built.

However, in 1940, the British government ordered 60 [[Ocean ship|Ocean-class]] [[cargo ship|freighter]]s from American yards to replace war losses and boost the merchant fleet. These were simple but fairly large (for the time) with a single {{convert|2500|hp|kW}} [[compound steam engine]] of outdated but reliable design. Britain specified coal-fired plants, because it then had extensive coal mines and no significant domestic oil production.{{refn |During WW&nbsp;II, Nazi Germany made the exact same decision, when they decided to mass-produce coal-powered, steam-engine driven [[Kriegslokomotive]]s.<ref>[[National Geographic]], 2017. ''"Nazi Megastructures: Hitler's War Trains"''</ref> Despite electrical industrial technology having begun to replace stationary steam engines in the late 19th century, and [[Internal combustion engine]]s in two-railcar, high speed [[Diesel-electric transmission|Diesel-electric]] [[Diesel locomotive|locomotive]] and train sets, developed by [[Maybach]], were series produced in Germany since 1935, the war also made Germany short on oil, but still rich in coal, especially in the [[Ruhr|Ruhr region]], and thus mass-produced old-fashioned but very effective steam locomotives for transporting goods and people across the large conquered European area.}}

The predecessor designs, which included the "Northeast Coast, Open Shelter Deck Steamer", were based on a simple ship originally produced in [[Sunderland, Tyne and Wear|Sunderland]] by [[J.L. Thompson and Sons|J.L. Thompson & Sons]] based on a 1939 design for a simple [[tramp steamer]], which was cheap to build and cheap to run (see [[Silver Line (shipping company)|Silver Line]]). Examples include SS ''Dorington Court'' built in 1939.<ref>{{Cite web |url=http://www.benjidog.co.uk/Court/Dorington%20Court%20%281939%29.html |title=Dorington Court (1939) |access-date=28 June 2015 |archive-url=https://web.archive.org/web/20150701004421/http://www.benjidog.co.uk/Court/Dorington%20Court%20%281939%29.html |archive-date=1 July 2015 |url-status=dead }}</ref> The order specified an {{convert|18|inch|m|adj=on}} increase in [[Draft (hull)|draft]] to boost displacement by {{convert|800|LT|MT}} to {{convert|10100|LT|MT}}. The accommodation, [[Bridge (nautical)|bridge]], and main engine were located amidships, with a tunnel connecting the main engine shaft to the propeller via a long aft extension. The first Ocean-class ship, SS ''Ocean Vanguard'', was [[Ceremonial ship launching|launched]] on 16 August 1941.

[[File:Liberty ship 140-ton VTE engine.jpg|thumb|upright|140-ton [[compound steam engine#Multiple-expansion engines|vertical triple expansion steam engine]] of the type used to power [[World War II]] Liberty ships, assembled for testing before delivery]] 
The design was modified by the [[United States Maritime Commission]], in part to increase conformity to American construction practices, but more importantly 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 {{convert|400|and|450|ft|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. It was adopted as a Merchant Marine Act design, and production awarded to a conglomerate of West Coast engineering and construction companies headed by [[Henry J. Kaiser]] known as the [[Six Companies]]. Liberty ships were designed to carry {{convert|10000|LT|MT|sigfig=3}} of cargo, usually one type per ship, but, during wartime, generally carried loads far exceeding this.<ref>{{Cite web|url=http://www.usmm.org/capacity.html|title=Capacity of One Liberty Ship|website=Usmm.org|access-date=11 March 2022}}</ref>

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.

===Variants===
The basic EC2-S-C1 cargo design was modified during construction into three major variants with the same basic dimensions and slight variance in tonnage. One variant, with basically the same features but different type numbers, had four rather than five [[Hold (partition)|holds]] served by large hatches and [[kingpost]] with large capacity booms. Those four hold ships were designated for transport of tanks and boxed aircraft.<ref name=FRtab>{{cite book |title=Federal Register |volume=11 |issue=161 |pages=8974 |publisher=U.S. Government |date=17 August 1946|url=https://www.govinfo.gov/content/pkg/FR-1946-08-17/pdf/FR-1946-08-17.pdf |access-date=20 June 2019}}</ref>

In the detailed Federal Register publication of the post war prices of Maritime Commission types the Liberty variants are noted as:<ref name=FRtab/>
; EC2-S-AW1
: Collier (All given names of coal seams as ''[[SS Banner Seam]]'', ''[[Beckley Seam]]'' and ''[[Bon Air Seam]]'')
;Z-EC2-S-C2
: Tank carrier (four holds, kingposts) – example {{SS|Frederic C. Howe}}{{efn|The Z-EC2-S-C2 Tank carrier type details had not been previously published until 17 August 1946 Federal Register.<ref name=FRtab/>}}
;Z-ET1-S-C3
: [[T1 tanker]] – example [[SS Carl R. Gray|SS ''Carl R. Gray'']]. Eighteen were commissioned into USN in 1943 as the {{sclass|Armadillo|tanker|1}}
;Z-EC2-S-C5
: Boxed aircraft transport (four holds, kingposts) – example {{SS|Charles A. Draper}}.{{efn|photo showing holds, kingposts}} Post war 16 of these Liberty ships were converted 1954–1958 into {{sclass|Guardian|radar picket ship|1}}

In preparation for the [[Normandy landings]] and afterward to support the rapid expansion of logistical transport ashore a modification was made to make standard Liberty vessels more suitable for mass transport of vehicles and in records are seen as "MT" for Motor Transport vessels. As MTs four holds were loaded with vehicles while the fifth was modified to house the drivers and assistants.<ref>{{cite book |last=Larson |first=Harold |title=The Army's Cargo Fleet In World War II |year=1945 |publisher=Office of the Chief of Transportation, Army Service Forces, U. S. Army |location=Washington, D.C. |pages=75–77 |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a438107.pdf |archive-url=https://web.archive.org/web/20200803052404/https://apps.dtic.mil/dtic/tr/fulltext/u2/a438107.pdf |url-status=live |archive-date=3 August 2020 |access-date=20 June 2019}}</ref>

The modifications into troop transports also were not given special type designations.

===Propulsion===
[[File:Liberty Ship Model (engine room detail).jpg|thumb|Engine room (model cutaway)]]

By 1941, the [[steam turbine]] was the preferred [[marine steam engine]] because of its greater efficiency compared to earlier reciprocating [[compound steam engine]]s. Steam turbine engines however, required very precise manufacturing techniques to machine their complicated [[Gear#Double helical|double helical reduction gears]], and the companies capable of producing them were already committed to the large construction program for [[warship]]s. Therefore, a {{convert|140|ST|adj=on}}<ref>''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).</ref> [[vertical triple expansion]] 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, simplicity and familiarity to seamen. 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—{{convert|21|feet|m}} long and {{convert|19|feet|m}} tall—was designed to operate at 76 [[revolutions per minute|rpm]] and propel a Liberty ship at about {{convert|11|knots}}.<ref>''Live'' (program of [[Project Liberty Ship]] provided for cruises of the Liberty ship {{SS|John W. Brown}}, 2013 edition, p. 10.</ref>

===Construction===
The ships were constructed of sections that were welded together. This is similar to the technique used by [[Palmers Shipbuilding and Iron Company Limited|Palmer's]] at [[Jarrow]], northeast England, but substituted [[welding]] for [[rivet]]ing. Riveted ships took several months to construct. The work force was newly trained as the yards responsible had not previously built welded ships. As America entered the war, the shipbuilding yards employed women, to replace men who were enlisting in the armed forces.{{sfn|Herman|2012|pp=135–136, 178–180}}

<gallery mode="packed" heights="200" caption="The construction of a Liberty ship at the Bethlehem-Fairfield Shipyards, Baltimore, Maryland, in March/April 1943">
File:Liberty ship construction 03 keel plates.jpg|Day 2 : Laying of the keel plates
File:Liberty ship construction 07 bulkheads.jpg|Day 6 : Bulkheads and girders below the second deck are in place.
File:Liberty ship construction 09 lower decks.jpg|Day 10 : Lower deck being completed and the upper deck amidship erected
File:Liberty ship construction 10 upper decks.jpg|Day 14 : Upper deck erected and mast houses and the after-deck house in place
File:Liberty ship construction 11 prepared for launch.jpg|Day 24 : Ship ready for launching
</gallery>
[[File:SS Patrick Henry launching on Liberty Fleet Day, 27 September 1941 (26580977380).jpg|thumb|right|Launch of [[SS Patrick Henry|SS ''Patrick Henry'']], the first Liberty ship, on 27 September 1941]]
The ships initially had a poor public image owing 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)|''Time'']] called it an "Ugly Duckling". 27 September 1941 was dubbed [[Liberty Fleet Day (Victory Fleet Day)|Liberty Fleet Day]] to try to assuage public opinion, since 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 ship would bring liberty to Europe, which gave rise to the name Liberty ship.

The first ships required about 230 days to build (''Patrick Henry'' took 244 days), but the median production time per ship dropped to 39 days by 1943.{{sfn|Davies|2004}} The record was set by {{SS|Robert E. Peary}}, which was launched 4 days and 15{{frac|1|2}} hours after the [[keel]] had been 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 [[United States Declaration of Independence|Declaration of Independence]]. Newsreel footage of the launching of the ship named for American author [[Jack London]] can be seen in the film [[Jack London (film)|Jack London]]. 17 of the Liberty ships were named in honor of outstanding African-Americans. The first, in honor of [[Booker T. Washington]], was christened by [[Marian Anderson]] in 1942, and the {{SS|Harriet Tubman}}, recognizing the only woman on the list, was christened on 3 June 1944.<ref>{{Cite web|url=http://www.usmm.org/african-americans.html|title=African-Americans in the U.S. Merchant Marine and U.S. Maritime Service during World War II|website=Usmm.org|access-date=10 March 2022}}</ref>

Any group that raised [[war bond]]s worth $2&nbsp;million could propose a name. Most bore the names of deceased people. The only living namesake was Francis J. O'Gara, the [[purser]] of {{SS|Jean Nicolet}}, who was thought to have been killed in [[Japanese submarine I-8#SS Jean Nicolet|a submarine attack]], but in fact survived the war in a Japanese [[prisoner of war]] camp. Not named after people were: {{SS|Stage Door Canteen}}, named after the [[United Service Organizations|USO]] club in New York; and {{SS|U.S.O.}}, named after the [[United Service Organizations]] (USO).<ref>[http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/116liberty_victory_ships/116facts1.htm Reading 1: Liberty Ships] {{Webarchive|url=https://web.archive.org/web/20050308175723/http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/116liberty_victory_ships/116facts1.htm |date=8 March 2005 }} ''[[National Park Service]] Cultural Resources.''</ref>

Another notable Liberty ship was {{SS|Stephen Hopkins}}, which sank the German [[commerce raider]] {{Ship|German auxiliary cruiser|Stier||2}} in a ship-to-ship gun battle in 1942 and became the first American ship to sink a German surface combatant.

[[File:Liberty Ship scaler HD-SN-99-02466.JPG|thumb|right|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.&nbsp;F. Joseph on behalf of the [[Office of War Information]], documenting the work of [[African-American]]s in the war effort]]

The wreck of {{SS|Richard Montgomery}} lies off the coast of [[Kent]] with {{convert|1,400|t|ST|order=flip|abbr=off|lk=on}} of [[explosive]]s still on board, enough to match a very small yield [[nuclear weapon]] should they ever go off.<ref>{{cite web|url=http://www.dft.gov.uk/mca/2000_survey_report_montgomery.pdf|archive-url=http://webarchive.nationalarchives.gov.uk/20121107103953/http://www.dft.gov.uk/mca/2000_survey_report_montgomery.pdf|url-status=dead|archive-date=2012-11-07|title=Report on the Wreck of the SS Richard Montgomery|website=Webarchive.nationalarchives.gov.uk|access-date=2022-03-11}}</ref><ref name="Nuclear yield">{{cite web|title=Little Boy and Fat Man|url=https://www.atomicheritage.org/history/little-boy-and-fat-man|website=[[Atomic Heritage Foundation]]|access-date=24 December 2017|archive-url=https://web.archive.org/web/20171224040030/https://www.atomicheritage.org/history/little-boy-and-fat-man|archive-date=24 December 2017|date=23 July 2014|quote=Little Boy yield: 15 kilotons / Fat Man yield: 21 kilotons}}</ref> {{SS|E. A. Bryan}} detonated with the energy of {{convert|2000|tonTNT|lk=on}} in July 1944 as it was being loaded, killing 320 sailors and civilians in what was called the [[Port Chicago disaster]]. Another 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 Force]], 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 Island|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.<ref>{{Cite web|url=http://cbi-theater-3.home.comcast.net/~cbi-theater-3/hoverfly/hoverfly.html|archiveurl=https://web.archive.org/web/20081022065117/http://cbi-theater-3.home.comcast.net/~cbi-theater-3/hoverfly/hoverfly.html|url-status=dead|title=The Hoverfly in CBI, Carl Warren Weidenburner|archive-date=22 October 2008|access-date=10 March 2022}}</ref>

The last new-build Liberty ship constructed was {{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]].<ref>{{cite web|url=http://www.history.navy.mil/danfs/a5/albert_m_boe.htm |title=SS ''Albert M. Boe'' |work=history.navy.mil |year=2004 |access-date=7 May 2012 |url-status=dead |archive-url=http://webarchive.loc.gov/all/20121007221940/http%3A//www%2Ehistory%2Enavy%2Emil/danfs/a5/albert_m_boe%2Ehtm |archive-date= 7 October 2012 }}</ref> In 1950, a "new" liberty ship was constructed by Industriale Maritime SpA, [[Genoa]], Italy by using the bow section of {{SS|Bert Williams||2}} and the stern section of {{SS|Nathaniel Bacon||2}}, both of which had been wrecked. The new ship was named {{SS|Boccadasse}}, and served until scrapped in 1962.<ref name=LibB>{{cite web |url=http://www.mariners-l.co.uk/LibShipsB.html |title=Liberty Ships – B |publisher=Mariners |access-date=6 January 2012}}</ref><ref name=LibN>{{cite web |url=http://www.mariners-l.co.uk/LibShipsN.html |title=Liberty Ships – N–O |publisher=Mariners |access-date=6 January 2012}}</ref>

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

===Problems===<!-- This section is linked from [[Problems of the Liberty ship]] redirect -->
[[File:JeremiahO'Brienbow27may07.jpg|thumb|upright|{{SS|Jeremiah O'Brien}}]]

====Hull cracks====
[[File:TankerSchenectady.jpg|right|thumb|The {{SS|Schenectady}} split apart by [[brittle fracture]] while in harbor, 1943. It was a 152-meter-long T2 tanker.]]
Early Liberty ships suffered hull and deck cracks, and a few were lost due to such structural defects. During World War II there were nearly 1,500 instances of significant [[brittle fracture]]s. Twelve ships, including three of the 2,710 Liberty ships built, broke in half without warning, including {{SS|John P. Gaines}},<ref>{{Cite web|url=http://www.armed-guard.com/gaines.html|title=John P Gaines|website=Armed-guard.com|access-date=10 March 2022|archive-date=23 January 2007|archive-url=https://web.archive.org/web/20070123125404/http://www.armed-guard.com/gaines.html|url-status=dead}}</ref><ref>[http://www.iste.co.uk/data/doc_cbornfqmtxga.pdf X-FEM for Crack Propagation – Introduction] Article which includes clear photograph of a ship broken in half.</ref> 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.

The [[Ministry of War Transport]] borrowed the British-built {{SS|Empire Duke||2}} for testing purposes.<ref name=UMA>{{cite journal|pmc=2604477 |title=Asbestos and Ship-Building: Fatal Consequences |first1=John |last1=Hedley-Whyte |first2=Debra R |last2=Milamed |publisher=Ulster Medical Society |journal=Ulster Medical Journal |year=2008 |volume=77 |issue=September 2008 |pages=191–200 |pmid=18956802}}</ref> [[Constance Tipper]] of [[Cambridge University]] demonstrated that the fractures did not start in the welds, but were due to the [[embrittlement]] of the steel used.<ref name=Tipper>{{Cite web|url=http://www-g.eng.cam.ac.uk/125/1925-1950/tipper.html|title=Constance Tipper|website=G.eng.cam.ac.uk|access-date=10 March 2022}}</ref> When used in riveted construction, however, the same steel did not have this problem. Tipper discovered that at a certain temperature, the steel the ships were made of changed from being [[Ductility|ductile]] to [[brittle]], allowing cracks to form and propagate. This temperature is known as the [[Ductile-brittle transition temperature#Ductile-brittle transition temperature|critical ductile-brittle transition temperature]]. Ships in the North Atlantic were exposed to temperatures that could fall below this critical point.<ref>{{cite report|url=http://www.shippai.org/fkd/en/cfen/CB1011020.html |title=Case Details - Brittle fracture of Liberty Ships |website=Failure Knowledge Database|last=Kobayashi |first=Hideo|date=n.d.|quote= "The brittle fractures that occurred in the Liberty Ships were caused by low notch toughness at low temperature of steel at welded joint, which started at weld cracks or stress concentration points of the structure. External forces or residual stress due to welding progress the fracture. Almost all accidents by brittle fractures occurred in winter (low temperature). In some cases, residual stress is main cause of fracture." |publisher=Association for the Study of Failure}}</ref> The predominantly welded hull construction, effectively a continuous sheet of steel, allowed small cracks to propagate unimpeded, unlike in a hull made of separate plates riveted together. 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 concentration|stress concentrators]]. Furthermore, the ships were frequently grossly overloaded, greatly increasing stress, and some of the structural problems occurred during or after severe storms that would have further increased stress. Minor revisions to the hatches and various reinforcements were applied to the Liberty ships to arrest the cracking problem. These are some of the first structural tests that gave birth to the study of materials. The successor [[Victory ship]]s used the same steel, also welded rather than riveted, but spacing between frames was widened from {{convert|30|in|mm}} to {{convert|36|in|mm}}, making the ships less stiff and more able to flex.{{citation needed|date=September 2023}}

==== Consequences and results ====
The sinking of the Liberty ships led to a new way of thinking about ship design and manufacturing. Ships today avoid the use of rectangular corners to avoid [[stress concentration]]. New types of steel were developed that have higher [[fracture toughness]], especially at lower temperatures. In addition, more talented and educated welders can produce welds without, or at least with fewer, flaws. While the context and time in which Liberty ships were constructed resulted in many failures, the lessons learned led to new innovations that allow for more efficient and safer shipbuilding today.<ref>{{Cite journal |last=Zhang |first=Wei |date=December 2016 |title=Technical Problem Identification for the Failures of the Liberty Ships |journal=Challenges |language=en |volume=7 |issue=2 |pages=20 |doi=10.3390/challe7020020 |doi-access=free |issn=2078-1547}}</ref>

== Service ==

===Use as troopships===
[[File:SS John W. Brown aerial photo.jpg|thumb|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.]]
In September 1943 strategic plans and shortage of more suitable hulls required that Liberty ships be pressed into emergency use as troop transports with about 225 eventually converted for this purpose.<ref name=Wardlow1>{{cite book |last1=Wardlow |first1=Chester |year=1956 |title=The Technical Services – The Transportation Corps: Movements, Training, And Supply  |series=United States Army In World War II |location=Washington, DC |publisher=Center Of Military History, United States Army |lccn=55060003  |pages=145–148}}</ref> The first general conversions were hastily undertaken by the [[War Shipping Administration]] (WSA) so that the ships could join convoys on the way to North Africa for [[Operation Torch]].<ref name=Wardlow /> Even earlier the [[South West Pacific Area (command)|Southwest Pacific Area command's]] U.S. Army Services of Supply had converted at least one, {{SS|William Ellery Channing||2}}, in Australia into an assault troop carrier with landing craft ([[Landing Craft Infantry|LCIs]] and [[LCVP (United States)|LCVs]]) and troops with the ship being reconverted for cargo after the Navy was given exclusive responsibility for amphibious assault operations.<ref>{{cite book |last=Masterson |first=Dr. James R. |title=U. S. Army Transportation In The Southwest Pacific Area 1941–1947  |year=1949 |publisher=Transportation Unit, Historical Division, Special Staff, U. S. Army |location=Washington, D. C. |pages=570–571}}</ref> Others in the Southwest Pacific were turned into makeshift troop transports for New Guinea operations by installing field kitchens on deck, latrines aft between #4 and #5 hatches flushed by hoses attached to fire hydrants and about 900 troops sleeping on deck or in [[Deck (ship)#Common names for decks|'tween deck]] spaces.<ref>{{cite book |last1=Bykofsky |first1=Joseph |last2=Larson |first2=Harold |year=1990 |title=The Technical Services – The Transportation Corps: Operations Overseas |series=United States Army In World War II |location=Washington, DC |publisher=Center Of Military History, United States Army |lccn=56060000 |page=450}}</ref> While most of the Liberty ships converted were intended to carry no more than 550 troops, thirty-three were converted to transport 1,600 on shorter voyages from mainland U.S. ports to Alaska, Hawaii and the Caribbean.<ref name=WardlowOPS>{{cite book |last1=Wardlow |first1=Chester |year=1999 |title=The Technical Services – The Transportation Corps: Responsibilities, Organization, And Operations |series=United States Army In World War II |location=Washington, DC |publisher=Center Of Military History, United States Army |lccn=99490905  |pages=300–301}}</ref>

The problem of hull cracks caused concern with the [[United States Coast Guard]], which recommended that Liberty ships be withdrawn from troop carrying in February 1944 although military commitments required their continued use.<ref name=Wardlow /> The more direct problem was the general unsuitability of the ships as troop transports, particularly with the hasty conversions in 1943, that generated considerable complaints regarding poor mess, food and water storage, sanitation, heating / ventilation and a lack of medical facilities.<ref name=Wardlow /> After the Allied victory in North Africa, about 250 Liberty ships were engaged in transporting prisoners of war to the United States.<ref name=WardlowOPS /> By November 1943 the Army's Chief of Transportation, Maj. Gen. [[Charles P. Gross]], and WSA, whose agents operated the ships, reached agreement on improvements, but operational requirements forced an increase of the maximum number of troops transported in a Liberty from 350 to 500.<ref name=Wardlow /> The increase in production of more suitable vessels did allow for returning the hastily converted Liberty ships to cargo-only operations by May 1944.<ref name=Wardlow /> Despite complaints, reservations, Navy requesting its personnel not travel aboard Liberty troopers and even Senate comment, the military necessities required use of the ships. The number of troops was increased to 550 on 200 Liberty ships for redeployment to the Pacific. The need for the troopship conversions persisted into the immediate postwar period in order to return troops from overseas as quickly as possible.<ref name=Wardlow />

===Combat===
[[File:SS Lawton B. Evans Shell practice.jpg|thumb|upright|Seamen during shell loading practice aboard SS ''[[SS Lawton B. Evans|Lawton B. Evans]]'' in 1943]]
On 27 September 1942 the {{SS|Stephen Hopkins}} was the only US merchant ship to sink a German surface combatant during the war. Ordered to stop, ''Stephen Hopkins'' refused to surrender, so the heavily armed German [[commerce raider]] {{ship|German auxiliary cruiser|Stier||2}} and her tender {{MS|Tannenfels|1938|2}} with one machine gun opened fire.  Although greatly outgunned, the crew of ''Stephen Hopkins'' fought back, replacing the [[United States Navy Armed Guard|Armed Guard]] crew of the ship's single {{convert|4|inch|mm|adj=on}} gun with volunteers as they fell. The fight was short, and both ships were wrecks.{{sfn|Sawyer|Mitchell|1985|pp=13, 141–142}}

On 10 March 1943 {{SS|Lawton B. Evans}} became the only ship to survive an attack by the {{GS|U-221}}.<ref>{{cite web|url=http://www.uboat.net/boats/successes/u221.html|title=Lawton B. Evans (American Steam merchant) – Ships hit by German U-boats during WWII|publisher=Gudmundur Helgason uboat.net |access-date=30 November 2016}}</ref> The following year from 22 to 30 January 1944, ''Lawton B. Evans'' was involved in the [[Battle of Anzio]] in Italy. It was under repeated bombardment from shore batteries and aircraft for eight days. It endured a prolonged barrage of shelling, machine-gun fire and bombs. The ship shot down five German planes.<ref>[[:commons:File:SS_Lawton_B._Evans_Commendation.pdf]]{{Circular reference|date=March 2024}}</ref>

===After the war===

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 including [[John Fredriksen]],<ref>{{cite web |title=John Fredriksen |url=https://nbl.snl.no/John_Fredriksen |work=Norsk Biografisk Lexsikon |date=25 February 2020 |access-date=9 July 2020 |language=no}}</ref> John Theodoracopoulos,<ref>The Shipping World and Shipbuilding & Marine Engineering News, 1952, p. 148.</ref> [[Aristotle Onassis]],<ref name=Elphick401>{{harvnb|Elphick|2006|p=[https://books.google.com/books?id=4_V-uphhRPsC&pg=PA401 401]}}</ref> [[Stavros Niarchos]],<ref name=Elphick401/> [[Stavros George Livanos]], the Goulandris brothers,<ref name=Elphick401/> and the Andreadis, Tsavliris, Achille Lauro, Grimaldi and Bottiglieri families were known to have started their fleets by buying Liberty ships. [[Andrea Corrado]], the dominant Italian shipping magnate at the time, and leader of the Italian shipping delegation, rebuilt his fleet under the programme. 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.

Some Liberty ships were lost after the war to [[naval mine]]s 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,{{sfn|Elphick|2006|p=309}} and the same month saw ''Colin P. Kelly Jnr'' take mortal damage from a mine hit off the Belgian port of [[Ostend]].{{sfn|Elphick|2006|p=166}} 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.{{sfn|Elphick|2006|p=271}} ''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''.{{sfn|Elphick|2006|p=108}}

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.{{sfn|Elphick|2006|p=402}} Other Liberty ships lost to mines after the end of the war include ''John Woolman'', ''Calvin Coolidge'', ''Cyrus Adler'', and ''Lord Delaware''.{{sfn|Elphick|2006|p=325}}

On April 16, 1947, a Liberty ship owned by the [[Compagnie Générale Transatlantique]] called the ''Grandcamp'' (originally built as the SS Benjamin R. Curtis) docked in Texas City, Texas to load a cargo of 2,300 tons of [[ammonium nitrate]] fertilizer. A fire broke out on board which eventually caused the entire ammonium nitrate cargo to explode. The massive explosion levelled Texas City and caused fires which detonated more ammonium nitrate in a nearby ship and warehouse. It was one of the largest non-nuclear explosions in US history. This incident is known as the [[Texas City disaster]] today.<ref>{{Cite web | url=http://www.local1259iaff.org/report.htm | title=Texas City Disaster Report }}</ref>

[[File:Quartette 03 noaa casserley.jpg|thumb|Propeller of the Liberty ship ''Quartette'' which ran aground in 1952 on the [[Pearl and Hermes Atoll]] in the Pacific Ocean]]
On December 21, 1952, the SS ''Quartette'', a {{convert|422|ft|m|adj=mid|-long}} Liberty Ship of 7,198 [[gross register ton]]s, struck the eastern reef of the [[Pearl and Hermes atoll]] at a speed of {{Cvt|10.5|kn||0}}. The ship was driven further onto the reef by rough waves and {{Cvt|35|mph|}} winds, which collapsed the forward bow and damaged two forward holds.<ref>{{cite web|title=Papahānaumokuākea Expedition 2007: Liberty Ship SS Quartette |url=https://sanctuaries.noaa.gov/maritime/expeditions/pmnm/quartette.html |website=Sanctuaries.noaa.gov |access-date=June 11, 2018}}</ref> The crew was evacuated by the [[SS Frontenac Victory|SS ''Frontenac Victory'']] the following day. The [[salvage tug]] ''Ono'' arrived on December 25 to attempt to tow the ship clear, but persistent stormy weather forced a delay of the rescue attempt. On January 3, before another rescue attempt could be made, the ship's anchors tore loose and the ''Quartette'' was blown onto the reef, and deemed a [[total loss]]. Several weeks later, it snapped in half at the [[keel]] and the two pieces sank.<ref>{{cite web |title=Papahānaumokuākea Marine National Monument: Liberty Ship SS Quartette|website=Papahanaumokuakea.gov |url=https://www.papahanaumokuakea.gov/maritime/quartette.html |access-date=December 26, 2017}}</ref> The wreck site now serves as an [[artificial reef]] which provides a habitat for many fish species.<ref name="PMNM-PAHA">{{cite web|title=Papahanaumokuakea Marine National Monument: Pearl and Hermes Atoll|website=Papahanaumokuakea.gov |url=https://www.papahanaumokuakea.gov/visit/pearl.html|access-date=December 26, 2017}}</ref>

In 1953, the [[Commodity Credit Corporation]] (CCC), began storing surplus grain in Liberty ships located in the [[Hudson River Reserve Fleet|Hudson River]], [[James River Reserve Fleet|James River]], Olympia, and Astoria [[National Defense Reserve Fleet]]s. In 1955, 22 ships in the [[Suisun Bay Reserve Fleet]] were withdrawn to be loaded with grain and were then transferred to the Olympia Fleet. In 1956, four ships were withdrawn from the Wilmington Fleet and transferred, loaded with grain, to the Hudson River Fleet.<ref>{{cite book |url= https://books.google.com/books?id=9hZFermhcf4C |title= Department of Agriculture Appropriations for 1961 |date= 1960 |access-date= 28 January 2020}}</ref>

Between 1955 and 1959, 16 former Liberty ships were repurchased by the United States Navy and converted to the {{sclass|Guardian|radar picket ship|1}}s for the [[Distant Early Warning Line#Atlantic and Pacific Barrier|Atlantic and Pacific Barrier]].

In the 1960s, three Liberty ships and two Victory ships were reactivated and converted to [[technical research ship]]s 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. The Liberty ships SS ''Samuel R. Aitken'' became {{USS|Oxford|AGTR-1|6}}, SS ''Robert W. Hart'' became {{USS|Georgetown|AGTR-2|6}}, SS ''J. Howland Gardner'' became {{USS|Jamestown|AGTR-3|6}} with the Victory ships being {{SS|Iran Victory}} which became {{USS|Belmont|AGTR-4|6}} and {{SS|Simmons Victory}} becoming {{USS|Liberty|AGTR-5|6}}.<ref>{{cite web |url=http://www.marad.dot.gov/sh/ShipHistory/Detail/4364 |title=''Samuel R. Aitken'' |author=Maritime Administration |work=Ship History Database |publisher=U.S. Department of Transportation, Maritime Administration |access-date=1 November 2014 |archive-date=4 November 2016 |archive-url=https://web.archive.org/web/20161104080755/https://www.marad.dot.gov/sh/ShipHistory/Detail/4364 |url-status=dead }}</ref><ref>{{cite web |url=http://www.marad.dot.gov/sh/ShipHistory/Detail/4203 |title=''Robert W. Hart'' |author=Maritime Administration Vessel Status Card |work=Ship History Database |publisher=U.S. Department of Transportation, Maritime Administration |access-date=1 November 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304054847/http://www.marad.dot.gov/sh/ShipHistory/Detail/4203 |url-status=dead }}</ref><ref>{{cite web |url=http://www.marad.dot.gov/sh/ShipHistory/Detail/2348 |title=''J. Howland Gardner'' |author=Maritime Administration Vessel Status Card |work=Ship History Database |publisher=U.S. Department of Transportation, Maritime Administration |access-date=1 November 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304054806/http://www.marad.dot.gov/sh/ShipHistory/Detail/2348 |url-status=dead }}</ref><ref>{{cite web |url=http://www.marad.dot.gov/sh/ShipHistory/Detail/2307 |title=''Iran Victory'' |author=Maritime Administration Vessel Status Card |work=Ship History Database |publisher=U.S. Department of Transportation, Maritime Administration |access-date=1 November 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304114548/http://www.marad.dot.gov/sh/ShipHistory/Detail/2307 |url-status=dead }}</ref><ref>{{cite web |url=http://www.marad.dot.gov/sh/ShipHistory/Detail/4577 |title=''Simmons Victory'' |author=Maritime Administration Vessel Status Card |work=Ship History Database |publisher=U.S. Department of Transportation, Maritime Administration |access-date=1 November 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304123950/http://www.marad.dot.gov/sh/ShipHistory/Detail/4577 |url-status=dead }}</ref> All of these ships were [[Ship decommissioning|decommissioned]] and struck from the [[Naval Vessel Register]] in 1969 and 1970.

[[File:Liberty Ships 1c.jpg|thumb|Liberty ships mothballed at Tongue Point, Astoria, Oregon, 1965]]
[[File:Liberty Ships 2c.jpg|thumb|Liberty Ships mothballed at Tongue Point, Astoria, Oregon, 1965]]
[[File:Novorossiysk IMO 5258585 G Hamburg 03-1974.jpg|thumb|''[[SS Edward Eggleston|Novorossiysk]]'', delivered 1943 to USSR, sailed until 1974]]
From 1946 to 1963, the [[United States Navy reserve fleets|Pacific Ready Reserve Fleet]] – Columbia River Group, retained as many as 500 Liberty ships.<ref>{{Cite web |url=http://navy.memorieshop.com/Reserve-Fleets/Astoria/index.html |title=Tongue Point Navy Ship Yard |access-date=24 April 2015 |archive-date=21 June 2015 |archive-url=https://web.archive.org/web/20150621004417/http://navy.memorieshop.com/Reserve-Fleets/Astoria/index.html |url-status=usurped }}</ref>

In 1946, Liberty ships were [[Mothball#In popular culture|mothball]]ed in the [[Hudson River Reserve Fleet]] near [[Tarrytown, New York]]. At its peak in 1965, 189 hulls were stored there. The last two were sold for scrap to Spain in 1971 and the reserve permanently shut down.<ref>{{Cite web|url=http://navalmarinearchive.com/research/hudson_ghost_fleet.html|title=Hudson River National Defense Reserve Fleet|website=Navalmarinearchive.com|access-date=11 March 2022|archive-date=7 April 2014|archive-url=https://web.archive.org/web/20140407075147/http://navalmarinearchive.com/research/hudson_ghost_fleet.html|url-status=dead}}</ref><ref>Image: Mothball Fleet of WWII Liberty Ships in Hudson River off Jones Point 1957 [https://www.panoramio.com/photo/4164580 Picture of mothballed liberty ships]</ref>

[[File:SS Hellas Liberty (restored).jpg|thumb|right|[[SS Arthur M. Huddell|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. ''John W. Brown'' has had a long career as a [[school ship]] and many internal modifications, while ''Jeremiah O'Brien'' remains largely in her original condition. Both are [[museum ship]]s that still put out to sea regularly. In 1994, ''Jeremiah O'Brien'' steamed from San Francisco to England and France for the 50th anniversary of [[D-Day]], the only large ship from the original [[Operation Overlord]] fleet to participate in the anniversary. In 2008, {{SS|Arthur M. Huddell}}, a ship converted in 1944 into a pipe transport to support [[Operation Pluto]],<ref>{{cite web |last=Walker, Ashley (Historic American Engineering Record) |title=Operation "Pluto" – Arthur M. Huddell, James River Reserve Fleet, Newport News, VA |publisher= Library of Congress Prints and Photographs Division Washington, D.C. |year=2009 |url=https://www.loc.gov/pictures/item/va2040.sheet.00020a/ |access-date=5 October 2014}}</ref> was transferred to Greece and converted to a floating museum dedicated to the history of the Greek merchant marine;<ref>{{cite web |url=http://www.hellasliberty.gr/ |title=The Hellas Liberty Project |archive-url=https://web.archive.org/web/20090303132509/http://www.hellasliberty.gr/ |archive-date= 3 March 2009 }}</ref> although 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.<ref>{{Cite web |url=http://www.portofportland.com/PortDispatch/PortDispatch.aspx?contentFile=Issue_2008_02%2FContent%2Fpage6.ascx |title=Did You Know: Liberty Ships Still Afloat in Portland |access-date=24 September 2015 |archive-url=https://web.archive.org/web/20150924080200/http://www.portofportland.com/PortDispatch/PortDispatch.aspx?contentFile=Issue_2008_02%2FContent%2Fpage6.ascx |archive-date=24 September 2015 |url-status=dead }}</ref> {{SS|Albert M. Boe}} survives as the ''Star of Kodiak'', a landlocked [[cannery]], in [[Kodiak, Alaska|Kodiak Harbor]] at {{coord|57|47|12|N|152|24|18|W|type:landmark_scale:2000}}.

{{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 to 1975. She was also used as a fresh water generating plant. She was anchored in the [[James River Reserve Fleet]].<ref>{{cite web |url=http://atomicinsights.com/1995/11/army-nuclear-power-plants.html |title=Army Nuclear Power Plants |first=Rod |last=Adams |work=atomicinsights.com |date=1 November 1995 |access-date=7 May 2012 |archive-url=https://web.archive.org/web/20120415115025/http://atomicinsights.com/1995/11/army-nuclear-power-plants.html |archive-date=15 April 2012 |url-status=dead  }}</ref> The ship was dismantled in 2019 in Brownsville, Texas.<ref name=maritime-executive-20190316>{{cite news |url=https://www.maritime-executive.com/article/floating-nuclear-plant-sturgis-dismantled |title=Floating Nuclear Plant Sturgis Dismantled |website=The Maritime Executive |date=16 March 2019 |access-date=17 March 2019}}</ref>

Fifty-eight Liberty ships were lengthened by {{convert|70|ft}} starting in 1958,<ref name="From Archive.org-6791407">{{cite web |url=http://www.modernshiphistory.com/ |title=The Calendar of Modern Shipping |work=modernshiphistory.com |date=26 February 2010 |access-date=9 June 2014 |archive-url=https://web.archive.org/web/20100226151708/http://www.modernshiphistory.com/ |archive-date=26 February 2010 |url-status=dead |author1=<!--Staff writer(s); no by-line.-->}}</ref> giving them additional carrying capacity at a small additional cost.<ref name="From Archive.org-6791407"/>{{Citation needed|date=June 2009}} The bridges of most of these were also enclosed in the mid-1960s in accordance with a design by naval architect Ion Livas.

In the 1950s, the [[United States Maritime Administration|Maritime Administration]] instituted the Liberty Ship Conversion and Engine Improvement Program, which had a goal to increase the speed of Liberty ships to {{convert|15|knots}}, making them competitive with more modern designs, as well as gaining experience with alternate propulsion systems. Four ships were converted in the $11 million program.<ref>{{Cite journal |title=Liberty ship new look |url=http://www.uscg.mil/proceedings/archive/1955/Vol12_No5_May1955.pdf |journal=Proceedings of the Merchant Marine Council|volume=12| issue = 5|date=May 1955|page=85|access-date=10 March 2022}}</ref> [[SS Benjamin Chew|SS ''Benjamin Chew'']] had its existing condensers modified and a new superheater and geared turbine installed to give the ship 6,000 shp, up from 2,500. [[SS Thomas Nelson|SS ''Thomas Nelson'']] had its bow lengthened, diesel engines installed in place of the original steam engine, and movable cranes outfitted in place of the original cargo handling gear. The GTS (Gas Turbine Ship) ''[[SS John Sergeant|John Sergeant]]'' had its bow extended, and its steam engine replaced with a General Electric gas turbine of 6,600 shp, connected to a reversible pitch propeller via reduction gearing. ''John Sergeant'' was considered overall to be a success, but problems with the reversible pitch propeller ended its trial after three years. GTS ''[[SS William Patterson|William Patterson]]'' had its bow extended and its steam engine replaced with 6 General Electric GE-14 free-piston gas generators, connected to two reversible turbines and capable of 6,000 shp total.  ''William Patterson'' was considered to be a failure as reliability was poor and the scalability of the design was poor.<ref name="Specht">Specht D. ''Evaluation of free piston-gas turbine marine propulsion machinery in GTS'' William Patterson ''(1961) SAE''</ref><ref>{{Cite journal |url=https://www.uscg.mil/proceedings/archive/1957/Vol14_No11_Nov1957.pdf |title=Lykes Bros. Operates GTS William Patterson |journal=Proceedings of the Merchant Marine Council |volume= 14| issue = 11|date=November 1957|page=183|access-date=10 March 2022}}</ref>  All four vessels were fueled with [[Bunker C]] fuel oil, though ''John Sergeant'' required a quality of fuel available at limited ports and also required further treatment to reduce contaminants.<ref name="Innovation">National Research Council (U.S.) ''Innovation in the Maritime Industry'' (1979) Maritime Transportation Research Board pp. 127–131</ref>  Three were scrapped in 1971 or 1972 and the diesel-equipped ''Thomas Nelson'' was scrapped in 1981.

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]].<ref>{{cite web|title=Postal Service Salutes U.S. Merchant Marine on Forever Stamps|url=http://about.usps.com/news/national-releases/2011/pr11_092.htm|work=Press Release|publisher=USPS|access-date=25 May 2012|date=28 July 2011}}</ref>
<!--not sure whether it belongs either here or in another section, but the other one was devoted to "Fictional appearances" rather than general culture; someone else can make that call-->

==Shipyards==
Liberty ships were built at eighteen shipyards located along the U.S. Atlantic, Pacific and Gulf coasts:<ref>{{cite web | url = http://www.coltoncompany.com/shipbldg/ussbldrs/wwii/merchantsbldg.htm | title = WWII Construction Records, Private-Sector Shipyards that Built Ships for the U.S. Maritime Commission | publisher=Colton Company | access-date =1 December 2007 |archive-url = https://web.archive.org/web/20071113060355/http://www.coltoncompany.com/shipbldg/ussbldrs/wwii/merchantsbldg.htm <!-- Bot retrieved archive --> |archive-date = 13 November 2007}}</ref>
* [[Alabama Drydock and Shipbuilding Company|Alabama Drydock and Shipbuilding]], [[Mobile, Alabama]]
* [[Bethlehem-Fairfield Shipyard]], [[Baltimore]], Maryland
* [[California Shipbuilding Corp.]], [[Los Angeles]], California
* [[American Ship Building Company#Delta Shipbuilding|Delta Shipbuilding Corp.]], [[New Orleans]], Louisiana
* [[J.A. Jones Construction]] Company
** [[Panama City, Florida]]
** [[Brunswick, Georgia]]<ref name=Veasey>{{cite journal|last1=Veasey|first1=Ashley|title=Liberty Shipyards: The Role of Savannah and Brunswick in the Allied Victory, 1941–1945|journal=Georgia Historical Quarterly|date=2009|volume=93|issue=2|pages=159–181|url=http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=43374729&site=eds-live&scope=site|access-date=14 February 2018}}</ref>
* [[Kaiser Shipyards|Kaiser Company]], [[Vancouver, Washington]]
* [[Marinship]], [[Sausalito, California]]
* [[New England Shipbuilding Corporation]], [[South Portland, Maine]] The East and West Yards were both on the same {{convert|60|acre|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]]
* [[Richmond Shipyards|Permanente Metals Corporation]], [[Richmond, California]] (a Kaiser facility)
**[[Kaiser Richmond No. 1 Yard]]
**[[Kaiser Richmond No. 2 Yard]]
* [[St. Johns River Shipbuilding]], [[Jacksonville, Florida]]
* [[Southeastern Shipbuilding Corporation]], [[Savannah, Georgia]]<ref name=Veasey />
* [[Todd Houston Shipbuilding]], [[Houston]], Texas
* [[Walsh-Kaiser Co., Inc.]], [[Providence, Rhode Island]]
**Small yard:
*[[Rheem Manufacturing Company]] built one ship the SS ''William Coddington''.<ref>[http://smallstatebighistory.com/sixty-four-ships-built-at-providence-rhode-island-labor-joins-the-fight-for-victory/ smallstatebighistory.com, SS William Coddington]</ref>

==Survivors==
[[File:Riveting the SS JOHN W BROWN.webm|thumb|Riveters from H. Hansen Industries work on the Liberty ship ''John W. Brown'' at Colonna's Shipyard, a ship repair facility located in the Port of [[Norfolk, Virginia]]. (December 2014)]]
There are four surviving Liberty Ships.
* {{SS|John W. Brown}}{{snd}}operational and in use as a museum ship in [[Baltimore]] Harbor, Maryland
* {{SS|Jeremiah O'Brien}}{{snd}}operational and in use as a museum ship, docked at Pier 35, [[San Francisco]], California
* {{SS|Arthur M. Huddell}}{{snd}}transferred to Greece in 2008 and renamed ''Hellas Liberty''. Restored for use as a maritime museum in [[Piraeus]] harbor, Greece.
* {{SS|Albert M. Boe}}{{snd}}The last Liberty ship built, sold to private ownership in 1964 and renamed ''Star of Kodiak''. Used as a fish cannery ship. She is currently landlocked but remains the headquarters of [[Trident Seafoods]] in [[Kodiak, Alaska]].

==Ships in class==
{{Main|List of Liberty ships}}

===World War II===
* EC2-S-AW1 [[Collier (ship)|Collier]], for [[coal]] transport, 24 built by Delta SB.<ref name="auto">{{Cite web|url=http://drawings.usmaritimecommission.de/drawings_ec2.htm|title=Outboard Profiles of Maritime Commission Designed Vessels|website=drawings.usmaritimecommission.de}}</ref>
* EC2-S-C1 dry cargo ships for Merchant Navy
**Converted to [[Troopship#World War II|troopship]]s 220 ships
**Converted to [[ammunition ship]]s
** One ship, SS ''Joseph Holt'', had engineering spaces converted to unmanned operation and was used with a reduced Navy crew as a temporary [[minesweeper]] in 1945 and 1946.<ref>[http://www.rpadden.com/200/looking_for_trouble.htm Looking for trouble, the ''Guinea Pig Squadron'']</ref><ref>[https://www.flickr.com/photos/7526187@N07/6013024595 Pratt Victory photo, mine Hunter]</ref>
* EC2-S-C1 converted for US Navy use
**[[Acubens-class general stores issue ship|''Acubens''-class general stores issue ships (AKS)]] 11 cargo ships
**''Basilan''-class Internal Combustion repair ships (ARG), 2 ships
**''Belle Isle''-class General Stores Issue Ships (AKS), 6 ships
**[[Crater-class cargo ship|''Crater''-class cargo ship (AK)]] 65 ships
***Two Crater-class were converted to Aviation Stores Issue Ships (AVS)
**[[Chourre-class aircraft repair ship|''Chourre''-class aircraft repair ships (ARV)]] 2 ships (1944–1945)
**[[USS Indus (AKN-1)|''Indus''-class net cargo ships (AKN)]], 4 built for support of [[Net laying ship]]s. (1943–1946)
**[[USS Luzon (ARG-2)|''Luzon''-class Internal Combustion repair ships (ARG)]] 12 conversions
**[[Xanthus-class repair ship|''Xanthus''-class repair ship (AR)]] 5 ships (1944–1946)
**Five converted to [[List of unclassified miscellaneous vessels of the United States Navy|unclassified miscellaneous (IX)]] dry bulk storage ships for [[Service Squadron]] use<ref group=A>these bulk storage ships were [[USS P.H. Burnett|USS Peter H. Burnett (IX-104)]], [[USS Antelope (IX-109)]], [[USS Don Marquis|USS Don Marquis (IX-215)]], [[USS Triana (IX-223)]], [[USS Inca (IX-229)]]</ref>
* EC2-S-C1 converted for US Coast Guard use
**[[USAS American Mariner|American Mariner-class ship]], US Coast Guard training (1943–1950)
* EC2-S-C1 converted for US Army use
**[[Operation Ivory Soap]] six conversions to US Army Air Force [[List of ships of the United States Army#Aircraft Repair Ship|aircraft repair]] and maintenance ships in 1944
* Z-ET1-S-C3 converted for US Navy use
**[[Armadillo-class tanker|''Armadillo''-class tankers (IX)]] 18 ships for Service Squadrons for bulk storage of [[fuel oil]], or [[Diesel fuel|diesel]] or [[gasoline]], Merchant Navy and US Navy crews<ref>{{Cite web|url=http://www.aukevisser.nl/t2tanker/t-tankers-2/id1125.htm|title=The Liberty ET- Tanker|website=www.aukevisser.nl}}</ref>
**[[USS Stag|''Stag''-class water distillation ships (IX, later AW)]], 2 ships for Service Squadrons
* Z-EC2-S-C2, eight [[Tank]] carriers, with larger hatches and a 30 tons crane. Built by J.A.Jones Construction in 1943 for Merchant Navy<ref>[http://drawings.usmaritimecommission.de/drawings_ec2.htm usmaritimecommission.de E-EC2-S-C5 Tank] carriers, Liberty ships</ref>
* Z-EC2-S-C5 ships for Merchant Navy
** Boxed aircraft transport with large larger hatches and 30 tons crane, 28 built by J.A.Jones Construction<ref name="auto"/>

===Post World War II===
* EC2-S-C1 ships for US Army
**[[USAS American Mariner|USAS ''American Mariner'']], Radar ship (1950–1963)
* EC2-S-C1 ships for US Air Force
**[[USAS American Mariner|USAFS ''American Mariner'']], Radar ship (1963–1964)
* EC2-S-C1 ships for US Navy
**[[USAS American Mariner|USNS ''American Mariner'' (T-AGM-12)]], Radar ship (1964–1966)
**Two converted to [[Weapon of mass destruction|WMD]] test ships (YAG) with laboratories and air sampling devices<ref group=A>[[USS George Eastman (YAG-39)|USS ''George Eastman'']] and [[USS Granville S. Hall|USS ''Granville S. Hall'']] were given the District Auxiliary, Miscellaneous (YAG) hull symbol</ref>
**Four converted to EC2-S-22a standard to become remote control minesweepers (YAG)<ref>[http://www.navsource.org/archives/14/2036.htm YAG-36]</ref><ref>[http://www.navsource.org/archives/14/2037.htm YAG-37]</ref><ref>[http://www.navsource.org/archives/14/2038.htm YAG-38]</ref><ref>{{cite web  |url=https://vesselhistory.marad.dot.gov/ShipHistory/Detail/4031 |title=R. Ney McNeely |author=Maritime Administration |work=Ship History Database Vessel Status Card |publisher=U.S. Department of Transportation, Maritime Administration |accessdate= 3 November 2017}}</ref><ref group=A>Three ships (MSC hull numbers 2802, 1122, and 2207) were converted and given hull symbols YAG-36, YAG-37, and YAG-38 respectively from the District Auxiliary, Miscellaneous (YAG) sequence. One ship [[SS R. Ney McNeely]] (MSC hull 1513) was also converted and was to have been given a YAG symbol but was returned to the inactive fleet after conversion and no YAG hull number was assigned</ref>
* Z-EC2-S-C5 ships for US Navy
**[[Guardian-class radar picket ship|''Guardian''-class radar picket ships (YAGR / AGR)]] 16 converted in 1955
**[[Oxford-class research ship|''Oxford''-class technical research ships (AGTR)]], 3 [[Sigint]] ships converted in 1961–1963
* US Army conversion
**[[MH-1A]] first [[floating nuclear power plant]] (1967–1976), nicknamed USS ''Sturgis''<ref group=A>''Sturgis'' was the actual name, but the USS prefix could not be used by an Army ship</ref>
*EC2-S-8a {{SS|Benjamin Chew}} converted to a high-speed cargo ship in 1956
*EC2-M-8b, {{SS|Thomas Nelson}} converted to a high-speed cargo ship in 1956
*Jumbo Liberty ship, in the 1950s some Liberty ships were lengthened in Japan. The SS Henry M. Stephens became the SS Andros Fairplay.<ref>{{Cite web|url=https://www.shipsnostalgia.com/media/andros-fairplay.37034/|title=ANDROS FAIRPLAY|website=Ships Nostalgia|date=19 May 2009 }}</ref>
*LNG, [[Liquid natural gas|Liquid Natural Gas]] Carrier conversion by [[Howaldtswerke Deutsche Werft AG]] at [[Kiel, Germany]]. Example {{SS|Thomas F. Bayard}} to SS ''Ultragaz São Paulo'' in 1952, scrapped in 1972.<ref name="auto"/>
*SS William P McArthur was converted to a [[floating crane]] in 1966.<ref>{{Cite web|url=http://shipbuildinghistory.com/merchantships/2libertyships2.htm|title=Liberty Ships}}</ref>
*{{SS|Arthur M. Huddell}} converted to a pipe carrier in 1944, then cable carrier for AT&T in 1956, then and a museum ship in Greece in 2008.
*Floating dock conversions: {{SS|Joe C. S. Blackburn}} in 1968 and S ''Jane Addams'' in 1947.

==See also==

* [[Allied technological cooperation during World War II]]
* [[Empire ships]]
* [[Hog Islander]], WW I-designed American cargo ship design that served in WW II
* [[List of Liberty ships]]
* [[Fort ship]]
* [[Park ship]]
* [[Type C2 ship]]
* [[Type T2 tanker]]
* [[U.S. Merchant Marine Academy]]
* [[Victory ship]]
* [[World War II United States Merchant Navy]]

== Notes ==
{{Notelist}}

==References==
{{reflist}}

==Footnotes==
{{reflist|group=A}}

==Sources==
* {{cite web |url=http://ww2ships.com/acrobat/us-os-001-f-r00.pdf |title=Liberty Cargo Ship |access-date=25 March 2008 |first=James |last=Davies |year=2004 |page=23|website=ww2ships.com}}
* {{cite book |last=Elphick |first=Peter |url=https://books.google.com/books?id=4_V-uphhRPsC |title=Liberty: The Ships that Won the War |publisher=Naval Institute Press |year=2006 |isbn=1591144515}}
*  {{cite book | title = Freedom's Forge: How American Business Produced Victory in World War II | first = Arthur | last = Herman | location = New York | publisher = Random House | year = 2012 | isbn = 978-1400069644 | url-access = registration | url = https://archive.org/details/freedomsforgehow00herm }}
* {{cite book |title=The Liberty Ships: The history of the "emergency" type cargo ships constructed in the United States during the Second World War |first1=L. A. |last1=Sawyer |first2=W. H. |last2=Mitchell |location=London |publisher=Lloyd's of London Press | year = 1985 | isbn =978-1850440499}}
* {{cite book|last1=Wise|first1=James E.|last2=Baron|first2=Scott|title=Soldiers Lost at Sea: A Chronicle of Troopship Disasters|edition=2004|year=2004|publisher=[[United States Naval Institute]] |isbn=978-1591149668|url-access=registration |url=https://archive.org/details/soldierslostatse0000wise}} <small> Total pages: 280 </small>

==Further reading==
* {{cite book |title=Ships for Victory: A History of Shipbuilding under the U.S. Maritime Commission in World War II |first=Frederic Chapin |last=Lane |author-link=Frederic Chapin Lane |location=Baltimore |publisher=Johns Hopkins University Press |orig-year=1951|year=2001|isbn=978-0801867521|oclc=45799004}}
* Chiles, James R [https://web.archive.org/web/20081203172219/http://www.americanheritage.com/articles/magazine/it/1988/3/1988_3_26.shtml  "The Ships That Broke Hilter's Blockade: How a crash effort by amateur shipbuilders turned out twenty-seven hundred Liberty freighters in four years"] Winter 1988, Volume 3, Issue 3. [[Invention and Technology Magazine]] at [[American Heritage (magazine)|''American Heritage'']]
* Lee, Bill [http://www.jajones.com/pdf/Liberty_Ships_of_WWII.pdf "The Liberty Ships of World War II"] An informative 30-page article about the ships, how they were built, and how they were used.

==External links==
{{toomanylinks|date=July 2024}}
{{Commons category|Liberty ships}}
*[https://www.youtube.com/watch?v=8qDxqBvK3NA&t=306s, youtube How A Cargo Ship Helped Win WW2: The Liberty Ship Story]
* [http://www.ssjeremiahobrien.org/ SS ''Jeremiah O'Brien'', Liberty museum ship moored at Fisherman's Wharf, San Francisco, California]
* [http://www.usmm.org/libertyships.html Liberty Ships built by the United States Maritime Commission in World War II] {{Webarchive|url=https://web.archive.org/web/20080509091805/http://www.usmm.org/libertyships.html |date=9 May 2008 }}
* [http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/116liberty_victory_ships/116liberty_victory_ships.htm Liberty Ships and Victory Ships, America's Lifeline in War] {{Webarchive|url=https://web.archive.org/web/20070611020841/http://www.cr.nps.gov/nr/twhp/wwwlps/lessons/116liberty_victory_ships/116liberty_victory_ships.htm |date=11 June 2007 }} A lesson on Liberty ships and Victory ships from the National Park Service's Teaching with Historic Places.
* [http://dlg.galileo.usg.edu/liberty_ships/?link=vsbg&Welcome Ships for Victory: J.A. Jones Construction Company and Liberty Ships in Brunswick, Georgia] Eighty-four black-and-white photographs from the J.A. Jones Construction Company collection at the Brunswick-Glynn County Library that depict the company's World War II cargo ship building activities in its Brunswick, Georgia shipyard from 1943 to 1945.
* [http://www.liberty-ship.com Project Liberty Ship – The Shipyards.] {{Webarchive|url=https://web.archive.org/web/20080531113321/http://www.liberty-ship.com/ |date=31 May 2008 }}
* [http://www-g.eng.cam.ac.uk/125/1925-1950/tipper3.html Summary of Constance Tipper's work]{{snd}}contains remarkable photo of fractured Liberty ship still afloat.
* [http://www.ssrichardmontgomery.com Danger presented by the wreck of liberty ship] {{SS|Richard Montgomery}}.
* [http://www.usmaritimecommission.de/  Shipbuilding under the United States Maritime Commission, 1936 to 1950]
* [https://web.archive.org/web/20080912035205/http://greenships.org/greenships42.html Liberty Ships and World War II – A Role Model]
* [https://archive.today/20130119151803/http://www.charlesmoore2.com/Default.aspx?g=mediaobject&moid=188 The Last Liberty Ship: Kaiser (video)]
* [https://www.hmdb.org/marker.asp?marker=12046 Brunswick's "Liberty Ships"] historical marker

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