Their production mirrored (albeit on a much larger scale) the manufacture of "Hog Islander" and similar standardized ship types during World War I.

The immensity of the effort, the number of ships built, the role of female workers in their construction, and the survival of some far longer than their original five-year design life combine to make them the subject of much continued interest.

However, in 1940, the British government ordered 60 Ocean-class freighters from American yards to replace war losses and boost the merchant fleet.

[7] The predecessor designs, which included the "Northeast Coast, Open Shelter Deck Steamer", were based on a simple ship originally produced in Sunderland by J.L.

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.

Steam turbine engines however, required very precise manufacturing techniques to machine their complicated double helical reduction gears, and the companies capable of producing them were already committed to the large construction program for warships.

In a speech announcing the emergency shipbuilding program President Franklin D. Roosevelt had referred to the ship as "a dreadful looking object", and Time called it an "Ugly Duckling".

The wreck of SS Richard Montgomery lies off the coast of Kent with 1,500 short tons (1,400 tonnes) of explosives still on board, enough to match a very small yield nuclear weapon should they ever go off.

[18][19] SS E. A. Bryan 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 Liberty ship that exploded was the rechristened SS Grandcamp, which caused the Texas City Disaster on 16 April 1947, killing at least 581 people.

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.

Suspicion fell on the shipyards, which had often used inexperienced workers and new welding techniques to produce large numbers of ships in great haste.

Tipper discovered that at a certain temperature, the steel the ships were made of changed from being ductile to brittle, allowing cracks to form and propagate.

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.

[29] 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.

[33] 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.

[3] 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.

[3] Despite complaints, reservations, Navy requesting its personnel not travel aboard Liberty troopers and even Senate comment, the military necessities required use of the ships.

Ordered to stop, Stephen Hopkins refused to surrender, so the heavily armed German commerce raider Stier and her tender Tannenfels with one machine gun opened fire.

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.

[41] 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.

[42] 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.

[43] 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.

[44] Other Liberty ships lost to mines after the end of the war include John Woolman, Calvin Coolidge, Cyrus Adler, and Lord Delaware.

The massive explosion levelled Texas City and caused fires which detonated more ammonium nitrate in a nearby ship and warehouse.

[46] On December 21, 1952, the SS Quartette, a 422-foot-long (129 m) Liberty Ship of 7,198 gross register tons, struck the eastern reef of the Pearl and Hermes atoll at a speed of 10.5 kn (19 km/h; 12 mph).

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.

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.

[65] 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.

GTS 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.