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Liberty Ships

When war broke out Europe in September 1939, the merchant fleet was caught unprepared to handle a massive sealift of war material. With continental Europe under German control, and Great Britain under devastating air attack, President Franklin Roosevelt decided to increase the pace of production to provide ships to America's British allies. In the early years of war, Great Britain relied heavily on allied shipping to supplement its dwindling supplies of food and raw materials. The fall of France in 1940 brought this situation to a crisis point with the German navy launching highly destructive U-boat strikes from ports all along the 2,500-mile French coast.

In July 1940 the Navy's shipbuilding program, which already occupied most of the available shipbuilding resources in the country, was authorized to expand even more. New yards were called for and old yards were re-equipped. Merchant shipbuilding was being seriously crowded by the Navy's priorities.

In an attempt to counter this deadly threat, Great Britain turned to the United States to provide 60 new cargo vessels based on a simple British design. The first of three emergency shipbuilding programs began when, in late 1940, the British obtained permission from the US to build 60 cargo ships in US yards. Due to the unavailability of turbines and gears, they settled on a slow, 11-knot, 10,000-ton freighter based on an old tramp steamer design.

Shortly after, in January 1941, President Roosevelt announced that the US would build 200 similar ships. Admiral Land and the Maritime Commission wanted to continue to build the new standard C-type ships that would be useful after the war. But emergency needs forced them to accept building the 200 British-style ships for use by the United States. The emergency fleet program introduced the assembly-line production of standardized ships -- the Liberty ships -- in 1941. The 60 vessels were followed by the implementation of an emergency building program in the U.S., which by 1942, called for 1,600 ships.

The Liberty ship represented the design solution that would fill the need for an emergency type of simple, standardized cargo steamer. Based on a British design, it could be mass-produced cheaply and quickly using assembly-line methods and could easily be converted to individual military service needs. Production speed grew more important as German submarines sank ships trying to break Hitler's naval blockade of Great Britain. The Allies needed ships by the hundreds to replace these losses and to increase the flow of supplies to England and, later, the Soviet Union.

The reality of war meant that ships had to be quickly, cheaply, and simply built. Much of the construction was pre-fabricated in large sections that were lifted into place. The EC2's were considered expendable and not expected to last beyond five years. Over 2700 Liberty ships were constructed between 1941 - 1945. During the war, the Libertys served in a number of capacities, under many different flags in all corners of the world.

Selection of sites for the new shipyards needed for this expanded construction program involved decisions on size and location of the yards. Adequate transportation and availability of labor and management were also most important considerations. The Kaiser/Todd Shipyard sites in Maine and Richmond, California, where new labor supplies were available, were selected for the construction of the 60 British freighters. By early 1941, nine yards around the country, with a total of 65 ways, were approved to build the 260 ships of the first emergency program. The number of shipways to be constructed increased over the next year to 200, in two more waves of expansion, with eleven new yards dedicated to building emergency-type vessels.

A total of eighteen shipyards located along the Atlantic, Pacific and Gulf Coasts built Liberty ships. At yards all over the country, 1.5 million workers learned to rivet and weld prefabricated components. The workday was divided up into three 8-hour shifts. The first two new shipyards established by the U.S. Maritime Commission in 1941 were the Oregon Shipbuilding Corporation in Portland, Oregon, and Bethlehem-Fairfield Shipyard, Incorporated in Baltimore, Maryland. The first ships were contracted on 14 March 1941, and by 1945, 3140 Libertys in five different versions had been ordered. Eventually 18 shipyards completed construction on 2710 Libertys.

Henry J. Kaiser of the Oregon yard, became a master of mass-production. He had previously completed construction of Hoover, Bonneville and Grand Coulee Dams ahead of schedule, but had never before built a ship. Kaiser's theories on mass-production created some mirth among conventional shipbuilders, but he continually reduced delivery times. His 75th ship, the JOSEPH N. TEAL, was completed in 10 days after the keel laying.

Many technological advances were made during the Liberty shipbuilding program. Under the direction of Henry Kaiser and the auspices of the Maritime Commission, the principles of mass production were, for the first time, incorporated into the shipbuilding trade on such a large and successful scale. Whereas traditional shipbuilding was from the keel up with the vessel being completely constructed on the ways, Kaiser's plan was based on modular hull construction and included the production of more than 30,000 components per ship in thou-sands of factories across the country. In shipyards on both coasts, entire bulkheads were pre-assembled in different areas of the yards from which they were moved in assembly-line fashion and attached to bow and stern sections. A steel cold-rolling process was developed to save steel in the making of lightweight cargo booms.

In another break from traditional construction techniques, the welding of hull plates replaced the labor-intensive practice of riveting, resulting in a much smoother hull with less friction through the water. Welding techniques also advanced sufficiently to produce the first all-welded ships. Prefabrication was perfected, with complete deckhouses, double-bottom sections, stern-frame assemblies and bow units speeding production of the ships.

Standardization was essential for success of the emergency program and in the new shipyards standardization was attempted nationwide. The advantages were construction specifications and drawings that could be rapidly reproduced for use in additional yards, and procurement of parts could flow from various vendors supplying interchangeable components to a number of shipyards. Nationwide standardization had its widest and most successful application in the emergency shipbuilding programs producing the Liberty ship.

The successful application of mass production to the Liberty Ship building program meant that more ships could be constructed in a smaller amount of space and with unprecedented speed. Ten to twelve months were required in 1917-18 to build an oceangoing ship. Liberty ships, though a third larger, were built in 1943 in as little as 16 days in regular production in one of the most efficient yards.

By the fall of 1942, the production rate of the Liberty Ships had far exceeded the expectations of the Maritime Commission with an average construction period of 70 days. In September, Henry Kaiser's Portland, Oregon yard set a record by completing the Joseph N. Teal in a mere 10 days. The Liberty ship ROBERT E. PEARY was built in a West Coast shipyard in the world's record time of one week flat. By 1944, the average time to build a ship was 42 days.

In all, 2,751 Liberties were built between 1941 and 1945, making them the largest class of ships built worldwide. Combined with the construction of other freighters and auxiliary naval craft, this massive undertaking resulted in an increase in U.S. shipbuilding for the years 1941 to 1945 of nearly 1,200 percent and an increase in the industry's workforce of nearly 1,400,000 workers.

America's wartime shipbuilding capacity for oceangoing vessels was 2,000 or more annually, provided manpower and materials are available. Some yards building Liberty ships have delivered these 441-foot vessels in 16 days in regular production. The first Liberty ship required 244 days to build. By the end of 1945, the average building time for all Liberty shipyards was under 40 days. The first Liberty ship was named after Patrick Henry. The last 100 have been named for merchant seamen who died in wartime service. The Liberty ship construction program of the Maritime Commission, after producing more than 2,500 ships in 3.5 years, ended in 1945.

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Page last modified: 22-07-2011 17:39:52 ZULU