First Liberty Ship built

Maryland Historical Society

Liberty ships were the largest class of general-purpose cargo ship built during World War II, and they carried every conceivable type of cargo to support the war effort and the needs of America’s Allies. Liberty ships were of average size for the time and measured 441 feet long, 6 inches long and 56 feet, 10 3/4 inches in breadth (beam), and had a loaded draft of 27 feet 9 1/4 inches. The basic Liberty ship had five cargo hatches and a capacity for about 10,800 tons of cargo and fuel, equivalent to the contents of approximately 300 railroad boxcars.

An Early Solution to Help Allied Powers
In early 1941, Nazi Germany controlled most of continental Europe, while England fought on alone. German U-boats were winning the Battle of the Atlantic and sinking merchant ships faster than they could be replaced. For England and democracy to prevail, it was clear that the U.S. would have to build the merchant ships needed for Allied victory.

President Roosevelt and Congress had recognized earlier the need to build up America’s Navy and merchant marine because of the strong probability of eventual U.S. involvement in the war. Utilizing the full capacity of existing American shipyards, a major naval building program began in the late 1930s. Before construction of emergency cargo ships (i.e., Liberty ships) could be started, however, new shipyards had to be built. These new yards began building ships even as the shipyards themselves were being completed. This was the beginning of the emergency shipbuilding program that produced Liberty ships in unprecedented numbers.

Liberty Ship

Project Liberty Ship

Design of Liberty Ships
The design of the Liberty ship—a term coined in September 1941—was based on a British tramp ship of the Depression era, with certain modifications to facilitate production in American yards and operation by American crews. A basic, no frills cargo ship, The Liberty ship could be constructed quickly without undue competition with important naval construction. It had a 2,500 horsepower, triple expansion, reciprocating steam engine that was already considered obsolete in the maritime industry. However, the engines were available while the more efficient steam turbines were being allocated to naval vessels. The naval architecture firm of Gibbs and Cox produced a detailed set of construction drawings from the general English plans and ultimately 18 shipyards would build Liberty ships from these drawings. As a result, Liberty ships produced in one yard were virtually identical to those built in another. The first Liberty ship, SS Patrick Henry, was launched in September 1941, three months before Pearl Harbor.

In addition to the standard Liberty design, there were some variations, including a Liberty tanker, a crated aircraft transport version, a collier, and a version designed to carry tanks. The Navy operated about 130 Liberty ships with naval crews, primarily as repair ships and attack cargo ships. Almost 300 Liberty ships were transferred for use by our Allies under the Lend-Lease program.

Fast Ship Production
Although a relatively untested technique in merchant ship construction, welding was chosen to speed production. Prefabricating large sections that were then assembled into the ship on the building ways also enhanced building efficiency. During peak Liberty ship production in 1943, the average time to build a Liberty (from keel laying to delivery) was just over 40 days. The record time for building a Liberty was four days, when the SS Robert E. Peary was delivered by Kaiser’s Richmond shipyard in November 1942. A total of 2,708 to 2,751 (totals vary) Liberty ships were built during the war, the largest shipbuilding program of a single design ever undertaken. They became the backbone of the American wartime merchant marine, delivering 6,000 tons of cargo every hour throughout the war. About 200 Liberty ships were lost during the war.

Baltimore Connection
Maryland’s Bethlehem-Fairfield yard in Baltimore produced more Libertys (384) than any other single shipyard, although Henry Kaiser’s yards collectively built more. Bethlehem-Fairfield had the distinction of building and launching the first Liberty, SS Patrick Henry, in September 1941. Bethlehem-Fairfield also built the SS John W. Brown, which is one of only two Liberty ships still operating.

Convoy System
Liberty ships were owned by the War Shipping Administration, operated by private steamship companies, and crewed by civilian merchant mariners. The typical crew of a Liberty was about 44 men. Subject to enemy attack, defensive armament was installed on the ships; Navy men, called the Naval Armed Guard, were assigned to man the guns and perform other duties when in convoy. The size of the Armed Guard crew varied on each ship depending on the number and type of guns installed, and generally ranged from 20 to 40 men.

Germany’s use of unrestricted submarine warfare against merchant ships led to the implementation of the convoy system early in the war, once naval escorts became available. Convoys consisted of a number of merchant ships, usually 20 to 80, sailing together and protected by a Naval escort. Convoy speed was determined by the slowest ship assigned and was generally 8 to 9 knots (9 to 10 mph) in the Atlantic.

When the war ended in 1945, cargo carrying requirements and the need for ships declined dramatically. Modern cargo ships with higher speed and more efficient cargo handling gear were being built, making Liberty ships obsolete. Some Libertys were transferred to U.S. steamship companies to replace their wartime losses, while they waited for new construction ships. Over 800 Libertys were transferred to foreign countries to rebuild their merchant fleets reduced by wartime losses. Others were tied up in Reserve Fleet anchorages around the country for possible future use.

Eventually, most Liberty ships were sold for scrap. Presently, only two of the Liberty ships built during World War II are still sailing and these are being preserved and operated as museum ships and memorials. They are the SS Jeremiah O’Brien, in San Francisco, and the SS John W. Brown, berthed in Baltimore.

Elphick, Peter. Liberty, The Ships that Won the War. U.S. Naval Institute Press, 2001.

Bunker, John G. Liberty Ships: The Ugly Ducklings of World War II. U.S. Naval Institute Press, 1972.

Cooper, Sherod. Liberty Ship: The Voyages of the John W. Brown 1942–1946. U.S. Naval Institute Press, 1997.