1941:SS Patrick Henry, the first Liberty ship, is launched at the Bethlehem-Fairfield shipyard near Baltimore.

Originally referred to as “emergency vessels,” these cargo ships were among the first to be mass-produced. Numbers were critical as the Allies hustled to recover from the staggering losses wrought by German submarines during the Battle of the Atlantic. The vessels became known as Liberty ships after President Franklin D. Roosevelt, christening the Patrick Henry, quoted the ship’s namesake: “Give me liberty, or give me death.”

Liberty ships represented the assembly line fully realized. The keel was laid in traditional fashion but the ship was then constructed from prefabricated sections welded together in the graving dock.

Although it took 244 days to build the Patrick Henry, the average dropped to a mere 42 days per ship by the middle of the war. One Liberty, the SS Robert E. Peary, was built in an astounding four days at the Kaiser shipyard in Richmond, California. This was largely a publicity and morale stunt, however, and the feat was not repeated.

Although the Patrick Henry slid down the ways nearly 10 weeks before the United States came fully into the war, the U.S. Navy was already engaged, helping to escort merchant convoys through the U-boat–infested waters of the North Atlantic.

Around 2,700 Liberty ships were built during World War II, and many survivors found their way into merchant fleets after the war. Two fully operational Liberty ships remain afloat: SS Jeremiah O’Brien is tied up in San Francisco, and SS John W. Brown is home-ported in Baltimore. The O’Brien has the distinction of being the sole surviving merchant vessel of the vast armada that took part in the Normandy invasion.

The Patrick Henry, meanwhile, survived the war and was scrapped in 1960.

Source: Various

Photo: The SS Patrick Henry was the first Liberty ship launched.

This article first appeared on Wired.com Sept. 27, 2007.