1. A modified British ship design led to the creation of the Liberty ship
During 1940, British merchant vessel losses increased steadily, due to the attacks on them by German surface raiders and U-boats. In response, the British ordered merchant vessels from American shipyards, under the “cash and carry” policy directed by America’s Neutrality Act. American yards could build the ships, but the British had to pay cash on delivery. Todd Shipyards Corporation accepted the contract to build 60 of the Ocean class design specified by the British, first building new shipyards in which to build the ships. American war planners immediately took interest in the British design, adopting most of its specifications in the early plans for a mass-produced class of cargo ships for America’s merchant marine. One modification altered the plans, requiring the use of welding technology in American hulls, rather than the riveting favored by British designers.
The modifications imposed in the new American design were in response to an increase in the number of merchant ships, crewed by civilian merchant mariners, demanded auxiliary service with the US Navy. The United States Maritime Commission reported that welded hulls reduced the number of man-hours required for the completion of each ship. By early 1941, Liberty ships were available for Lend-Lease, and another increase of the number under construction ensued. The first, SS Patrick Henry, was laid down (construction started) in April 1941. Launched in September, the ship entered active service in late December 1941. By then the United States was no longer neutral. The most massive nationwide shipbuilding effort in history began only weeks after Pearl Harbor. So did a major shift in the makeup of the workforce required to build the ships.