Please give credit when using. Some history: Liberty ships were a class of cargo ship built in the United States during World War II under the Emergency Shipbuilding Program. Though British in concept, the design was adopted by the United States for its simple, low-cost construction. Mass-produced on an unprecedented scale, the Liberty ship came to symbolize U.S. wartime industrial output. The class was developed to meet British orders for transports to replace ships that had been lost. Eighteen American shipyards built 2,710 Liberty ships between 1941 and 1945 (an average of three ships every two days), easily the largest number of ships ever produced to a single design. Source: https://en.wikipedia.org/wiki/Liberty_ship