The Liberty ship was a class of cargo ship built in the United States during World War II. Though British in conception, the design was adapted by the U.S. for its simple, low-cost construction. Mass produced on an unprecedented scale, the now iconic Liberty ship came to symbolize U.S. wartime industrial output. The class was developed to meet British orders for transports to replace those torpedoed by German U-boats. The vessels were purchased both for the U.S.