Cargo ships were list to submarine warfare at an astounding rate during World War II. The U.S. Government quickly realized that the production methods used by automobile and other large manufactures could be applied to the construction of new ships.
The craft were created to help ensure victory in Europe, hence the naming convention of Victory Ships.
As seen in this photo, east coast shipyards quickly adapted to the mass manufacture of the ships. Thanks to the supplies they cargo they carried to troops and allies the war was won and the Axis was defeated.