Note: The USAS American Mariner, originally commissioned as the SS George Calvert (build number 2007/MC Hull 20) should not be confused with the SS George Calvert (build number 2016/MC Hull 29) which was constructed shortly thereafter.SS George Calvert was a Liberty ship, Maritime Commission hull number 29, built by the Bethlehem Shipbuilding Corporation at the Bethlehem-Fairfield Yard in Baltimore, Maryland, and launched on 14 March 1942.The ship served as a freighter to carry goods during World War II.