The Merchant Shipbuilding Corporation was an American corporation established in 1917 by railroad heir W. Averell Harriman to build merchant ships for the Allied war effort in World War I. The MSC operated two shipyards: the former shipyard of John Roach & Sons at Chester, Pennsylvania, and a second, newly established emergency yard at Bristol, Pennsylvania, operated by the MSC on behalf of the U.S. Shipping Board's Emergency Fleet Corporation. Wikipedia