PLYMOUTH MEETING, Pa. and SAN DIEGO, May 31, 2013 -- General Dynamics NASSCO, a wholly owned subsidiary of General Dynamics (NYSE: GD), announced today that it has entered into a contract with an affiliate of American Petroleum Tankers (APT), a company majority owned by funds managed by Blackstone on behalf of its investors, for the design and construction of four 50,000 deadweight ton LNG-conversion-ready product carriers with a 330,000 barrel cargo capacity. The contract includes options to build four additional ships.