Photo #: NH 103437 O class submarines At the Charleston Navy Yard, South Carolina, circa Christmas 1918. Note holiday greenery displayed on the submarines' superstructures and masts. USS O-10 (Submarine # 71) is partially visible at the extreme left. USS O-7 (Submarine # 68) is in the middle of this nest of five submarines. USS Hartford, the Navy Yard's station ship, is in the background. Collection of Christopher H.W. Lloyd. Donated by Virginia Agostini, 1990. U.S. Naval History and Heritage Command Photograph.