A U.S. Marine assigned to the 13th Marine Expeditionary Unit embarked aboard the amphibious assault ship USS Boxer (LHD 4) looks down a ladderwell during a visit, board, search and seizure exercise aboard the guided missile destroyer USS Mason (DDG 87) Jan. 12, 2014, in the Gulf of Oman. The Mason was deployed as part of the Harry S. Truman Carrier Strike Group in support of maritime security operations and theater security cooperation efforts in the U.S. 5th Fleet area of responsibility.