160221-N-YR245-056 PACIFIC OCEAN (Feb. 21, 2016) Chief Engineman Derek Robinson performs maintenance on one of two diesel engines used for emergency electrical supply aboard amphibious assault ship USS Boxer (LHD 4). More than 4,500 Sailors and Marines from Boxer Amphibious Ready Group and the 13th Marine Expeditionary Unit (13thMEU) are conducting sustainment training off the coast of Hawaii in preparation for entering the U.S. 5th and 7th Fleet areas of operations. (U.S. Navy photo by Mass Communication Specialist Seaman Craig Z. Rodarte/Released)