180727-N-NO842-1001 NIIHAU, Hawaii (July 27, 2018) Naval Aircrewman (Helicopter) 1st Class Justin Greene, a search and rescue swimmer from the �Black Knights� of Helicopter Sea Combat Squadron (HSC) 4, responds to a distress call on the island of Niihau. Mariners issued a distress call after their 36-foot vessel ran aground in shallow water. HSC 4 is embarked on board the aircraft carrier USS Carl Vinson (CVN 70). (U.S. Navy photo by Naval Aircrewman 2nd Class Sebastian Mendieta/Released)