English: The U.S. Navy destroyer USS Hazelwood (DD-531) underway at sea, in early 1960. In 1958, Hazelwood began extensive testing of helicopters for anti-submarine warfare both in Narragansett Bay and out of the Naval Ordnance Laboratory in Maryland (USA). Assigned to the Destroyer Development Division, she participated in tests on equipment used with radar and electronic counter-measure systems. Her primary research and development work involved the testing of the Drone Anti-Submarine Helicopter (DASH) (see DASH landing deck aft).