fleet exercises and in Operation "Keystone" and visiting France, Italy, Spain, Greece, and Turkey in a three-month tour. Returning to New London in August 1954, Sea Owl spent the next two years in Atlantic and Caribbean waters training submarine school students and reserve personnel. After engaging in special operations in the late fall of 1956 and early 1957, the submarine resumed normal duties in the New London area until 1 September when she departed to engage in NATO exercises "Fishplay" and "Strikeback" in the northern Atlantic, returning to New London in October. In April and May 1958, Sea Owl participated in NATO Exercise "New Broom" and, upon returning to New London, engaged in local operations for the remainder of the year. After a five-month overhaul early in 1959, she participated in NATO Exercise "Fishplay" and spent the latter months of 1960 in her second deployment to the Mediterranean. Sea Owl commenced 1961 with an extended upkeep period followed by local operations in the New London area. On 6 March, she departed for another Mediterranean tour followed by a scheduled overhaul in the Portsmouth Naval Shipyard. 1962 – 1969 After the 1962 Christmas holidays, Sea Owl departed for the Caribbean to take part in the second phase of operation "Springboard" including antisubmarine warfare exercises and visits to Puerto Rico and the Virgin Islands. Immediately following, she was engaged in a two-week antisubmarine warfare exercise with surface and air units of the Royal Canadian Navy in the vicinity of Bermuda. In April 1963, she participated in Exercise "New Broom XI" with joint forces of the United States and Canada. The remainder of the year consisted of submarine school operations and training exercises in the New London area. In July 2021, declassified documentation in relation to a FIOA law-suit surrounding USS Thresher’s loss, indicate Sea Owl was ordered to and participated in the search for the stricken nuclear submarine. This documentation states that Sea Owl join with nuclear submarine Seawolf, in search procedures on 11 April 1963, and that Seawolf managed to make contact on four separate dives that day, while Sea Owl stood guard to keep interlopers away from the casualty site. This new information surrounding this event is still coming to light, including how much Sea Owl was involved. On 8 February 1964, Sea Owl commenced a five-week availability at the Philadelphia Naval Shipyard followed by participation in Exercise "Long Hook"