the pennant number S 74. Okanagan was assigned to the First Canadian Submarine Squadron, joined by her sister boats and served her entire career with Maritime Forces Atlantic (MARLANT) in the North Atlantic. Okanagan spent time training with the Royal Navy after an exchange program was instituted in the 1960s that would see submarines from both the Royal Navy and Royal Canadian Navy spend time with each other's forces. This allowed Canadian submarines on intelligence-gathering missions. Beginning in the 1970s, Canada began underwater surveillance patrols in the western Atlantic, tracking Soviet sub and surface fleet vessels, especially the ballistic missile submarines, usually in concert with an Argus or Aurora patrol aircraft. In July 1973, Okanagan collided with the Royal Fleet Auxiliary vessel while exercising in British waters off the coast of Scotland. The submarine was running submerged off the mouth of the River Clyde when the tanker hit Okanagan. There were no injuries to the submarine's complement. However, the submarine suffered damaged to her fin and mast. The submarine returned to Faslane to effect repairs. On 30 June 1983, Okanagan was deployed on a 19-day anti-Soviet submarine patrol. Okanagan underwent her SOUP refit beginning in 1984, being handed over to HMC Dockyard at Halifax, Nova Scotia on 2 April. The refit began on 12 June 1985 and lasted until 7 April 1986. Following the SOUP refit and the introduction of the Mark 48 torpedoes, the Oberons were considered fully operational and counted the same as other offensive fleet units in Maritime Command (MARCOM). In October–November 1990, Okanagan cruised the Great Lakes, the first Canadian submarine to do so. Following the end of the Cold War, the Oberons were retasked, performing patrols on behalf of federal institutions such as the Department of Fisheries and Oceans and the Solicitor General of Canada between 1991 and 1994. The delay of the introduction of the Victoria-class submarines led to the Oberons working past their life expectancy. During the Turbot War, the Oberons were tasked with monitoring European fishing fleets off the Grand Banks of Newfoundland. Their presence served as a deterrent in the escalating crisis. In early September 1998, Okanagan was used to search the ocean floor for the flight recorders of the crashed Swissair Flight 111 off the coast of Nova Scotia. She was paid off from MARCOM on 12 September 1998. In May 2005, the Halifax Chronicle-Herald announced that MARCOM was looking