In Fall 1960 the prospective crew was sent to New London, Connecticut for US submarine training. On 17 January 1961 the submarine was recommissioned into the United States Navy as SS-312. The sub was then decommissioned from the United States Navy on 11 May 1961 and recommissioned into the Royal Canadian Navy at New London as HMCS "Grilse" (SS 71), the second vessel to bear the name. "Grilse" underwent one month of sea trials before transiting to her new homeport at Esquimalt, British Columbia, arriving on 14 July 1961.