reserve 17 December 1956 and laid up in the Atlantic Reserve Fleet. Service with the Royal Canadian Navy The Royal Canadian Navy was interested in reestablishing its submarine service in the late 1950s and as an essential stopgap to further purchases, they sought a boat to train in. The United States Navy gave them a choice from among ten boats in the Reserve Fleet and Burrfish was selected. An official agreement to loan a submarine to the Royal Canadian Navy was finalized after approval by the Canadian Cabinet and ratification by the United States Congress in May 1960. The loan agreement would last for five years and would include $1,764,000 for the cost of reactivation and modification. 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. Having reestablished the Canadian submarine service, Grilse was acquired by the Royal Canadian Navy for use as a training vessel for anti-submarine warfare training on the Pacific coast. However, the boat lacked the speed of more modern subs and her sensor and weapons outfit were not up to the task of anti-submarine warfare. As a result, Grilse spent most of her time as "clockwork mice" for surface ships and aircraft, as a passive target for their training. The submarine participated in joint Royal Canadian Navy/Royal Canadian Air Force and joint US/Canada training exercises in the Pacific. In May 1966, her five-year loan was renewed for $1 million, and the sub underwent a refit in 1967 for $1.2 million. In Spring 1968, Grilse was sent on a training cruise to Japan. Once there, the boat trained with units of the Japanese Maritime Self-Defense Force and the United States Navy. In 1968, the Canadian Navy, now called Maritime Command, was offered a more modern by the US. Maritime Command chose to accept the offer and was purchased as a direct replacement for Grilse on the west coast. With the arrival of Rainbow, Grilse never sailed again.