 The year 1970 represented a significant period in the history of the squadron.During this period, the units of the 627/640 class completed Pacific service and departed for conversion to the Poseidon Weapons System, while 616 class overhaul units reported for duty as replacements in the Pacific Fleet strategic deterrent force.On the morning of 14 October 1971, the submarine tender entered Apra Harbor, Guam and immediately upon mooring at Polaris Point, set about the complex chore of relieving "Proteus".