BREMERTON, Wash. -- Fully refreshed after more than two years of refitting, the U.S. Navy’s oldest guided missile submarine is once again ready to set sail in defense of the nation. USS Ohio (SSGN 726) completed its maintenance availability at Puget Sound Naval Shipyard & Intermediate Maintenance Facility Wednesday, bringing to a close a 27-month major maintenance period that saw updates and upgrades to most major onboard systems. Almost 400,000 man-days of work by the shipyard’s Ohio project team, ship’s force, contractors and others were needed to return Ohio to the fleet. Major repairs included preservation and structural work on the submarine’s sail, tanks and superstructure. Ohio’s maintenance period began on April 25, 2017, when - fresh off a 20-month Pacific deployment - the ship arrived in dry dock for the start of its availability. Originally commissioned as the lead boat of its class of ballistic missile submarine fleet on November 11, 1981, Ohio was also the first submarine to be converted to a guided missile platform. The conversion ended when the Ohio returned to service as an SSGN in 2006.