190306-N-N0101-125 WASHINGTON (March 6, 2019) An artist rendering of the future Columbia-class ballistic missile submarines. The 12 submarines of the Columbia class are a shipbuilding priority and will replace the Ohio-class submarines reaching maximum extended service life. The Columbia-class Program Executive Office is on track to begin construction with USS Columbia (SSBN 826) in fiscal year 2021, deliver in fiscal year 2028, and on patrol in 2031. (U.S. Navy illustration/Released)