The Columbia-class ships are to replace the Ohio-class submarines.

The contract will support the scheduled repair and maintenance of nuclear attack submarines at the main government shipyards of the U.S. Navy.

The United States Navy (USN) has announced the award of contracts for 25 companies totaling $1.1 billion, with the potential to grow to $1.9 billion if suppliers exercise contractual options.

The contract covers discrete, non-discrete and other production work to support the START state shipyards in carrying out repairs, maintenance and modernization of nuclear attack submarines, where maintenance of the Chief of Naval Operations (CNO) is planned.

Work will be carried out in varying proportions at four major shipyards: Norfolk, Virginia (35%); Bremerton, Washington (25%); Kittery, Maine (20%); and Pearl Harbor, Hawaii (20%).

The operation is expected to be completed by August.