The U.S. Navy wants to purchase a new class of submarines, called Large Payload Submarines, to replace the capability provided by the current Ohio-class guided-missile submarines (SSGN), according to a Congressional Budget Office (CBO) report on the Navy’s Fiscal Year 2019 Shipbuilding Plan.
The new submarines, which were not on the Navy’s last 10 shipbuilding plans, would be similar to an SSGN, but which the Navy describes as a “large-diameter, next-generation payload-based submarine. The ship would be capable of performing missions similar to those currently conducted by SSGNs and, in the future, by Virginia-class fast attack submarines (SSN) with the Virginia payload module (VPM), as well as other missions.
According to the Navy, the first ship would be ordered in 2036, after the completion of production of the future Columbia-class ballistic missile submarines which would replace the current Ohio-class SSBNs. Thereafter, the Navy would purchase one ship every three years, for a total of 5 by 2048. The Navy’s 2019 shipbuilding plan does not indicate the final inventory objective for these ships.
The Navy estimated that the cost of the 5 ships in the plan would average $7.0 billion per ship but the CBO report estimated that they would cost $7.6 billion per ship.
The Navy provided little information about the size and capabilities of the large payload submarine in its FY 2019 shipbuilding plan with the CBO assuming that it would be based on the Columbia class hull with its missile tube section reconfigured to perform whatever missions the Navy might want and that other sections of the ship would receive the necessary equipment and modifications to support the payloads the submarine might carry.