Report to Congress on Navy Next-Generation Attack Submarine

March 22, 2024 4:50 PM

The following is the March 21, 2024, Congressional Research In Focus report, Navy Next-Generation Attack Submarine (SSN[X]) Program: Background and Issues for Congress.

From the report

Submarine Construction Industrial Base

U.S. Navy submarines are built by General Dynamics’ Electric Boat Division (GD/EB) of Groton, CT, and Quonset Point, RI, and Huntington Ingalls Industries’ Newport News Shipbuilding (HII/NNS), of Newport News, VA. These are the only two shipyards in the country capable of building nuclear-powered ships. GD/EB builds submarines only, while HII/NNS also builds nuclear-powered aircraft carriers. The submarine construction industrial base also includes hundreds of supplier firms, as well as laboratories and research facilities, in numerous states. Much of the material procured from supplier firms for building submarines comes from sole-source suppliers.

SSN(X) Program

Program Designation

In the designation SSN(X), the “X” means that the exact design of the boat has not yet been determined.

Procurement Schedule

The Navy’s FY2024 budget submission envisaged procuring the first SSN(X) in FY2035. The Navy’s FY2025 budget submission defers the envisaged procurement of the first SSN(X) from FY2035 to FY2040. The Navy’s FY2025 30-year (FY2035-FY2054) shipbuilding plan states: “The delay of SSN(X) construction start from the mid-2030s to the early 2040s presents a significant challenge to the submarine design industrial base associated with the extended gap between the Columbia class and SSN(X) design programs, which the Navy will manage.”

Design of the SSN(X)

The Navy states that the SSN(X) “will be designed to counter the growing threat posed by near peer adversary competition for undersea supremacy. It will provide greater speed, increased horizontal [i.e., torpedo-room] payload capacity, improved acoustic superiority and non-acoustic signatures, and higher operational availability. SSN(X) will conduct full spectrum undersea warfare and be able to coordinate with a larger contingent of off-hull vehicles, sensors, and friendly forces.” (Budget-justification book for FY2025 Research, Development, Test, and Evaluation, Navy account, Vol. 3 [Budget Activity 5], p. 1299.)

Navy officials have stated that the Navy wants the SSN(X) to incorporate the speed and payload of the Navy’s fast and heavily armed Seawolf (SSN-21) class SSN design, the acoustic quietness and sensors of the Virginia-class design, and the operational availability and service life of the Columbia-class design. These requirements will likely result in an SSN(X) design that is larger than the original Virginia-class design, which has a submerged displacement of about 7,800 tons, and possibly larger than the original SSN-21 design, which has a submerged displacement of 9,138 tons. Due to technological changes over the years for improved quieting and other purposes, the designs of U.S. Navy submarines with similar payloads have generally been growing in displacement from one generation to the next.

Potential Procurement Cost

An October 2023 Congressional Budget Office (CBO) report on the Navy’s FY2024 30-year shipbuilding plan states that in constant FY2023 dollars, the SSN(X)’s average unit procurement cost is estimated at $6.7 billion to $7.0 billion by the Navy and $7.7 billion to $8.0 billion by CBO. CBO’s estimate is about 14% to 15% higher than the Navy’s estimate. The CBO report states that CBO’s estimate assumes that the SSN(X) design would have a submerged displacement of about 10,100 tons, about 11% more than that of the SSN-21 design.

Download the document here.

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