The following is the Feb. 23, 2020 Congressional Research Service report, Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress.
From the report
The Navy has been procuring Virginia (SSN-774) class nuclear-powered attack submarines (SSNs) since FY1998, and a total of 34 have been procured through FY2021. Since FY2011, Virginia-class boats have been procured at a rate of two per year. Virginia-class boats scheduled for procurement in FY2019-FY2023 are being procured under a multiyear procurement (MYP) contract. Most Virginia-class boats procured in FY2019 and subsequent years are to be built with the Virginia Payload Module (VPM), an additional, 84-foot-long, mid-body section equipped with four large-diameter, vertical launch tubes for storing and launching additional Tomahawk missiles or other payloads. When procured at a rate of two boats per year, VPM-equipped Virginia-class SSNs have an estimated procurement cost of about $3.4 billion per boat.
The Navy’s current force-level goal, which was released in December 2016, calls for achieving a maintaining a fleet of 355 ships, including 66 SSNs. On December 9, 2020, the outgoing Trump Administration released a document that can be viewed as its own vision for future Navy force structure and/or a draft version of the FY2022 30-year Navy shipbuilding plan. The document presents an envisioned Navy force-level goal for achieving by 2045 a Navy with 72 to 78 SSNs. The SSN force at the end of FY2020 included 50 SSNs.
A key issue for Congress concerns the SSN procurement rate in FY2022 and subsequent years:
The Navy’s FY2020 30-year (FY2020-FY2049) shipbuilding plan, which was submitted to Congress in March 2019, projected a steady procurement rate of two SSNs per year from FY2022 through FY2049, and projected that a 66-boat SSN force would be achieved in FY2048.
The Navy did not submit an FY2021 30-year (FY2021-FY2050) shipbuilding plan, but the Navy’s FY2021 budget submission projected a steady procurement rate of two Virginia-class SSNs per year during the period FY2022-FY2025.
The December 9, 2020, shipbuilding document showed projected annual Virginia-class SSN procurement quantities of 2-2-2-3 during the period FY2022-FY2025, and an average SSN procurement rate of about 2.6 boats per year during the period FY2026-FY2051. The document projected that a 66-boat SSN force being achieved in FY2042, a 72-boat SSN force being achieved in FY2045, and a 79-boat SSN force being achieved in FY2049. In establishing its force-level goals and shipbuilding plans for the Navy, the Biden Administration can choose to adopt, revise, or set aside the December 9, 2020, document.
Factors that Congress may consider in assessing the SSN procurement rate in FY2022 and subsequent years include but are not necessarily limited to the following:
what the SSN force-level goal should be, and (if it is greater than 50 boats) how soon that goal should be achieved, in the context of the national defense strategy;
the funding that would be needed in a given year to procure three rather than two Virginia-class boats, and to operate and support the SSN force, and the potential impact of those funding requirements on funding available for other Navy shipbuilding programs, other Navy programs in general, or other DOD programs in general; and
the capacity of the submarine construction industrial base to take on the additional work generated by years in which three rather than two SSNs are procured.