The Navy released its 30-year shipbuilding plan to supplement the Fiscal Year 2017 budget request, which continues the service’s request to put its remaining cruisers into a phased modernization plan and notes the requirement for 52 small surface combatants despite Defense Secretary Ash Carter curtailing the program at 40 Littoral Combat Ships and frigates.

The plan incorporates the many changes Congress has made to the Navy’s shipbuilding profile, in some cases to bump up procurement to get ahead of funding challenge in the 2020s due to the Ohio Replacement Program ballistic missile submarine. The shipbuilding plan reflects Congress’s intent to speed up production of the next Expeditionary Sea Base (ESB), formerly called the Afloat Forward Staging Base, for which lawmakers added money in the FY 2016 spending plan. And the shipbuilding plan acknowledges that lawmakers provided $1 billion for an additional Arleigh Burke-class destroyer, though the actual ship procurement charts were not updated to reflect the possible additional ship because “there are insufficient resources available to complete that ship” at this time.

The 30-year plan also outlines exactly how the Navy will pay for the every-other-generation SSBNs, which serve as the nation’s sea-based nuclear deterrent. The lead ship will be paid for incrementally over three years: 41 percent in FY 2021, 35 percent in FY 2022 and 24 percent in FY 2023. The second ship will be paid for in both FY 2024 and 2025, and beginning in FY 2026 the Navy will buy one boat a year.

The shipbuilding plan still advocates a phased modernization plan for the cruiser fleet despite vehement opposition from lawmakers. The document notes that the first four ships are being inducted into Congress’s preferred modernization plan, which keeps the ships out of service for a much shorter time, compared to the Navy’s proposal to put the non-modernized cruisers into a reduced readiness state and modernize them as older cruisers approach decommissioning. The document notes the Navy supports putting the final seven non-modernized cruisers into its preferred modernization program, which will ensure enough cruisers to fill the air defense commander role in a carrier strike group through FY 2042 “and will maintain a greater number of operational large surface combatants in the latter part of the 2020s and early 2030s as the DDG-51s begin to retire.”

Overall, though Navy Secretary Ray Mabus and others talk about the Navy meeting its stated goal of a 308-ship fleet by 2021, the document notes that “the shipbuilding plan described in this report achieves the shipbuilding plan objective of 308 battle force ships from FY2021 through FY2028, albeit not with the (Force Structure Assessment) required mix of ships. The rate of large and small surface combatant and SSN (attack submarine) retirements beyond FY2028 exceeds the ability of the Navy to finance a build rate that sustains the 308 ship force structure. As a result, Navy force structure declines below 300 ships in FY2031 and remains below hat force level for the remainder of the 30 year period.”

At these lower force structure levels, the Navy will be able to meet the highest priorities laid out in the Defense Strategic Guidance, the report notes, but will take risk in the ability to fill lower-priority missions, such as presence missions outside of areas of conflict.

Everything within the report is subject to change, though. Navy leadership made clear this year that its force structure assessment – completed in 2012, with an update in 2014 – is no longer relevant given new threats that continue to arise. The Navy is conducting a new FSA that will inform the FY 2018 budget submission to Congress and will outline new requirements for attack submarines, small surface combatants and other ship types.