This CRS report summarizes three studies submitted to Congress in 2005 on potential future Navy ship force structures, and is intended as a lasting reference source on these three studies. The contents of this CRS report previously appeared as an appendix to another CRS report. Two of the three studies were conducted in response to Section 216 of the conference report ( H.Rept. 108-354 of November 7, 2003) on the FY2004 defense authorization act ( H.R. 1588 / P.L. 108-136 of November 24, 2003), which required the Secretary of Defense to provide for two independently performed studies on potential future fleet platform architectures (i.e., potential force structure plans) for the Navy. The two studies were conducted by the Center for Naval Analyses (CNA) and the Office of Force Transformation (OFT, which was then a part of the Office of the Secretary of Defense), and were submitted to the congressional defense committees in February 2005. OFT was disestablished on October 1, 2006, and its activities were transferred to other DOD offices. The third study was conducted by the Center for Strategic and Budgetary Assessments (CSBA), an independent defense-policy research organization, on its own initiative. The study was made available to congressional and other audiences in March 2005. The CNA report uses essentially the same kinds of ships and naval formations as those planned by the Navy. The report recommends a Navy force structure range of 256 to 380 ships. The low end of the range assumed a greater use of crew rotation and overseas homeporting of Navy ships than the high end. Table 1 below compares the CNA-recommended force range to the Navy's 375-ship fleet proposal of 2002-2004 and the notional 260- and 325-ship fleets for FY2035 presented in a March 2005 Navy report to Congress. The OFT report employs eight new ship designs that differ substantially from the designs of most ships currently in the fleet, under construction, or planned for procurement. Among the eight new ship designs were four types of large surface ships that would be built from a common, relatively inexpensive, merchant-like hull design developed in 2004 for the Navy's Maritime Prepositioning Force (Future) analysis of alternatives. These four types of ships, which would all displace 57,000 tons, include: An aircraft carrier that would embark a notional air wing of 30 Joint Strike Fighters (JSFs), 6 MV-22 Osprey tilt-rotor aircraft, and 15 unmanned air vehicles (UAVs). The total of 36 manned aircraft is about half as many as in today's carrier air wings, and the OFT architecture envisaged substituting two of these new carriers for each of today's carriers. This new carrier would also have support spaces for unmanned underwater vehicles (UUVs), unmanned surface vehicles (USVs), and mission modules for the 1,000-ton surface combatant described below. A missile-and-rocket ship that would be equipped with 360 vertical launch system (VLS) missile tubes and 4 trainable rocket launchers. Additional spaces on this ship could be used to support UUVs, USVs, and mission modules for the 1,000-ton surface combatant. Alternatively, these spaces could be used to provide limited stowage and working space for the 100-ton surface combatant described below, and mission modules for these 100-ton ships. An amphibious assault ship that would embark a notional air wing of either 30 CH-46 equivalents or 6 JSFs, 18 MV-22s, and 3 gyrocopter heavy-lift helicopters. It would also have spaces for Marine Corps equipment, unmanned vehicles, and mission modules for the 1,000-ton surface combatant. A " mother ship " for small combatants that would contain stowage and support spaces for the 100-ton surface combatant described below. The four other new-design ships in the OFT architecture are: A 13,500-ton aircraft carrier based on a conceptual surface effect ship (SES)/catamaran hull design developed in 2001 by a team at the Naval Postgraduate School. This ship would embark a notional air wing of 8 JSFs, 2 MV-22s, and 8 UAVs. The total of 10 manned aircraft is roughly one-eighth as many as in today's carrier air wings, and the OFT architecture envisages substituting eight of these new carriers for each of today's carriers. This new ship would have a maximum speed of 50 to 60 knots. A 1,000-ton surface combatant with a maximum speed of 40 to 50 knots and standard interfaces for accepting various modular mission packages. These ships would self-deploy to the theater and would be supported in theater by one or more of the 57,000-ton ships described above. A 100-ton surface combatant with a maximum speed of 60 knots and standard interfaces for accepting various modular mission packages. These ships would be transported to the theater by the 57,000-ton mother ship and would be supported in theater by that ship and possibly also the 57,000-ton missile-and-rocket ship. A non-nuclear-powered submarine equipped with an air-independent propulsion (AIP) system. These AIP submarines would be lower-cost supplements to the Navy's nuclear-powered submarines (SSNs) and would be transported from home port to the theater of operations by transport ships. The OFT architecture envisaged substituting four of these submarines for the SSN in each carrier strike group. The 1,000- and 100-ton surface combatants would be built as relatively inexpensive sea frames, like the Littoral Combat Ship (LCS). The OFT report combines these eight types of ships, plus the Navy's currently planned TAOE-class resupply ship, into a fleet that would include a much larger total number of ships than planned by the Navy, about the same number of carrier-based aircraft as planned by the Navy, and large numbers of unmanned systems. The OFT report presents three alternative versions of this fleet, which the report called Alternatives A, B, and C. The report calculates that each of these alternatives would be equal in cost to the equivalent parts of the Navy's 375-ship proposal. Each of these alternative force structures, like the equivalent parts of the Navy's 375-ship proposal, would be organized into 12 carrier strike groups (CSGs), 12 expeditionary strike groups (ESGs), and 9 surface strike groups (SSGs). The three alternative force structures are shown in Table 2 below. The totals shown in the table do not include SSNs, cruise missile submarines (SSGNs), and ballistic missile submarines (SSBNs) operating independently of the 12 CSGs, 12 ESGs, and 9 SSGs. The totals also do not include combat logistics ships other than the TAOEs (e.g., oilers, ammunition ships, and general stores ships) and fleet support ships. The Navy's 375-ship proposal, by comparison, included all these kinds of ships. As also can be seen from the table, the difference between Alternatives A and B is that the former uses 1,000-ton surface combatants while the latter uses 100-ton surface combatants that are transported into the theater by mother ships, and the difference between Alternatives B and C is that the former uses 57,000-ton aircraft carriers while the latter substituted 13,500-ton carriers. The CSBA report uses many of the same ship designs currently planned by the Navy, but also proposes some new ship designs. The CSBA report also proposed ship formations that in some cases are different than those planned by the Navy. Table 3 below compares the CSBA-recommended force structure to CNA's recommended force range, the Navy's 375-ship fleet proposal of 2002-2004, and the notional 260- and 325-ship fleets for FY2035 presented in the Navy's March 2005 report to Congress. The CSBA report makes numerous specific recommendations for ship force structure and ship acquisition, including the following: When the George H.W. Bush (CVN-77) enters service in 2008 or 2009: Retire the two remaining conventional carriers—the Kitty Hawk CV-63) and the Kennedy (CV-67). Convert the Enterprise (CVN-65) into an afloat forward staging base (AFSB) with a mixed active/reserve/civilian crew, to be used in peacetime for aviation testing and in crises for embarking special operations forces, Army or Marine Corps forces, or joint air wings. Begin replacing the 10 Nimitz (CVN-68) class carriers on a one-for-one basis with CVN-21-class carriers procured once every five years using incremental funding. Redesignate the LHA(R) as a medium sized carrier (CVE) and procure one every three years starting in FY2007 using incremental funding. Maintain Virginia-class SSN procurement at one per year for the next several years, producing an eventual total of perhaps 20 Virginia-class boats. Begin immediately to design a new "undersea superiority system" with a procurement cost 50% to 67% that of the Virginia-class design, with the goal of achieving a procurement rate of two or three of these boats per year no later than FY2019. Study options for extending the service lives of the three Seawolf SSNs and the 31 final Los Angeles-class SSNs to mitigate the projected drop in SSN force levels during the 2020s. Reduce the SSBN force from 14 ships to 12 ships and convert an additional two SSBNs into SSGNs, for a total of six SSGNs.