Modernizing the surface combatant force need not be as expensive a proposition as the program in the 30-Year Shipbuilding Report or the Navy's 160-ship plan would be. This chapter presents three alternatives for structuring the surface combatant force, each of which would cost no more than what the Navy is spending today on surface combatants. All of the options would result in a larger surface combatant force in 2025 than exists now but a smaller force than the one envisioned in the Navy's 160-ship plan.

Each of these options emphasizes different trade-offs between keeping the current force of surface combatants and transforming it over 25 years. The first option would make maximum use of the still-capable Cold War-generation ships that are in the fleet today. Conversely, the second option would accelerate the process of incorporating next-generation ships into the surface combatant force by retiring many of those Cold War-era ships before the end of their expected service lives and slightly speeding up development of the CG(X) cruiser. The third option would procure smaller numbers of next-generation cruisers, destroyers, and littoral combat ships but would use multiple crews on them, thus significantly increasing the amount of forward presence each individual ship could provide.

In developing the different force structures in these options, the Congressional Budget Office restricted the funding that would be allocated for surface combatants to an average of $6.6 billion a year (in 2003 dollars) for procurement and direct operation and support costs between 2003 and 2025.⁽¹⁾ Both procurement costs and operation and support costs should be considered because they are related and because CBO's force structures make explicit trade-offs between them. Retaining older ships would require higher operation and support costs compared with retiring those ships and speeding up the procurement of new surface combatants. (The discussion in Chapter 1 of the costs of the Navy's 160-ship plan addressed only procurement costs.) CBO chose the $6.6 billion figure because that is what the Congress appropriated to the Navy for its surface combatant force in 2002, expressed in 2003 dollars. It also represents about the amount of money needed to sustain and operate today's surface combatant force in steady state (that is, at the current size indefinitely).

This chapter describes the different force structure options in detail. The next chapter addresses how capable those force structures would be in both peacetime and wartime compared with today's surface combatant force and with the forces implied by the Navy's 160-ship plan and the 30-Year Shipbuilding Report.
 

Option I: Delay the Transition to Next-Generation Ships by Making the Most of the Existing Fleet

Under this approach, the Navy would emphasize keeping its existing ships through the end of their notional expected service lives rather than retiring some of them early, as under current plans. That approach would make the most of the legacy fleet (capital assets the Navy already has) and would ease the shortage of ships that some admirals argue now exists.⁽²⁾ At the same time, the Navy would start the transition to the next generation of surface combatants by building a different ship from the ones currently planned.

With respect to specific programs, the Navy would upgrade all 27 Ticonderoga class (CG-47) cruisers and keep them to the end of their extended 40-year service lives (see Table 4). It would also retain all 17 Spruance class (DD-963) destroyers and 33 Oliver Hazard Perry class (FFG-7) frigates, upgrading their systems as necessary. It would buy 64 Arleigh Burke class (DDG-51) destroyers (two more than under the Navy's 160-ship plan) and cancel the DD(X) destroyer and littoral combat ship programs. To replace legacy destroyers and frigates, the Navy would instead build 40 new frigates that were more capable than the littoral combat ship but much smaller and less expensive than the DD(X). (To be consistent with the DD(X)-family terminology, this study refers to the new frigate as the FFG(X).) In addition, because Ticonderoga cruisers would stay in service longer, the CG(X) program would be delayed for five years. With those changes, the steady-state surface combatant force would number 24 cruisers, 64 destroyers, and 40 frigates, for a total of 128 ships.

Under this approach, the surface combatant force would be much larger through 2013 than under the Navy's 160-ship plan (see Figure 5). The force would reach 134 surface combatants in 2009 as new Arleigh Burke destroyers were commissioned and older ships were retained. Once the Spruance destroyers and Perry frigates began reaching the end of their full service lives, however, the surface combatant force would shrink before the new frigate began boosting its numbers again. From 2014 on, this option would produce a smaller surface combatant force than the Navy's 160-ship plan would. Moreover, for a few years (between 2015 and 2018), the force would fall below the current size of 115 ships.
 

Figure 5.

Inventory of Surface Combatants Under Option I, 2001-2025

Source: Congressional Budget Office.

Note: DD-963 = Spruance class general-purpose destroyer; FFG-7 = Oliver Hazard Perry class guided-missile frigate; CG-47 = Ticonderoga class guided-missile cruiser; DDG-51 = Arleigh Burke class guided-missile destroyer; FFG(X) = future guided-missile frigate; CG(X) = future guided-missile cruiser.

Any change in production plans for surface combatants would have implications for the industrial base--the two U.S. shipyards currently capable of building large surface combatants: Bath Iron Works, owned by General Dynamics, and Ingalls Shipbuilding, owned by Northrup Grumman Ship Systems. The 2003 Future Years Defense Program envisioned building no more than two surface combatants a year through 2007. (The 2004 FYDP, in contrast, would produce between one and seven surface combatants a year through 2009.) In general, this option would continue to build two surface combatants a year through 2009 (see Figure 6) as well as pursue the full conversion program for Ticonderoga cruisers and substantial upgrades to Spruance destroyers. Those efforts might prove to be just enough work to keep the two shipyards in business, assuming that the amphibious ships called for in the 2004 FYDP were built as well. The period through 2009, while surface combatants were being built at relatively low rates, could prove difficult for Bath Iron Works. After that, when procurement rates for new surface combatants increased to three or four a year, the shipyards would be on a sounder footing. Overall, this option would build an average of 2.7 ships per year between 2003 and 2025.
 

Figure 6.

Annual Purchases of Surface Combatants Under Option I, 2001-2025

Source: Congressional Budget Office.

Note: DDG-51 = Arleigh Burke class guided-missile destroyer; FFG(X) = future guided-missile frigate; CG(X) = future guided-missile cruiser.

Average Annual Costs
This approach would cost much less than either the program in the 30-Year Shipbuilding Report or the Navy's 160-ship plan. From 2003 through 2010, the Navy would spend an average of $6.6 billion a year on procurement and operation and support costs (see Table 5). That amount would drop slightly, to $6.1 billion a year, between 2011 and 2020. But between 2021 and 2025, when Ticonderoga cruisers would finally begin to retire and have to be replaced, average annual costs would rise to $7.9 billion. Nevertheless, those costs are lower than under the Navy's 160-ship plan, which would require average annual spending of $8.3 billion, $9.5 billion, and $10.3 billion, respectively, for those same periods.

The Navy argues that keeping older ships, particularly Spruance destroyers, around longer is not cost-effective because those ships are more expensive to operate than either an Arleigh Burke destroyer or an Oliver Hazard Perry frigate. If the Navy kept the Spruances and invested $100 million per ship to improve their reliability and self-defense capabilities, the amortized annual cost of retaining those ships in the fleet for a 35-year service life would be about $45 million apiece. That amount compares favorably with the costs of buying and operating a new Arleigh Burke destroyer, which would total about $60 million a year--although the Arleigh Burkes are much more capable ships. A littoral combat ship would cost about $30 million a year to buy and operate, assuming a 25-year service life.

Is one Spruance class destroyer worth 1.5 littoral combat ships? That, in effect, is the relative cost-effectiveness decision that the Navy has made in favor of the LCS.⁽³⁾

The FFG(X)
The most significant difference between this option and the Navy's plan is that this option would cancel the DD(X) and LCS programs. If spending on the surface combatant force is restricted to existing budget levels, the Navy cannot afford both new ships. Moreover, as discussed in Chapter 1, it is not clear that either the DD(X) or the LCS is what the Navy will need in the future. Rather than replace Cold War-generation destroyers and frigates with 16 DD(X) destroyers and 56 focused-mission but modular littoral combat ships, this option would design and buy 40 multimission frigates.

Those FFG(X)s would be modeled in part on Spain's F-100 guided-missile frigates.⁽⁴⁾ The F-100, which went into service last year, is a state-of-the-art frigate that can perform a variety of missions, including antisubmarine, antiship, and antiair warfare. The F-100 is equipped with a single 5-inch, 54-caliber gun and 48 VLS cells, which can carry 96 area air-defense missiles, point air-defense missiles, land-attack missiles, and antisubmarine missiles.⁽⁵⁾ The ship is also equipped with the Aegis combat system and can embark two helicopters. It has a range of 5,000 nautical miles at 18 knots and is capable of a sustained speed as high as 27 knots.

The FFG(X) created under this option would not be Aegis-capable; instead, the money saved from not buying the Aegis system would be used to introduce the new all-electric propulsion system, reduce the ship's signature, decrease crew size through improvements in automation, and introduce a littoral antisubmarine warfare (ASW) suite. Those improvements would more than offset the cost of the Aegis system. In addition, the FFG(X) would be incorporated into the Navy's sensor and communication networks.

This kind of frigate would not be nearly as fast as the littoral combat ship is supposed to be, but it would be much more capable and have greater endurance. Moreover, it is not clear that the Navy needs a very high speed ship to perform the missions that the Navy has in mind if the ship is capable of embarking helicopters (see Box 2 in Chapter 1). This frigate could operate effectively as part of a larger group of ships or independently, as long as it was not expected to encounter a particularly intense air threat.⁽⁶⁾ The average cost of the FFG(X) would be about $700 million, CBO estimates. (For more details about that estimate, see the appendix.) By comparison, Spain's Aegis-capable F-100 frigate reportedly costs about $600 million.⁽⁷⁾

The Risks Posed by Future Threats
This option's approach is based on two premises: that serious area-denial threats will not materialize in the next 10 to 15 years and that a large legacy force can handle any near-term threats that do arise. That approach makes sense if one believes, for example, that the nation's principal military problem in the near term will be the war on terrorism, which will require a large number of surface combatants to be in many places at once, performing a variety of missions. An especially important mission may be to conduct more and more maritime interception and escort operations to find terrorists and protect shipping.

In such an environment, the multimission FFG(X) would be more versatile than the LCS and at least as effective, if not more so. Designed to accommodate both helicopters and future unmanned systems as well as a littoral ASW suite, the FFG(X) would represent a good combination of the large DD(X) and the smaller LCS.

Critics might argue that this approach would make more of the surface combatant force vulnerable to threats from diesel-electric submarines, small boats armed with antiship cruise missiles, and mines than under the Navy's 160-ship plan. However, this force would probably be more vulnerable only to antiship cruise missiles; it would be equally as vulnerable to submarines and mines as the currently planned force would be. Diesel-electric submarines find their targets largely through acoustic sonars, and the Spruance class destroyers that this option would retain have a relatively quiet acoustic signature. Mines would pose the same level of threat to a Spruance destroyer as to a DD(X) destroyer. But the much larger radar cross section of today's surface combatants would make it far easier for targeting radars to identify the coordinates of those ships than of much stealthier vessels.

The central question in regard to that concern is, How capable will potential opponents of the United States be in finding surface ships and targeting them with cruise missiles? So far, potential opponents have yet to demonstrate an operationally effective ability to target U.S. naval forces 150 to 200 miles from shore. Moreover, they would have to overcome many technological hurdles to develop that ability.

A different scenario would be much more challenging for this option's surface combatant force. If, around 2010, a Middle Eastern country blockaded the Persian Gulf and the U.S. Navy needed to force its way into the Strait of Hormuz, cruise missile attacks at relatively short ranges could pose a grave threat. None of this option's new stealthy frigates would be in the fleet yet, and the only way the Navy could ensure the safety of its ships would be to attack the enemy's cruise missile sites and boats first. However, the Navy's 160-ship force would confront the same problem: few of its stealthy ships would be commissioned by 2010, and it would have fewer ships of other types to conduct operations than under this option. If the same scenario occurred in 2020, the odds would improve for both fleets, although the Navy's 160-ship force would have more next-generation ships than the force resulting from this approach.

In summary, the risks to the surface combatant force in certain scenarios would arguably be somewhat greater under this option than under alternative approaches that emphasize introducing next-generation surface combatants more quickly. But, as Option II will illustrate, those other approaches risk not having enough ships over the next 10 years for all of the other jobs that the Navy is called on to perform.
 

Option II: Accelerate the Transition to Next-Generation Ships by Retiring Much of the Existing Force Early

Under this option, the Navy would hasten the introduction of new ships into the fleet--which some admirals say they need--at the cost of reducing the number of legacy surface combatants. This approach would enable the programs of the Navy's 160-ship plan to fit within the budget constraint of $6.6 billion annually, on average, between 2003 and 2025. The result would be a surface combatant force that was substantially smaller than any other force structure discussed in this study. This approach is built on the premise (which CBO assumes for the purposes of this option) that, to the extent that network-centric warfare increases the combat capabilities of a given group of ships, a smaller number of new ships built with such warfare in mind will probably be more capable than a larger number of older ships, all other factors being equal.

With respect to specific programs, this option would follow the Navy's plan to retire all Spruance class destroyers by 2006 (see Table 4). In addition, it would retire all Oliver Hazard Perry class frigates by 2010 and upgrade only 13 of the 27 Ticonderoga class cruisers. The first five cruisers would be retired by 2006, as in the Navy's 160-ship plan, and an additional nine would be retired by 2014 to save money. The 13 upgraded Ticonderogas would have 40-year service lives.⁽⁸⁾ This option would also halt the production run of Arleigh Burke destroyers at 61. In regard to next-generation ships, it would accelerate the CG(X) cruiser by two years but would buy only 16 of the total 24 within the 2025 time frame. This option would also purchase only 12 DD(X) destroyers, eliminating the four dedicated to wartime surge. It would begin procuring the littoral combat ship in 2005 but, for affordability reasons, would buy only 30 of them.

Overall, Option II would trade off legacy ships in the near term for a more modern, more capable force in the longer term. It would implicitly accept near-term operational risk in order to reduce operational risk when area-denial threats were likely to be more severe. For example, in the war on terrorism, far fewer ships would be available for maritime interception, escort, or forward presence. By 2009, the surface combatant force would have shrunk to just 84 ships, before new ships, especially the LCS, began to increase the fleet size (see Figure 7). By 2025, the surface combatant force would number 123 ships, eight more than today's fleet. Assuming that the Arleigh Burkes were eventually replaced on a one-for-one basis, the steady-state force under this option would ultimately total 125 ships.
 

Figure 7.

Inventory of Surface Combatants Under Option II, 2001-2025

Source: Congressional Budget Office.

Note: DD-963 = Spruance class general-purpose destroyer; FFG-7 = Oliver Hazard Perry class guided-missile frigate; CG-47 = Ticonderoga class guided-missile cruiser; DDG-51 = Arleigh Burke class guided-missile destroyer; DD(X) = future general-purpose destroyer; LCS = littoral combat ship; CG(X) = future guided-missile cruiser.

Compared with Option I, this approach would pose fewer risks for the industrial base. It would generally build three or more surface combatants a year starting in 2005, limiting the period of constructing two surface combatants annually to only a few years (see Figure 8). Overall, this option would build an average of 2.8 ships per year during the 2003-2025 period.
 

Figure 8.

Annual Purchases of Surface Combatants Under Option II, 2001-2025

Source: Congressional Budget Office.

Note: DDG-51 = Arleigh Burke class guided-missile destroyer; DD(X) = future general-purpose destroyer; LCS = littoral combat ship; CG(X) = future guided-missile cruiser.

Average Annual Costs
As with Options I and III, this force structure would fit within the budgetary constraint of an average of $6.6 billion a year for procurement and operation and support costs; therefore, it would cost much less than the Navy's 160-ship plan would. Through 2010, the Navy would spend an average of $7.1 billion a year on procurement and operation and support under this approach (see Table 5). That figure would be lower in later years: an average of $6.3 billion annually between 2011 and 2020 (when the Navy will need to invest heavily in attack submarines) and $6.7 billion a year between 2021 and 2025. Because this option would buy more next-generation ships earlier, its average annual costs between 2021 and 2025 would be lower than Option I's.

The Role of Stealth in Navy Warships
This option would yield a more capable next-generation force than the other options analyzed in this chapter, especially with respect to stealth. But do surface ships need to be stealthy? The answer depends on assumptions about what navies should do. In peacetime, the United States keeps about 30 percent of its naval forces forward deployed to exert political influence overseas by reassuring friends and deterring enemies. For the types of missions performed during peacetime--such as conducting maritime interception, enforcing sanctions, or engaging with allies--stealth is of little importance.

Stealth achieves its real value on the rare occasions when the Navy must go to war. That value occurs on two levels: operational and tactical. Operational stealth refers to whether an enemy can locate and track a ship. (Such operational stealth preserves the possibility of tactical surprise, making it more difficult for the enemy to focus its defenses.) Tactical stealth refers to the ease with which a ship can be targeted and destroyed, especially in the final antiship engagement.

The Logic of Operational Stealth. Buying operationally stealthy ships is a competitive strategy that seeks to impose costs on potential enemies who want to restrict the Navy's freedom of action. By making its ships difficult to find, the Navy in effect forces adversaries to invest heavily in over-the-horizon detection and targeting systems, such as space-based radars or infrared systems (which might also be put on high-altitude aircraft or unmanned aerial vehicles).

Nevertheless, there are limits on what stealth in surface ships can achieve. For example, a ship with a conventional hull form will always be detectable to an enemy using the appropriate technology. Such a ship leaves a substantial wake (a V-shaped pattern trailing behind it) that an opponent with a sophisticated space-based or aircraft-based synthetic aperture radar can detect. Although different hull forms can substantially reduce the wake of a ship, even in 2030, most of the Navy's large warships--such as aircraft carriers, amphibious ships, destroyers, and logistics support ships--will still have a conventional hull.⁽⁹⁾

Depending on which opponents the United States expects to face over the next 30 years, operational stealth may be either a worthwhile investment or a short-lived, wasting asset. It is doubtful that small, relatively poor adversaries could develop or buy the sophisticated systems needed for a comprehensive over-the-horizon detection and targeting capability. Richer and more technologically sophisticated opponents might decide to make that investment. If so, the question becomes, to what extent is the investment in operational stealth more or less costly to the United States than an opponent's investment in over-the-horizon detection systems is to itself? The answer may hinge in part on future advances in computers and sensor technology. By spending money to make new ships operationally stealthy, the Navy is betting that improvements in sensors and information technology (such as computer processing power) will not come fast enough to degrade the value of stealth fairly early in the life of a ship class.

The Logic of Tactical Stealth. In a wartime environment, a stealthy ship will have a much better chance of surviving antiship engagements than a nonstealthy ship will. The value of that stealth derives from the way in which a ship defends itself against radar-guided antiship cruise missiles. A surface combatant's defenses include a low radar cross section that makes it difficult for a radar-guided antiship missile to find the ship, decoys that provide alternative targets for incoming missiles, medium- and short-range self-defense missiles designed to intercept antiship missiles, and close-in, rapid-fire projectile weapon systems employed as the defense of last resort.

Reducing a ship's radar cross section works in tandem with decoy systems. For example, if a 10,000-ton ship can be made stealthy enough to look like a 3,000-ton ship, it is harder to distinguish from nonmilitary traffic. If the chaff cloud a decoy puts up can look larger than a 3,000-ton ship, the homing radar of an incoming antiship missile will target the "larger" vessel.⁽¹⁰⁾ (For that reason, decoys are not as useful with ships that have very large radar cross sections.) Similarly, reducing a ship's magnetic signature will allow it to thwart many types of mines, and a very low acoustic signature makes the ship less detectable by submarines.

New weapon systems could pose problems in the future for ships that were tactically stealthy. Antiship missiles with imaging warheads would not be fooled by the decoy systems that the Navy has now or plans to acquire.⁽¹¹⁾ Such weapons would aim for targets that matched the images in their on-board computer libraries. Chaff clouds or other decoys would not present an image of a ship to an incoming imaging warhead. The United States is developing and planning to acquire the AIM-9X air-to-air missile. Because that missile will have an imaging warhead, flares will not be a useful defense against it. A similar warhead for an antiship missile has not yet been developed, but it may be only a matter of time before the new technology in air-to-air weapons is applied to antiship weapons.

As is the case with operational stealth, the type of opponents the Navy expects to face over the next 30 years is an important factor in decisions about investing in tactical stealth. Whether many of the United States' potential enemies could afford those new weapon systems in quantity is uncertain. And even if an adversary could afford to buy them, it might not be able to operate them. Still, a rich, technologically sophisticated opponent might eventually find it relatively easy to overcome the tactical stealthiness of future Navy warships.

Unless the threat posed by antiship cruise missiles and diesel-electric submarines is completely eliminated, a ship providing gunfire support to ground forces will be detectable and targetable by the sound of its guns. The new DD(X) destroyer is slated to carry 155-millimeter guns to provide the Marine Corps with naval fire support. An enemy could detect and locate a DD(X) by the firing of its guns, using a series of microphones along the shore and triangulating the ship's position.

This discussion of the value of stealth is not intended to be conclusive. It is meant to raise questions because--as this option illustrates--the cost of a stealthier fleet is high. On the one hand, does it make sense to accelerate the transition to next-generation ships, throwing away many capable ships in the process, when few countries appear to be investing heavily in antiaccess technologies? On the other hand, if the Navy delays that transition too long, will a potential opponent be able to build an antiaccess network far more quickly than the Navy can construct and field highly stealthy, next-generation warships? That trade-off is one of the key issues that the Navy will confront over the next two decades. Clearly, the Bush Administration's choice is to speed up the transition to stealthy, next-generation surface combatants.
 

Option III: Buy Fewer Next-Generation Ships by Assigning Multiple Crews to New Ship Classes

Under this approach, the Navy would transform the surface combatant force in large part through operating its ships differently. By employing three crews to operate two ships, the Navy could provide as much forward presence as under its 160-ship plan but with a smaller force and for much less money. The Navy is experimenting with a similar crewing concept on some current ships. Nevertheless, for the purposes of this analysis, CBO restricted the new crewing concept to the future ship classes--the DD(X), CG(X), and littoral combat ship--on the premise that designing new ships to accommodate multiple crews would be easier than imposing that change on existing ships.

The 2001 Quadrennial Defense Review implied that transformation should help the U.S. military increase its overseas presence; that increase was mandated by the subsequent Defense Planning Guidance. Some independent analysts have explicitly argued that the Navy should examine different crewing concepts for its ships as part of the overall naval transformation effort.⁽¹²⁾

Like the Navy's 160-ship plan, this option would retire all Spruance class destroyers by 2006; modernize all Oliver Hazard Perry class frigates, retiring them by 2018; and convert all but the first five Ticonderoga cruisers, which would be retired by 2006 (see Table 4). However, this option would buy 61 Arleigh Burke destroyers instead of 62. More important, it would buy both the DD(X) and the littoral combat ship in reduced numbers: eight and 28, respectively. It would also delay the first purchase of the CG(X) until 2018 and then buy only 15 of them. Because those three classes of next-generation surface combatants would employ three crews for two ships and thus have a higher operating tempo than a single-crewed ship, they would cost more to operate (see Table 6). Finally, this option would buy six more combat logistics ships to sustain the large additional forward presence it would provide.

Despite the reduced purchases, this approach would still produce a larger surface combatant force by 2025 than exists today: 124 ships compared with 115 now (see Figure 9). Moreover, multiple crewing would make that force equivalent to 165 ships in peacetime--comparable with the Navy's 160-ship plan. Eventually, however, the steady-state force would number 112 ships, slightly smaller than today's force but much more capable. In peacetime presence, that steady-state force would be equivalent to 163 ships. Thus, Option III would achieve a much higher overall level of peacetime capability than the other options but have a lower wartime capability, as multiple crews provide no extra benefit during war. (The number of actual hulls is the wartime force.)
 

Figure 9.

Inventory of Surface Combatants Under Option III, 2001-2025

Source: Congressional Budget Office.

Note: DD-963 = Spruance class general-purpose destroyer; FFG-7 = Oliver Hazard Perry class guided-missile frigate; CG-47 = Ticonderoga class guided-missile cruiser; DDG-51 = Arleigh Burke class guided-missile destroyer; DD(X) = future general-purpose destroyer; LCS = littoral combat ship; CG(X) = future guided-missile cruiser.

This approach would provide the least amount of shipbuilding work for the industrial base of any of the options analyzed here. Construction rates would increase to a consistent level of three ships a year between 2009 and 2020 (see Figure 10), but during that period, one class--the littoral combat ship--would represent most of the annual production. Overall, this option would purchase 58 surface combatants between 2003 and 2025, for an average construction rate of 2.5 ships a year, lower than in Option I.
 

Figure 10.

Annual Purchases of Surface Combatants Under Option III, 2001-2025

Source: Congressional Budget Office.

Note: DDG-51 = Arleigh Burke class guided-missile destroyer; DD(X) = future general-purpose destroyer; LCS = littoral combat ship; CG(X) = future guided-missile cruiser.

Average Annual Costs
This approach would do a slightly better job than the other options of conforming to the budgetary constraints of this analysis. Between 2003 and 2010, this option would cost an average of $7.1 billion a year for procurement and operation and support (see Table 5). During the succeeding decade, it would cost just $5.6 billion a year, thus imposing the smallest demand on the Navy's budget in the period when the service may want to make major purchases of attack submarines. Between 2021 and 2025, annual costs would rise markedly, to an average of $8.2 billion, reflecting both operating costs for multiple-crewed ships and procurement of large numbers of CG(X) cruisers. (Those costs also include investments in training facilities for the additional crews, which are discussed below.)

How Multiple Crewing Would Work
The Navy is currently experimenting with a new multiple-crewing concept called Sea Swap. Notionally, the crew of a typical surface combatant now spends about 18 months training, performing maintenance, and resting before taking its ship on a six-month deployment. In contrast, Sea Swap uses three crews and three ships to keep one surface combatant deployed for 18 months. The first crew takes the ship out on deployment while two other crews continue with their training and maintenance cycles on two other ships. After six months, the second crew flies to an overseas location to meet the deployed ship and relieve the first crew. Six months later, the third crew relieves the second and then brings the ship home for maintenance (or, in the case of Spruance destroyers, retirement) at the end of the 18-month period.

The benefits of Sea Swap are significant. According to the Navy, three ships that each deploy from the United States and return independently after six months will provide a total of 300 days on-station over an 18-month period. By eliminating transit time and allowing time for crews to turn over, the Sea Swap concept increases the amount of presence that each ship provides by 35 percent. Thus, a Sea Swap ship is equivalent to 1.35 ships deploying independently. For simplicity, CBO assumed that none of the surface combatants in any of its options or in the Navy's 160-ship plan would be operated using the Sea Swap concept. To the extent that the concept was used on new ship classes, the relative peacetime advantages of CBO's three options would not be as large as reported here.

To achieve even greater benefits, this option would take the Sea Swap approach one step farther by eliminating one of the two ships that would otherwise remain in the United States. Instead, three crews would take turns operating a pair of surface combatants. When one ship deployed for 18 months, the other would be used for at-sea training by the two crews supporting the forward deployment of the sister ship and its crew.

The schedules of the two surface combatants would be divided into 180-day (six-month) increments (see Figure 11):

• The first crew would deploy with the ship for six months, while the second crew trained with the second surface combatant. The third crew would be assigned to shore during that period, where it would conduct more-basic training at shore-based installations. It could also spend a modest amount of time at sea if necessary.
  
  
• Near the end of the first six months, the second crew would be flown to the theater of the deployed surface combatant and exchange places with the first crew. The third crew would then assume primary control of the second surface combatant for more-advanced shore training and much more at-sea training. The first crew would fly home and be assigned to shore for rest and to begin the process of basic training all over again. During its first months back in the United States, the first crew would also experience many of its transfers, retirements, and new assignees.
  
  
• After the second six-month period, the third crew would rotate out to the deployed surface combatant, eventually bringing it home. The second crew would go ashore and begin the process again. The first crew would assume control of the second surface combatant, eventually taking it on its deployment. When the first surface combatant returned with the third crew, it would become the training ship (or another ship would be substituted for it).

Figure 11.

Notional Multiple-Crew Deployment Cycle for Future Surface Combatants

Source: Congressional Budget Office.

The virtue of that approach, especially when used with newly acquired surface combatants, is that it would save the procurement costs of a third ship. If Sea Swap provides an additional 35 percent of on-station time for each of three surface combatants, this option would provide about a 100 percent increase in on-station time for each of the two surface combatants. In terms of peacetime forward presence, one multiple-crewed surface combatant would be equal to about two single-crewed surface combatants.

Furthermore, over a three-year period, a crew's personnel tempo (the amount of time it spends at sea) would be 44 percent--less than the 48 percent that occurs now with the two-year cycle of a single-crewed surface combatant.⁽¹³⁾ However, there would be one two-year window during that period in which the crew's personnel tempo was 57 percent. In that period, the Navy (under Department of Defense rules) would have to pay every sailor $100 for each day over 400 days (out of 730) that he or she was deployed or training away from the home port. Even including those costs, multiple crewing is still far more cost-effective than single crewing. The amortized procurement and operating costs for an on-station day for a multiple-crewed DD(X) would be about $800,000, versus $1.8 million for a single-crewed DD(X).⁽¹⁴⁾

Additional Investments
Making that crewing model work for a large number of surface combatants would require several investments in training and maintenance. First, CBO assumed that the Navy would probably need two new, large training facilities--one on the East Coast of the United States and one on the West Coast--to keep the crews that were not on deployment proficient. Such facilities might require large-scale mock-ups of the ships that would be multiple crewed as well as numerous state-of-the-art training systems and simulators. The Navy does not know how much such facilities might cost, but CBO's cost estimate for this option assumed an average of $100 million per year between 2003 and 2025 to buy and operate those facilities.

Second, because the surface combatant force would have a higher average operating tempo under this option and thus spend more time at sea, CBO assumed that the Navy would need to reactivate a destroyer tender to help provide maintenance overseas and also buy more support ships to keep the surface combatants resupplied. Under this approach, the surface combatant force could have almost 50 percent more ships deployed than today's force does, and many of those ships would spend one-third less time in port. Thus, it stands to reason that an additional maintenance ship might be necessary overseas to make this option work. Consequently, CBO assumed that the Navy would return one destroyer tender now in the Reserve to the active-duty force. The costs to operate that ship--about $50 million a year--are included in the costs of this option discussed above, as are the costs to buy and operate six more combat logistics ships to provide additional logistics support.