To evaluate the different force structures described in Chapter 2 and how they compare with the 30-Year Shipbuilding Report and the Navy's 160-ship plan, the Congressional Budget Office used a variety of measures of both peacetime and wartime capability. The principal measures are:

• The total number of surface combatants,
  
  
• The number capable of providing long-range fleet air defense,
  
  
• The number of helicopter hangars on those surface combatants,
  
  
• The total number of vertical launch system cells on those ships,
  
  
• The number of penetrating littoral antisubmarine warfare suites that they carry,
  
  
• The number of 155-millimeter advanced gun systems and 5-inch guns capable of firing the extended-range guided munition (ERGM) in the surface combatant force to provide long-range fire support for the Marine Corps,
  
  
• The total number of next-generation ships,
  
  
• The average age of the surface combatant force, and
  
  
• The total crew size.

The Navy's principal mission in peacetime is maintaining a combat-credible forward presence, so arguably the most important measure of how well the surface combatant force performs during peacetime is the capabilities it has on-station (in its theaters of operations). In wartime, a better measure is how much actual firepower the force can bring to bear in a particular period. Thus, for each of the measures listed above, CBO calculated a given force structure's capability on-station in peacetime and its surge capacity 14 days and 36 days after the beginning of a wartime mobilization.⁽¹⁾

The measures that CBO examined offer a fairly reliable guide to a given force's ability to provide ships for peacetime naval presence, wartime surge, air and missile defense, land attack, and operations against small, fast boats. Measuring the ability of a force to conduct antisubmarine warfare in coastal areas or to counter mines is more difficult. Success in performing those missions will depend heavily on the new systems that the Navy plans to develop over the next 10 to 15 years--some or most of which may be unmanned. For the purposes of this analysis, however, a reasonable proxy for antisubmarine warfare is the number of penetrating littoral ASW suites that will be deployed on DD(X)s and littoral combat ships, as well as the number of helicopter hangars in the surface combatant force. The number of helicopter hangars also provides some insight into a force's ability to defeat mines because surface ships deploy helicopters to carry mine-detection systems.

CBO's measures of capability have limitations, however. If transformation is judged by whether the future surface combatant force is larger, carries more VLS cells, has more land-attack capability, and incorporates more fleet air-defense capability than today's force, the measures that CBO has used will be revealing. But if, as some naval analysts maintain, the test of naval transformation is whether the surface combatant force can defeat diesel-electric submarines, mines, and small, fast boats armed with cruise missiles, these measures will not capture all aspects of those potential missions. As noted above, for those missions, the Navy expects eventually to rely heavily on new unmanned underwater, air, and surface vehicles. Because those vehicles have not yet been developed, their effectiveness cannot be determined or captured by any measure that CBO has available.

Another potential criticism of CBO's measures is that they are simple and ignore potentially significant changes in systems, tactics, and doctrine associated with transformation. The Navy is investing heavily in what it calls FORCEnet--an effort to link all of the communication, sensor, and warfare systems of Navy ships so that every ship in a task force receives the same tactical data. CBO's measures do not quantitatively capture the benefits of that effect or even the benefits of a general improvement in sensors and communications or the potential to upgrade the weapons of a particular platform. If a group of networked ships is more capable and lethal than the same group of unnetworked ships, it may also be true that new ships built with networking in mind will be substantially more capable than existing ships that have been networked together. CBO's measures do not reflect such an effect. Thus, they may underestimate the capabilities offered by Option II (which would speed up the transition to next-generation ships) and, by implication, the Navy's 160-ship plan (which would also retire older surface combatants early and accelerate the development and procurement of new ships). As of this writing, neither the Navy, CBO, nor any studies that CBO is aware of have been able to quantify the operational and tactical benefits of those improvements.⁽²⁾

Finally, in choosing its measures, CBO hoped to address the tension between numbers and capabilities that exists in deciding how to alter the size and composition of the surface combatant force. Some Navy officials contend that the service needs more ships, while others argue that the emphasis should be on fleet capabilities. For example, recently departed Secretary of the Navy Gordon England stated that, "it is capabilities, not numbers that matter . . . our 300 ships are far more potent than our 600-ship Navy [was]."⁽³⁾ At the same time, Admiral Vernon Clark, Chief of Naval Operations, has maintained that the Navy needs 375 ships to do all of the things asked of it, adding, "You can only be in one place at one time with one ship and so numbers do matter. Numbers do have a quality all their own."⁽⁴⁾ Although neither man would disagree with the other's viewpoint, those quotations capture the tension in planning future naval force structure. By examining a variety of numerical and qualitative measures in terms of peacetime presence as well as wartime surge, CBO has attempted to address both sides of that issue.
 

Number of Surface Combatants

The number of surface combatants in the fleet measures how many ships the Navy can keep on-station in peacetime and how many potential combatants it has in wartime. Although numbers alone do not determine how capable the force is, they are the first measure to which most people turn.

With respect to peacetime, the number of surface combatants on-station around the world varies significantly between the 30-Year Shipbuilding Report and the Navy's 160-ship plan (discussed in Chapter 1) and CBO's three options (discussed in Chapter 2). CBO computed the number of ships on-station using a simple arithmetic model based on data provided by the Navy. On average, it takes about 6.3 single-crewed or 3.2 multiple-crewed surface combatants to keep one of them on-station at any given time. On the basis of those figures, Option I would provide the greatest number of surface combatants on-station over the next 10 years, peaking at about 21 in the 2007-2012 period (see Figure 12). By retaining and upgrading the Navy's older ships, that option would maintain a far higher level of overseas presence than any other approach discussed in this study. Conversely, Option II, by retiring more existing ships early, would provide the smallest number of ships on-station: 13 in 2009. After that, however, Option III (which would use multiple crewing on next-generation ships) and the Navy's 160-ship plan would achieve the highest level of overseas presence: 26 ships on-station by 2025.
 

Figure 12.

Number of Surface Combatants On-Station in Peacetime Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

In the wartime analysis, CBO calculated the number of ships that could be in-theater in Northeast Asia or the Persian Gulf 14 days and 36 days into a wartime surge. As in the peacetime case, the results vary significantly depending on the year being examined. Option I would fare the best in 2010 in wartime as well as peacetime by providing more surface combatants for a conflict in either location (see Figure 13). In 2025, all three options discussed in Chapter 2 would perform almost equally well because, by that time, they would have roughly the same size surface combatant force.
 

Figure 13.

Number of Surface Combatants That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

For example, in a war in the Persian Gulf in 2010, Option I would provide 19 surface combatants after 14 days; Option II, only 12; Option III, 16; and the Navy's 160-ship plan, 17. As the war proceeded, the numbers would jump considerably. After 36 days, Option I would bring 67 surface combatants to the fight; Option II, only 43; and the others, 56 to 59.

If that war occurred in 2025, however, the story would be very different. After 14 days, the Navy would be able to bring 24 surface combatants to the fight under its 160-ship plan, compared with 18 to 19 under the other approaches. By that time, Option I would have lost its advantage, and Option II would fare as well as the other approaches. A similar pattern would be visible 36 days after the start of wartime mobilization.
 

Ships Capable of Long-Range Fleet Air and Missile Defense

Over the past 20 years, the development of the Aegis combat system has introduced a major improvement in fleet air defenses and naval operations. Surface ships can now perform missions in environments that have greater threats from enemy aircraft and missiles without requiring the support of an aircraft carrier. The Navy can therefore provide more presence in more places than it could before the Aegis system was developed. For that reason, the Navy continues to invest in Aegis ships and plans to eventually have more than 80 surface combatants capable of long-range air defense. The importance of that investment was illustrated by a Navy spokesman when he said (somewhat inaccurately), "If it's not Aegis, it simply doesn't have a significant role in our future."⁽⁵⁾ For this measure of capability, CBO chose to interpret "Aegis" in that comment to mean ships capable of defending a fleet from long-range air and missile attack. Ships such as the DD(X) and LCS are not counted in this measure, but the CG(X), which is expected to have a next-generation air-defense system, is included.

By this measure, Option I would perform the best in peacetime almost throughout the entire period because it would retain all of the Ticonderoga class cruisers and upgrade them (see Figure 14). The 30-Year Shipbuilding Report would perform almost equally well, although cruiser conversions were not included in that plan. The Navy's 160-ship plan would fall slightly short of Option I in peacetime fleet defense, reflecting five fewer cruisers and two fewer Arleigh Burke class destroyers. Option II would fare the worst throughout the 2003-2025 period according to this measure because it would retain and upgrade only 13 Ticonderogas. Significant changes would occur between 2019 and 2025, however. In 2019, the number of fleet air-defense ships in the Navy's 160-ship plan would begin to grow because of the apparent overlap between the cruiser conversion and CG(X) programs. By 2023, Option III would begin to reap the benefits of using multiple crews on the CG(X) cruiser. Despite those differences, all of the approaches that CBO examined would be far more capable than today's surface combatant force with respect to long-range fleet air and missile defense.
 

Figure 14.

Number of Ships Capable of Long-Range Air and Missile Defense On-Station in Peacetime Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Similar patterns are evident for wartime surge. All of the force structures discussed in this study would provide essentially the same number of ships capable of long-range air and missile defense in Northeast Asia and the Persian Gulf early in a conflict (see Figure 15). As a war progressed, however, the 30-Year Shipbuilding Report, the Navy's 160-ship plan, and Option I would put a larger number of ships in-theater than Options II and III would.
 

Figure 15.

Number of Ships Capable of Long-Range Air and Missile Defense That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Helicopter Hangars

Generally, the most effective weapon against quiet diesel-electric submarines and small, fast boats armed with torpedoes or cruise missiles is a helicopter equipped with missiles. Counting the number of helicopter hangars on surface ships reveals the number of helicopters that the Navy could have available to counter such threats. The more hangars available on-station during peacetime or in-theater during a war, the more flexible the surface combatant force is, and the better equipped it will be to perform its missions, particularly defeating antiaccess threats.

During both peacetime and wartime, Option I would outperform the other options through 2014 because it would retain Spruance class destroyers, which are capable of embarking two helicopters apiece. In peacetime, Option I would provide a substantially greater number of helicopter hangars on-station between 2003 and 2014 than any other force structure (see Figure 16). After 2014, the Navy's 160-ship plan and Option III would provide about the same amount of helicopter capability.
 

Figure 16.

Number of Helicopter Hangars On-Station in Peacetime Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

In wartime, the results are similar. Option I would provide the most helicopter hangars during a surge to either Northeast Asia or the Persian Gulf in 2010. By 2025, Options II and III would provide about the same amount of capability as each other. Only the Navy's 160-ship plan would be able to surge substantially higher numbers of helicopter hangars: 139 to Northeast Asia and 106 to the Persian Gulf in 36 days (see Figure 17). Option I would provide the next highest numbers: 134 and 102, respectively. Options II and III would put the fewest hangars in-theater during that time: about 100 in Northeast Asia and 80 in the Persian Gulf.
 

Figure 17.

Number of Helicopter Hangars That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Vertical Launch System Cells

The development and deployment of VLS cells have played an important role in vastly increasing the capability of surface ships. In peacetime, the Navy's regional combatant commanders require a certain number of Tomahawk missiles to be on-station in their respective theaters. Those Tomahawks are usually launched from VLS cells (although not every cell on a surface ship is filled with land-attack missiles). Thus, the number of VLS cells can be used to approximate how well a force structure would meet those peacetime requirements. In addition, given the premium that the Defense Planning Guidance puts on winning wars quickly with forward-stationed forces, this measure can serve as a proxy for combat power on the first day of a war. As the war proceeds, however, the number of VLS cells that can be surged to a theater approximates the ability of the surface combatant force to conduct long-range strike operations in support of military objectives.⁽⁶⁾

As with many of the previous measures, Option I holds a significant advantage over the alternatives in the number of VLS cells through about 2012 (see Figure 18). The reason is that Option I would retain the Spruance class destroyers--which each carry 61 VLS cells (normally armed with Tomahawks)--through their 35-year service life. None of the other force structures would do that. On average, Option I would be able to keep about 140 more VLS cells on-station than any other option would. After the Spruances retired, however, Option I would lose its advantage for the rest of the period of this analysis. After 2012, the plan outlined in the 30-Year Shipbuilding Report would outperform the alternatives because it is the only one that would buy 32 DD(X) destroyers, each carrying 128 VLS cells. By 2025, that force structure would still yield the most cells, although the Navy's 160-ship plan would produce similar results. Options I and II would provide the least cells.
 

Figure 18.

Number of VLS Cells on Surface Combatants On-Station in Peacetime Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Notes: VLS = vertical launch system.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

That pattern would also occur in the event of war. During a wartime surge, Option I would put more VLS cells in-theater in 2010 than any other approach, but by 2025, it would fall behind both the 30-Year Shipbuilding Report and the Navy's 160-ship plan (see Figure 19). However, in both theaters and in various years, Option I would outperform the other options with limited budgets because all of the new frigates that it would buy would carry 48 VLS cells, unlike the littoral combat ship included in the Navy's 160-ship plan and Options II and III.
 

Figure 19.

Number of VLS Cells on Surface Combatants That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Notes: VLS = vertical launch system.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Penetrating Littoral Antisubmarine Warfare Suites

The ASW combat system on today's cruisers, destroyers, and frigates (the AN/SQQ89) was designed primarily for open-ocean warfare against Soviet submarines. The AN/SQQ89 has been modernized to give it some shallow-water capabilities. Nevertheless, a better indicator of the ASW prowess of a future surface combatant force might be the number of ships equipped with a new ASW system that was designed from the outset to sweep for submarines in littoral waters.

For this analysis, CBO assumed that the littoral combat ship, the DD(X), and the FFG(X) envisioned in Option I would have such littoral ASW systems. Littoral combat ships are intended to be focused-mission ships, however, so CBO assumed that only one-third of them would be equipped with the littoral ASW module at any one time. CBO included the DD(X) in this group because, historically, general-purpose destroyers have been assigned the ASW mission, even though in practice Navy commanders might be reluctant to use such an expensive ship for littoral antisubmarine warfare. The CG(X) could also have a new ASW system, but that ship would probably not be used for early-penetration operations since its primary mission is supposed to be fleet air and missile defense.

With respect to peacetime forward presence, Option III would provide the most new ASW capability through 2020 because of the multiple-crewing concept used for new ship classes (see Figure 20). After that, however, Option I's new frigates--all of which are assumed to be capable of antisubmarine warfare--would provide the largest forward-deployed force. The Navy's 160-ship plan would be in the middle of the pack. Option II would provide the least new ASW capability because its LCS force is limited to 30 ships, so only 10 are assumed to be configured for antisubmarine warfare.
 

Figure 20.

Number of Ships with Penetrating Littoral ASW Suites On-Station in Peacetime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Notes: ASW = antisubmarine warfare.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

In wartime, the pattern would be different. The Navy's 160-ship plan would put the most littoral ASW capability in-theater until 2020 (see Figure 21). But after that, Option I's frigates would again hold sway. Option III would lose its advantage in these scenarios because multiple crewing provides no extra benefit in wartime, and that option's force structure would have the smallest number of next-generation ASW ships available.
 

Figure 21.

Number of Ships with Penetrating Littoral ASW Suites That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Notes: ASW = antisubmarine warfare.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

ERGM and 155-Millimeter Guns

As noted earlier, one of the principal missions of surface combatants is to provide fire support to Marine amphibious forces. Historically, that support was provided by the conventional guns that surface ships carry. With the final retirement of the Iowa class battleships, however, the largest gun on a Navy ship was 5 inches and 54 caliber, with a range of about 13 nautical miles. Although many Marines have never considered the 5-inch gun adequate for their fire-support needs, it is at least capable of providing gunfire for a Marine landing on a beach.

The Marine Corps's future warfighting doctrine envisions flying over beaches and dropping Marines farther inland to avoid area-denial threats (such as mines and diesel-electric submarines) or troop concentrations close to shore. That doctrine will require much longer range fire support from both guns and missiles. In response, the Navy is developing the extended-range guided munition (ERGM), a rocket-propelled projectile shot from a 5-inch, 62-caliber gun, which is capable of going 63 nautical miles. In addition, as was discussed in Chapter 1, the new DD(X) destroyer will carry one or two 155-mm guns, which are intended to be much more powerful than 5-inch guns and capable of firing rocket-propelled projectiles up to 100 nautical miles. Because few ERGM-capable guns and no 155-mm guns are in the fleet today, CBO used the numbers of those weapons in the surface combatant force as a measure of future fire-support capability.

The number of guns on ships that are forward deployed around the globe in peacetime measures the availability of gun firepower in the event that the Marines need to conduct an operation very quickly. Between now and 2015, the force structures discussed in this study would provide roughly similar amounts of firepower on-station during peacetime--with the exception of Option I, which would have no 155-mm guns because it would cancel the DD(X) destroyer but would have a much larger number of ERGM-capable guns (see Figure 22). By 2025, there would be notably more variance with respect to the 30-Year Shipbuilding Report, which would have twice as many 155-mm guns as other force structures because it would buy 32 DD(X) destroyers and no littoral combat ships. The only other significant difference is that it and Option II would have fewer ERGM-capable guns since Option II would cancel much of the cruiser conversion program, which proposes putting those weapons on about half of the Ticonderoga class cruisers.
 

Figure 22.

Amount of Gunfire Support On-Station in Peacetime Under Alternative Force Structures, 2015 and 2025

Source: Congressional Budget Office.

Notes: ERGM = extended-range guided munition.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

In the event of war in 2015, the surface combatant force of the Navy's 160-ship plan would put the largest total number of guns in the theater of operations after 14 or 36 days (see Figure 23). Option I could not put any 155-mm guns in-theater. Option III would surge fewer 155-mm guns than the alternatives would because its dual-crewed DD(X) destroyers would be fewer in number than under either Option II or the Navy's 160-ship plan. In 2025, the force structure of the 30-Year Shipbuilding Report would provide the most firepower. It would put the same total number of guns in-theater as Option I, but two-thirds of them would be 155-mm guns.
 

Figure 23.

Amount of Gunfire Support That Could Be Surged to Northeast Asia and the Persian Gulf in Wartime Under Alternative Force Structures, 2015 and 2025

Source: Congressional Budget Office.

Notes: ERGM = extended-range guided munition; mm = millimeter.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Next-Generation Ships

As a final measure of capability, CBO looked at the number of next-generation ships in each surface combatant force. Next-generation ships include the DD(X), the CG(X), the littoral combat ship, and the new frigate included in Option I. This measure captures how effectively the transition to next-generation ships has occurred as well as assessing how stealthy the surface combatant force is. Because stealth in surface ships is not necessary to perform peacetime missions, it should be regarded primarily as a wartime measure.

Under this measure, the surface combatant force implied by the Navy's 160-ship plan would have by far the most next-generation ships between 2010 and 2025 (see Figure 24). Option II, with its emphasis on a speedy transition, would have the next-largest number of next-generation ships. Options I and III and the 30-Year Shipbuilding Report would be close together at the back of the pack for much of the 2010-2025 period.
 

Figure 24.

Total Number of Next-Generation Ships Under Alternative Force Structures, 2010-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Total Crew Size

The total number of sailors serving on surface combatants provides a useful measure of how many sailors could be put at risk in a wartime situation as well as the Navy's potential difficulty in recruiting. Options that required more sailors would obviously pose a greater recruiting challenge. Conversely, if next-generation ships needed fewer sailors to run them, they might require better educated and more technically trained personnel than older ships do. Thus, options with larger numbers of next-generation ships might necessitate more higher-ranking officers and, especially, enlisted personnel.

Of the approaches in this study, Option I would have the most demanding crew requirements through 2014 (see Figure 25). By retaining and operating the legacy fleet, it would not benefit from a smaller force structure and thus from lower personnel requirements. After 2020, the Navy's 160-ship plan would have the largest personnel requirements because it would have by far the biggest force structure. By 2025, Option III (which would use three crews for two ships of each new class) would have the second-highest personnel requirements. Option II would place the least pressure on the Navy's personnel system because its surface combatant force would be smaller than those of Options I and III and the Navy's 160-ship plan. (Option II's force structure would be larger than that of the 30-Year Shipbuilding Report, on average, but the latter's ships would require higher personnel levels than many of the ships in Option II.)
 

Figure 25.

Total Crew Size of the Surface Combatant Force Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Note: Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Average Age

The last measure that CBO examined was the average age of the surface combatant force under the various approaches. The service life of a surface combatant can range from 20 to 40 years depending on the kind of ship it is and on whether its combat systems are routinely upgraded to maintain operational effectiveness. CBO estimates that the average service life of the Navy's surface combatants is between 28 and 38 years.⁽⁷⁾ (That range reflects the Navy's uncertainty about how long a ship will remain useful.)

In general, if the average age of a weapon system is within the range of half its service life, the system can be considered relatively healthy. If, however, its average age exceeds that half-life range, the system is aging overall. Unless that aging is stopped, the military must eventually spend large sums of money for replacements or see the stocks of that weapon system shrink. The same principle holds true for the Navy's surface combatants. By CBO's estimate, their half-life range is 14 to 19 years.

In all the force structures that CBO examined, the average age of the surface combatant force would remain within or below the half-life range through 2022 (see Figure 26). The Navy's 160-ship plan would keep that age in the lower part of the half-life range. Option I would produce the oldest force of surface combatants throughout most of the 2003-2025 period, and the average age would exceed the half-life range by 2023. Option II would result in the youngest force, with an average age below that range until 2016. Because it would buy fewer new ships, Option III would see the average age of surface combatants rise after 2014, exceeding the half-life range by 2024.
 

Figure 26.

Average Age of the Surface Combatant Force Under Alternative Force Structures, 2001-2025

Source: Congressional Budget Office.

Notes: Half-life refers to half the expected service life of a surface combatant. However, because actual and expected service lives have varied over time, CBO assumed a range for the half-life to reflect that variation. If the average age for a class of surface combatants remains within the half-life range, that indicates that the force is being replaced relatively steadily. If the average age exceeds or falls short of the half-life range, the force is being replaced either at levels less than or greater than the level required for steady-state replacement.

Option I would delay the transition to next-generation surface combatants by making the most of the existing fleet. Option II would accelerate the transition to next-generation ships by retiring much of the existing force early. Option III would buy fewer next-generation ships by assigning multiple crews to new ship classes.

Implications of the Analysis

The first and most important conclusion that can be drawn from this analysis is that even if the Navy restricted spending on the surface combatant force to today's levels, it could have a larger and more capable group of ships over the course of 25 years than it has today (see Table 7). In doing so, the Navy might free up resources to pursue other transformation efforts or buy larger numbers of other types of ships. Of course, if the Navy bought all of the ships implied by the 160-ship plan, it would have an even bigger and more powerful surface combatant force than it could achieve under the current funding level. But as Chapter 1 described, unless the Navy's shipbuilding budget grew significantly, making such an investment would be difficult because of competing priorities and could end up retarding transformation in other areas.

How effectively would the different options in this an-alysis transform the surface combatant force? The answer depends on the definition of transformation. The force-structure options outlined in Chapter 2 would all substantially boost the effectiveness of the surface combatant force, but they arguably would not provide the "dramatic" increase in military capability that President Bush referred to in describing transformation.

If naval transformation is measured by the ability to defeat threats from mines, diesel-electric submarines, and small, fast boats, the answer is less clear. Today, mines are an intractable problem that the Navy is not certain it can solve. Diesel-electric submarines, especially those with air-independent propulsion, could prove just as hard to deal with. (Recent history demonstrates that such submarines--even without air-independent propulsion--make Navy commanders very nervous.) No one knows whether the remote systems that the Navy is developing to address both of those threats will be effective, because they are far from complete.⁽⁸⁾ In the case of the small-boat threat, the helicopters that surface combatants carry should be able to overcome it, so long as the number of boats is not great enough to saturate a task force's defenses. Those problems afflict all of the force structures examined in this study, not just the three CBO options.

What happens after 2025? The answer will be determined largely by what the Navy decides to do with its Arleigh Burke class destroyers. CBO assumed for this analysis that those ships would not receive any midlife upgrades and would serve for 35 years. That assumption may not be a reasonable one, however. Historically, surface combatants become less effective in wartime operational environments well before the end of their notional 35-year service lives in the absence of midlife improvements to their combat systems. If the Arleigh Burkes do not receive such upgrades, they may be retired after only 25 years, beginning around 2016. That would leave all of the force structures in this study much smaller by 2025 than reported here. If, by contrast, those ships receive midlife improvements, they may be able to serve for 40 years--the estimated service life of a converted Ticonderoga class cruiser. In that case, the first Arleigh Burke would not leave the fleet until 2036, which means that the surface combatant forces in this analysis would look fairly robust for the next three decades.

Upgrading Arleigh Burke destroyers, however, would require funding that has not been accounted for in this analysis. CBO has no way of knowing what midlife improvements the Arleigh Burkes might need in 10 to 15 years or how much the upgrades might cost, which is why it did not address that important issue. But those destroyers will eventually represent about one-third to one-half of the surface combatant force, so how the Navy ultimately deals with them will have far-reaching implications for both the size of that force and the resources needed to sustain it.

If the Arleigh Burkes stayed in the fleet throughout their 35-year service lives and no additional money was spent to improve their combat systems, the surface combatant force would begin to shrink after 2025 under all three CBO options. That decline would occur because the force structures in Options I and II cannot be sustained and operated indefinitely on an average annual budget of $6.6 billion. Option I would require $7.3 billion a year to sustain and operate a steady-state force of 64 Arleigh Burke destroyers, 24 cruisers, and 40 FFG(X)s. Option II would need $7.5 billion annually to sustain a steady-state force of 61 Arleigh Burkes, 12 DD(X)s, 24 CG(X)s, and 30 littoral combat ships. By contrast, Option III's steady-state force of 112 ships, including 51 multiple-crewed ones, could be sustained and operated for $6.6 billion year. (In 2025, Option III's force structure is actually about 10 ships larger than its steady-state size.)

The three options described in this study represent effective ways to defer significantly higher spending on surface combatants for the next 20 years. In the meantime, the Navy could use the money that was not spent on surface combatants to pay for different transformation efforts or other ship programs. Of course, whether the Navy should do that is a matter for defense officials and lawmakers to decide. It is beyond the scope of this analysis and of CBO's mandate.