CBO

SEPTEMBER 2005

Options for 

Strategic Military 

Transportation 

Systems

A

STUDY

CONGRESS OF THE UNITED STATES

CONGRESSIONAL BUDGET OFFICE

The Congress of the United States O Congressional Budget Office

CBO

Options for Strategic Military 

Transportation Systems

September 2005

A

STUDY
Notes

Unless otherwise indicated, all cargo weights mentioned in this report are in short tons; the 

years referred to in the appendix are fiscal years,

Numbers in the text and tables may not add up to totals because of rounding.

On the cover, the drawings of the conceptual airship are from the Naval Air Systems 

Command; the photograph of the C-17 airplane was taken by Staff Sgt. Sean M. Worrell, 

U.S. Air Force; and the photograph of the large, medium-speed roll-on/roll-off ship is from 

the Military Sealift Command.
Preface

The Administration’s strategy for national defense emphasizes the ability to respond 

rapidly to military crises wherever they might arise. To that end, the Department of Defense 

(DoD) is pursuing a variety of initiatives designed to reduce the time necessary to deploy 

combat forces around the world. Those initiatives include ongoing production of C-17 transport aircraft by the Air Force, development of concepts for the sea basing of military forces by 

the Navy and Marine Corps, and development of lighter, more easily transportable combat 

vehicles by the Army as part of its Future Combat Systems program.

This Congressional Budget Office study—prepared at the request of the Readiness Subcommittee of the House Committee on Armed Services—looks at the technical, operational, and 

cost issues associated with alternative transportation systems that DoD might develop and 

procure to reduce the time needed to deploy forces. The study compares the advantages, 

disadvantages, and costs of six transportation alternatives: four that would use existing technologies and two that would develop more-advanced systems. In keeping with CBO’s mandate to provide objective, impartial analysis, this study makes no recommendations.

David Arthur of CBO’s National Security Division wrote the study under the supervision of 

J. Michael Gilmore. Raymond Hall of CBO’s Budget Analysis Division, with assistance from 

David Newman and Jason Wheelock, prepared the cost estimates and wrote the appendix 

under the supervision of Jo Ann Vines. Craig Cammarata, Robert Dennis, and Adebayo 

Adedeji of CBO provided thoughtful comments on earlier drafts, as did Robert Button of 

RAND Corporation. (The assistance of an external participant implies no responsibility for 

the final product, which rests solely with CBO.)

Christian Spoor edited the study, and John Skeen proofread it. Cynthia Cleveland produced 

drafts of the tables. Maureen Costantino, along with Andrew Hemstreet of Art Services, Inc., 

designed the cover. Lenny Skutnik printed the initial copies, and Simone Thomas and 

Annette Kalicki prepared the electronic version for CBO’s Web site (www.cbo.gov).

Douglas Holtz-Eakin

Director

September 2005

Summary ix

1 Today’s Strategic Transportation Capabilities 1

The Evolution of U.S. Strategic 

Transportation Forces 1

The Structure of Current Strategic Mobility Forces 2

The Delivery Rate of Today’s Strategic Mobility Forces 6

Perceived Shortfalls of Current Forces 9

2 Factors That Affect Delivery Times

of Strategic Transportation Forces 11

The Time Needed to Move a Unit 

to Its Destination 11

The Importance of Payload 16

3 Options for Improving

Strategic Transportation Forces 19

Approach for Developing 

the Alternatives 19

Options to Improve Airlift 21

Options to Improve Surge Sealift 24

Options to Expand 

Prepositioned Forces 28

4 Comparison of Strategic Transportation Options 31

Promptness and Throughput Capacity 31

The Impact of Infrastructure 

Constraints 33

Length of the RSOI Stage 37

Survivability 39

Other Considerations 39

A How CBO Estimated the Costs

of the Options in This Study 41

Glossary of Abbreviations 47

CONTENTS
vi OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Tables

S-1. The Size of Current Strategic Transportation Forces x

S-2. Options for Expanding Strategic Transportation Forces xi

1-1. Characteristics of Strategic Transport Aircraft 3

1-2. Characteristics of Roll-On/Roll-Off Sealift Ships 5

1-3. Airlift, Sealift, and Afloat Prepositioning Forces 

Used to Estimate Current Capability 8

2-1. Reduced Operating Status of Surge Sealift Ships 13

2-2. Planned Loading and Unloading Times for Ships and Aircraft 14

2-3. Number of Loads Needed to Deploy Army Units 18

3-1. The Options for Expanding Strategic Transportation Forces 

Examined in the Analysis 20

3-2. Characteristics of Proposed High-Speed Ships 27

A-1. Costs of the Options for Improving Strategic Mobility Forces 42

Figures

S-1. Cargo Delivery Capability of Current Mobility Forces xii

S-2. Increases in Cargo Deliveries, by Week, Under Various Options xiv

S-3. Time Needed to Deliver First Additional Stryker Brigade 

Combat Team at Various Deployment Distances xvi

1-1. Cargo Delivery Capability of Current Mobility Forces 9

1-2. Relative Contributions of Different Mobility Systems to a 

Notional Deployment 10

2-1. Mobility Stages of a Strategic Deployment 11

2-2. Transit Times for Sealift at Different Distances and Ship Speeds 15

2-3. Total Delivery Times for Different Strategic Mobility Platforms 17

3-1. Improvement in Deliveries from Buying Another 

21 C-17s (Option 1A) 22

3-2. Artist’s Rendition of a Potential Heavy-Lift 

Hybrid Airship 22

3-3. Improvement in Deliveries from Buying 15 Heavy-Lift 

Hybrid Airships (Option 1B) 23
CONTENTS vii

3-4. Improvement in Deliveries from Buying Another 

17 LMSRs (Option 2A) 25

3-5. Decrease in Transit Time Relative to That of a 

24-Knot Ship 26

3-6. Improvement in Deliveries from Buying Six High-Speed 

Sealift Ships (Option 2B) 28

3-7. Improvement in Deliveries from Buying Four Stryker 

BCT Equipment Sets and Prepositioning Them on 

Four New LMSRs (Option 3A) 28

3-8. Improvement in Deliveries from Buying Five Stryker 

BCT Equipment Sets and Prepositioning Them on 

LMSRs Taken from the Surge Sealift Fleet (Option 3B) 29

4-1. Promptness and Capacity to Deliver Five Brigades Under 

Various Options for Expanding Strategic Mobility Forces 32

4-2. Percentage Increase in Cargo Deliveries Under Option 3A at 

Various Transit Distances 33

4-3. Time Needed to Deliver First Additional Stryker Brigade 

Combat Team at Various Deployment Distances 34

4-4. Airlift Deliveries Under Varying Degrees of Constraints on 

Airfield Infrastructure 35

4-5. Demand for Seaport Infrastructure Under Various Options 37

Summary

S ince the end of World War II, the United States 

has maintained the ability to project combat power rapidly around the globe. That ability has been achieved 

through a dual approach: “forward basing” units overseas 

in regions of particular importance and fielding longrange (strategic) transportation systems that can move 

forces around the world quickly, either to reinforce the 

forward-based units or to respond to needs that arise 

elsewhere.

Following the Cold War, emphasis has shifted away from 

forward basing and toward increasing the mobility of 

forces based in the United States. In the past 15 years, the 

U.S. military has cut the number of forward-based troops 

by about half and has improved its strategic transportation capability by fielding such systems as C-17 airlift aircraft and large, medium-speed roll-on/roll-off ships 

(LMSRs) for sealift. In addition, the Army is largely focusing its current “transformation” efforts on changing 

equipment and organization to create units that can be 

deployed more quickly and easily. Nevertheless, officials 

in the Department of Defense (DoD) seek to increase the 

speed of military deployments to an even greater degree, 

because the ability to deliver forces to a distant theater in 

the first few days or weeks of a crisis is seen as critical to 

ensuring a favorable outcome.

Several general approaches exist for speeding up the U.S. 

military’s response to crises, such as:

B Better matching the locations of forward bases to locations where conflicts are likely to arise,

B Redesigning ground combat and support units and 

their equipment to make them easier to transport, and

B Improving strategic transportation forces.

Previous studies by the Congressional Budget Office 

(CBO) have analyzed the first two approaches and concluded that they would reduce the deployment times of 

large forces to only a limited extent.1

 This study looks at 

the third approach; it analyzes how potential changes in 

strategic mobility forces could speed the deployment of 

ground troops and equipment to a distant theater early in 

an operation.

Today’s strategic transportation forces have three main 

components: airlift aircraft, surge sealift ships, and afloat 

prepositioned equipment (see Summary Table 1). The 

latter consists of equipment for Marine Corps or Army 

units that is kept on ships stationed at forward locations—such as ports on the Mediterranean Sea, the island 

of Guam in the western Pacific Ocean, and the island of 

Diego Garcia in the Indian Ocean—which are closer 

than U.S.-based ships to many regions where military 

forces might be needed.

This study analyzes six options for improving today’s strategic mobility forces. Four of the options would purchase 

greater quantities of existing systems: C-17 airlift aircraft, 

LMSRs, and equipment for afloat prepositioning forces. 

To examine the potential benefits of new technologies, 

the other two options would develop new systems: large, 

blimp-like airships capable of transporting heavy loads of 

cargo, and high-speed sealift ships. CBO selected the 

number of systems that would be purchased in each option so that all of the alternatives would have similar total 

costs over a 30-year service life (see Summary Table 2).2

This analysis focuses on how the options would affect 

1. See Congressional Budget Office, Options for Changing the Army’s 

Overseas Basing (May 2004) and Options for Restructuring the Army 

(May 2005).

2. CBO chose to create options with similar costs and compare their 

capabilities rather than define a target capability and compare the 

costs of achieving it because of uncertainty about what capabilities 

DoD will desire for its future mobility forces. Several DoD studies 

are currently examining that issue.
x OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Summary Table 1.

The Size of Current Strategic 

Transportation Forces

Table (Summary) 1. The Size of Current Strategic Transportation Forces

Source: Congressional Budget Office.

a. The 180th C-17 will not be delivered until around 2010.

b. Quantities vary as participation in the Civil Reserve Air Fleet 

varies.

c. Eight large, medium-speed roll-on/roll-off ships and two container ships.

the “promptness” of the transportation force (its ability to 

get cargo to a distant theater in the initial days of a deployment), its “throughput capacity” (the amount of 

cargo transported over time), and the extent to which its 

ability to deliver cargo could be hurt by limitations on infrastructure at air bases or seaports at the destination site.

Within the context of similar cost levels, CBO’s analysis 

of the options points to several general conclusions:

B Prepositioning sets of unit equipment offers greater 

improvements in the promptness of cargo deliveries 

than the other options that CBO examined. Prepositioned ships have much larger payloads than aircraft 

do, and they arrive more quickly than ships sailing 

from the United States because they avoid lengthy 

loading times and travel shorter distances. The use of 

prepositioned equipment can be delayed, however, if 

adequate port facilities are not available for unloading 

the ships.

B Increasing the number of existing ships and aircraft 

(LMSRs and C-17s) would offer very limited improvements in the promptness of unit deliveries during large deployments. Although LMSRs are faster 

than many of the other ships in the current sealift 

force, they still need more than three weeks to reach 

destinations on the other side of the globe, such as the 

Persian Gulf. Aircraft offer rapid delivery of individual 

loads, but any attempt to significantly increase their 

total cargo deliveries to a distant theater would probably be hampered by constrained infrastructure at airfields, which is anticipated for many, if not most, 

future conflicts.3

B Heavy-lift airships and high-speed sealift ships would 

have a promptness and throughput capacity intermediate between those of existing airlift and sealift forces. 

Initial airship deliveries would occur earlier, but the 

later-arriving high-speed ships would deliver substantially greater amounts of cargo.

B Airships would be virtually independent of air bases 

and would be well suited to deliver combat-ready 

troops, along with their vehicles and other equipment, 

directly to their destination. (With current mobility 

forces, by contrast, troops and equipment usually 

travel separately.) Delivering fully equipped units 

straight to their destination would reduce the time 

that units typically spend between arriving in a theater 

and beginning operations. High-speed ships could be 

designed to be less dependent on seaports and to 

transport cargo and passengers together, but such 

capabilities would probably result in higher costs for a 

given amount of throughput capacity.

The Capabilities of Today’s Strategic 

Transportation Force

To provide a basis with which to compare the options, 

CBO assessed the throughput capacity of the current mobility systems that are most critical to deploying ground 

forces early in a crisis: strategic airlift, roll-on/roll-off 

ships (RO/ROs), and Marine Corps and Army preposiQuantity

180 a

126

59

Cargo aircraft More than 100 b

Passenger aircraft More than 100 b

8

11

31

27

16

10 c

9

With Marine Corps equipment

With Army equipment

With other sustainment supplies

Civil Reserve Air Fleet

Large, medium-speed roll-on/roll-off ships

Other roll-on/roll-off ships

Other

C-17s

Afloat Prepositioning Ships

Surge Sealift Ships

Airlift Aircraft

C-5s

KC-10s

Fast sealift ships 

3. The observation that more C-17s would offer little improvement 

in the context of a large deployment to a single theater does not 

imply that more C-17s would not be useful to support the military’s broader worldwide demands for airlift aircraft.
SUMMARY xi

Summary Table 2.

Options for Expanding Strategic Transportation Forces Table (Summary) 2. Options for Expanding Strategic Transportation Forces

Source: Congressional Budget Office.

Note: nm = nautical miles; LMSR = large, medium-speed roll-on/roll-off ship; sq ft = square feet.

a. Includes costs for research and development (if necessary), procurement, and 30 years of operations and support (after delivery of the 

option’s first aircraft or ship), over and above the costs needed to maintain current strategic mobility capabilities.

tioned forces.4 CBO did not use a specific planning scenario for its assessment, but it chose deployment distances similar to those expected for a scenario set in the 

Persian Gulf or Indian Ocean—7,000 nautical miles 

(nm) by air and about 10,000 nm by sea from the United 

States—for its base-case calculation of cargo deliveries. 

Such distances represent about the longest possible on the 

globe, thus allowing alternative mobility forces to be 

compared under stressing circumstances. (As part of its 

analysis, CBO explored how sensitive the results of its 

calculations were to the assumptions of the base case.)

Total Investment

and Operating

Costs (Billions

Production Considerations of 2006 dollars)a

Option 1A: Buy 21 Continued production of existing design 11.3

Additional C-17 Aircraft

Option 1B: Develop and Buy 11.3

14 to 16 Heavy-Lift Airships

Option 2A: Buy 17 Additional production of existing design 11.3

Additional LMSRs or 18,000 tons 

Option 2B: Develop and Buy 11.1

Six Advanced-Technology or 10,000 tons 

High-Speed Sealift Ships

Option 3A: Buy Four Sets of 11.4

Stryker Brigade Equipment

and Four LMSRs conflicts

Option 3B: Buy Five Sets of 11.1

Stryker Brigade Equipment and

Store Them on Existing LMSRs conflicts

Airlift

Average payload: 45 tons

Average speed: 410 knots 

Afloat Prepositioning

Range: 3,200 nm 

Payload: 500 tons

Speed: 100 knots 

Range: 6,000 nm 

Surge Sealift

Speed: 24 knots 

Speed: 24 knots 

Based close to anticipated 

Design is beyond state of the art, 

requiring advanced materials, hull 

design, and water-jet technology

Use or continued production of existing 

ships and Army equipment

Payload: 200,000 sq ft 

Speed: 45 knots 

Key Characteristics

Concept never demonstrated at that size; 

component technology exists, but largescale integration of it is unproven

Continued production of existing ships 

and Army equipment

Range: 5,000 nm 

Power: 335,000 horsepower

Speed: 24 knots 

Based close to anticipated 

Range: 10,000 nm 

Power: 64,000 horsepower

Payload: 380,000 sq ft 

4. The assessment did not explicitly consider other transportation 

systems, such as container ships, which are used primarily to bring 

sustainment supplies to units already operating in a theater. Such 

systems are more easily obtained from the commercial sector (for 

example, through emergency charters) than are the specialized 

vehicle carriers that are preferable for transporting unit equipment.
xii OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

If adequate support infrastructure was available at the 

destination, the current transportation systems described 

above would be able to deliver an average of about 

30,000 tons of cargo each day to the notional theater over 

the first 60 days of a large deployment, although deliveries during the first week to 10 days would be substantially 

below that average (see Summary Figure 1). Airlift aircraft would start arriving after one or two days and would 

deliver cargo at a relatively steady rate (the smoothly increasing wedge for airlift in Summary Figure 1 reflects 

many individual aircraft with small loads rapidly cycling 

through the delivery system). Sealift arrivals would come 

in surges. Ships carrying prepositioned equipment would 

arrive soonest, beginning on day 6, because they are kept 

in a higher state of readiness and have much shorter distances to travel than sealift ships based in the United 

States. The fastest sealift vessels (fast sealift ships and 

LMSRs) would arrive next, on about day 21. Finally, the 

slower RO/ROs in the Ready Reserve Force would begin 

making deliveries around day 35. That throughput would 

be reduced if the transportation systems were slowed by 

infrastructure constraints such as inadequate airfields or 

port facilities.

Whether those delivery rates meet DoD’s requirements 

depends on the outcomes of ongoing DoD studies of requirements for mobility capability. Previous requirement 

studies have generally concluded that a shortfall exists in 

the ability to deliver cargo in the early days of a deployment but that after several weeks, the throughput capacity of the strategic transportation system catches up with 

the stated delivery requirements.

Options for Improving Strategic

Transportation

The alternatives for improving strategic transportation in 

this analysis focus on approaches that would increase deliveries in the initial days of a deployment. CBO examined six options, two each for airlift, sealift, and afloat 

prepositioned forces. The options, which would add to 

the existing strategic transportation forces, were sized to 

cost a total of about $11 billion in 2006 dollars for research and development (if any), procurement, and 30 

years of operations once the first new system had been delivered.5

 (By comparison, DoD has spent an average of 

about $12 billion per year on all strategic transportation 

programs and activities over the past two decades, according to data in the 2006 Future Years Defense Program.)

Summary Figure 1.

Cargo Delivery Capability of Current 

Mobility Forces

(Thousands of tons)

Source: Congressional Budget Office.

Notes: This notional delivery scenario assumes a theater of operations in the Persian Gulf or Indian Ocean region with no constraints on infrastructure in the theater. Surge sealift in this 

figure includes only roll-on/roll-off ships. 

LMSR = large, medium-speed roll-on/roll-off ship; FSS = 

fast sealift ship; RRF = Ready Reserve Force; RO/RO = rollon/roll-off ship.

The estimated costs for those options represent incremental spending in addition to the spending necessary to 

maintain and operate the current strategic mobility 

forces.6

5. The figure of $11 billion results from the need to have a whole 

rather than a fractional number of prepositioned units (four in 

Option 3A and five in Option 3B). Those units are the most 

expensive system, per increment of capability provided, in CBO’s 

analysis.

6. The improvements offered by the options might enable DoD to 

retire some of today’s older, slower systems, but CBO did not 

assume such savings in its estimates of the costs of the options.

0 15 30 45 60

0

500

1,000

1,500

2,000

Airlift

Afloat

Prepositioning

Faster Surge Sealift

(LMSRs/FSSs)

Slower Surge Sealift

(RRF RO/ROs)

Days

Average: About 30,000

Tons per Day
SUMMARY xiii

The first airlift option (1A) would purchase 21 additional 

C-17 aircraft like those already in DoD’s inventory. The 

second airlift option (1B) would be more innovative: it 

would develop and buy 14 to 16 heavy-lift airships similar to concepts being explored by the Defense Advanced 

Research Projects Agency under the Walrus program and 

by the Naval Air Systems Command. The notional airship in Option 1B would carry more than 10 times the 

average payload of a C-17 but would travel at only onefourth the speed (see Summary Table 2). Lift would be 

generated both by the buoyant force of the helium inside 

the airship and by the airfoil shape of the airship’s hull, 

which would act like a wing when the craft was moving 

forward. That hybrid design would eliminate the need for 

large transfers of ballast during loading and unloading 

and would make the airship easier to handle on the 

ground. High winds could still present problems, however.

The sealift alternatives also offer a choice between existing and conceptual systems. Option 2A would buy 17 

additional LMSRs; Option 2B would develop and procure six high-speed sealift (HSS) ships that would have 

only half the range and cargo capacity of an LMSR but 

almost twice the speed. Proposals have been advanced for 

sealift ships with speeds as high as 75 knots (nautical 

miles per hour), but the technology needed to realize 

such performance is well beyond today’s state of the art. 

The speed of the notional HSS ship in Option 2B—45 

knots—would also be very technically challenging for so 

large a vessel. However, that HSS ship would offer substantial improvements over current sealift ships without 

the greater technical and cost risks inherent in an even 

more advanced design.

Compared with the approaches that would use existing 

systems, the options to develop a heavy-lift airship or a 

high-speed sealift ship would take advantage of modern 

and emerging technologies but would be subject to 

greater uncertainty about technical feasibility, operational 

performance, and cost.

The last two options would preposition additional equipment for the Army’s new medium-weight Stryker brigade 

combat teams (BCTs). Option 3A would buy four sets of 

Stryker BCT equipment and four LMSRs to store them 

on. Option 3B would purchase five such unit sets but 

keep them on existing LMSRs, which would be taken 

from the surge sealift fleet. 

Comparison of the Options’ 

Capabilities

Although all of the options analyzed in this study could 

improve the strategic mobility force, each alternative 

offers a distinct combination of operational capabilities 

relative to those of today’s force. The primary capabilities—promptness, throughput capacity, and dependence 

on support infrastructure—are discussed below. (Other 

factors, such as the potential impact that an option might 

have on efforts to modernize the current force, are 

described in Chapter 4.)

Promptness and Throughput Capacity

Constraining each option to have roughly equal costs results in very different improvements in promptness and 

throughput capacity (see Summary Figure 2).

The alternatives for afloat prepositioning would offer 

both an improvement in promptness and a relatively large 

improvement in capacity over the base case. By the end of 

the first week of operations, Options 3A and 3B would 

have delivered two of their sets of Stryker BCT equipment, with the remainder arriving before the end of the 

second week. That promptness would come at the expense of some flexibility, however, because the equipment 

to be delivered would have been determined before the 

specifics of a conflict could be known. Option 3A would 

increase the overall throughput capacity of the transportation force because it would purchase both ships and 

equipment for prepositioning. Option 3B would not increase overall capacity because its ships would be drawn 

from the surge sealift force. Instead, that option shifts deliveries to earlier in the representative scenario. The advance in deliveries early in the scenario under Option 3B 

begins to shrink relative to the base case during the fourth 

week because the extra arrivals of prepositioned equipment early in the scenario would be offset by the corresponding reduction in arrivals by the now-smaller surge 

sealift force.

The airlift options (1A and 1B) would also increase cargo 

deliveries in the first week, but that cargo could be tailored to the specific situation. The airship option (1B) 

would deliver cargo at rate nearly three times greater than 

that of the C-17 option. Both options’ deliveries, however, would be much smaller overall than those of the 

prepositioning alternatives. For example, by the end of 

the fourth week, airship deliveries would approach the
xiv OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Summary Figure 2.

Increases in Cargo Deliveries, by Week, Under Various Options

Source: Congressional Budget Office.

Notes: This notional delivery scenario assumes a theater of operations in the Persian Gulf or Indian Ocean region with no constraints on infrastructure in the theater. The numbers shown here are increases beyond the capability of current mobility forces. Note that the scale of 

the y axes changes with each week as more cargo accumulates in the theater. Only about half of the LMSRs under Option 2A have 

arrived at the end of the fourth week.

Option key:

1A---Buy 21 additional C-17 aircraft

1B---Develop and buy 15 heavy-lift hybrid airships

2A---Buy 17 additional LMSRs

2B---Develop and buy six advanced-technology high-speed sealift ships

3A---Buy four sets of Stryker brigade equipment and four LMSRs on which to preposition it

3B---Buy five sets of Stryker brigade equipment and preposition it on five LMSRs from the existing surge sealift force.

BCT = brigade combat team; LMSR = large, medium-speed roll-on/roll-off ship.

1A 1B 2A 2B 3A 3B

0

5

10

15

20

25

30

0

1

2 Thousands of Tons Stryker BCT Equivalents

Options

Week 1

1A 1B 2A 2B 3A 3B

0

15

30

45

60

75

0

1

2

3

4

5 Thousands of Tons Stryker BCT Equivalents

Options

Week 2

1A 1B 2A 2B 3A 3B

0

15

30

45

60

75

0

1

2

3

4

5 Thousands of Tons Stryker BCT Equivalents

Options

Week 3

1A 1B 2A 2B 3A 3B

0

15

30

45

60

75

90

105

120

0

1

2

3

4

5

6

7

8 Thousands of Tons Stryker BCT Equivalents

Options

Week 4

Cumulative Deliveries

by Current Forces:

83,000 Tons

Cumulative Deliveries

by Current Forces:

440,000 Tons

Cumulative Deliveries

by Current Forces:

530,000 Tons

Cumulative Deliveries

by Current Forces:

810,000 Tons
SUMMARY xv

amount delivered by the prepositioning options (3A and 

3B) in the first week.

Of the sealift options, the high-speed ships in Option 2B 

arrive by the end of the third week with slightly less cargo 

than prepositioning option 3A provided. The LMSRs in 

Option 2A would arrive last (during the fourth week), 

but with far more cargo than transported under the other 

options.

The promptness of those options depends on the performance characteristics of each system. Throughput capacity, in turn, depends both on promptness and on the 

number of systems purchased. If there are no constraints 

on support infrastructure, purchasing greater quantities 

of a system can increase throughput capacity. But 

promptness limits that approach for boosting throughput 

capacity, because having an unlimited number of aircraft 

or ships will not increase the speed with which the first 

ones arrive in a theater. The relative value of promptness 

versus throughput capacity—and hence the types and 

quantities of strategic transportation systems that the military might choose to buy—will depend on DoD’s determination of its plans and requirements for responding to 

future crises.

The relative performance of the six options would be 

essentially the same under a wide range of deployment 

distances from the United States. At the distances 

assumed in the base-case scenario (7,000 nm for airlift 

aircraft and 9,900 for sealift ships), a Stryker BCT prepositioned afloat no farther than 6,000 nm from its destination—a distance that would represent a poorly selected 

location for a prepositioned force—would arrive in about 

14 days: less time than under any of the options that 

would leave from the United States. The airship and 

high-speed-ship options would deliver the same amount 

of cargo a few days later. Those two options would compete favorably with a prepositioned force located at 6,000 

nm for shorter deployment distances from the United 

States, but better prepositioning locations (say, 4,000 nm 

or 2,000 nm away) would negate that advantage (see 

Summary Figure 3). The extra aircraft or ships transporting forces from the United States in Options 1A and 2A 

would not compete favorably with even the poorly 

located prepositioned force unless the transit distances 

from the United States were about one-third of those to 

the Persian Gulf or Indian Ocean region.

Reliance on Support Infrastructure

The delivery results discussed above are based on the 

assumption of an unconstrained support infrastructure at 

the destination site. The strategic transportation system 

would not be able to realize that full potential if it was 

limited by air-base or seaport constraints. The availability 

of such facilities can vary widely. For example, the large 

seaports and spacious airfields in Saudi Arabia are favorable for deployments. At the other extreme, Afghanistan 

has a limited number of air bases and no seaports; cargo 

sent there by ship would have to travel an additional distance by air or land through another country. Rather than 

select some arbitrary level of infrastructure for its scenario, CBO assessed each option’s dependence on infrastructure in terms of how the option would alter the need 

for support relative to that of the base-case force.

Option 1A, which would buy additional C-17s, would 

require about 3 percent more airfield infrastructure than 

needed by the airlift force in the base case. However, the 

need for airfield infrastructure in the base case is already 

quite high. For example, CBO estimates that the basecase airlift force would require about 40 percent more infrastructure capacity than was available during Operation 

Desert Shield in the Arabian Peninsula. If the base-case 

airlift force was constrained with regard to the infrastructure available, its throughput capacity would be lower 

than estimated here, and the additional aircraft under 

Option 1A would produce little or no improvement.

The heavy-lift airship option (1B) would have the least 

impact on the demand for infrastructure. Under proposed designs, the airship would be able to operate from 

open areas only about two to three times its size. It would 

not require a runway upon arrival in the theater, and the 

roll-on/roll-off design of its cargo bay would minimize 

the need for cargo-handling equipment.7 Besides not 

competing with other aircraft for airfield support, that independence would give commanders greater flexibility to 

choose where forces would be delivered. Such flexibility 

would typically offer the advantage of decreasing the time 

between when a unit was delivered to a theater and when 

it finally reached its assigned area of operations. Depend7. An airship would require a much larger open area at its loading 

site, because a fully loaded and fueled airship would need the aerodynamic lift from a takeoff run to get airborne. Less lift (and 

hence less speed) would be needed for landing because fuel would 

have been burned during transit. Once unloaded, the airship 

could take off almost vertically.
xvi OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Summary Figure 3.

Time Needed to Deliver First Additional Stryker Brigade Combat Team

at Various Deployment Distances

(Days)

Source: Congressional Budget Office.

Notes: The transit distances assumed in the base-case deployment scenario are 7,000 nm for C-17s; 8,500 nm for airships; and 9,900 nm for 

LMSRs and high-speed sealift ships.

LMSR = large, medium-speed roll-on/roll-off ship; nm = nautical miles. 

ing on the scenario, a unit might need several days to assemble and then move (or be moved) to its final destination. An airship’s ability to deliver cargo regardless of airbase or port locations could help reduce that time. In 

such a situation, the airship option would be, in effect, 

more prompt relative to the other options than is shown 

here. However, factors such as the airship’s vulnerability 

to enemy fire would remain a consideration.

Like Option 1A, the sealift and afloat prepositioning options would increase the demand for support infrastructure (in this case, seaports). The average need for port 

support, as measured by the number of ships in port over 

time, would rise by about 25 percent during the first 60 

days of an operation under Option 2A and by about 10 

percent to 20 percent under the other sealift and prepositioning options. Unlike with air-base support, however, 

the demand for port infrastructure is uneven over time 

because ships arrive less frequently. Consequently, although those options would result in a higher average demand, only Options 2A and 3B would have a peak demand for port infrastructure that exceeded that in the 

base case (by one ship on one day and two ships on two 

days, respectively).

Of course, some situations could arise in which the available infrastructure would not accommodate either the 

base-case transportation force or the additions to it envisioned under these options. A new sealift ship designed to 

fit into smaller ports or to operate independently of ports 

could mitigate some constraints, but such a ship would 

have a smaller payload and higher cost than current ships. 

Alternatively, the Navy and Marine Corps are developing 

sea-basing concepts that would involve transferring cargo 

and personnel at sea from large strategic transports to 

smaller intratheater systems capable of operating without 

support infrastructure. Those plans are still in the early 

stages of concept definition.

0 10 20 30 40 50 60 70 80 90 100

0

5

10

15

20

25

30

35

40

45

50

Prepositioning 6,000 nm Away

Prepositioning 4,000 nm Away

Prepositioning 2,000 nm Away

Distance from United States to Theater

Relative to Base Case (Percent)

Option 1A: 21 More C-17s

Option 2A: 17 More LMSRs

Option 1B: 15 Hybrid Airships

Option 2B: Six High-Speed

Sealift Ships
1

Today’s Strategic Transportation Capabilities

The United States maintains considerable capabilities to transport its military forces to distant locations. 

Even so, the Department of Defense (DoD) seeks to improve those strategic transportation capabilities, particularly the promptness with which units can be moved to 

their destinations.1 The experience of Operations Desert 

Shield and Desert Storm in 1990 and 1991 led many 

planners to conclude that the ability to deploy units more 

rapidly would be needed because a future adversary 

would be unlikely to permit a lengthy buildup of U.S. 

forces, as Iraq did then. Today’s focus on military “transformation” has further emphasized the desire for rapid 

deployments, because the proposed shift to smaller, 

lighter networked units places a premium on getting 

them to their destinations as early as possible so their firepower or other capabilities can be applied quickly and decisively.

This Congressional Budget Office (CBO) study looks at 

the potential operational effectiveness and costs of various 

options for expanding strategic mobility forces to speed 

up the deployment of military units. The study considers 

improvements that might result from purchasing additional transportation systems—either existing types or 

newly designed, better-performing types—as well as 

improvements that could stem from changing the ways 

in which existing forces are used.

The Evolution of U.S. Strategic 

Transportation Forces

After World War II, the United States’ desire to help 

reestablish and maintain international stability resulted 

in greater global military commitments than ever before. 

The most notable was the commitment to defend Western Europe against a possible Soviet invasion, but smaller 

events, such as the blockade of West Berlin and North 

Korea’s invasion of South Korea, illustrated how the need 

for military forces could occur with little warning almost 

anywhere in the world. The U.S. military’s previous practice—deliberately mobilizing units based in the United 

States and then transporting them to a conflict by ship—

was seen as no longer adequate to address needs for military forces that planners thought might arise.

The United States oriented its military posture, and 

fielded transportation forces, accordingly. First, substantial combat forces were forward deployed to counter what 

were thought to be the most likely or most serious 

threats. The largest contingents were placed in Europe, 

where more than 300,000 U.S. personnel were based 

through the 1980s, and in East Asia and the Pacific, 

where about 100,000 personnel were stationed in South 

Korea, Japan, and the Philippines during that period. 

Those troops were augmented by additional sets of unit 

equipment that were stored (or prepositioned) in strategic 

locations to be ready for use by soldiers or marines flown 

from the United States.2

CHAPTER

1. Strategic transportation (or mobility) systems are those designed 

primarily to deliver military units and supplies to theaters far from 

the United States, by contrast with tactical systems, which are 

designed to move units and supplies over shorter distances within 

a theater. (Although Navy amphibious ships carry Marine Corps 

units over long distances, they are typically thought of as combat 

assets rather than transportation assets.)

2. During the Cold War, the Army had a stated requirement for 13 

brigade-equivalent unit sets of prepositioned equipment under the 

Prepositioning of Overseas Materiel Configured to Unit Sets program, and the Marine Corps kept prepositioned equipment for a 

Marine expeditionary brigade in Norway.
2 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Second, the U.S. military invested in strategic transportation forces that could move units to distant theaters, 

either to conflicts in unanticipated locations or in support of forward-deployed forces. To better provide traditional transport by ship, the Military Sealift Transportation Service was established in 1949 as a single agency to 

oversee movement by sea. That agency—which was renamed the Military Sealift Command in 1970—provides 

strategic lift for large forces, particularly heavy units, with 

their many armored and support vehicles. Its assets include both afloat prepositioning ships and surge sealift 

ships. The former are loaded with unit sets of equipment 

and kept at forward locations; the latter are used to transport shore-based units when necessary.

In addition to sealift, advances in aircraft technology during World War II enabled militarily significant cargoes to 

be transported over long distances by air. Although aircraft payloads are orders of magnitude smaller than payloads of large cargo ships, the much higher speed of aircraft makes them ideal for rapidly transporting timecritical cargo and passengers. The Military Air Transport 

Service was established in 1948 as part of the newly 

formed Air Force. It became the Military Airlift Command in 1966 and the Air Mobility Command in 1992. 

To better coordinate mobility operations, the President in 

1987 ordered the establishment of what would become 

the U.S. Transportation Command (USTRANSCOM), with 

the Military Sealift Command, the Military Airlift Command, and the Army’s Military Traffic Management 

Command (now known as the Military Surface Deployment and Distribution Command) as its three major 

components.

With the end of the Cold War, having the flexibility to 

move forces to regional conflicts as the need arose became 

more important than having large forward-deployed 

forces arrayed against specific threats, such as the Soviet 

Union. Consequently, the importance of the transportation services provided by USTRANSCOM increased as well. 

As forward-deployed forces have been reduced by nearly 

half since the Berlin Wall came down (and additional 

reductions have been proposed), strategic transportation 

capabilities have been steadily enhanced.

USTRANSCOM’s first experience with trying to rapidly 

deploy large forces to a major theater war came in Operations Desert Shield and Desert Storm in 1990 and 1991. 

Although the military was able to move 3.7 million tons 

of dry cargo, 6.1 million tons of petroleum products, 

and more than 500,000 personnel to the Persian Gulf in 

about seven months, lessons learned from that operation 

indicated a need for improved transportation systems as 

well as better planning, coordination, and execution of 

such missions. 

In response to that experience and to the results of mobility studies conducted in the early 1990s, DoD has upgraded its strategic transportation forces. Improvements 

have included buying 180 C-17 airlift aircraft (the last of 

which is scheduled for delivery around 2010) and 19 

large, medium-speed roll-on/roll-off ships (LMSRs). Although the C-17s are nominally being purchased to 

replace earlier C-141 transport planes, they offer a considerable improvement in capability. In particular, C-17s 

can carry larger pieces of cargo than C-141s can, making 

them more effective at transporting the equipment of 

Army units, and they can operate from smaller runways, 

potentially increasing the number of locations to which 

cargo can be delivered. The LMSRs have added to already-significant improvements in sealift that the Navy 

made during the 1980s.3 Eight of the 19 LMSRs are 

loaded with Army equipment and prepositioned at forward locations. Additionally, improvements in planning 

and execution processes have helped eliminate many of 

the problems experienced during Desert Shield and 

Desert Storm.

The Structure of Current Strategic 

Mobility Forces

Today’s strategic transportation forces fall into three general categories: airlift, sealift, and prepositioning. Each 

has particular advantages and disadvantages in terms of 

the capabilities it offers to the regional combatant commanders that USTRANSCOM may be directed to support. 

Airlift aircraft travel the fastest but carry relatively small 

loads. Sealift ships take longer to arrive but can transport 

large of amounts of cargo, especially vehicles. Depending 

on where it is based, prepositioned equipment can arrive 

in a theater before sealift ships do, but because it is preloaded, it cannot easily be reconfigured in response to the 

needs of a particular operation.

3. At the beginning of that decade, the Navy formally recognized 

sealift as a major naval function and began upgrading its sealift 

forces with the goal of being able to move a mechanized division 

to Europe in five days or to the Persian Gulf in two weeks. 
CHAPTER ONE TODAY’S STRATEGIC TRANSPORTATION CAPABILITIES 3

Airlift

Strategic airlift is provided by a mix of large jet transport 

aircraft owned by the Air Force and (in the case of major 

operations) commercial aircraft from the Civil Reserve 

Air Fleet (CRAF). The CRAF is a voluntary partnership 

between DoD and commercial air carriers that is used to 

augment Air Force airlift. As an incentive for carriers to 

enter into contractual commitments with the CRAF, 

DoD makes peacetime charter business available to participants. When Air Force aircraft and commercial charters cannot meet deployment needs in times of crisis, 

DoD can activate the CRAF to help close the gap. If fully 

activated, the CRAF would provide about one-third of 

the theoretical throughput capacity (total cargo delivered) 

of the combined military/civilian airlift force.4

Air Force Aircraft. The Air Force’s current strategic airlift 

force consists mainly of 126 C-5A/B Galaxy and 138 

C-17A Globemaster III jet transports.5 The C-5A was 

developed in the 1960s and is one of the world’s largest 

operational aircraft, with a length of 248 feet and a wingspan stretching 223 feet (see Table 1-1). The last C-5A 

was delivered in 1973, and 50 C-5B models, which incorporated some improvements in reliability, were purchased during the 1980s. To help address problems with 

the aging and reliability of the C-5 fleet, the Air Force 

plans to upgrade 109 of its C-5s with modern engines, 

digital avionics, and other improvements. That effort is 

scheduled to be completed around 2018 and is expected 

to cost about $10 billion. C-17A aircraft were produced 

starting in the mid-1990s, and a total of 180 are planned 

for delivery through 2010. Although the commander of 

the Air Mobility Command has expressed a need for at 

least 42 more C-17As, no current plans exist to continue 

production beyond 180 aircraft.

Table 1-1.

Characteristics of Strategic 

Transport Aircraft

Table 1-1. Characteristics of Strategic Transport Aircraft

Source: Congressional Budget Office based on Department of the 

Air Force, Air Mobility Planning Factors, Pamphlet 10-

1403 (December 18, 2003).

a. Based on a flight of 3,200 nautical miles for the C-5 and C-17 or 

3,500 nautical miles for the B-747.

Both the C-5 and C-17 are designed to carry large, heavy 

pieces of military equipment. They have wide fuselages 

and doors as well as low cargo floors with ramps that 

allow vehicles to be driven on and off the aircraft, greatly 

easing the task of loading and unloading a ground unit’s 

equipment. Although the two are generally similar in layout and can both carry outsize cargo, the C-5 is considerably larger than the C-17 (see Table 1-1).6 The C-17’s 

smaller size and special flaps and engine thrust reversers 

enable it to operate from substantially smaller airfields 

than the C-5, giving it access to many more air bases 

around the world. The greater flexibility of the C-17 is 

offset by its smaller payload relative to that of the C-5.

4. Theoretical throughput capacity is the amount that the entire fleet 

could carry in the absence of external constraints or inefficiencies. 

Usually measured in terms of millions of ton-miles per day, it 

overstates actual delivery rates because of inevitable constraints or 

inefficiencies during conflict. The CRAF’s percentage contribution to theoretical throughput capacity varies slightly from year to 

year with changes in the Air Force’s force structure and the number of aircraft participating in the CRAF. 

5. Tanker aircraft, especially the larger KC-10A, can also contribute 

to the amount of Air Force airlift available. They can be especially 

useful for moving Air Force squadrons, refueling a squadron’s aircraft en route while simultaneously carrying some of its ground 

equipment. The primary mission of KC-10s is refueling, however, 

and their contribution to airlift is small compared with that of the 

C-5s and C-17s.

6. “Outsize” is the Air Force’s largest cargo category. It is loosely 

defined as cargo that will fit only on C-5s or C-17s. An item’s 

weight or external dimensions determine whether it is outsize, 

“oversize” (cargo that can fit on some smaller military and some 

commercial airplanes), or “bulk” (small items that can be loaded 

onto standard shipping pallets and transported on all types of 

cargo aircraft).

Civilian

C-5 C-17 B-747

248 174 232

223 169 196

840,000 585,000 836,000

89 65 113

Yes Yes No

Yes Yes No

Length 6,000 3,500 6,600

Width 147 90 90

0.77 0.76 0.84

Roll-On/Roll-Off Capability

Gross Weight (Pounds)

Mininimum Runway for

Cruise Speed (Mach)

Landing (Feet)

Cargo

Wingspan (Feet)

Maximum Takeoff 

Maximum Payload (Tons)a

Ability to Carry Outsize 

Length (Feet)

Air Force
4 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Civilian Aircraft. The Civil Reserve Air Fleet contains 

many different types of commercial aircraft, which can be 

broadly separated into two categories: those configured to 

carry cargo (air freighters) and those configured to carry 

passengers. The largest CRAF air freighter is the Boeing 

747. Although air freighters in the CRAF lack the low 

floors and integral ramps of their C-5 and C-17 counterparts, their doors are large enough for loading items of 

moderate size. Because they have large payloads and are 

designed for economical operation (to maximize the return on their owners’ investment), air freighters are ideal 

for carrying cargo on pallets, freeing up military aircraft 

to carry more of the larger, hard-to-load pieces of equipment, such as military vehicles. (The practical implications of the differences between military transports and 

commercial air freighters are discussed in Chapter 2.)

Passenger aircraft are a critical component of the CRAF. 

Because they are designed to carry people, they have a 

much higher capacity than a similarly sized military cargo 

plane. For example, the Boeing 767 is similar in length 

and wingspan to the C-17, but it can carry more than 

twice as many passengers (190 versus 90). Passenger aircraft are also much more comfortable for the troops being 

deployed. For those reasons, DoD tends to prefer CRAF 

aircraft for moving large numbers of people. During 

Desert Shield and Desert Storm, for example, CRAF 

planes carried only about one-quarter of the cargo transported by air but nearly two-thirds of the personnel.

Surge Sealift 

The strategic sealift forces available to DoD consist of 

ships belonging to the Military Sealift Command; ships 

in the Ready Reserve Force (RRF), which are owned and 

maintained by the Department of Transportation’s Maritime Administration; and commercial ships that have 

been committed to the Voluntary Intermodal Sealift 

Agreement, an arrangement that is conceptually similar 

to the CRAF. Ships with prepositioned cargo are also part 

of strategic sealift forces, but they are treated separately in 

this study from the surge sealift forces that are used for 

transport. Surge sealift forces include various types of 

ships:

B Roll-on/roll-off ships (RO/ROs), such as LMSRs;

B Other dry-cargo ships, including container, heavy-lift, 

auxiliary crane, break-bulk, and specialty support 

ships;

B Tankers; and

B Hospital ships.

Most of those vessels are maintained in a reduced operating status (ROS) and require four to 20 days for activation. The use of such status decreases peacetime operating 

expenses while matching the time when a ship can be 

available to the availability of its cargo. For example, in 

most cases, even if a transport ship was ready at a moment’s notice, its cargo (say, an Army unit) would need at 

least several days before being ready for transport.

The most important type of sealift ship for CBO’s study 

of rapid unit deployment is roll-on/roll-off ships. Those 

vessels are designed to facilitate the loading, transport, 

and unloading of vehicular cargo. Vehicles can be driven 

aboard using built-in ramps lowered from the ship to the 

pier and then driven to their stowage location on internal 

ramps (much like those in a parking garage) between 

decks.7 RO/ROs are preferred for vehicle-dominated 

cargo and hence for deploying most ground units, because vehicles can be loaded and unloaded much faster 

than on other ships and with less need for port infrastructure, such as large cranes. DoD’s RO/RO fleet is particularly important for deploying units because the U.S. commercial fleet does not include many ships of that type.

Today’s strategic surge sealift RO/ROs include eight fast 

sealift ships (FSSs) and 11 LMSRs under the Military 

Sealift Command plus 31 RO/ROs of varying size and 

speed in the Ready Reserve Force. During peacetime, the 

FSS and LMSR fleets are held in four-day reduced operating status, denoted as ROS-4, whereas most of the 

RRF’s roll-on/roll-off ships are held in ROS-5.8 The one7. Although the layout of a RO/RO ship can be likened to that of a 

parking garage, the size and awkward handling of many military 

vehicles, and the need to pack them densely aboard ship, make the 

loader’s job difficult.

8. As a result of ongoing operations in the war on terrorism, some 

ships normally kept in ROS are now active, and some prepositioned ships are currently unloaded or in some stage of reconstitution if their embarked unit equipment was needed in Iraq or 

Afghanistan. Unless otherwise noted, this text refers to nominal 

conditions in peacetime.
CHAPTER ONE TODAY’S STRATEGIC TRANSPORTATION CAPABILITIES 5

Table 1-2.

Characteristics of Roll-On/Roll-Off Sealift Ships

Table 1-2. Characteristics of Roll-On/Roll-Off Sealift Ships

Source: Congressional Budget Office based on Military Traffic Management Command, Transportation Engineering Agency, Logistics Handbook for Strategic Mobility Planning, Pamphlet 700-2 (September 2002).

Note: LMSR = large, medium-speed roll-on/roll-off ship.

day shorter ROS and higher sustained speeds of the FSSs 

and LMSRs mean that they are usually the first ships 

from the United States to arrive in a theater. (Prepositioned ships typically arrive earlier because of their forward location.)

Fast sealift ships are conversions of the eight SL-7 container ships built for the Sealand Corporation in the early 

1970s. At 946 feet in length, they are nearly as long as 

Nimitz class aircraft carriers. Sealand hoped the 33 knot 

speed of the ships (about double that of typical freighters 

at that time) would be attractive to customers with timesensitive cargoes. However, the rising cost of fuel in the 

1970s made the SL-7s not cost-effective as merchant 

ships. The Navy purchased all eight of them in the early 

1980s and converted them to their present roll-on/rolloff configuration. Although initially rated at 33 knots, 

fast sealift ships are usually expected to achieve a sustained speed of between 27 and 30 knots.

Mobility studies after Operation Desert Storm indicated 

a need to augment the FSS fleet with more relatively 

speedy RO/ROs. Consequently, between 1997 and 2003, 

the Navy bought 19 LMSRs capable of sustained speeds 

of about 24 knots. Although slower than an FSS, each 

LMSR can carry a substantially greater load despite having a similar length, beam, and draft (see Table 1-2). 

DoD did not try to match the speed of the fast sealift 

ships, deciding instead that 24 knots was adequate to 

support deployment plans and thus avoiding the added 

cost associated with ships designed for higher speeds (see 

Chapter 3). Of the 19 LMSRs, 15 were newly constructed and four were conversions of existing ships to a 

roll-on/roll-off configuration. Today, 11 of those LMSRs 

are based in the United States and assigned to deploy domestically based forces. The other eight are part of the 

afloat prepositioned forces discussed below.

Prepositioning

Prepositioned sets of unit equipment are stored either on 

land or on ships (afloat). Much of that equipment has 

been put into service in Operation Iraqi Freedom and is 

either still in use or in some stage of reconstitution. It is 

unclear whether, after that operation, DoD will try to 

reconstitute those prepositioned assets as they existed 

before or whether changes in the United States’ global 

military posture or new initiatives (such as the Navy’s seabasing concepts and the Army’s proposed reorganization 

into “modular” units) will result in very different prepositioned forces.9

During peacetime, the land prepositioning force comprises six brigade sets of Army equipment—three in 

Europe, two in the Persian Gulf (Kuwait and Qatar), and 

one in South Korea—and one set of Marine Corps equipment in Norway. The Army sets in Kuwait and Qatar, 

LMSRs

946 907–954 499–750

106 106 75-105

37 34–36 28–36

33 24 14–19

Usable square feet 150,000–155,000 226,000–290,000 66,000–222,000

Cargo deadweight (Tons) 16,000–17,000 17,000–21,000 10,000–32,000

Fast Sealift Ships

Speed (Knots)

Cargo Capacity

Ready Reserve Force 

Length (Feet)

Beam (Feet)

Maximum Draft (Feet)

9. For information about sea basing, see Congressional Budget 

Office, The Future of the Navy’s Amphibious and Maritime Prepositioning Forces (November 2004); for information about the Army’s 

modularity initiative, see Congressional Budget Office, Options for 

Restructuring the Army (May 2005).
6 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

plus some of the equipment from the sets in Europe, were 

issued for use in Iraq. The Marine Corps set in Norway is 

only partially filled; because the Soviet Union no longer 

poses a threat to the northern flank of NATO, the Marine Corps is exploring other uses for that equipment.

The afloat prepositioning force consists of 36 ships:

B Sixteen ships in the Marine Corps’ Maritime Prepositioning Force (MPF),

B Ten ships in the Army Prepositioning Stock (APS) 

program,

B Seven ships with sustainment supplies (four Air Force 

and one Navy ammunition ship and two tankers for 

the Defense Logistics Agency),

B Two aviation logistics support ships, and

B One high-speed catamaran, the Westpac Express

(although listed as part of the prepositioning force, 

that chartered ship is not kept loaded with equipment 

but rather is used by the Marine Corps for intratheater 

lift).

All of those ships are maintained in full operating status, 

ready for movement at any time, except the two aviation 

logistics support ships, which are kept in ROS-5. The 16 

MPF and 10 APS ships are most relevant to analyses of 

the deployment of unit equipment.

The Maritime Prepositioning Force is organized into 

three squadrons, each of which contains equipment and 

supplies to support a Marine expeditionary brigade for up 

to 30 days. Ordinarily, those squadrons are based in the 

Mediterranean Sea, at Diego Garcia in the Indian Ocean, 

and at Guam in the western Pacific. When needed, an 

MPF squadron sails to the appropriate port, where its 

equipment is unloaded and picked up by Marine Corps 

personnel flown in from their home base.10 The MPF 

squadrons in Mediterranean and Diego Garcia have been 

off-loaded, and their equipment is being used in Operation Iraqi Freedom.

Of the 16 ships in the MPF, three are government-owned 

and 13 are on long-term charter. As part of its 2006 budget request, the Military Sealift Command is seeking 

about $750 million to purchase the 13 chartered ships. 

Eventually, the Marine Corps would like to replace today’s MPF with more-capable MPF (Future), or MPF(F), 

ships. Although the characteristics of the MPF(F) are not 

yet well defined, emerging ideas about it and the broader 

concept of sea basing suggest a focus on greater independence from infrastructure and flexibility of employment 

rather than a desire for faster arrival times (although 

quicker arrivals would result from those other improvements if infrastructure was constrained). In assessing the 

effectiveness of options for strategic mobility forces, CBO 

looked at the improvements they would offer over the 

capability of today’s force, noting (where appropriate) the 

potential impact if some form of MPF(F) is eventually 

fielded.

The Army’s afloat prepositioned equipment is stored on 

the eight LMSRs mentioned above plus two chartered 

container ships. In all, those stocks include more than 

enough equipment for a heavy brigade plus a variety of 

other combat-support equipment that the Army would 

need to set up large-scale operations in a theater. Most of 

the unit equipment and much of the combat-support 

equipment is being used in Iraq.

The Delivery Rate of Today’s Strategic 

Mobility Forces

The transportation capability offered by a strategic 

mobility system is a function of three main factors:

B The system’s throughput capacity—the total rate at 

which it can move military units;

B The system’s promptness—the amount of time it takes 

to move cargo a given distance after the decision to do 

so has been made; and

B The system’s independence from external constraints, 

such as limited airfield or seaport facilities, that can 

increase the time needed to make deliveries.

Those three factors combine to determine how rapidly 

military forces can be transported where needed. Although the first two factors are similar, a distinction exists 

between the average rate at which a transportation system 

can move military units (throughput capacity) and the 

10. Those Marine expeditionary brigades are distinct from amphibious forces, which travel on Navy ships specially designed to support forcible-entry operations. See Congressional Budget Office, 

The Future of the Navy’s Amphibious and Maritime Prepositioning 

Forces.
CHAPTER ONE TODAY’S STRATEGIC TRANSPORTATION CAPABILITIES 7

time needed to deliver a particular unit or load (promptness). For example, a system capable of delivering one 

brigade on the fifth day of an operation and a second brigade on the tenth day has the same throughput capacity 

as a system that can deliver two brigades on the tenth day. 

But the former is more prompt because it can deliver the 

first brigade five days earlier.

To assess the effects of options to expand strategic transportation forces, CBO first calculated the rate at which 

current forces can deliver cargo to a distant theater (the 

base case in this analysis). That delivery rate depends 

mainly on the distance that the combat units being 

deployed must travel, the size and characteristics of the 

mobility force executing the deployment, and the capacity of transportation infrastructure (such as ports and airfields) necessary to support the deployment. 

Parameters of the Base-Case Assessment

CBO did not use a specific planning scenario for its basecase calculations, but it choose deployment distances similar to ones expected for an operation set in the Persian 

Gulf or Indian Ocean region: about 7,000 nautical miles 

(nm) by air and 10,000 nm by sea from the United 

States. Deployment to those regions represents about the 

longest distance possible from the United States, allowing 

CBO to compare alternative mobility forces under stressing circumstances. Additionally, because the current positioning of afloat prepositioned equipment is oriented 

toward the Persian Gulf region, CBO could use actual 

prepositioning locations as part of the base case. (Landbased prepositioned units were not included in the base 

case, but the possible effects of such units are considered 

in the discussion of options in Chapters 3 and 4. That 

discussion also looks at how CBO’s estimates would differ using different deployment distances, both for prepositioned units and for U.S.-based units.)

Besides deployment distance, another factor that influences the delivery rate that a given mobility force can 

achieve is the availability of transportation infrastructure. 

A theater with large airfields and modern port facilities 

will generally be able to receive military forces at a higher 

rate than a less developed theater will. CBO did not make 

any assumptions about the level of infrastructure that 

might be available in a future conflict. Instead, it calculated the capability of the current force and of various 

alternatives in the absence of constraints on infrastructure 

and then analyzed the relative sensitivity of each force to 

decreases in available infrastructure. (That analysis is also 

part of the comparison of options in Chapter 4.)

Because this study focuses on options to speed the deployment of military forces in the early phases of a conflict, CBO limited its assessment of current capabilities to 

mobility systems that are most critical to that mission—

strategic airlift (both Air Force and CRAF), afloat prepositioned forces with Army equipment and two of the 

MPF squadrons with Marine Corps equipment (the 

other squadron was held in reserve in case another conflict arose), and RO/ROs for transporting units based in 

the United States (see Table 1-3). Of the characteristics of 

those systems, speed and ground or port time determine 

the total time needed to complete a delivery mission; payload determines how much is delivered in each mission; 

and, in the case of aircraft, the utilization rate constrains 

the operational tempo that the fleet can maintain.

Limiting the assessment to that subset of today’s strategic 

mobility forces allows for a more useful comparison of 

current capabilities with those of various alternatives. 

(For example, the improvement offered by new roll-on/

roll-off ships is best compared with the throughput capacity of current RO/ROs, not with total throughput capacity.) Transportation systems such as container ships to 

carry sustainment supplies are also very important for 

supporting large military operations, but they were excluded from the assessment because they are more numerous than the systems listed above and can be more 

easily obtained from the commercial sector. Likewise, 

CBO did not explicitly track the movement of passengers 

to its notional theater because commercial airlines have 

sufficient throughput capacity to support very large deployments. Passenger flights to a theater can, however, 

contribute to congestion at airfields. For that reason, 

CBO included the estimated impact of passenger flights 

on airlift delivery rates as part of its assessment of the effects of constrained infrastructure in Chapter 4.

Results of the Base-Case Assessment

Each element of the mobility forces described above—

airlift, afloat prepositioned units, fast RO/ROs (fast sealift ships and LMSRs), and slower RO/ROs in the Ready 

Reserve Force—can deliver at least one load of equipment to the theater within 45 days under the conditions 

of CBO’s assessment. By that time, the forces will have 

delivered a total of about 1.4 million tons of cargo, CBO 

estimates (see Figure 1-1). By day 45, each ship will have 
8 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Table 1-3.

Airlift, Sealift, and Afloat Prepositioning Forces 

Used to Estimate Current Capability

Table 1-3. Airlift, Sealift, and Afloat Prepositioning Forces Used to Estimate Current Capability

Source: Congressional Budget Office based on Department of the Air Force, Air Mobility Planning Factors, Pamphlet 10-1403 (December 18, 

2003), and Military Traffic Management Command, Transportation Engineering Agency, Logistics Handbook for Strategic Mobility 

Planning, Pamphlet 700-2 (September 2002).

Note: n.a. = not applicable; LMSR = large, medium-speed roll-on/roll-off ship; RO/RO = roll-on/roll-off ship.

a. Payloads of RO/RO ships are usually measured in square feet. CBO used weight to allow more-direct comparisons between ships and aircraft. The weight of cargo varies widely depending on its density (for example, a tank is much heavier per square foot of deck space than 

a helicopter is). Weights for prepositioning ships are for expected loads. Weights for surge sealift ships are derived from Army data on 

logistics planning factors and reflect a weighted average of light-unit and heavy-unit loads.

b. Utilization rate is the fleetwide average number of hours per day that a type of aircraft can fly. It applies only to long-term, large-scale 

operations. The surge utilization rate is a flying-hour goal set by a command for the first 45 days of an operation. It assumes that normal 

maintenance is deferred, spare parts are fully funded and stocked, and active and reserve forces are fully mobilized. The subsequent sustained utilization rate is based on normal-duty days and assumes that maintenance deferred during the surge period is performed.

c. The number of stops that an aircraft must make en route for refueling depends on the distance to be traveled.

d. B-747 equivalent aircraft.

e. Two of three Maritime Prepositioning Force brigades activated.

delivered one load, and each aircraft will have delivered 

between 10 and 20 loads. 

Although that total equates to a forcewide average delivery rate of 31,600 tons per day, actual deliveries vary 

widely from day to day (the stair-step profile in Figure 1-

1) as different parts of the mobility force complete their 

missions. Airlift arrives first because of its high speed and 

then quickly settles into a smooth delivery profile (characteristic of smaller payloads, relative to those of ships, 

being delivered by many individual aircraft cycling rapidly through the system). Sealift arrivals come in surges, 

with each subcategory arriving at a different time based 

on its distance traveled, its ROS (which determines how 

soon it can begin its mission), and its speed. Ships carrying prepositioned equipment arrive earliest, on day 6 in 

the base-case deployment, because they are assumed to 

have a much shorter distance to travel than sealift ships 

from the United States (2,000 nm to 6,000 nm versus 

10,000 nm) and because they are not kept in reduced operating status. Fast sealift ships arrive next, around day 

21, and finally the slower RRF ships arrive on about day 

35.

Assuming that no land-based prepositioned equipment is 

already in the theater, airlift provides all of the cargo 

C-17 155 45 409 14.5 12.5 3.25 2.25 3.25

C-5 95 61 420 11.5 8.1 4.25 3.25 4.25

KC-10 37 33 440 9.8 8.6 4.25 3.25 4.25

Civil Reserve Air Fleetd 85 98 460 10.0 10.0 5.00 1.50 5.00

Fast Sealift Ships 8 13,000 27 n.a. n.a. 72 n.a. 48

LMSRs 11 16,500 24 n.a. n.a. 96 n.a. 72

Ready Reserve Force RO/ROs 31 15,000 16 n.a. n.a. 72 n.a. 48

Maritime Prepositioning Forcee 11 18,000 16 n.a. n.a. 0 n.a. 72

Army Prepositioning Stock 8 21,600 24 n.a. n.a. 0 n.a. 72

Loading

Average

 (Tons)

Payloada

Sustained

Speed

(Knots) Surge

Average Utilization Rateb

En Route Stopc

Time on the Ground or in Port (Hours)

Unloading

Airlift Aircraft

Surge Sealift Ships

Afloat Prepositioning Ships

Number

(Hours per day)
CHAPTER ONE TODAY’S STRATEGIC TRANSPORTATION CAPABILITIES 9

delivered during the first week of CBO’s notional deployment (see Figure 1-2). As other assets arrive, airlift’s contribution drops to around 20 percent of deliveries. That 

percentage is high relative to experience (a figure of about 

5 percent is often quoted for Operations Desert Shield 

and Desert Storm) for three main reasons. First, the assessment includes only the roll-on/roll-off portion of the 

sealift fleet. Airlift’s percentage would drop if other sealift, 

such as container ships with sustainment cargo, was included in total deliveries. Second, the base case assumes 

no constraints on infrastructure, a condition that is seldom realized in practice. (The implications of such constraints are discussed in Chapter 4.) Third, the calculations do not reflect inefficiencies that often plague airlift 

because of its great speed and flexibility. Inevitably over 

the course of a deployment, airlift is diverted to move unexpected cargoes as the specifics of the conflict require. As 

a result, aircraft can be forced to wait for late-arriving 

emergency cargo or fly missions with inefficient loads or 

on inefficient routes. CBO’s calculations do not attempt 

to predict such occurrences but rather estimate the capability of each element of the mobility force. The extent to 

which that capability is actually realized will differ from 

operation to operation.

Nonetheless, CBO’s calculations are consistent with 

DoD’s more-detailed analytical methodologies for calculating strategic mobility. CBO tested its methodology by 

trying to replicate results from earlier DoD studies. 

When the same forces and assumptions were used, delivery estimates from CBO’s methodology were within a few 

percent of DoD’s results.

Perceived Shortfalls of Current Forces

Two often-cited shortcomings of today’s strategic mobility forces are inadequate cargo delivery early in deployment and overreliance on support infrastructure in the 

theater of operations. Those concerns are reflected in two 

common proposals by DoD officials for improving mobility: purchasing additional C-17s, thus increasing deliveries (possibly to small airfields) early in a deployment, 

and developing shallow-draft high-speed sealift ships, 

with the greater speed improving promptness and the 

shallow draft reducing the need for deepwater ports.

Mobility studies by DoD over the past decade have emphasized shortfalls in the ability to deliver forces in the

Figure 1-1.

Cargo Delivery Capability of Current 

Mobility Forces

(Thousands of tons)

Source: Congressional Budget Office.

Notes: This notional delivery scenario assumes a theater of operations in the Persian Gulf or Indian Ocean region with no constraints on infrastructure in the theater. Surge sealift in this 

figure includes only roll-on/roll-off ships.

The prepositioned cargo shown arriving around day 50 is not 

actually part of a prepositioned unit but rather a second load 

of cargo carried by the prepositioning force ships, which 

CBO assumes return to the United States for additional loads 

after delivering their preloaded cargo.

LMSR = large, medium-speed roll-on/roll-off ship; FSS = 

fast sealift ship; RRF = Ready Reserve Force; RO/RO = rollon/roll-off ship.

early days of a conflict. Ideally, a commander wants all 

forces in place immediately, because the time needed to 

amass forces represents a period of vulnerability that an 

adversary might be able to exploit. In addition, the 

Army’s transformation efforts have focused largely on getting more forces to a conflict in less time, placing an even 

greater premium on promptness than in the past. Except 

in cases in which forces are forward deployed at the right

0 15 30 45 60

0

500

1,000

1,500

2,000

Airlift

Afloat

Prepositioning

Faster Surge Sealift

(LMSRs/FSSs)

Slower Surge Sealift

(RRF RO/ROs)

Days

Average: About 30,000

Tons per Day
10 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 1-2.

Relative Contributions of Different 

Mobility Systems to a Notional 

Deployment

(Percent)

Source: Congressional Budget Office.

Notes: This notional delivery scenario assumes a theater of operations in the Persian Gulf or Indian Ocean region with no constraints on infrastructure in the theater. Surge sealift in this 

figure includes only roll-on/roll-off ships. 

FSS = fast sealift ship; LMSR = large, medium-speed rollon/roll-off ship; RRF = Ready Reserve Force; RO/RO = rollon/roll-off ship.

place and time, however, requirements for mobility must 

be tempered by the feasibility of transportation. A mobility system with adequate throughput capacity over a 

longer time scale can fall short at earlier times if initial 

units cannot be moved promptly.

In keeping with that focus on promptness, CBO’s analysis emphasized factors that affect unit delivery times and 

examined options that would shorten those times. (Expanding mobility systems to improve promptness would 

also increase total throughput capacity, unless slower systems were retired as faster systems were introduced.) 

CBO did not choose options to meet a specific requirement for mobility, because new requirements are currently being defined. When this report was being prepared, DoD was completing a new Mobility Capabilities 

Study to update its requirements, and results of that 

effort were not available.

Analysis of the other perceived shortcoming—excessive 

reliance on local support infrastructure—is complicated 

by the degree to which such reliance depends on the conditions of particular scenarios. Studying scenarios with 

constrained infrastructure typically leads to the conclusion that infrastructure independence is essential. However, regions with little or no infrastructure are unlikely to 

have large enough economies to support strong opposition forces, nor are they likely to have sufficient importance for national security to require the deployment of 

large, heavy U.S. forces. Some observers have noted that 

the U.S. military was able to prevail easily in Afghanistan 

with light forces and air power because a country with so 

little infrastructure could not field a formidable military. 

Others have argued, however, that such a light force was 

adequate only because a friendly local force (the Northern Alliance) was in place, an advantage that cannot be 

expected in future conflicts. 

In scenarios that include large ports and airfields in good 

locations relative to units' destinations, an infrastructureindependent system may actually perform worse than 

other alternatives by some measures. For example, C-17s 

can operate from shorter, softer runways than similarly 

sized aircraft because of their special thrust reversers, 

flaps, and high flotation landing gear; but that equipment 

adds weight and complexity to the C-17, increasing its 

cost and reducing its range and payload from what they 

might be otherwise. In scenarios in which the operational 

flexibility of the C-17 was unnecessary, that flexibility 

adds cost while it degrades performance. 

As noted above, CBO's analysis made no judgments 

about the support infrastructure that might exist in future 

scenarios. However, CBO assessed the infrastructure dependence of the options in this study and, where appropriate, estimated the effects on cost and throughput capacity of less dependent variations.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

10

20

30

40

50

60

70

80

90

100

Airlift

Afloat Prepositioning

Faster Surge Sealift (LMSRs/FSSs)

Slower Surge Sealift (RRF RO/ROs)

Days
2

Factors That Affect Delivery Times

of Strategic Transportation Forces

Various factors determine the promptness of a strategic mobility system, and external constraints can act to 

slow otherwise prompt systems. The time required for 

each stage of a strategic mobility mission—from origin to 

destination—contributes to total delivery time. The time 

per stage can differ between airlift, surge sealift, and prepositioning, and each stage is subject to different constraints on infrastructure. The interaction of those factors 

underlies the framework that the Congressional Budget 

Office used to select the strategic mobility options 

described in Chapter 3.

The Time Needed to Move a Unit 

to Its Destination

The amount of time necessary to transport a unit from its 

point of origin to its destination is not simply the distance to be traveled divided by the speed of the transportation platform. Transit time, although significant, is only 

one of the components of total delivery time. The act of 

moving a unit from its point of origin to its destination is 

composed of several stages, each of which contributes to 

the overall movement time (see Figure 2-1). The lengths 

of those stages depend on the characteristics of the unit 

being transported, the characteristics of the mobility system, and the details of the specific scenario. Two especially important scenario-dependent factors are the transit 

distance and the availability of transportation infrastructure, such as airfields or ports. 

The sequence of five stages shown in Figure 2-1 is representative of a unit deploying from the United States to 

another continent. In other circumstances, some of those 

stages would not occur. (For example, in the case of a 

force prepositioned on ships, there would essentially be 

no initial movement or loading stages. The force would

Figure 2-1.

Mobility Stages of a Strategic

Deployment

Source: Congressional Budget Office.

simply begin its transit when ordered to deploy.) Nevertheless, the five-stage sequence provides a useful general 

framework for discussing unit movement times.

Stage 1: Move to Embarkation

In general, the first stage of unit movement lasts from 

when the order to deploy is received until the first elements of a unit reach the embarkation point (usually an 

CHAPTER

-OVETO0ORTOR!IRFIELDFOR%MBARKATION

,OAD%QUIPMENTONTO3HIPSOR!IRCRAFT

4RANSITTO4HEATEROF/PERATIONS

5NLOAD%QUIPMENTFROM3HIPSOR!IRCRAFT

2ECEPTION3TAGING/NWARD-OVEMENTAND)NTEGRATION
12 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

airfield or seaport) and begin being loaded on the mobility platform that will carry them to the theater of operations. Two main factors contribute to the length of this 

stage: the time needed to prepare the unit being deployed 

and get it to the loading site, and the time needed to activate the platforms that will carry the unit and get them to 

the loading location. Because those activities typically 

take place at the same time, the longer of the two usually 

determines the time needed for this stage.1 (The description that follows of the move-to-embarkation time for a 

ship or aircraft applies only to its first load. For subsequent loads, the length of this stage consists of the return 

transit time from the destination plus any maintenance 

time that may be necessary.)

Moving Units. The time needed to prepare a unit for deployment and move it to its point of embarkation varies 

widely. For example, light units held on alert status and 

located near suitable airfields can be ready for deployment by air in a matter of hours. In contrast, a heavy unit 

based far from its port of embarkation can take several 

days to more than a week to reach its assigned ships. For 

instance, moving a heavy brigade from Fort Riley, Kansas, 

to a potential embarkation port more than 800 miles 

away in Beaumont, Texas, might take as long as 10 days. 

Basing units closer to their embarkation points could 

shorten that time, but the port facilities needed to accommodate large sealift ships are typically in urban industrial 

areas that do not offer the open space that heavy units 

need for day-to-day training. (CBO did not examine 

alternative domestic or overseas basing locations that are 

closer to embarkation ports, because the time savings offered by such alternatives are limited compared with 

other alternatives for improving delivery times and because relocating the home bases of units would have implications far beyond strategic mobility.)2

Besides the distance between the base and the embarkation point, the throughput capacity of the transportation 

infrastructure between those two (usually railways or 

roads) and the unit’s proficiency at packing up and moving on that infrastructure will affect its move-toembarkation times. Inadequate transportation networks 

could have bottlenecks that would slow movement. However, by design, transportation infrastructure in the 

United States is usually adequate to handle planned rates 

of unit movement. Units prepositioned on land in other 

countries would have a similar reliance on infrastructure 

in their host nation and would thus need to be located 

near adequate airport or seaport facilities to minimize the 

time required to reach their embarkation point. 

Whether based in the United States or prepositioned elsewhere, units slated for early deployment in a crisis also 

need to be well versed in efficiently using the infrastructure if overall deployment times are to be kept as short 

as possible. For example, personnel might need to be 

trained to load their vehicles on rail cars rapidly. (As 

noted above, units prepositioned afloat do not require 

any time to reach an embarkation point because they 

have already embarked.)

Moving Ships and Aircraft. If the time needed to move 

transport ships or aircraft to their initial loading locations 

is greater than a unit’s time to reach them, the ship or aircraft movement will determine the elapsed time before 

the loading stage can begin. Some Air Force aircraft are 

generally available for loading in a matter of hours, if not 

immediately. For example, McChord Air Force Base in 

Washington State, the main western U.S. base for C-17s, 

is located adjacent to Fort Lewis, home of the Army’s first 

Stryker brigade combat teams.3

 But some aircraft might 

require several days to reach embarkation points, because 

at any given time, strategic airlift aircraft are in use 

around the world. Depending on their status, units and 

aircraft in the Air Force Reserve and Air National Guard 

might require extra time for activation. The rate at which 

aircraft in the Civil Reserve Air Fleet are activated by the 

Secretary of Defense or the President will depend on the 

severity of the need for additional airlift. 

Those considerations are reflected in the aircraftgeneration schedule (the schedule by which aircraft are 

1. That statement assumes that once the initial elements of a unit 

have arrived at the loading location, the arrival of subsequent elements will occur more quickly than the mobility platform(s) carrying them can be loaded. If the rate of loading is faster than the 

unit’s rate of arrival, the loading time (stage 2) will be subsumed 

by the move-to-embarkation time (stage 1), and the end of the 

loading stage will be determined by when the unit’s final elements 

arrive at the embarkation point, not by the inherent loading time 

of the mobility system.

2. See Congressional Budget Office, Options for Changing the Army’s 

Overseas Basing (May 2004).

3. Stryker brigade combat teams are relatively new medium-weight 

armored units that are designed to be easier to transport than traditional heavy units. 
CHAPTER TWO FACTORS THAT AFFECT DELIVERY TIMES OF STRATEGIC TRANSPORTATION FORCES 13

Table 2-1.

Reduced Operating Status 

of Surge Sealift Ships

Table 2-1. Reduced Operating Status of Surge Sealift Ships

Source: Congressional Budget Office based on information from 

the Military Sealift Command.

Notes: LMSR = large, medium-speed roll-on/roll-off ship;

RO/RO = roll-on/roll-off ship.

Ships in reduced operating status are manned by skeleton 

crews that maintain systems to allow the ships to be activated in the number of days allotted.

introduced into the strategic flow) that CBO used for this 

analysis. It assumes that the small fleet of KC-10 tankers 

(which can be used for carrying equipment as well as 

refueling) is fully introduced, or generated, the soonest 

because all of those aircraft are in the active component of 

the Air Force. C-17s and C-5s are fully generated slightly 

later, although still quite quickly, because some of them 

have been allocated to the Guard and Reserve. The 

CRAF fleet is fully generated last, reflecting the sequential call-up of commercial aircraft as the need for them 

grows. CBO’s generation rates are representative of schedules used in past DoD analyses of mobility.

Move-to-embarkation times are typically longer for surge 

sealift ships than for aircraft, primarily because those 

ships are kept in a state of reduced readiness during 

peacetime. As noted in Chapter 1, most surge sealift ships 

are maintained in four-, five-, 10-, or 20-day reduced 

operating status until they are activated for a mission (see 

Table 2-1). Ships in reduced operating status have small 

crews on board to ensure that the ship’s primary systems 

are maintained and that the vessel can be ready to sail in 

the time allotted. Reduced operating status results in 

lower peacetime operating costs and serves to match 

ships’ arrivals at their embarkation ports with the arrivals 

of units they will carry (having the ship ready to load on 

day 1 is of little use if the cargo will not arrive until day 

4). That matching is designed to minimize any adverse 

impact on overall deployment times.

Stage 2: Loading

The loading stage can begin after the deploying unit (or 

its lead elements) and its assigned ship or aircraft have 

reached the embarkation point. The time required for 

loading depends on the availability of support infrastructure, the type of unit being loaded, and the characteristics 

of the mobility platforms.

As with transportation infrastructure for the move-toembarkation stage, it is usually assumed that loading 

infrastructure—piers at which to dock ships, cranes for 

loading cargo on ships, and airfield materiel-handling 

equipment—will be in adequate supply at the embarkation point, because loading requirements can be estimated in advance, allowing planners to match their 

demand for infrastructure with its local availability. The 

type of unit can be an important factor in that planning. 

Units with particularly heavy or bulky equipment generally need more time for loading because such items are 

more difficult to fit on mobility platforms, must be more 

carefully positioned on board to maintain a proper 

weight distribution, and may require additional tie-down 

points to secure them for transit. As an extreme example, 

equipment such as helicopters must be partly disassembled to fit on some types of transport aircraft.

Loading times for ships vary widely, from as little as two 

days for a fast sealift ship to more than five days for some 

large container ships (see Table 2-2). Those times are 

influenced by a ship’s ease of loading and by the total 

cargo to be loaded. For example, a roll-on/roll-off ship 

with two vehicle ramps to the pier can theoretically be 

loaded twice as fast as a RO/RO with only one ramp. The 

number of items to be loaded can be a more important 

factor than their cumulative size or weight because each 

item (such as a truck or a container of supplies) must be 

individually moved into the ship’s hold and secured in 

place.4

 Part of the Army’s move toward shipping supplies 

in commercial containers has been motivated by the benefits of having fewer items to handle: a single container

4 5 10 20

8000

11 0 0 0

RO/ROs 0 27 4 0

Auxiliary crane ships 4 4 1 1

Other 0 8 8 1

Reduced Operating

Status (Days)

Fast Sealift Ships

LMSRs

Ready Reserve Force

4. Of course, the size or weight of an individual item has some effect 

on loading time. A tank might take longer to load than a truck 

because it is more difficult to maneuver on the ship’s ramps and 

might require a greater number of tie-down lines in the ship’s 

hold.
14 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Table 2-2.

Planned Loading and Unloading Times 

for Ships and Aircraft

Table 2-2. Planned Loading and Unloading Times for Ships and Aircraft

Source: Congressional Budget Office based on Military Traffic 

Management Command, Transportation Engineering 

Agency, Logistics Handbook for Strategic Mobility Planning, Pamphlet 700-2 (September 2002), and Department 

of the Air Force, Air Mobility Planning Factors, Pamphlet 

10-1403 (December 18, 2003).

Note: LMSR = large, medium-speed roll-on/roll-off ship.

a. Times depend on the size of the ship (the number of containers) 

and the speed of the cranes servicing it.

b. Figures are for total ground time at the loading or unloading 

location, including time spent in fueling or maintenance.

can consolidate many items that would need to be handled individually on a break-bulk type of cargo ship. 

(Containers also have the advantage of rapid tie down 

because they are designed to be easily secured to the ship.)

Loading times for aircraft are subject to similar considerations, although they are measured in hours rather than 

days (see Table 2-2). Those times depend on the amount 

of cargo, the type of cargo, and the type of aircraft. C-17 

and C-5 military airlifters are designed specifically for vehicular cargo and for operations with less support infrastructure than is typically needed with commercial aircraft (or derivatives of commercial aircraft, such as the 

KC-10A). Both the C-17 and C-5 have cargo floors that 

are low to the ground (only about 64 inches high for the 

C-17) and integral ramps that allow vehicles to be driven 

directly aboard. As a result, special materiel-handling

equipment, such as the Air Force’s 60K loaders, are not 

always necessary to lift cargo up to the aircraft’s cargodeck level. Moreover, the C-17’s and C-5’s cargo doors 

and ramps are coaxial with the aircraft fuselage, so vehicles do not have to be maneuvered through an often 

tricky and time-consuming 90-degree turn, as can be the 

case when loading them through a side cargo door. For 

nonvehicular equipment and bulk supplies, rollers built 

into the cargo floor of the C-17 and C-5 allow items to 

be slid aboard directly from trucks or other cargo carriers.

Commercial aircraft designs such as the KC-10 and 

Boeing 747 usually have floor rollers too, but their cargo 

decks are typically many feet above the ground (about 15 

feet for the KC-10), and materiel-handling equipment is 

required for all items of cargo. As a result, the loading 

times for commercial aircraft tend to be longer than for 

their military counterparts. Additionally, commercial aircraft are more limited in the size of individual items that 

will fit on board because they have smaller cargo doors 

and weaker cargo floors. (Many commercial air freighters 

have only a side cargo door, and on a 747, the height of 

the nose door opening is limited by the presence of the 

flight deck above it.) Because of the greater difficulty of 

loading commercial aircraft, planners try to allocate bulk 

supplies to them and vehicles to military aircraft.

The loading times needed for aircraft are not entirely determined by the mechanics of getting cargo aboard. The 

aircraft loading times shown in Table 2-2 are more accurately described as the planned ground time for the aircraft’s loading stage. Fueling and other aircraft maintenance can contribute to that time—although, insofar as 

possible, those activities are conducted while the plane is 

being loaded.

Stage 3: Transit

Transit time is the elapsed span between when the transport ship or aircraft departs from its embarkation point 

and when it arrives at its debarkation point. This stage 

includes time spent moving as well as any time spent at 

stops on the way. The primary factors that influence transit time are the distance to be traveled (including routing 

through canals or around denied airspace), the speed of 

the transport platform, and the number and duration of 

any stops en route.

For today’s cargo ships, transit time is made up almost 

exclusively of time spent under way. Those ships can gen48–72 24–36

72 48

70–95 70–95

Seabee 79–92 79–92

Lighter aboard ship 232–264 232–264

88–136 88–136

3.25 1.75–3.25

4.25 2.00–4.25

4.25 3.25–4.25

5.00 5.00

3.00 3.00

Hours for Hours for

Ships

Fast sealift ship

LMSR

Loading Unloading

Auxiliary crane ship (Break bulk)

Barge carrier 

Container shipa

Aircraftb

C-17

C-5

KC-10

B-747

B-767
CHAPTER TWO FACTORS THAT AFFECT DELIVERY TIMES OF STRATEGIC TRANSPORTATION FORCES 15

Figure 2-2.

Transit Times for Sealift at Different Distances and Ship Speeds

(Days)

Source: Congressional Budget Office.

Note: The transit times shown here do not include stops for fuel or passage through canals. 

erally travel around 10,000 nautical miles or more without refueling, so stops for fuel are seldom necessary. 

Speeds range from about 16 knots for a typical commercial ship up to about 30 knots for the Military Sealift 

Command’s fleet of fast sealift ships, meaning that transit 

times over the same distance can vary by about a factor of 

two (see Figure 2-2). 

Transit times can be significantly longer if—as is almost 

always the case—a ship cannot steam directly from its 

origin to its destination. For example, as the crow flies, 

the shortest distance from the port of Charleston, South 

Carolina, to Kuwait is about 6,000 nm. A ship, however, 

must pass through the Mediterranean Sea, transit the 

Suez Canal, and sail around the Arabian Peninsula, for a 

total of nearly 10,000 nm. That distance would increase 

to about 12,000 nm if the Suez Canal was closed and the 

ship had to travel around the Cape of Good Hope. That 

longer route would add several days to the transit time of 

a 24-knot ship (see Figure 2-2). Even if it could use the 

Suez Canal, the ship might have to wait for access to the 

canal and would be restricted to a lower speed once in the 

canal. (Army planners have recommended adding 16 

hours to assumed schedules to reflect passage through the 

Suez or Panama Canal.) Delays resulting from canals and 

other restricted sea lanes mean that transit times will not 

necessarily decline in proportion to the increases in speed 

offered by faster ships.

Despite the greater flexibility of aircraft, they, too, can 

seldom take a direct route to their destination. Countries 

along the shortest path may deny overflight rights, and 

the need to make en route stops for fuel will usually result 

in a longer one-way flight distance and transit time. For 

instance, a C-17 flying from Charleston to Kuwait would 

travel about 7,000 nm with a typical set of en route stops 

(two or three stops, each with a planned ground time of 

2.25 hours). The need for such stops could be reduced 

with aerial refueling, if it was available and deemed necessary. Of course, even when they must stop along the way, 

aircraft have much shorter transit times than ships do—

hours rather than weeks—because of their much higher 

speeds. A typical airlift mission from the United States to 

Kuwait, for instance, could have a transit time of less than 

0 2,000 4,000 6,000 8,000 10,000 12,000

0

5

10

15

20

25

30

35

16 Knots

24 Knots

32 Knots

40 Knots

48 Knots

12,000 nm at 24 Knots

10,000 nm at 24 Knots

Distance (Nautical miles)
16 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

24 hours, compared with about three weeks for a 20-knot 

ship.

Stage 4: Unloading

The factors that influence unloading times are generally 

similar to those that affect loading. However, unloading 

times are subject to much greater uncertainty in planning, because the location will not be known until a particular crisis arises, and the characteristics of potential 

unloading locations around the world vary greatly. Deployment to an area with spacious deepwater ports and 

large airfields will generally involve shorter unloading 

times. If, by contrast, the local infrastructure limits the 

number of aircraft or ships that can be unloaded simultaneously, this stage will lengthen as transportation platforms wait before support infrastructure is available. In 

some cases, infrastructure constraints could also slow the 

act of unloading itself. For example, some sealift ships 

carry barges that can be used to shuttle cargo ashore if 

adequate port facilities are not available, but that process 

is much slower than unloading at a pier. Ship and aircraft 

designs that offer greater independence from support infrastructure—such as shallow-draft ships that can unload 

at ports too small to accommodate deeper-draft ships—

have the potential to substantially improve unloading 

times in austere theaters.

The Navy and Marine Corps are exploring the feasibility 

of bypassing ports altogether by employing and supporting ground units directly from specially configured 

ships—a concept known as sea basing. However, sea basing would still require a potentially time-consuming cycle 

of transporting units between ship and shore.5

The unloading situation is similar for airlift aircraft. The 

availability of runways long enough and strong enough to 

support large transport aircraft can limit the flow of cargo 

at its unloading point. The availability of other airfield 

services, such as materiel-handling equipment, can also 

force aircraft to wait before unloading their cargo. C-17 

aircraft have been designed to operate from smaller airfields to help ease such constraints. But that capability 

may be of limited use, because a unit delivered to a small 

airfield would arrive slowly (perhaps only one C-17 load 

at a time), which could unacceptably slow the buildup of 

combat power. Moreover, such a unit might have to move 

significant distances on the ground to link up with units 

delivered to other locations.

Stage 5: Reception, Staging, 

Onward Movement, and Integration

The final mobility stage of a strategic deployment extends 

from when the unit is unloaded from its transportation 

platform until it is in place and ready for operations—a 

stage known as reception, staging, onward movement, 

and integration (RSOI). As its name suggests, RSOI 

comprises several activities, most of which are functions 

of the type of unit and its level of training. Typically, personnel fly into an airfield, move to the place (port or airfield) where their equipment is being unloaded, prepare 

the equipment, assemble into units, and proceed to the 

final destination to begin operations. Thus, RSOI technically occurs after the unit has exited the strategic mobility 

system. 

Although RSOI is generally thought of as a series of 

intratheater functions, it is relevant to the discussion of 

strategic mobility because a strategic system can strongly 

influence the time required for that stage in several ways. 

First, a strategic system that can deliver its cargo closer to 

the final destination offers shorter onward-movement 

times. Aircraft can usually deliver cargo as close or closer 

to the final destination as ships can (although the extent 

depends on the characteristics of a particular scenario), 

because airfield locations are not limited to coastlines. 

Similarly, aircraft or ships that are able to make deliveries 

to smaller airfields or ports can potentially get cargo 

closer to its final destination, because there are a greater 

number of smaller facilities spread around the world. 

Second, a mobility system that allows personnel to travel 

with their equipment has the potential to shorten the 

RSOI stage by shortening the reception time.

Because RSOI is a function of the attributes of a given 

scenario, CBO did not estimate specific times for that 

stage for the base case or the options. Rather, the discussion of options in Chapter 4 includes only qualitative 

comparisons of their advantages or disadvantages for 

RSOI.

The Importance of Payload

The total time needed to transport a load of cargo from 

origin to destination is the sum of the first four stages 

described above. For existing aircraft, that time can be as

5. For more details, see Congressional Budget Office, The Future of 

the Navy’s Amphibious and Maritime Prepositioning Forces (November 2004). 
CHAPTER TWO FACTORS THAT AFFECT DELIVERY TIMES OF STRATEGIC TRANSPORTATION FORCES 17

Figure 2-3.

Total Delivery Times for Different Strategic Mobility Platforms

(Days)

Source: Congressional Budget Office.

Notes: The times shown here are for a notional deployment from the United States (or the location of afloat prepositioning forces) to the Persian Gulf. They assume that prepositioning ships travel at a speed of 20 knots and that LMSRs and fast sealift ships in the United States 

are kept in four-day reduced operating status (ROS-4), whereas ships of the Ready Reserve Force are kept in ROS-5.

The RSOI portion of the bars is included as a reminder that additional time may be needed after delivery before a unit can begin operations. The times shown here do not represent estimates of actual RSOI times.

RSOI = reception, staging, onward movement, and integration; nm = nautical mile; LMSR = large, medium-speed roll-on/roll-off 

ship.

short as two days for an initial load delivered from the 

United States to the Persian Gulf (see Figure 2-3). Surge 

sealift ships from the United States need about a month. 

Prepositioned ships have shorter delivery times than 

U.S.-based ships because they do not need to move to the 

initial port or load equipment and because, if positioned 

wisely, they will have shorter transit distances as well. 

The times shown in Figure 2-3 are single-mission delivery 

times. From the perspective of combat power delivered, 

the time when the last elements of a unit arrive—the unit 

closure time—is more important. Only then is the unit 

ready to fully join the operation. The payloads of mobility platforms play a role in closure times because payloads 

determine how many trips each mobility platform must 

make to deliver an entire unit. Ground units of any significant size are larger than any single transportation platform can carry in one load (see Table 2-3). Ships can 

transport even very large units, such as an armored 

(heavy) division, in relatively few loads, whereas aircraft 

need to fly hundreds more missions because of their 

smaller payloads. For example, although C-17s are very 

prompt—they can carry a single load from the United 

States to the Persian Gulf in about one-tenth the time of 

LMSRs—about 30 of the aircraft, flying a total of almost 

300 missions, would be required to deliver an entire 

Stryker brigade in the same total amount of time as an 

LMSR (about 27 days).

The interactions between payload and delivery times 

suggest two initial conclusions. First, in the case of airlift, 

unit closure times could most easily be improved by 

C-17 2,000 nm 4,000 nm 6,000 nm LMSR Fast Sealift Ship Ready Reserve Force

0

5

10

15

20

25

30

35

40

45

Movement to Port

Loading

Transit

Unloading

RSOI

Afloat Prepositioning

(Distance from theater)
18 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Table 2-3.

Number of Loads Needed to Deploy 

Army Units

Table 2-3. Number of Loads Needed to Deploy Army Units

Sources: Congressional Budget Office; Military Traffic Management 

Command, Transportation Engineering Agency, Logistics 

Handbook for Strategic Mobility Planning, Pamphlet 700-2 

(September 2002); and Alan Vick and others, The Stryker 

Brigade Combat Team: Rethinking Strategic Responsiveness and Assessing Deployment Options, MR-1606-AF 

(Santa Monica, Calif.: RAND Corporation, 2002).

Note: LMSR = large, medium-speed roll-on/roll-off ship; FSS = 

fast sealift ship.

increasing throughput capacity with either more aircraft 

or larger aircraft rather than increasing promptness with 

faster aircraft or shorter ground times. The reason is that 

aircraft already have very short delivery times even for 

long transit distances, such as from the United States to 

Asia, so there is little room for substantial improvement 

on an absolute scale—a 50 percent improvement, for 

example, would save less than one day. Although such 

savings might be important in small, specialized missions 

(such as inserting a force to protect an embassy), they 

would be less beneficial in the context of larger deployments that involve many missions for each aircraft. 

Increasing airspeed and shortening ground times would 

yield improvements on the order of a few extra loads per 

aircraft over a several-week deployment.6

Second, in the case of sealift, existing ships are already 

of a size and payload to require good port facilities for 

timely loading and unloading. Increasing the capacity of 

sealift ships would come at the cost of reducing operational flexibility, because fewer ports could handle larger 

vessels. Increasing ships’ speed, by contrast, could cut 

many days off the time needed to deliver large loads. 

CBO developed six illustrative options for improving 

strategic mobility on the basis of the ways in which 

promptness and throughput capacity combine to determine the overall capability to deliver military cargo in a 

timely manner. Those options are described in Chapter 3, 

and their effects on the capability of current mobility 

forces are compared in Chapter 4.

LMSR FSS

Stryker Brigade Combat Team 330 1.0 2.0

Heavy Brigade Combat Team 543 1.6 3.0

Light Infantry Division 425 2.0 3.7

Heavy Division 1,722 5.4 9.8

C-17

6. In any event, substantially reducing round-trip times for airlifters 

would be very challenging technically. Military air transports are 

already designed for rapid loading and unloading, and they fly at 

about 450 knots (or about 0.77 Mach). Higher speeds would 

require some combination of smaller payloads (and thus more 

missions to move a given force), shorter ranges (and thus more 

delays for refueling stops), or larger aircraft (and thus higher costs 

and possibly greater demand for infrastructure at airfields).
3

Options for Improving

Strategic Transportation Forces

Many different ways exist to improve the military’s strategic mobility capabilities. Potential approaches 

can be broadly grouped into five categories:

B Buying greater numbers of the existing systems that 

have the shortest delivery times (such as airlift aircraft);

B Developing new versions of those systems with greater 

payloads (such as larger airlifters);

B Developing prompter versions of current systems 

(such as higher-speed surge sealift ships);

B Deploying existing systems differently (such as moving surge sealift ships into the prepositioning force and 

loading them with new or existing equipment); or

B Lightening military equipment so that greater quantities can be carried by fewer lift assets.

For this analysis, the Congressional Budget Office developed six illustrative options to explore a variety of ways to 

enhance strategic mobility (see Table 3-1). Those options 

are based on all but the last approach listed above. (A previous CBO study concluded that fielding lighter equipment for ground combat units would offer only limited 

improvement in deployment times, because ships would 

still be needed to deliver most unit equipment during a 

large deployment.)1

This chapter describes the changes to strategic mobility 

forces that would be made under each option. The next 

chapter compares the extent to which the options would 

improve cargo deliveries in a long-range deployment—

such as one from the United States to the Persian Gulf or 

Indian Ocean region—and other characteristics of the 

options, including dependence on infrastructure and 

survivability.

Approach for Developing 

the Alternatives

In developing the options for this analysis, CBO focused 

on alternative ways to spend the same amount of money: 

roughly $11 billion (in 2006 dollars) beyond the amount 

needed to maintain current strategic mobility capabilities. 

That additional expenditure includes costs for research 

and development (if necessary), procurement, and operations and support for 30 years after the first new system is 

delivered. By comparison, the Department of Defense 

has spent an average of about $12 billion per year on strategic transportation, including investment and operations, over the past 20 years, CBO estimates. 

CBO chose the target value of approximately $11 billion 

as sufficient to develop and purchase enough systems 

under each option to allow for a meaningful comparison 

of their resulting capabilities. The actual costs of the six 

options range from $11.1 billion to $11.4 billion (see 

Table 3-1) because the alternatives were sized so that they 

would use whole numbers of force elements, such as 

prepositioned units, and so that their costs would be as 

close to one another as possible. Although a lower target 

cost could make some of the options impractical, a higher 

target would not significantly alter the relative improvements in capability offered by the options. The reason is 

that capability increases in proportion with force size, and

CHAPTER

1. See Congressional Budget Office, Options for Restructuring the 

Army (May 2005).
20 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Table 3-1.

The Options for Expanding Strategic Transportation Forces 

Examined in the Analysis

Table 3-1. The Options for Expanding Strategic Transportation Forces Examined in the Analysis

Source: Congressional Budget Office.

Note: LMSR = large, medium-speed roll-on/roll-off ship.

a. Includes costs for research and development (if necessary), procurement, and 30 years of operations and support (after delivery of the 

option’s first aircraft or ship), over and above the costs needed to maintain current strategic mobility capabilities.

the bulk of funds for the options would be spent on procuring and maintaining force structure.2

Designing alternatives around a constant cost rather than 

a specific requirement for mobility was done for two reasons. First, as noted in Chapter 1, information about 

DoD’s current definition of mobility requirements, and 

hence about what mobility shortfalls DoD might try to 

correct, was not available to CBO. Second, the national 

security environment and thus DoD’s perceived mobility 

requirements are likely to change by the time many of the 

systems considered in these options could be fielded. 

Given that uncertainty, the constant-cost approach provides broader information about the relative costeffectiveness of different options over a range of total strategic lift capabilities.

CBO included operation and support (O&S) costs for 

the systems purchased under each option in the total 

costs for the option because O&S costs could differ significantly among the alternatives. For example, afloat 

prepositioned forces require maintenance of the unit 

equipment on board the ships, not just of the ships themselves. Similarly, a surge sealift ship can be maintained in 

Major Effect

Option 1A: Buy 21 Increases the number of the most prompt type of system 11.3

Additional C-17 Aircraft

Option 1B: Develop and Buy Provides large improvement in payload relative to other airlifters 11.3

14 to 16 Heavy-Lift Airships

Option 2A: Buy 17 Shifts cargo from slow Ready Reserve Force ships to faster LMSRs 11.3

Additional LMSRs

Option 2B: Develop and Buy Provides ship-sized payloads much earlier in a deployment 11.1

Six Advanced-Technology 

High-Speed Sealift Ships

Option 3A: Buy Four Sets of Puts more unit equipment close to likely areas of conflict 11.4

Stryker Brigade Equipment

and Four LMSRs

Option 3B: Buy Five Sets of Puts even more unit equipment close to likely areas of conflict 11.1

Stryker Brigade Equipment and but shrinks the surge sealift fleet

Store Them on Existing LMSRs

Total Investment and 

Surge Sealift

Operating Costsa

(Billions of 2006 dollars)

Airlift

Afloat Prepositioning

2. An option with a large fraction of spending devoted to research 

and development could show a greater relative improvement in 

capability if additional funds were made available. The potential 

impact of that fact is noted in the discussion of the options that 

would develop new systems if the development costs would significantly affect the number of systems that could be purchased.
CHAPTER THREE OPTIONS FOR IMPROVING STRATEGIC TRANSPORTATION FORCES 21

a less-expensive reduced operating status, whereas a prepositioned ship needs to be maintained in full operating 

status to provide the most responsiveness to a deployment 

order. A 30-year window for O&S costs, although longer 

than the time lines used in many past studies, is consistent with the long operational lives expected for today’s 

ships and transport aircraft. The 30-year window begins 

with the delivery of an option’s first ship or aircraft.

In developing the options, CBO assumed that the bulk of 

the strategic mobility forces would remain as planned: a 

mix of airlift, surge sealift, and prepositioned equipment 

similar to that described in Chapter 1. Current plans call 

for the Navy to purchase the existing Maritime Prepositioning Force ships when their leases expire and to continue operating them until they can be replaced with proposed MPF (Future) squadrons. Some of the roll-on/rolloff ships in the Ready Reserve Force and some fast sealift 

ships may also need to be replaced in coming decades. 

This study considers such changes or replacements to be 

part of the cost of maintaining the current base-case capabilities. However, the analysis notes ways in which particular options might affect that background cost.

Options to Improve Airlift

Given the interactions between payload and delivery time 

described at the end of Chapter 2, CBO’s options for improving airlift capabilities focus on increasing the amount 

of cargo that the strategic airlift force can carry instead of 

the speed of individual aircraft. Option 1A would expand 

throughput capacity by purchasing more conventional 

aircraft: 21 additional C-17s. Option 1B explores the potential improvement offered by a new airlifter—in this 

case, a helium-filled hybrid airship—with a payload 

many times larger than those of current aircraft.

Option 1A: Purchase More C-17s

The first approach in CBO’s analysis would speed up 

strategic deployments by increasing the throughput capacity of the conventional airlift force, the most prompt 

form of transportation in today’s strategic mobility forces. 

This option would expand the currently planned fleet of 

C-17s by 21 aircraft, or 12 percent. That approach has 

the advantage of relying on a proven airlifter rather than 

on more-advanced and not yet proven concepts that 

might be developed. However, it has the disadvantage of 

adding to the already substantial demand for support 

infrastructure of the current airlift force. In an 

infrastructure-constrained theater, more aircraft might offer little or no improvement in capability (see Chapter 

4).3

CBO selected the C-17 for its conventional-airlift option 

for several reasons. First, that aircraft is the only military 

strategic airlifter now in domestic production. The Administration’s current plans call for purchasing 15 C-17s 

in 2006 and a final 12 in 2007, bringing the total 

throughout the program to 180 aircraft. Second, other 

existing options for increasing the throughput capacity of 

airlift lack the C-17’s performance. For example, the

C-130J (which is also in production) is a tactical transport plane with a much shorter range, a much smaller 

payload, and an inability to carry outsize cargo. Another 

possible alternative might be to get more private-sector 

aircraft into the Civil Reserve Air Fleet, but CRAF aircraft have limited ability to carry the vehicle cargos that 

dominate unit deployments. Third, the C-17 is the most 

efficient airlifter in terms of cargo delivered per amount 

of support infrastructure needed—a potentially important advantage in locations with constrained infrastructure.

Buying 21 additional C-17s would cost $4.4 billion, 

CBO estimates, assuming a purchase price of about $210 

million per aircraft. Operating the new aircraft would 

cost another $6.9 billion over 30 years. That figure is 

based on the Air Force’s estimate of annual operating 

costs for the C-17 of about $12 million per aircraft. The 

estimate may be optimistic for a 30-year period, however, 

because it is based on the current operations of a relatively young C-17 fleet (the first production C-17s were 

delivered in the mid-1990s). Maintenance costs tend to 

rise as aircraft get older and are especially sensitive to the 

number of hours flown, the number of takeoffs and landings, and even the characteristics of individual missions.4

(For more details of how CBO estimated the costs of the 

various options in this study, see the appendix.)

3. The implication of trying to avoid infrastructure constraints by 

developing a strategic airlifter that can operate from even smaller 

airfields is also discussed in Chapter 4.

4. For example, missions involving very heavy loads, landings on 

unimproved runways, or aerial refueling (when an aircraft must fly 

in the turbulent wake of the tanker) put greater wear and tear on 

an airlifter than do missions with light loads, long and smooth 

runways, and no aerial refueling.
22 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 3-1.

Improvement in Deliveries from 

Buying Another 21 C-17s (Option 1A)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

Because some fraction of the airlift fleet is usually 

assumed to be unavailable for reasons such as depot 

maintenance, CBO assumed that 19 of the 21 additional 

C-17s would be available to contribute to this analysis’s 

representative deployment. In the absence of infrastructure constraints, those aircraft would provide increased 

deliveries to the theater in just one to two days. By day 6 

(when the first prepositioned ship would arrive), this 

option could deliver about 1,400 more tons of cargo than 

the current force—a 7 percent increase in total deliveries 

to that point (see Figure ). After day 6, the percentage improvement offered by Option 1A would drop because 

prepositioned ships would have begun unloading large 

amounts of cargo. Nevertheless, Option 1A would continue to increase deliveries to the theater by about 350 

tons per day during surge operations.

Option 1B: Develop Heavy-Lift Airships

Instead of buying more aircraft with the payload size of 

current airlifters, this option would develop and field an 

aircraft with a significantly larger payload. Two very different approaches have been proposed for such a heavylift aircraft: one would develop new fixed-wing aircraft 

with larger payloads and longer ranges than current airlifters, and the other would develop heavy-lift airships 

(which would have propulsion and steering systems and 

be lighter than air or nearly so).

An example of the first approach is a blended-wing body 

concept, an airframe that would combine efficient 

high-lift wings and a wide airfoil-shaped body to generate 

lift and minimize drag, thus increasing fuel economy. 

Such a design has been proposed for a wide variety of 

missions, including strategic transportation, aerial refueling, and aerial launch of long-range air-to-surface missiles. In addition to its larger payload, the longer range of 

such an aircraft could improve cycle times (the total time 

from loading one cargo to returning for the next) by reducing the number of en route stops needed to reach a 

distant theater. The disadvantage of a larger fixed-wing 

aircraft is that it would probably be more constrained to 

operate from large airfields than current aircraft are. Consequently, that approach would add to the current force’s 

already substantial capability to deliver cargo to large air 

bases but would run counter to the trend of seeking 

greater flexibility to operate airlifters from the more 

numerous smaller airfields available around the world.

Because of those drawbacks, CBO chose the second 

approach for Option 1B—a conceptual heavy-lift hybrid 

airship (see Figure 3-2 for an artist’s conception of such 

an aircraft). A hybrid airship differs from a conventional 

airship, such as a blimp, in that it derives its lift from 

more than just the buoyancy of the helium inside the 

hull. The airfoil shape of the hull provides additional lift,

Figure 3-2.

Artist’s Rendition of a Potential 

Heavy-Lift Hybrid Airship

Used by permission.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

1

2

3

4

5

6

7

0

5

10

15

20

Additional Cargo

Delivered (Right scale)

Days

Percentage Increase

in Deliveries

(Left scale)
CHAPTER THREE OPTIONS FOR IMPROVING STRATEGIC TRANSPORTATION FORCES 23

essentially acting as a wing when the airship is moving 

forward. Specific design concepts for such an airship vary, 

but roughly speaking, the static lift provided by the helium-filled gas bags in the hull supports the weight of the 

airship and its fuel, and the dynamic lift provided by the 

hull’s shape offers the extra lift to allow the ship and its 

payload to make the transition to flight. Some concepts 

also include actual wings to provide dynamic lift. Forward speed comes from propellers, much as with current 

airships. 

The balancing of static and dynamic lift means that total 

lift is much easier to control—both on the ground and in 

the air—than with conventional airships. (Old newsreel 

footage of a crowd of ground handlers being lifted into 

the air when a gust of wind hit a Zeppelin during docking graphically illustrates the problem of controlling a 

large conventional airship.) In principle, a hybrid airship 

would not need to be held down with strong tethers upon 

landing or to have ballast added during unloading 

because the ship, minus its payload, would be about neutrally buoyant. High winds could still be a problem, however, because the size of the hull would present a large sail 

area for winds to act on.

Option 1B would develop and field a hybrid airship similar in performance to the goals of the Defense Advanced 

Research Projects Agency’s (DARPA’s) Walrus program: 

an aircraft with a payload of at least 500 tons that could 

operate from unimproved locations and transport its load 

anywhere in the world in a few days.5

 Specific designs 

could vary significantly, but concept designs envision an 

airship roughly 1,000 feet long and 300 feet wide. Its 

structure would probably consist of a nonrigid hull to 

hold the helium and an underslung gondola to carry 

cargo and troops. Estimates of achievable speeds for 

hybrid airships range from about 80 knots to 120 knots. 

For this analysis, CBO assumed an average speed of 100 

knots.

This option would have a total cost of $11.3 billion, 

CBO estimates—about $3.0 billion to $4.0 billion to develop the airship and the rest to purchase 14 to 16 airships and operate them for 30 years.6 Those estimates are 

Figure 3-3.

Improvement in Deliveries from 

Buying 15 Heavy-Lift Hybrid Airships 

(Option 1B)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

based on a DoD study of advanced mobility concepts and 

on contractor data for proposed heavy-lift airships (see 

the appendix for more details). CBO assumed that all of 

the airships would be available for operations in the event 

of a crisis. (The calculations of the additional capability 

provided by this option assume a fleet of 15 airships.)

Although not as prompt as conventional aircraft, hybrid 

airships could still begin arriving in the Persian Gulf 

region from the United States in about five days (see 

Figure 3-3), assuming that the units they transported 

were ready for loading immediately. The 15 airships 

would deliver about 1,000 tons of cargo per day—about 

three times as much as the 21 C-17s in Option 1A. Despite delivering more cargo than Option 1A, this option 

shows a similar percentage increase in cargo delivered 

early in the scenario, a peak of about 7 percent, because 

the first prepositioning ships would be arriving at about 

the same time as the airships under the assumptions of 

CBO’s deployment scenario. If the prepositioned ships 

were located farther from the theater and hence arrived 

later, the initial percentage increase in deliveries attributable to this option would be higher.

5. In addition to DARPA, the Naval Air Systems Command and 

DoD’s Office of Force Transformation are exploring the potential 

utility of ultralarge airlifters.

6. There is significant uncertainty about development costs for the 

hybrid airship because of the lack of historical experience with 

similar systems (see the appendix).

0 5 10 15 20 25 30 35 40 45 50 55 60

0

1

2

3

4

5

6

7

0

10

20

30

40

50

60

Days

Percentage Increase

in Deliveries

(Left scale)

Additional Cargo

Delivered (Right scale)
24 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

The throughput capacity of Option 1B would decline if 

the cost of the airships grew relative to CBO’s estimates 

and reduced the number of airships that could be bought 

within the spending target for these options. Among 

other possibilities, unforeseen technical hurdles during 

development could increase development costs. Alternatively, lower development costs could allow the purchase 

of a slightly larger airship fleet, with a corresponding 

increase in throughput capacity. (For example, a development cost half that of CBO’s low estimate would allow 

the purchase of three additional airships within the total 

cost target.)

Aside from very large payloads, the biggest advantage of 

hybrid airships would be their potential ability to operate 

essentially independently of large air bases in a theater. 

Such airships could also offer shorter time lines for reception, staging, onward movement, and integration than 

would the other alternatives, both because cargo could be 

delivered closer to its final destination and because airships have the potential to efficiently carry troops with 

their equipment, eliminating the need for personnel to 

marry up with equipment that has been transported on a 

different platform. (Those factors are discussed in more 

detail in Chapter 4.)

Set against those positive features, there are potential disadvantages to pursuing large hybrid airships. Proponents 

argue that the technical risk inherent in developing such 

aircraft is lower than might be expected because the necessary component technologies have, for the most part, 

already been developed for other applications. However, a 

hybrid airship with a payload on the order of 500 tons 

and an approximate gas volume of 25 million to 35 million cubic feet would be much larger than any previous 

airship—four to five times larger than the biggest airships 

of the 1930s. Although the expertise to build individual 

components may already exist, integrating them into 

such a large structure could prove more difficult than 

expected. 

Other possible disadvantages of an airship relative to conventional aircraft are its potential vulnerability both to 

military action, such as antiaircraft fire, and to political 

action, such as countries along its route refusing to let it 

fly through their airspace. Both of those vulnerabilities 

are increased because the hybrid airship would fly at a 

lower speed and altitude than aircraft such as the C-17: 

at 80 to 100 knots (versus more than 400 knots for the 

C-17) and at less than 10,000 feet (compared with more 

than 30,000 feet). Overflight rights might be more difficult to obtain for airships because their passage would be 

much more apparent than that of a conventional aircraft. 

Consequently, nations willing to quietly allow highaltitude overflights might be more reluctant to permit 

low, slow overflights by airships. (To capture the effect of 

possible restrictions on overflight rights, CBO’s deployment scenario assumes a transit distance of 8,500 nautical 

miles for airships, halfway between the values for conventional airlifters and surge sealift ships.)

Options to Improve Surge Sealift

CBO’s alternatives for expanding surge sealift capabilities 

are based on increasing the speed of the strategic sealift 

force instead of the payload of individual ships. (As noted 

in Chapter 2, sealift ships larger than those in the current 

force would be seriously limited in terms of the number 

of ports around the world that could accommodate 

them.) As with airlift, one of the sealift alternatives would 

increase the number of current ships, and the other 

would design a new vessel. Specifically, Option 2A would 

buy more of today’s faster roll-on/roll-off ships, and 

Option 2B would develop a new sealift ship capable of 

achieving much higher speeds than current ships of similar size.

Option 2A: Purchase More LMSRs

This option would speed strategic deployments by adding 

to the number of large, medium-speed roll-on/roll-off 

ships in the strategic sealift force. Although the Military 

Sealift Command’s fast sealift ships are faster, CBO chose 

LMSRs for this option because they were in production 

much more recently (the last one was delivered in 2003, 

whereas the FSSs were produced in the early 1970s) and 

because they were built domestically. Thus, LMSRs offer 

the advantage of a proven ship design with which U.S. 

shipyards have recent production experience. Trying to 

build a ship with FSS-like performance would entail 

greater technical and cost risks and would require extra 

expenditure on new design work.

This option would buy 17 additional LMSRs at a total 

cost of $8.4 billion, CBO estimates, with production 

split between the two shipyards that built the current fleet 

of LMSRs (National Steel and Shipbuilding in California 

and Avondale in Mississippi). No funds would be needed 

for development. Operating the new LMSRs would cost 

about $7 million per ship per year, or about $2.9 billion 

over the 30 years after the first ship was delivered. Those
CHAPTER THREE OPTIONS FOR IMPROVING STRATEGIC TRANSPORTATION FORCES 25

Figure 3-4.

Improvement in Deliveries from 

Buying Another 17 LMSRs (Option 2A)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

Note: LMSR = large, medium-speed roll-on/roll-off ship.

operating costs assume that the LMSRs would be maintained in four-day reduced operating status, as current 

surge sealift ships are.

The 17 ships purchased under Option 2A could deliver 

their first cargo to a Persian Gulf conflict in about 24 

days, making this option the least prompt alternative in 

CBO’s analysis. However, the average throughput capacity of this option would be very high. Assuming no constraints on infrastructure, by day 35 the additional 

LMSRs could deliver about 280,000 tons of cargo (more 

than enough equipment for two heavy divisions) from 

the United States—approximately a 30 percent increase 

over the base case (see Figure 3-4).7 The throughput 

capacity offered by this option is so large that it would 

probably allow the Department of Defense to retire older 

RO/RO ships in the Ready Reserve Force in exchange for 

the new LMSRs, which could arrive 10 days earlier. (That 

potential implication for the modernization of the basecase sealift force is discussed in Chapter 4.)

If this option bought FSS-like ships instead of LMSRs, 

initial deliveries would occur five days earlier, assuming 

that the new ships could maintain an average speed of 33 

knots. The amount of cargo delivered in the first wave of 

arrivals would be much smaller, however, for two reasons. 

First, each FSS-like ship would have a smaller payload 

than an LMSR. Second, a new FSS-like design could possibly be more expensive than an LMSR, allowing fewer to 

be purchased under the spending target for these options.

Option 2B: Develop High-Speed Sealift Ships

Faster ships could improve the promptness of strategic 

sealift by substantially shortening the transit stage. For 

example, approximately doubling the speed of an LMSR 

from 24 knots to more than 45 knots would cut delivery 

time for a 10,000 nm transit by about nine days (see 

Figure 3-5). As noted in Chapter 2, transit time is the 

largest component of total delivery time (excluding 

scenario-specific RSOI) for a notional deployment by 

ship—whether to the Persian Gulf, which is at the upper 

end of transit distances from the United States, or over 

much shorter distances.

As with aircraft, increasing the speed of ships requires 

making design compromises that affect the hull form, 

range, payload, overall size, and cost. Such compromises 

can reduce the advantage offered by greater speed. For example, a very high speed ship might have a short range, 

requiring many time-consuming stops for 

refueling. A good choice of speed for a future sealift ship 

should balance those factors against the benefit of shorter 

transit times and the technical risk inherent in pursuing a 

design significantly more advanced than those of contemporary ships. That balancing act is especially important 

given the declining marginal benefit of adding each knot 

of speed as overall speed increases (an effect illustrated by 

the fact that the lines in Figure 3-5 are closer together at 

higher speeds).

Various designs have been proposed for high-speed sealift 

ships (see Table 3-2). They show how greater speed 

comes at the cost of much larger power requirements and

7. Payloads of RO/ROs are typically measured in square feet of vehicle-parking space instead of in weight. The weight of cargo varies 

greatly depending on its density (for example, a tank is much 

heavier per square foot of deck space than is a helicopter). However, CBO used weight in this analysis to allow more-direct comparisons with airlift. Payload figures for prepositioned ships (the 

Maritime Prepositioning Force and Army Prepositioning Stock) 

are for expected loads. Payload figures for surge sealift ships are 

derived from Army data on logistics planning factors and reflect a 

weighted average of light-unit and heavy-unit loads.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

5

10

15

20

25

30

35

0

50

100

150

200

250

300

Percent Thousands of Tons

Additional Cargo

Delivered

(Right scale)

Days

Percentage Increase

in Deliveries

(Left scale)
26 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 3-5.

Decrease in Transit Time Relative to That of a 24-Knot Ship

(Number of days less)

Source: Congressional Budget Office.

smaller payloads (over a given range) for ships with external dimensions similar to those of current sealift ships.8

Improvements in technology over time have the potential 

to reduce the impact of those performance compromises; 

for example, advanced lightweight structural materials 

and propulsion plants might enable the 55-knot trimaran 

proposed by Naval Sea Systems Command (NAVSEA) to 

achieve similar ranges and payloads as a 37-knot ship 

with today’s technology. But such advanced technologies 

can be difficult to realize and are likely to be more expensive than current technologies.

For its illustrative high-speed sealift (HSS) option, CBO 

selected a monohull design with a speed midway between 

those of the NAVSEA Rapid Strategic Lift Ship concept 

and the advanced-technology NAVSEA trimaran (see 

Table 3-2). Despite being slower than the conceptual trimaran, CBO’s notional high-speed ship still represents a 

very advanced design that would push the current state of 

the art in hull-form design, materials technology (for 

lightweight hulls that can withstand the pounding of 

high-speed movement through water), and propulsion 

technology. 

The characteristics of that notional HSS ship are an amalgamation of several specific designs that CBO reviewed. 

The ship’s size would allow it to transit the Panama and 

Suez Canals, if necessary, and give it at least the same port 

accessibility as today’s LMSRs. With a cruising speed of 

45 knots, the HSS ship could travel 10,000 nm in eight 

fewer days than a current LMSR and just one to two 

more days than the 55-knot trimaran. That slightly 

longer delivery time would be balanced against having a 

design that was less reliant on undeveloped technology 

than the trimaran’s. A drawback of CBO’s notional ship is 

that, barring great technological leaps, it would not have 

a long enough range to travel anywhere in the world (carrying its full payload of 10,000 tons) without refueling. 

Consequently, it would require a ship for refueling that

0 2,000 4,000 6,000 8,000 10,000 12,000

0

2

4

6

8

10

12

14

16

75 Knots

65 Knots

55 Knots

45 Knots

35 Knots

Nominal transit distance from

Atlantic coast of the United States

to Persian Gulf/Indian Ocean region

Distance (Nautical miles)

8. Larger ships might offer both higher speed and payloads similar to 

those of current FSSs and LMSRs, but such ships would require 

even more power (to propel the increased hull and fuel weight), 

would be more costly, and would be very limited in the ports they 

could use. The world’s supposed largest-capacity container ship, 

scheduled for delivery in 2007, is expected to be about 1,200 feet 

long and have a 150-foot beam, approaching the limits of even the 

biggest container terminals.
CHAPTER THREE OPTIONS FOR IMPROVING STRATEGIC TRANSPORTATION FORCES 27

Table 3-2.

Characteristics of Proposed High-Speed Ships Table 3-2. Characteristics of Proposed High-Speed Ships

Sources: Congressional Budget Office; and Naval Sea Systems Command briefings.

Note: nm = nautical miles; LMSR = large, medium-speed roll-on/roll-off ship; FSS = fast sealift ship; NAVSEA = Naval Sea Systems

Command.

a. Payload figures for LMSRs and FSSs come from MTMCTEA PAM 700-2; operational payloads are usually smaller. Payloads for the NAVSEA 

ships could be larger with midocean refueling.

b. This design is not a roll-on/roll-off ship but a ship intended to carry troops and high-value cargo, such as Marine Corps aircraft.

could be dispatched ahead or prepositioned in likely locations for that task. Alternatively, the HSS ship could carry 

extra fuel to extend its range, but at the expense of cargo 

space. This option would purchase two oilers to provide 

underway refueling for the HSS ships; one for transAtlantic missions and one for trans-Pacific missions.9

Less reliance on advanced technologies, coupled with the 

greater experience that shipyards have with monohull designs, should also make the notional HSS ship less expensive than a faster design. CBO estimates that developing 

the ship would cost about $2.0 billion (building on 

research already in progress), and buying six of them 

would cost $6.4 billion. The six ships would cost a total 

of $1.6 billion to operate for 30 years, or about $10 million annually per ship, if they were kept in four-day ROS. 

Despite having the same operating status, an HSS ship 

would cost more to operate than an LMSR, primarily 

because it would consume more fuel when in use. The 

additional procurement and operation costs of the two 

oilers would bring the total for this option to about $11.1 

billion.

The six high-speed ships purchased under this option 

could make their first deliveries to a Persian Gulf deployment in about 14 days (see Figure 3-6), including an 

at-sea refueling so the ships could maintain a speed of 45 

knots with a 10,000-ton load. That arrival time would be 

seven days earlier than for current fast sealift ships and 10 

days earlier than for today’s LMSRs, though HSS ships 

would deliver less cargo than those vessels because of their 

smaller payloads. The high-speed ships would complete 

delivery of a payload equivalent in weight to one Stryker 

brigade combat team around day 16. The base-case FSS 

and LMSR fleets would complete equivalent deliveries by 

about day 21 and day 24, respectively, under the assumptions of CBO’s notional scenario. The HSS ships could 

deliver a second load from the United States around day 

40, shortly after the first ships from the Ready Reserve 

Force would be expected to arrive. The deliveries from 

the first wave of HSS ships would increase the amount of 

cargo that could be delivered by almost 11 percent 

around day 20 (see Figure 3-6). That figure is not higher 

because by the time the first HSS ships arrived, a large 

amount of cargo would already have been delivered by 

prepositioned ships.

LMSR-Type Ship 24 48 17.0 20,000

FSS-Type Ship 30 90 14.0 16,000

NAVSEA Rapid Strategic Lift Ship

Concept (Near-term technology)b 36 144 11.6 5,100

CBO's Notional High-Speed Ship 45 250 9.0 10,000

NAVSEA Trimaran Concept 

(Long-term technology) 55 360 8.0 5,000

5,000

8,700

Sustained Speed Installed Power

(Mwatts) (Tons)a

Time to Transit

10,000 nm (Days)

Nominal Payload

8,000

Range (nm)

More than 10,000

More than 10,000

(Knots)

9. HSS ships might also be able to refuel from Navy support ships 

already located in forward locations, if the naval task groups supported by those refueling ships could spare the fuel.
28 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 3-6.

Improvement in Deliveries from 

Buying Six High-Speed Sealift Ships 

(Option 2B)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

Options to Expand 

Prepositioned Forces

Another approach for improving strategic mobility is to 

change how units are based or deployed in peacetime. A 

previous CBO analysis looked at how altering the locations of Army bases might affect deployment times. It 

concluded that such changes would yield only small improvements in response times to conflicts worldwide 

because deployment times to many potential trouble 

spots from the likely locations of new bases would not be 

significantly shorter than deployment times from current 

bases.10 This study examines how greater use of prepositioned equipment might improve response times to distant conflicts.

CBO considered two approaches to expand prepositioning. For almost the same total cost, the first approach 

(Option 3A) would purchase both additional Army 

equipment and new LMSRs to carry it. The second 

approach (Option 3B) would buy a greater amount of 

Army equipment but would preposition it on LMSRs 

taken from the current surge sealift fleet. The additional 

equipment would be purchased in sets configured for 

Stryker brigade combat teams (BCTs). The Army is fielding medium-weight Stryker BCTs as an interim way to 

provide armored forces that can be transported more easily than traditional heavy units can. The Army’s ultimate 

goal is to field even lighter, more transportable Future 

Combat Systems (FCS) “units of action” sometime in the 

next decade. CBO based these options on the interim 

Stryker forces because considerable uncertainty remains 

about the structure and cost of the proposed FCS forces.

Option 3A: Purchase New Prepositioning Ships 

and Army Unit Sets

This option would buy four sets of Stryker BCT equipment and four LMSRs on which the equipment would be 

prepositioned afloat. In addition, a chartered container 

ship would be included for each brigade set in order to 

provide additional sustainment supplies to the brigade in 

case it was deployed for a long independent operation. 

Procurement costs would comprise $2.0 billion for the 

four LMSRs and $6.0 billion for the four Army unit sets.

Figure 3-7.

Improvement in Deliveries from 

Buying Four Stryker BCT Equipment 

Sets and Prepositioning Them on Four 

New LMSRs (Option 3A)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

Note: BCT = brigade combat team; LMSR = large, medium-speed 

roll-on/roll-off ship. 10. See Congressional Budget Office, Options for Changing the Army’s 

Overseas Basing (May 2004). 

0 5 10 15 20 25 30 35 40 45 50 55 60

0

2

4

6

8

10

12

0

20

40

60

80

100

120

Additional Cargo

Delivered (Right scale)

Days

Percentage

Increase

in Deliveries

(Left scale)

0 5 10 15 20 25 30 35 40 45 50 55 60

0

20

40

60

80

100

120

0

2

4

6

8

1

1

Additional Cargo

Delivered (Right scale)

Days

Percentage Increase

in Deliveries (Left scale)
CHAPTER THREE OPTIONS FOR IMPROVING STRATEGIC TRANSPORTATION FORCES 29

Operations over 30 years would cost $3.5 billion. Of 

course, if more-expensive Army units were chosen for 

prepositioning (estimates for a similar-size unit equipped 

with the proposed FCS range as high as $7 billion), fewer 

sets of equipment could be purchased.

If two of the new brigade sets were prepositioned 2,000 

nm from the site of CBO’s representative deployment 

scenario and the other two were located 4,000 nm from 

that site (distances representative of past locations of 

prepositioned equipment), initial deliveries would begin 

around day 4 and would be completed around day 12.

The new prepositioned brigades would arrive earlier than 

the existing Maritime Prepositioning Force because these 

LMSRs are faster than the MPF ships. After day 45, the 

LMSRs could begin arriving with second loads transported from the United States.

This option would produce a large percentage increase in 

the amount of cargo delivered early in a conflict—more 

than doubling cargo deliveries on day 6, for example (see 

Figure 3-7). The reason is that the four LMSRs would be 

the first ships to arrive in the theater (only aircraft would 

have been making deliveries before then). The percentage 

improvement in cargo deliveries would drop quickly 

thereafter as the current MPF ships began to arrive. The 

peak improvement would be substantially lower if this 

option’s four prepositioned ships were located farther 

from their destination. (The sensitivity of the results to 

assumptions about the locations of afloat prepositioned 

forces is discussed in Chapter 4.)

Option 3B: Purchase Army Unit Sets 

and Preposition Them on Existing LMSRs

The other prepositioning option in this analysis would 

buy five sets of Stryker BCT equipment rather than four. 

To make up for the greater spending on equipment, it 

would preposition those sets on existing LMSRs taken 

from the surge sealift force. As in Option 3A, a chartered 

container ship would be included with each brigade set to 

provide additional sustainment supplies if necessary. The 

costs of this option would total $11.1 billion: $7.5 billion 

for procurement of the Army unit sets and about $3.6 

billion for operations and support over 30 years.

Initially, this option would produce the same improvement in deliveries as Option 3A, as the first four brigade

Figure 3-8.

Improvement in Deliveries from 

Buying Five Stryker BCT Equipment 

Sets and Prepositioning Them on 

LMSRs Taken from the Surge Sealift 

Fleet (Option 3B)

(Percent) (Thousands of tons)

Source: Congressional Budget Office.

Note: BCT = brigade combat team; LMSR = large, medium-speed 

roll-on/roll-off ship.

sets arrived from their propositioning locations 2,000 and 

4,000 nm away. Around day 16, however, this option 

would deliver more than the previous alternative because 

the additional brigade set would arrive (see Figure 3-8).11

At about day 30, the amount of additional cargo delivered relative to the base case would drop to zero because 

the extra arrivals of prepositioned equipment early in the 

scenario would be cancelled by the corresponding reduction in arrivals by the now-smaller surge sealift force. The 

net effect would be positive, however, because even 

though the total amount of cargo delivered over time 

would not increase, each load carried by the five LMSRs 

transferred from the surge force to the prepositioned 

force would arrive several weeks earlier.

11. CBO assumed that the fifth brigade set would be prepositioned 

farther away (6,000 nm) to cover another part of the world but 

that it would be pressed into service in the notional scenario.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

20

40

60

80

100

120

0

20

40

60

80

100

120

Additional Cargo

Delivered

(Right scale)

Days

Percentage Increase

in Deliveries (Left scale)

4

Comparison of Strategic Transportation Options

Although the options for improving strategic 

mobility described in Chapter 3 would have roughly the 

same total costs, according to the Congressional Budget 

Office’s estimates, they differ greatly in the military capabilities they offer. For example, the airlift options would 

improve the promptness of strategic deployments to a 

greater extent than the sealift options would; however, 

their addition to throughput capacity would be lower, on 

average. Some options would surpass others in terms of 

ability to operate with limited support infrastructure, to 

get units on their way quickly once cargo had been 

unloaded, and to survive enemy attack. Of course, a given 

capability may be more or less valuable depending on 

how the future unfolds. This chapter compares the six 

options according to various measures and describes the 

sensitivity of each option’s performance to changes in the 

conditions of CBO’s representative deployment scenario.

Promptness and Throughput Capacity

The amount of time needed to move military units a 

given distance after a deployment order and the amount 

of cargo that a transportation system can move are the 

primary measures that CBO used to assess the effectiveness of the options to expand mobility forces. As illustrated in Chapter 3, each option would have its own 

characteristic delivery profile, and differences between 

those profiles result in different improvements in cargo 

deliveries (relative to those of the base-case force) at any 

particular point in the scenario. Only the airlift and prepositioning options would improve deliveries in the first 

week of a notional deployment to the Persian Gulf or 

Indian Ocean region, and the prepositioning options 

would deliver significantly more cargo than the airlift 

options during that time. By the end of the second week, 

the more distant prepositioned brigades would have 

arrived, and the high-speed sealift ships in Option 2B 

would begin to arrive as well. By the end of week 3, the 

HSS force would have completed its first deliveries, and 

the contributions of airlift would continue to grow. The 

new large, medium-speed roll-on/roll-off ships in Option 

2A would not arrive until the fourth week, but when they 

did, their enormous capacity would dwarf the deliveries 

of the other options.

In terms of delivering enough cargo for a Stryker brigade 

combat team, the prepositioning options (3A and 3B) 

would offer the best combination of promptness and 

throughput capacity (see Figure 4-1). In the figure, 

promptness is plotted on the vertical axis and measured 

by the time needed for the additional systems to make 

their first delivery to the theater of operations. Throughput capacity is plotted on the horizontal axis and is measured by the time required to complete delivery of 

amounts of cargo equivalent to those needed for successive Stryker BCTs (marked as diamonds on the line for 

each option).

The promptness of the options depends on the performance characteristics of each system. Throughput capacity, in turn, depends both on promptness and on the 

number of systems purchased. If there are no constraints 

on support infrastructure, purchasing greater quantities 

of a system can increase throughput capacity. But 

promptness limits this approach for boosting throughput 

capacity, because having an unlimited number of aircraft 

or ships will not increase the speed with which the first 

ones arrive in a theater. (Purchasing greater quantities of a 

system would shift deliveries to the left only as far as the 

dashed line in the figure, which denotes the earliest arrival of a type of ship or aircraft.) The relative value of 

promptness versus throughput capacity—and hence the 

types and quantities of strategic transportation systems 

that the military might choose to buy—will depend on

CHAPTER
32 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 4-1.

Promptness and Capacity to Deliver Five Brigades Under Various Options 

for Expanding Strategic Mobility Forces

Source: Congressional Budget Office.

Note: The diamonds represent successive Stryker brigade combat teams arriving in the notional theater of operations. These deliveries are 

in addition to those made by current strategic mobility forces. The dashed line indicates the earliest possible delivery time for a brigade using a given transportation system. (The distance between that line and the first diamond represents the potential room for 

improvement from adding to the number of platforms in that system.)

a. Option 3B, which would preposition equipment for five additional brigades on large, medium-speed roll-on/roll-off ships (LMSRs) transferred from the surge sealift fleet, is not shown. It would deliver four Stryker brigade combat teams at the same times as Option 3A and a 

fifth about two days later. During the fourth week, however, those additional arrivals would be negated by the fact that the LMSR fleet 

arriving at that time would have five fewer ships.

DoD’s determination of its plans and requirements for responding to future crises.

The relative results between options are sensitive to the 

geographic assumptions that underlie the base-case scenario—most important, how far the destination point is 

assumed to be from the location of prepositioning ships 

and from the United States. In the prepositioning 

options, only those brigade sets located 2,000 nautical 

miles from the theater would arrive in the first week of 

the notional scenario. Sets based 4,000 nm away would 

not arrive until the second week. Greater transit distances 

not only delay arrival times but also lower the percentage 

increase in cargo delivered at a given time (see Figure 4-

2). Nevertheless, for a deployment from the United States 

to the Persian Gulf, the peak improvements offered by 

the prepositioning options (even under very pessimistic 

assumptions about the locations of prepositioned equipment) would be better than those of the other options.

Just as distance affects deliveries of prepositioned equipment, cargo deliveries from the United States by airlift or 

surge sealift could increase early in a conflict for scenarios 

closer to North America. As long as support infrastructure is not a constraining factor, shorter transit distances 

will allow more-rapid cargo delivery. Under the base-case

0

5

10

15

20

25

30

0 10 20 30 40 50 60

Capacity: Days to Deliver Successive Brigades (Diamonds)

Promptness: Day of First Delivery

Option 1A: 21 More C-17s

Option 1B: 15 Heavy-Lift Hybrid Airships

Option 2B: Six High-Speed Sealift Ships

Option 2A: 17 More LMSRs

Option 3A: Four More Prepositioned Brigades a
CHAPTER FOUR COMPARISON OF STRATEGIC TRANSPORTATION OPTIONS 33

Figure 4-2.

Percentage Increase in Cargo Deliveries Under Option 3A at Various 

Transit Distances 

(Percent)

Source: Congressional Budget Office.

Note: The shaded area shows, for comparison, the largest increase in deliveries offered on a given day by the airlift or sealift options (1A, 1B, 

2A, or 2B). This figure assumes that the locations of current prepositioned forces remain the same.

a. The distances used in Option 3A.

scenario’s assumptions about transit distances from the 

United States, airlift and sealift would take more time to 

deliver a Stryker brigade combat team than would an 

afloat prepositioning ship located 6,000 nm from its destination—a poor location for prepositioned forces. Of 

the airlift and sealift options, the high-speed ships in 

Option 2B could deliver a complete BCT from the 

United States in the least time (although still about two 

more days than an afloat prepositioned force located 

6,000 nm from the conflict), and the heavy-lift airships 

in Option 1B would take about a day longer.

Deliveries for the high-speed ship and airship options 

match or beat those of the prepositioned forces located 

6,000 nm from a conflict as the deployment distance 

from the United States decreases to less than about 75 

percent of that of the base case (see Figure 4-3). The extra 

C-17s, LMSRs, or HSS ships deploying forces from the 

United States do not compete favorably with such prepositioning unless their transit distances are less than about 

one-third of those from the United States to the Persian 

Gulf or Indian Ocean region. Those aircraft or ships do 

not compete favorably with better-located prepositioned 

forces unless the distance to the conflict is actually shorter 

from the United States than from the site of the prepositioned equipment.

The Impact of Infrastructure 

Constraints

With few exceptions, today’s strategic transportation systems rely on support infrastructure in a theater of operations to complete their deliveries. Aircraft require air 

bases and most sealift ships require deepwater ports for

0 5 10 15 20 25 30 35 40 45

0

20

40

60

80

100

120

 2,000/4,000a

 2,500/5,000

 3,000/6,000

 4,000/8,000

 5,000/10,000

Transit Distances for Prepositioned Forces in Nautical Miles

(Near brigades/far brigades)

Days
34 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Figure 4-3.

Time Needed to Deliver First Additional Stryker Brigade Combat Team

at Various Deployment Distances

(Days)

Source: Congressional Budget Office.

Notes: The transit distances assumed in the base-case deployment scenario are 7,000 nm for C-17s; 8,500 nm for airships; and 9,900 nm for 

LMSRs and high-speed sealift ships. 

LMSR = large, medium-speed roll-on/roll-off ship; nm = nautical miles.

unloading.1 In many cases, the availability of such facilities—not the availability of the transportation systems 

themselves—determines the rate at which cargo can be 

delivered to a theater. When infrastructure is a bottleneck, adding mobility systems that rely on the same infrastructure typically does little to improve the rate of cargo 

delivery.

Infrastructure for Airlift

The airfield infrastructure in a theater is measured by a 

quantity called maximum on ground, or MOG. The 

term MOG evokes an image of the number of aircraft 

that can physically be parked on an air base’s tarmac. 

That number, however, is only a subset of MOG called 

“parking MOG.” Of greater interest to mobility calculations is “working MOG,” a measure of an air base’s ability 

to process airlift missions, not just provide places to park. 

Working MOG is defined as the number of aircraft that a 

base can process simultaneously within each aircraft’s 

planned ground time. Many factors can constrain working 

MOG, including limits on parking space, cargohandling equipment, ability to refuel aircraft, and local 

air traffic control. Many of those factors change over time 

(for example, extra cargo loaders can be flown to a base), 

so MOG is a dynamic quantity. Each type of aircraft 

“consumes” some amount of MOG depending on such 

characteristics as its ground time, need for fuel, need for 

special loading equipment, and physical size. A theater’s 

MOG is a situation-dependent aggregation of the MOGs 

of the constituent air bases.2

0 10 20 30 40 50 60 70 80 90 100

0

5

10

15

20

25

30

35

40

45

50

Prepositioning 6,000 nm Away

Prepositioning 4,000 nm Away

Prepositioning 2,000 nm Away

Distance from United States to Theater

Relative to Base Case (Percent)

Option 1A: 21 More C-17s

Option 2A: 17 More LMSRs

Option 1B: 15 Hybrid Airships

Option 2B: Six High-Speed

Sealift Ships

1. Exceptions might be airdrops of airborne units and the use of 

“over the shore” lighterage (barges) to unload transport ships. 

However, those and other alternative means of delivery are very 

limited in the types of cargo they can handle and the rate at which 

they can deliver it.

2. Theater MOG is not necessarily a simple sum of the MOGs of 

individual air bases. For example, planners usually assume that a 

C-5 transport plane consumes two C-17 MOG equivalents. A 

large air base with a MOG of 2 might have the capacity for two C17s or one C-5. That capacity is not the same as a MOG of 2 that 

represents two smaller bases, each of which could handle one C17 but might be too small for a C-5 to land.
CHAPTER FOUR COMPARISON OF STRATEGIC TRANSPORTATION OPTIONS 35

Figure 4-4.

Airlift Deliveries Under Varying Degrees of Constraints on Airfield Infrastructure

(Thousands of tons)

Source: Congressional Budget Office.

Note: Maximum on ground (MOG) is a measure of the number of aircraft that a base can process simultaneously within the aircraft’s planned 

ground times. It is affected by limits on parking space, cargo-handling equipment, ability to refuel aircraft, and local air traffic control, 

among other factors. MOG is usually defined in C-17 equivalents.

a. As estimated in Institute for Defense Analyses, Cost and Operational Effectiveness of the C-17 Program (Alexandria, Va.: IDA, 1993).

The base-case airlift fleet and deployment distances used 

in this analysis would require a working MOG of about 

36 C-17 equivalents for unconstrained surge operations, 

CBO estimates.3 That figure assumes there are no queuing inefficiencies at the offload base and includes the 

MOG needed for enough passenger aircraft from the 

Civil Reserve Air Fleet to deliver personnel at a rate commensurate with the rate at which unit equipment arrives. 

If the MOG available in the theater was less than 36, airlift deliveries would be constrained to a lower level (see 

Figure 4-4). Deliveries would be reduced by about 25 

percent, for example, in a theater whose working MOG 

was roughly equivalent to that available in Operation 

Desert Shield. Many experts expect that limited infrastructure will be the norm in future conflicts.

In the case of infrastructure constraints, the 21 additional 

C-17s in Option 1A would not provide the improvement 

in deliveries estimated above. Those aircraft would add 

about 1.1 C-17 MOG equivalents to the total demand 

for airlift MOG, a demand that would already be higher 

than very extensive infrastructure could support. Some 

improvement might be realized if the additional C-17s 

displaced other aircraft in the scenario, because C-17s are 

more efficient in terms of payload delivered per unit of 

MOG consumed than those aircraft. That improvement 

would only be the difference between the two aircraft, 

however. Additional C-17s could also increase the effective MOG available in a theater by taking greater advantage of small airfields that other airlifters cannot use, 

although the 155 C-17s already in the base-case force 

would be likely to saturate those airfields as well.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

50

100

150

200

250

300

350

400

450 CBO's Base Case:

Unconstrained Infrastructure

(MOG greater than 36)

Infrastructure Constraints

of Operations Desert Shield

and Desert Storm (MOG = 26)

Infrastructure Constraints

of a Major Theater War in

Northeast Asia (MOG = 11)

Austere Theater

(MOG less than 5)

a

Days

3. Deployment distance influences the demand for MOG because 

aircraft can arrive at a destination more frequently when the 

round-trip time is shorter, driving up the demand for MOG. 

Defining MOG in terms of an aircraft type-equivalent allows the 

aggregation of the MOG demands of the particular aircraft types 

that might be supporting an operation.
36 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

The possibility that additional C-17s might offer little or 

no improvement in a large deployment to a single theater 

does not necessarily mean that more C-17s would not be 

useful in other circumstances. The Air Mobility Command supports military activities around the world. On 

any given day, those activities could include Presidential 

support flights, humanitarian relief missions, and missions to support the military’s regional combatant commanders. Because this analysis did not assess those dayto-day demands for strategic airlift, its conclusions are 

only one piece of the information needed to make judgments about the appropriate force structure for the Air 

Mobility Command.

The hybrid airships in Option 1B would have the advantage of being virtually independent of airfield constraints. 

When departing its loading site with a full load, a hybrid 

airship would need a long runway or other open space to 

gain enough speed, and hence dynamic lift, for takeoff. 

That would probably not be a serious operational constraint, however, because loading locations would usually 

be in the United States, where they could be planned for 

in advance. Upon arriving in a theater, a hybrid airship 

should be able to land in a much shorter distance than on 

takeoff because it would have burned much of its fuel and 

thus would need less speed-generated dynamic lift for a 

gentle landing. After unloading, the now neutrally (or 

perhaps slightly positively) buoyant airship should be able 

to take off almost vertically.

Infrastructure for Sealift 

The sealift alternatives analyzed in this study—both the 

surge options (2A and 2B) and the afloat prepositioning 

options (3A and 3B)—would require large deepwater 

ports so that ships could be unloaded at pier-side via their 

ramps. Because similar facilities would be needed for all 

of the sealift options, a comparison of their infrastructure 

requirements necessarily focuses on the extent to which 

each option would change the need for port infrastructure in the theater of operations.

The demand for port infrastructure varies over time as 

sealift ships arrive in the theater, are unloaded, and depart. That demand is uneven because similar types of 

ships require a similar amount of time to reach their destination and thus tend to arrive in clusters. Consequently, 

although the number of ships in port at any one time in 

the base-case scenario averages only about 3.4, that simultaneous demand peaks at 13 ships on days 12 and 13, 

when the second MPF squadron begins to arrive and 

Army prepositioned ships are being unloaded. If necessary, the peaks and valleys of demand for port infrastructure could be smoothed by deliberately scheduling ship 

arrivals. However, such scheduling would require delaying some arrivals, which would slow delivery rates.

Of the four ship-based options, only Option 2A, with its 

17 additional LMSRs, and Option 3B, with its five additional prepositioned brigades, would result in a greater 

peak demand for port infrastructure than the base case. 

That peak would be exceeded on only one day (day 27) 

and by a total of just one ship for Option 2A, and on two 

days (day 12 and day 13) by two ships for Option 3B (see 

Figure 4-5). Otherwise, CBO’s analysis indicates that a 

port infrastructure able to accommodate the base-case 

mobility force could accommodate the additions to that 

force under the surge sealift and afloat prepositioning 

options. Average demand for port facilities would 

increase by slightly more than one ship.

If adequate port facilities are not available, current mobility forces have some capability to move cargo ashore. 

Some MPF and Ready Reserve Force ships carry their 

own barges or other lighterage for that purpose, and the 

Joint Logistics Over the Shore system of portable causeways and lighterage can also move cargo from sealift 

ships. Those systems are slow, however, resulting in much 

longer unloading times than when a ship is at a pier. In 

addition, current over-the-shore systems cannot operate 

in poor weather or rough seas. 

In the future, the Department of Defense would like to 

develop shallow-draft sealift ships (preferably with high 

speed as well) that could deliver cargo to smaller ports. 

Although such ships could increase a theater’s total port 

capacity, (much as the C-17’s ability to use small airfields 

can increase a theater’s MOG), it is unlikely that even the 

best over-the-shore systems operating from smaller ports 

could match the unloading rates achieved in a large established port. Moreover, such shallow-draft sealift ships 

would be challenging to develop. When loaded, a ship 

with a large payload and a transoceanic range will be very 

heavy and thus will have to displace a great deal of water, 

making shallow draft a difficult objective. CBO did not 

include such an option in this analysis because of the 

uncertainty about when or even whether those ships 

could be developed. 

Alternatively, concern about future access to foreign ports 

has led the Navy and Marine Corps to explore new sea-
CHAPTER FOUR COMPARISON OF STRATEGIC TRANSPORTATION OPTIONS 37

Figure 4-5.

Demand for Seaport Infrastructure Under Various Options

(Number of ships at debarkation ports)

Source: Congressional Budget Office.

Note: LMSR = large, medium-speed roll-on/roll-off ship.

basing concepts that try to avoid port constraints altogether. Sea basing would involve transferring cargo and 

personnel at sea from large strategic transports onto 

smaller, intratheater systems capable of operating without 

support infrastructure. However, the at-sea transfer and 

intratheater transit could themselves become a bottleneck 

to deliveries, compared with all but the most constrained 

scenarios. Plans for sea basing are still in the early stages 

of concept definition.

Length of the RSOI Stage

As described in Chapter 2, after a military unit is first unloaded in a theater, it goes through the process of reception, staging, onward movement, and integration before 

it is ready to operate where it is needed. RSOI includes 

activities such as marrying up equipment and personnel 

that arrive separately, converting equipment from its 

transport configuration to its combat configuration (if 

0 15 30 45 60

0

2

4

6

8

10

12

14

16

Option 2A: 17 Additional LMSRs

Base-Case

Maximum

Demand Under

Option 2A

Demand Under

Base Case

Days

0

2

4

6

8

10

12

14

16

Option 2B: Six High-Speed Sealift Ships

Base-Case

Maximum

Demand Under

Option 2B

Demand Under

Base Case

Days

0 15 30 45 60

0

2

4

6

8

10

12

14

16

Option 3A: Four Prepositioned Brigades

on New LMSRs

Base-Case

Maximum

Demand Under

Option 3A

Demand Under

Base Case

Days

0 15 30 45 60

0

2

4

6

8

10

12

14

16

Option 3B: Five Prepositioned Brigades

on Existing LMSRs

Base-Case

Maximum

Demand Under

Option 3B Demand Under

Base Case

Days

0 15 30 45 60
38 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

necessary), arming weapons and fueling vehicles, assembling into units, and marching to the final destination.

An ideal strategic mobility system could deliver combatconfigured units with their personnel directly to where 

they were needed in the theater. Unfortunately, the different transport needs of humans and cargo, plus the requirement that most transportation systems have for 

fixed infrastructure support, make achieving an RSOIless deployment impractical with today’s transportation 

platforms.4

In general, RSOI times can be expected to range from a 

few days to more than a week depending on the distance 

from the debarkation point to the operations area and the 

quality of the local road or rail infrastructure in between. 

A RAND Corporation study of Stryker BCT deployments, for example, estimated road-march times that varied from almost nothing for an Indonesian scenario 

(where every location is near the coast) to slightly over a 

week for an intervention in Rwanda in central Africa.5

Because of that dependence on the specifics of a scenario, 

it is not possible to make absolute comparisons of RSOI 

times for different transportation options. Several general 

conclusions are possible, however. First, under most circumstances, cargo delivered by aircraft should arrive at 

least as close to a unit’s final operations area as cargo 

delivered by ship. Most locations with port facilities large 

enough to support sealift ships will have large airfields 

nearby, and aircraft also have the possibility of making 

deliveries inland. Second, although aircraft may be able to 

deliver units closer to their destinations, the piecemeal 

arrival of equipment (a few tens of tons at a time) could 

make the staging process more inefficient and time consuming. In any large deployment, individual aircraft will 

experience delays because of factors such as poor weather 

or maintenance problems. The randomness that such 

delays can introduce into the flow of equipment to a theater can increase the time needed for reception and staging.6 In contrast, a single ship load can contain large portions of a unit—if not the entire unit—easing the task of 

reception and staging.

Among CBO’s options for improving strategic mobility, 

only the hybrid airships in Option 1B would have different implications for RSOI times than the transportation 

systems in the current force. The ships and aircraft in the 

other options would be delivering their cargoes to the 

same locations as the base-case force. An airship, by contrast, might be able to deliver its cargo to any open area 

large enough to accommodate its size and low approach 

speed. Such an open area need not have a runway and 

could potentially be as short as twice the length of the airship, depending on the local conditions and the airship’s 

weight when loaded. Of course, the landing area would 

need to be far enough from the action that there was not 

a significant risk of ground fire against the airship. Although proponents claim that hybrid airships would be 

able to withstand some attacks, CBO has seen no suggestions that they might be suitable for assault landings 

under enemy fire. (That issue is discussed in the next 

section.)

Another characteristic that might allow airships to reduce 

RSOI times could be the ability to transport personnel 

together with their equipment, avoiding the step of marrying up troops with their vehicles and other equipment. 

Today, aircraft are the preferred means of transport for 

personnel, because a flight to the other side of the world 

can be completed in hours, whereas a sea voyage would 

take weeks. Equipment can be carried along with personnel on military airlifters, but only at the expense of substantially reducing payloads because of space and safety 

considerations for composite loads.7 Because space 

should not be an issue on a hybrid airship, it might be 

able to provide shiplike accommodations for troops traveling with their equipment. Some airship proponents 

suggest that units could even conduct mission planning 

4. Strategic brigade airdrops come close to having little or no RSOI, 

as do Marine Corps amphibious assaults, although the marines 

might need some time for onward movement if their objective was 

inland.

5. See Alan Vick and others, The Stryker Brigade Combat Team: 

Rethinking Strategic Responsiveness and Assessing Deployment 

Options, MR-1606-AF (Santa Monica, Calif: RAND Corporation, 2002), available at www.rand.org/publications/MR/

MR1606/.

6. DoD is trying to ease that problem by improving the in-transit 

visibility of cargo—that is, being able to track cargo loads in transit, much as commercial customers can track the progress of packages on shippers’ Internet sites. Knowing where a load of cargo is 

in the transportation system should allow for a smoother reception when the load arrives in the theater.

7. The C-5 is an exception because it has an upper deck that can 

carry 73 people separately from the cargo hold below. The weight 

of the personnel must be factored into the allowable payload, 

however.
CHAPTER FOUR COMPARISON OF STRATEGIC TRANSPORTATION OPTIONS 39

and tabletop rehearsals during transit, much as marines 

can do today on board amphibious assault ships. An 

objective of DARPA’s Walrus airship program is to deliver 

units or portions of units—both equipment and personnel—that would be ready for combat operations within 

six hours of arriving in the theater. A future high-speed 

sealift ship could also be designed to carry troops with 

their equipment because of the shorter transit times relative to today’s slower ships. Accommodations for people 

would come at the expense of space for cargo, however.

Survivability

Although strategic transportation forces are usually 

responsible for delivering cargo and troops to secure locations, situations can arise in which airlifters and sealift 

ships are sent into harm’s way. For example, during Operation Iraqi Freedom, several airlift aircraft have been hit 

by ground fire while flying into Baghdad. In addition, the 

Iraqi naval mines that damaged the guided missile cruiser 

U.S.S. Princeton and the amphibious assault ship U.S.S. 

Tripoli during Operation Desert Storm could have damaged sealift ships delivering forces to Saudi Arabia, and 

the terrorist attack against the destroyer U.S.S. Cole in 

Yemen could just as easily have been directed against a 

sealift ship. In such situations, the ability of a transportation system to avoid being hit—or to survive if hit—can 

be important, especially since the cargo it carries may be 

critical to the success of operations on the ground.

To protect against attack, airlifters are often equipped 

with countermeasures, including missile warning systems 

to help them avoid threats and flares to try to fool infrared missiles (such as those launched by shoulder-fired 

surface-to-air missile systems). Additionally, in a threatening environment, airlifters might operate only at night, 

to make visual tracking more difficult for an enemy, and 

might fly much steeper approaches and departures, to 

stay out of the range of ground fire as long as possible. 

Sealift ships, for their part, are protected by security 

forces when in port and by naval forces when at sea (if the 

threat warrants an escort).

The options in this analysis that would rely on C-17s 

(Option 1A) or LMSRs (Options 2A, 3A, and 3B) would 

have much the same survivability as current strategic 

transportation forces. The high-speed sealift ships in 

Option 2B might be more survivable than slower ships 

because they could, for example, outrun any threatening 

submarines they encountered. However, most of the 

threats facing sealift ships would probably occur near the 

ship’s destination, where even HSS ships would have 

slowed down prior to entering port.

As was the case with RSOI, the hybrid airships in Option 

1B could have unique advantages in terms of survivability. On one hand, their large size, low altitude, and slow 

speed would make airships very easy to detect, track, 

and shoot at. On the other hand, proponents argue that 

although an airship might be easy to hit, it could operate 

successfully in a threatening environment for several 

reasons:

B A large airship could easily carry an extensive set of 

defensive systems, such as missile countermeasures 

and even air-to-air missiles to defend against hostile 

aircraft.

B The cargo compartments could be armored with 

materials that are too heavy or bulky for use on conventional aircraft.

B The low speed of an airship means that if it was hit, it 

would not be susceptible to the large dynamic stresses 

that can cause conventional aircraft to break up in 

flight when damaged.

B The helium in the compartments of the hull would be 

at only a slightly higher pressure than the ambient 

atmosphere, so it would leak very slowly out of any 

holes shot in the hull. Consequently, if an airship was 

hit by ground fire, it would not pop like a rubber 

balloon but rather lose buoyancy slowly like a mylar 

balloon.

Investigating the feasibility of those proposed characteristics would be an important part of any program to 

develop a heavy-lift hybrid airship.

Other Considerations

Besides affecting promptness, throughput capacity, infrastructure dependence, RSOI times, and survivability in a 

strategic deployment, the options in this analysis would 

have implications for the military’s ability to support 

peacetime missions and to modernize current strategic 

transportation forces.
40 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Support for Peacetime Missions 

The U.S. military uses its mobility systems to support 

missions around the world on a daily basis. Options that 

could contribute substantively to those day-to-day activities would have a usefulness not reflected in CBO’s analysis of a major deployment. Although the additional forces 

in any of the six options could be used to support smaller 

operations, those in the airlift alternatives—especially the 

C-17s in Option 1A—would probably have the greatest 

day-to-day utility. 

Sealift ships and prepositioned sets of unit equipment are 

less likely to be called on frequently because they represent relatively large increments of combat power and 

because, if they were used for small operations, they 

would need a fairly long period to return to a state of 

readiness for a major operation. (Prepositioned equipment would have to be serviced and reloaded on ships, 

and the ships would have to steam to where they were 

needed.) In contrast, airlift aircraft, especially C-17s, 

offer smaller increments of power that are better matched 

to peacetime needs and that can be rapidly redirected to 

support a major operation, should one arise.

For the two airlift options (1A and 1B), the estimates of 

operation and support costs described in Chapter 3 and 

the appendix are based on historical data for C-17 operations that include peacetime missions. CBO included 

those costs under the assumption that if the Air Force had 

the additional planes or airships, it would use them. More 

C-17s or airships could be purchased within the spending 

target if the airlift options were artificially assigned lower 

annual support costs to more closely match those of the 

sealift options. For example, if the estimated support 

costs for Option 1A were reduced by half, nine additional 

C-17s could be purchased. Such differences would not

affect the broad conclusions of this analysis, however.

Impact on the Base-Case Strategic Mobility Force 

Because this study focused on options for improving strategic mobility, it did not look at what actions might be 

necessary over the next few decades to maintain the capabilities already in hand. Current plans suggest little need 

for concern about the C-17 and C-5 fleets, since the 

C-17s are relatively young and the C-5s are scheduled for 

extensive modernization. The situation is not as clear for 

sealift, however. Both the roll-on/roll-off ships in the 

Ready Reserve Force and the Military Sealift Command’s 

fast sealift ships are quite old and may need to be replaced 

or refurbished in coming years. 

The sealift options (2A and 2B) and the prepositioning 

option that would purchase additional LMSRs (3A) 

would substantially increase throughput capacity in a 

deployment as well as improve promptness. Thus, those 

options could serve as at least a part of any program to 

replace the existing strategic mobility force. If the additional average throughput capacity was not needed, those 

options could allow older ships to be retired without 

replacement, greatly reducing the costs for operating and 

maintaining the base-case force. The extent to which 

such savings might offset the costs of the options would 

depend on what DoD defined as its future requirements 

for strategic mobility.
A

How CBO Estimated the Costs

of the Options in This Study

The cost estimates for the options described in this 

analysis have two major components: one-time investment costs that would arise over the next decade or so 

when the airlift or sealift systems were being developed 

and built, and operation costs that would be incurred 

over 30 years once the first new system was delivered. 

This appendix describes the methods that the Congressional Budget Office (CBO) used to estimate the costs of 

development efforts, equipment purchases, and operations. The estimates represent incremental costs—the 

expenses that would occur in addition to the total cost of 

maintaining current strategic mobility capabilities. All of 

the cost estimates are in 2006 dollars; they are summarized in Table A-1.

Significant uncertainty exists about the capabilities, technologies, and costs associated with developing, purchasing, and operating the airships and high-speed sealift 

ships envisioned in Options 1B and 2B, respectively. Programs such as those, which are either in the early stages of 

development or are conceptual in nature, entail a greater 

risk of cost and schedule overruns than do programs that 

are better defined and based on proven technologies. 

CBO’s cost estimates for those options represent one 

possible outcome, calculated under specific assumptions. 

Although the estimates take such risk into account to 

some extent, CBO expects that its estimates would 

change, perhaps significantly, as the design of a particular 

system was more fully defined. 

Methods for Estimating the Costs 

of C-17 Aircraft

CBO estimates that buying and operating another 21 

C-17s to enhance airlift capacity (Option 1A) would cost 

a total of $11.3 billion: $4.4 billion for procurement and 

$6.9 billion for operations. Since the option would 

simply purchase more units of an aircraft that is already 

in production, there would be no additional costs for 

research and development.

Procurement Costs

CBO estimated the procurement costs for 21 additional 

C-17 aircraft by extrapolating the actual costs of the 143 

C-17s purchased between 1992 and 2005. On average, 

those aircraft cost approximately $300 million apiece in 

2006 dollars—although the last 15 C-17s ordered by the 

Air Force in 2005 cost just over $215 million each—including the costs of support equipment, simulators, and 

spare parts. CBO estimates that the unit production cost 

for an additional 21 C-17s would average about $210 

million. CBO assumed that 15 of the aircraft would be 

purchased in 2008 and the other six in 2009 (the years 

immediately following completion of currently planned 

production) and would enter the inventory in 2010 and 

2011.

Operation Costs 

CBO based its estimates of operation and support (O&S) 

costs for the additional C-17s on actual O&S costs for 

the aircraft as reported in the Air Force’s Total Ownership 

Costs (AFTOC) database. Those data indicate that operating a C-17 costs about $12 million a year, including 

costs for military pay, fuel, and maintenance that are directly associated with the operations of the C-17 fleet as 

well as costs for indirect activities such as training and 

base support. CBO assumed that 19 of the 21 additional 

C-17s would be part of the operational inventory, and the 

other two would serve as reserves in case any of the primary aircraft were lost or otherwise unavailable. The reserve aircraft would have minimal annual operating costs.

APPENDIX
42 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Table A-1.

Costs of the Options for Improving Strategic Mobility Forces

Table A-1. Costs of the Options for Improving Strategic Mobility Forces

Source: Congressional Budget Office.

a. Operation costs are for 30 years from the year in which the first system is delivered.

b. Operation costs relative to Option 3A are not proportional to the number of brigades because ship costs include only the difference 

between LMSRs in the prepositioning force and LMSRs in the surge sealift force.

Methods for Estimating the Costs 

of Airships

For total costs of a little over $11 billion, the Department 

of Defense (DoD) could improve its airlift capacity by 

developing, buying, and operating 14 to 16 hybrid airships with a payload of 500 tons (Option 1B), CBO estimates.1

 That quantity range reflects ranges of estimates 

for development, procurement, and operation costs. As 

noted above, significant uncertainty exists about the 

capabilities and technologies associated with such a 

heavy-lift airship, which translates into significant cost 

risk. 

Research and Development Costs 

Analysts usually rely on previous analogous programs as 

the basis for estimating the cost of new systems. In this 

case, airships in operation today include various commercial blimps such as those of Goodyear and Fujifilm, and a 

handful of platforms from other countries. DoD’s recent 

experience with airships is limited to a dozen aerostats 

(tethered balloons) operated by the Air Force. Development costs for both the commercial and DoD programs 

averaged less than $100 million. One exception was a 

commercial program to develop a lighter-than-air cargo 

lifter (referred to as the CL-160) that would be capable of 

carrying 160 tons. The program never entered production, but development costs totaled about $400 million 

at the time work on the aircraft ceased.

Existing blimps are smaller and less complex than the 

hybrid airship envisioned in Option 1B—the new airship 

would have 10 times the volume of those smaller platforms, significantly greater lift capability, and a different 

hull shape (designed to provide dynamic lift in addition 

to static lift). Lacking an appropriate analogous system, 

CBO had no basis on which to make an independent 

estimate of the costs to develop the new airship. Thus, for 

this study, CBO sought information from a variety of 

sources including aerospace industry contractors to guide 

its estimate of the costs for developing a 500-ton-payload 

airship.

Option Description Quantity Procurement Total

1A Buy more C-17s 21 0 4.4 6.9 11.3

1B 16 3.0 (low) 4.8 3.4 11.2

14 4.0 (high) 4.3 3.0 11.3

2A Buy more LMSRs 17 0 8.4 2.9 11.3

2B 6 2.0 7.2 1.9 11.1

3A 4 0 8.0 3.5 11.4

3B 5 0 7.5 3.6 b 11.1

 Costs (Billions of 2006 dollars)

Buy Stryker brigade sets and preposition 

them on existing LMSRs

Develop and buy heavy-lift hybrid 

airships

Develop and buy advanced-technology 

high-speed sealift ships

Buy Stryker brigade sets and LMSRs for 

prepositioning

Operationsa Development

1. The characteristics of CBO’s notional airship are similar to the 

objective characteristics of the alternatives for heavy-lift airships 

being studied as part of the Defense Advanced Research Projects 

Agency’s Walrus program.
A P P E N D I X HOW CBO ESTIMATED THE COSTS OF THE OPTIONS IN THIS STUDY 43

CBO factored into its estimate the costs of building prototypes, conducting a vigorous program of testing and 

evaluation, the costs of government activities such as systems engineering and program management, and past 

rates of cost growth in DoD’s aircraft programs. The costs 

to develop the hybrid airship would total between $3 billion and $4 billion, CBO estimates.

Procurement Costs 

Similarly, CBO used information from contractors as a 

starting point to estimate procurement costs for Option 

1B. As with the estimate of development costs, CBO included government costs and historical cost growth in its 

estimate. With those factors, CBO estimated that the first 

airship could be purchased in 2012 at a total cost of 

about $400 million and delivered three years later.

Depending on the amount spent on research and development, CBO estimates that DoD could buy 14 to 16 

airships within the spending target of roughly $11 billion 

set for these options. CBO assumed that the remaining 

airships would be bought in successive years—at a peak 

rate of three per year—and that the cost per airship 

would decline by 10 percent each time total purchases 

doubled, because annual buy quantities are small. The 14 

to 16 airships would have an average cost of roughly $300 

million apiece, CBO estimates.

Operation Costs

Lacking data on comparable airship operations, CBO 

estimated O&S costs for the new airships by using actual 

costs for C-17 and C-5B airlifters. Although some types 

of operating costs will be higher for conventional aircraft 

than for airships, others may be lower. For example, fuel 

costs are likely to be higher for conventional aircraft 

because of their need for greater power and speed, but 

some maintenance costs are apt to be higher for airships 

because of their more-fragile skin and their need for specialized maintenance facilities. 

Using information from the AFTOC database, CBO 

calculated that O&S costs per flight hour total about 

$9,000 for a C-17 and $26,000 for a C-5B, or an average 

of about $18,000 between the two. On the basis of that 

hourly cost, CBO estimated that operating one heavy-lift 

airship would cost about $8 million per year, assuming 

that the airship provided the same number of ton-miles 

of work (the payload carried times the distance moved) in 

that period as the average C-17. Thus, over 30 years, 

O&S costs for 14 to 16 hybrid airships would range from 

$3.0 billion to $3.4 billion.

Methods for Estimating the Costs 

of LMSRs

Three of the six options in this analysis feature large, 

medium-speed roll-on/roll-off ships (LMSRs). Option 

2A would add 17 LMSRs to the surge sealift fleet, and 

Option 3A would buy four more of the ships for afloat 

prepositioning. Option 3B would shift five LMSRs that 

are now part of the surge sealift fleet to the prepositioning 

force. Since all three of those options would either continue production of a recently produced ship or reassign 

existing vessels, CBO estimates that they would not 

require any significant research and development costs.

Procurement Costs 

For this analysis, CBO assumed that any new LMSRs 

would be similar to the Bob Hope class LMSRs built 

between 1993 and 2004, with a weight of roughly 36,000 

tons. CBO estimated the procurement costs for those 

additional LMSRs by using the actual costs of the seven 

ships of the Bob Hope class. The lead ship of that class 

costs about $465 million (in 2006 dollars) to build, and 

the average cost of all seven ships was about $420 million. 

CBO converted the actual costs for those LMSRs into 

2006 dollars using factors provided by the Navy that 

account for the real (after-inflation) growth that occurred 

in the cost of labor and materials in the naval shipbuilding industry over the 1985-2004 period and that the 

Navy expects to experience for the next decade. On the 

basis of that information, CBO estimated that such real 

growth averaged about 1.7 percent a year between 1993 

and 2004; it is expected to average about 1.3 percent a 

year over the next decade.

For Options 2A and 3A, CBO assumed that the first 

additional LMSR would be purchased in 2007 and delivered five years later. Using the real growth rate of 1.3 percent a year mentioned above and accounting for the gap 

in production since 2004, CBO estimated that production costs for the first new LMSR would total about $470 

million in 2007. Under Option 2A, the Navy would buy 

a second ship in 2008, two per year over the 2009-2015 

period, and one in 2016, for a total of 17 new LMSRs. 

Under Option 3A, the Navy would buy only four of the 

ships, one per year from 2007 to 2010. 
44 OPTIONS FOR STRATEGIC MILITARY TRANSPORTATION SYSTEMS

Analysis of past shipbuilding programs indicates that unit 

costs tend to remain fairly constant when production 

rates are low. Thus, applying the estimated real-growth 

factors mentioned above, CBO estimated that the 

LMSRs built during the 2008-2016 period would have a 

slightly higher unit cost than the first new ship. As a 

result, the 17 additional LMSRs in Option 2A would 

cost an average of about $500 million each (including 

spare parts and shipboard maintenance tools), and the 

four new LMSRs in Option 3A would cost an average of 

about $490 million apiece.

Operation Costs

CBO’s estimates of O&S costs for the additional LMSRs 

are based on actual operation costs for those ships as 

reported in the Navy’s Visibility and Management of 

Operating and Support Costs (or VAMOSC) database. 

Those data show that an LMSR for prepositioning costs 

about $18 million a year to operate, whereas an LMSR 

for sealift, which is maintained at reduced operating status, costs less than half as much: $7 million annually. 

Those figures include costs for military pay, fuel, and 

maintenance that is directly associated with the operations of the LMSR fleet as well as costs for indirect activities such as training and base utilities.

Methods for Estimating the Costs

of High-Speed Sealift Ships

Option 2B would expand sealift capability by developing 

an advanced-technology ship that was at least one-third 

faster than anything in today’s surge sealift fleet. (LMSRs 

have a speed of about 24 knots, and existing fast sealift 

ships were originally rated at about 33 knots.) CBO 

assumed that the high-speed sealift (HSS) ship would 

have a monohull design and be propelled by high-power 

water jets to a speed of about 45 knots. Developing, buying, and operating six of those ships would cost a total of 

$11.1 billion, CBO estimates, although the extensive 

uncertainty surrounding their capabilities and technologies implies a significant risk of cost growth. Because the 

HSS ship would lack sufficient range to reach scenarios 

anywhere in the world, CBO included the purchase of 

two oilers (one for HSS ships crossing the Pacific and one 

for those crossing the Atlantic) to provide underway refueling. The oilers would be forward based (in Hawaii, for 

example) in a reduced operating status.

Research and Development Costs

Ordinarily, CBO uses the historical costs of developing 

similar ships to estimate the costs of developing a new 

ship. In this case, however, CBO determined that such 

comparisons would be inappropriate because the HSS 

ship would be so much faster than existing sealift ships. 

Therefore, to estimate research and development costs, 

CBO started with Navy estimates for two designs for 

high-speed sealift ships—one that would employ a traditional hull similar to those of current prepositioning ships 

but have a slightly higher speed (about 36 knots) and one 

that envisions a trimaran hull and a much faster speed 

(55 knots). The Navy estimates that the monohull ship 

would cost $150 million (in 2006 dollars) to develop, 

and the trimaran would cost $1.8 billion.

CBO added just over 15 percent to those estimates to 

account for the cost growth that has occurred in past 

research and development programs for Navy ships. With 

that adjustment, the estimates for the two ship designs 

would be $200 million and $2 billion. CBO concluded 

that research and development costs for the 45-knot sealift ship in Option 2B would be closer to the $2 billion 

estimate for the 55-knot ship because comparable technological hurdles would have to be cleared to achieve 

both speeds. Consequently, CBO used that higher figure 

in this analysis.

Procurement Costs 

Given the $11 billion spending target for the options, the 

Navy could buy six of the new high-speed sealift ships, 

CBO estimates, at a total cost of $6.4 billion. CBO estimated procurement costs for those ships using a costper-thousand-tons methodology. On the basis of cost 

estimates by the Center for Naval Analyses of alternatives 

for the Maritime Prepositioning Force (Future) program, 

CBO estimated that the HSS ships in Option 2B would 

cost about $50 million per thousand tons to build, or an 

average of roughly $1.1 billion apiece.2

 That estimate 

includes the real growth in labor and materials costs mentioned above. It assumes that the first HSS ship would be 

bought in 2012 and delivered five years later. The other 

five ships would be purchased at a rate of one per year 

thereafter. CBO estimated an additional procurement 

cost of about $800 million for the two oilers based on the 

2. Robert M. Souders and others, MPF(F) Analysis of Alternatives: 

Final Summary Report, CRM D0009841.A1/SR1 (Alexandria, 

Virginia: Center for Naval Analyses, February 2004).
A P P E N D I X HOW CBO ESTIMATED THE COSTS OF THE OPTIONS IN THIS STUDY 45

costs of the fleet of oilers of the Henry J. Kaiser class built 

in the late 1980s and early 1990s.

Operation Costs

Estimated O&S costs for those high-speed sealift ships 

are based on actual costs for existing LMSRs. According 

to the Navy’s VAMOSC database, fuel accounts for about 

one-third of the $7 million in annual operating costs for 

an LMSR in the surge sealift force. CBO compared the 

amount of fuel needed per mile traveled for existing 

LMSRs to the estimated fuel needed per mile traveled for 

the conceptual HSS ship. With fuel costs adjusted by the 

ratio of the two ships, but with other operating costs kept 

constant, CBO estimated that operating a high-speed 

sealift ship would cost a total of about $10 million annually. The annual O&S costs for the two oilers were 

assumed to be about $7 million, the same as LMSRs in 

ROS-4.

Methods for Estimating the Costs

of Prepositioned Army Equipment

As noted above, the options to expand afloat prepositioning would either buy additional LMSRs for the prepositioning force (Option 3A) or transfer existing ones from 

the surge sealift fleet (Option 3B). In either case, the 

Army would need to buy more sets of equipment to 

deploy on those ships. Because those options would purchase equipment that is already being produced for the 

Army, CBO estimated that no research and development 

would be necessary.

Procurement Costs

For this analysis, CBO assumed that the Army would buy 

equipment for its new Stryker brigade combat teams to 

preposition on the LMSRs. Using Army budget data, 

CBO estimated that one additional set of equipment—

including about 300 Stryker vehicles, various tactical and 

support vehicles, communications and navigational systems, and other necessary combat equipment and supplies—would cost about $1.5 billion to procure.

Operation Costs 

Each new set of prepositioned equipment would cost 

about $5 million a year to maintain. CBO based that estimate on actual costs for the Army’s and the Marine 

Corps’ afloat prepositioned forces. In addition, as noted 

above, the LMSRs on which the equipment was stored 

would have annual operating costs of about $18 million 

apiece—or a total of $23 million per year for a ship and 

its prepositioned cargo. In the case of Option 3B, that 

annual figure would be offset by $7 million in savings 

from no longer operating the LMSR as a surge sealift 

ship.

Besides its LMSR, each prepositioned brigade set would 

include another cargo ship, because it is not certain that a 

single LMSR is large enough to carry a full brigade plus 

other equipment and sustainment supplies that would be 

needed for independent operations. Those additional 

ships—which need not be large RO/ROs—could carry 

miscellaneous equipment, small vehicles (if necessary), 

and sustainment supplies. CBO assumed that the cargo 

ships could be chartered for about $10 million per year, 

based on current costs for chartered prepositioned ships. 

That figure is included in the estimated operating costs 

for the prepositioning options.

Glossary of Abbreviations

AFTOC: Air Force Total Ownership Cost (database)

APS: Army Prepositioning Stock

BCT: brigade combat team

CBO: Congressional Budget Office

CRAF: Civil Reserve Air Fleet

DARPA: Defense Advanced Research Projects Agency

DoD: Department of Defense

FCS: Future Combat Systems

FSS: fast sealift ship

HSS: high-speed sealift (ship)

LMSR: large, medium-speed roll-on/roll-off ship

MOG: maximum on ground

MPF: Maritime Prepositioning Force

MPF(F): Maritime Prepositioning Force (Future)

NATO: North Atlantic Treaty Organization

NAVSEA: Naval Sea Systems Command

nm: nautical mile

O&S: operation and support

RO/RO: roll-on/roll-off ship

ROS: reduced operating status

RRF: Ready Reserve Force

RSOI: reception, staging, onward movement, and integration

USTRANSCOM: U.S. Transportation Command

VAMOSC: Visibility and Management of Operating and 

Support Costs (Navy database)


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