CONGRESS OF THE UNITED STATES

CONGRESSIONAL BUDGET OFFICE

A

CBO

STUDY

NOVEMBER 2004

The Future of

the Navy’s

Amphibious

and Maritime

Prepositioning

Forces

The Congress of the United States O Congressional Budget Office

CBO

The Future of the Navy’s

Amphibious and

Maritime Prepositioning Forces

November 2004

A

STUDY
Notes

Unless otherwise indicated, all years referred to in this study are fiscal years (which run from 

October 1 to September 30), and all dollar amounts are in 2005 dollars.

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

The cover shows various Wasp class amphibious assault ships and Maersk-type maritime

prepositioning ships.
Preface

Today, the U.S. Navy numbers about 293 battle force ships, including 35 amphibious 

warfare ships, which are designed to carry marines and their equipment into combat. In addition, the Navy has 16 cargo ships that make up the maritime prepositioning force, which carries equipment and 30 days’ worth of supplies for three Marine infantry brigades (though not 

the marines themselves). The Navy plans to modernize both its amphibious and maritime 

prepositioning ships over the next 30 years. Its plans include developing a sea-basing capability that would allow the Navy to deploy and sustain Marine Corps units on shore without 

needing to build up a supply depot on land. Carrying out those plans would require the Navy 

to spend an average of $2.4 billion a year over the next three decades to buy new amphibious 

and maritime prepositioning ships—more than twice what it has spent on those categories of 

ships since 1980. At the same time, the Navy has modernization plans for other types of ships 

that, if fully implemented, would also require more resources than the Navy now spends on 

ship construction.

Are there ways to modernize the amphibious and maritime prepositioning forces at a lower 

cost than what the Navy plans to spend? This Congressional Budget Office (CBO) study—

prepared at the request of the Subcommittee on Seapower of the Senate Committee on Armed 

Services—addresses that question. It examines the Navy’s modernizations plans for amphibious and maritime prepositioning ships and their budgetary implications. It also evaluates four 

lower-cost options for those ships, two of which would cost roughly what the Navy has spent 

annually since 1980 and two of which would require a spending increase of a little over onethird. Those alternatives would result in smaller, less capable forces than the Navy envisions— 

or than exist now—but they would provide some of the capabilities that the Navy and Marine 

Corps desire. In keeping with CBO’s mandate to provide objective, impartial analysis, this 

study makes no recommendations.

Eric J. Labs of CBO’s National Security Division wrote the study under the general supervision of J. Michael Gilmore. Raymond Hall of CBO’s Budget Analysis Division prepared the 

cost estimates under the general supervision of Jo Ann Vines. Hannah Robinson provided 

assistance in preparing some of the figures, and Natalie Fries (a former CBO intern who is 

now a commissioned naval officer) provided early research for this project. Michael Simpson, 

Barbara Edwards, Arlene Holen, and Elizabeth Robinson of CBO provided thoughtful comments on an earlier draft of the study. In addition, numerous officials and analysts from the 

Navy and Marine Corps provided information that improved the analysis, and Robert Work 

of the Center for Strategic and Budgetary Assessments offered valuable insights and comments. (The assistance of such external participants implies no responsibility for the final 

product, which rests solely with CBO.)
Christian Spoor edited the study, and Christine Bogusz and Leah Mazade proofread it. Cynthia Cleveland formatted the tables. Maureen Costantino designed the cover, produced the 

figures, and prepared the study for publication. Lenny Skutnik printed the initial copies, and 

Annette Kalicki prepared the electronic versions of the report for CBO’s Web site 

(www.cbo.gov).

Douglas Holtz-Eakin

Director

November 2004
Summary ix

1 Introduction 1

Today’s Amphibious and Maritime Prepositioning Forces 2

Requirements for Amphibious and Maritime Prepositioning Forces 7

The Navy’s and Marine Corps’s Vision for Sea Basing 10

2 The Navy’s Plan for Modernizing the Amphibious and

Maritime Prepositioning Forces 15

The LPD-17 Amphibious Transport Dock 16

The LHA(R) Amphibious Assault Ship 18

The LSD(X) Dock Landing Ship 22

The Future Maritime Prepositioning Ship 22

Budgetary Implications of the Navy’s Plan 26

3 Lower-Cost Alternatives to the Navy’s Plan for Amphibious 

and Maritime Prepositioning Forces 31

Option 1A: Buy Fewer, More-Capable Ships Within Historical

Spending Levels 31

Option 1B: Buy More, Less-Capable Ships Within Historical 

Spending Levels 34

Option 2: Create a More Survivable Sea-Basing Force 37

Option 3: Deemphasize Sea Basing in Favor of Forward Presence 41

Effects of the Options on the Industrial Base 42

4 Measures of Capability Under the Options 47

Number of Amphibious Warfare and Maritime Prepositioning Ships 47

Amount of Amphibious Lift on L-Class Ships 48

Total Amount of Lift on Amphibious Warfare and Maritime

Prepositioning Ships 50

Number of JSFs Carried on Large Amphibious Assault Ships 50

Number of Forward-Deployed Expeditionary Strike Groups 50

Time Needed to Deploy Marine Infantry Battalions to a Conflict 53

Implications of the Analysis 56

CONTENTS
vi THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Tables

S-1. Schedule for Replacing Existing Amphibious and Maritime

Prepositioning Ships with New Classes xii

S-2. The Amphibious and Maritime Prepositioning Forces in 2035

Under Alternative Force Structures xviii

1-1. Characteristics of Current Amphibious Warfare Ships 4

2-1. Schedule for Replacing Existing Amphibious and Maritime

Prepositioning Ships with New Classes 16

2-2. Characteristics of Current and Proposed Amphibious and

Maritime Prepositioning Ships 20

2-3. Average Annual Construction Spending and Procurement for

Amphibious and Maritime Prepositioning Ships, 2005 to 2035 27

2-4. Shortfalls in Sustaining a 293-Ship Navy, 1990 to 2025 28

3-1. Projected Average Annual Spending for Construction and

Operation and Support, 2005 to 2035 35

3-2. Estimated Costs of New Amphibious and Maritime

Prepositioning Ships 41

Figures

S-1. Composition of the Current and 375-Ship Battle Force Fleets x

S-2. Inventory of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan xiii

S-3. Projected Funding to Construct a 375-Ship Fleet

Compared with Actual Ship Funding xiv

S-4. Inventory of Amphibious and Maritime Prepositioning Ships

Under Alternative Force Structures xvi

1-1. Composition of the Current and 375-Ship Battle Force Fleets 2

1-2. Composition of the Amphibious and Maritime Prepositioning Forces 3

1-3. Comparison of an Amphibious Ready Group and an Expeditionary

Strike Group 5

2-1. Inventory of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan 17

2-2. Amphibious Lift, by Category, Under the Navy’s Plan 18

2-3. Annual Purchases of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan 19
CONTENTS vii

2-4. Projected Funding to Construct a 375-Ship Fleet Compared with

Actual Ship Funding 29

3-1. Annual Purchases and Costs of Amphibious and Maritime

Prepositioning Ships Under Option 1A 33

3-2. Inventory of Amphibious and Maritime Prepositioning Ships Under

Option 1A 34

3-3. Annual Purchases and Costs of Amphibious and Maritime

Prepositioning Ships Under Option 1B 36

3-4. Inventory of Amphibious and Maritime Prepositioning Ships Under

Option 1B 37

3-5. Annual Purchases and Costs of Amphibious and Maritime

Prepositioning Ships Under Option 2 39

3-6. Inventory of Amphibious and Maritime Prepositioning Ships Under

Option 2 40

3-7. Annual Purchases and Costs of Amphibious and Maritime

Prepositioning Ships Under Option 3 43

3-8. Inventory of Amphibious and Maritime Prepositioning Ships Under

Option 3 44

4-1. Total Number of Amphibious and Maritime Prepositioning Ships

Under Alternative Force Structures 48

4-2. Components of Amphibious Lift on L-Class Ships Under Alternative

Force Structures 49

4-3. Lift Capacity for Troops and Vehicles on L-Class Ships Under

Alternative Force Structures 51

4-4. Total Lift Provided by the Amphibious and Maritime Prepositioning

Forces Under Alternative Force Structures 52

4-5. Total Number of Joint Strike Fighters Carried by Amphibious Ships

Under Alternative Force Structures 53

4-6. Average Number of Expeditionary Strike Groups Forward Deployed

Under Alternative Force Structures 54

4-7. Time Needed to Deploy Marine Infantry Battalions in a Hostile

Environment Under the Navy’s Plan 55

4-8. Time Needed to Deploy Marine Infantry Battalions in a Hostile

Environment Under Alternative Force Structures 57
viii THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Boxes

S-1. The Roles of Different Amphibious Ships in Conducting

Amphibious Operations xi

1-1. The Requirement for Amphibious Lift 8

1-2. Sea and Air Connectors for the Sea Base 13

2-1. Developing Cost Estimates for Amphibious and Maritime

Prepositioning Ships 21

2-2. The Survivability of Surface Ships in the Navy 25
Summary

The Department of the Navy’s vision for military 

transformation, known as Sea Power 21, rests on three 

key concepts: Sea Strike, Sea Shield, and Sea Basing. The 

first two concepts focus on improving the Navy’s and 

Marine Corps’s offensive and defensive capabilities, respectively. But the third, Sea Basing, is considered by 

many in the Department of Defense to be the most transformational of the three ideas. It envisions putting a substantial Marine Corps ground force on shore and sustaining it from ships at sea rather than from a land base. 

Thus, the Navy and Marine Corps could conduct amphibious assaults (including “forcible-entry” operations, 

like those conducted on Japanese-held Pacific islands 

during World War II) without needing to seize enemy 

territory to build a base or to get permission from a 

nearby country to use an existing base. Supporters argue 

that sea basing would therefore allow U.S. forces to operate overseas more independently, flexibly, and quickly. 

Although the entire fleet would play a role in the “sea 

base,” the most important vessels for that concept are the 

Navy’s amphibious warfare ships—which carry marines 

and their equipment—and new prepositioning vessels intended to provide much of the logistics support for Marine Corps units operating on shore.1

 Over the next 30 

years, the Navy plans to replace most of its amphibious 

ships as well as buy the new class of logistics ships, which 

it calls the Maritime Prepositioning Force (Future), or 

MPF(F). 

Carrying out that plan would cost more than twice as 

much per year, on average, as the Navy has spent on amphibious ships since 1980, the Congressional Budget Office (CBO) estimates.2 Such a spending increase may not 

prove feasible; consequently, this study looks at four ways 

to modernize the Navy’s amphibious and maritime prepositioning forces at lower cost. Some of those alternatives would support sea basing and some would emphasize other capabilities, such as providing overseas (forward) presence. 

Organization of the Amphibious and 

Maritime Prepositioning Forces

Today, amphibious ships make up 12 percent of the 

Navy’s fleet, or 35 out of 293 ships (see Summary Figure 

1). Those vessels—referred to collectively as L-class 

ships—include 12 large amphibious assault ships (known 

as LHAs or LHDs), 11 amphibious transport docks 

(LPDs), and 12 dock landing ships (LSDs). All three 

types of ships carry marines, vehicles, and the landing 

craft that are used to ferry troops and equipment to 

shore; some also carry helicopters and fixed-wing aircraft. 

(For a description of the different types of amphibious 

warfare ships and the roles they play, see Summary 

Box 1.) Together, L-class ships provide the lift (transport 

capacity) to carry 1.9 Marine expeditionary brigades 

(MEBs), or about 27,000 troops and their equipment—

less than the Navy’s stated goal of 2.5 MEBs’ worth of 

lift. 

In the past, amphibious warfare ships were organized into 

12 amphibious ready groups (usually of three ships each), 

which generally operated independently of other ships in 

the fleet. Each group carried a Marine expeditionary unit 

of about 2,200 troops, equivalent to an infantry battalion. Under a plan announced in 2003, however, the 

Navy is reorganizing its fleet to assign three surface combat ships and one submarine to operate with each amphibious ready group. The resulting task forces are called 

expeditionary strike groups, which is the term used in this 

study. 

Separate from its main fleet, the Navy has 16 maritime 

prepositioning ships—conventional cargo vessels oper1. In military terms, “prepositioning” refers to the practice of storing 

equipment on land or at sea in areas near where U.S. forces might 

be called on to operate overseas.

2. Most of the Navy’s current maritime prepositioning ships are 

leased. The funding for the few that the Navy purchased is 

included in the historical average.
x THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Summary Figure 1.

Composition of the Current and 375-Ship Battle Force Fleets

Source: Congressional Budget Office based on data from the Navy.

Notes: Current maritime prepositioning ships are not included in the 293-ship fleet because the Navy does not consider them battle force 

ships. In the 375-ship plan, new, more-capable maritime prepositioning ships are included and are called sea-basing ships.

Attack submarines include four Ohio class ballistic missile submarines that are being converted to carry conventional guided missiles.

a. The Navy’s plan for a 375-ship fleet, submitted in May 2003, included 37 amphibious ships and 18 sea-basing ships. CBO’s analysis, consistent with more-recent information, assumes that the 375-ship fleet would include 36 amphibious ships and 16 sea-basing ships.

ated by the Military Sealift Command (the organization 

responsible for providing ocean transportation services to 

the Department of Defense). Unlike amphibious warfare 

ships, maritime prepositioning ships do not carry troops, 

only equipment. They are organized into three squadrons 

of five or six ships apiece and are based at ports in the 

Mediterranean Sea, the Indian Ocean, and the western 

Pacific. Each squadron holds all of the military hardware 

and supplies needed to equip a Marine expeditionary brigade and sustain it for 30 days. Thus, those ships together 

provide a total lift capacity of 3.0 MEBs.

Maritime prepositioning vessels are not counted in what 

the Navy call its ship battle forces and do not have the capability to engage in forcible-entry operations. Instead, 

they require a secure port for unloading equipment and a 

secure airfield where troops can fly in from the United 

States to pick up the equipment and assemble for operations. The Navy and Marine Corps assume, on the basis 

of various planning factors, that if the Marines needed to 

forcibly seize a port and airfield first, the first Marine unit 

getting its equipment from a maritime prepositioning 

squadron would be ready to operate in eight weeks. If a 

port and airfield were already available—as was the case 

in both wars against Iraq—the first such unit could be 

ready within two weeks.

In March 2003, the Navy sent a report to the Congress 

that proposed building a fleet of 375 ships, including 37 

amphibious ships and 18 new maritime prepositioning 

ships capable of conducting sea-basing operations (see 

Summary Figure 1). Under the 375-ship plan, some or all 

of those new prepositioning ships would be counted as 

part of the battle fleet by virtue of their combat capability. Together, amphibious and maritime prepositioning 

ships would make up 15 percent of that fleet. (Morerecent information suggests that the 375-ship fleet would 

include 36 amphibious ships and 16 sea-basing ships.) 

Logistics, Mine-Warfare,

and Auxiliary Ships

Amphibious

Ships

Ballistic Missile

Submarines

Attack Submarines

Aircraft Carrier

Surface

Combatants

Current 293-Ship Fleet

70

35

58

14 12

104

Logistics, Mine-Warfare,

and Auxiliary Ships

Attack Submarines Aircraft Carriers

Surface

Combatants

Notional 375-Ship Plan

Sea-Basing

Ships

Amphibious

Ships

Ballistic Missile

Submarines

a

75

37

59

14

12

18

160
SUMMARY xi

Summary Box 1.

The Roles of Different Amphibious Ships in Conducting

Amphibious Operations

(Silhouettes not to scale) The two classes of amphibious assault ship, the Tarawa (LHA) and the 

Wasp (LHD), are the centerpieces of the Navy’s expeditionary strike 

groups. More than twice as big as any other amphibious vessel in the fleet 

today, each amphibious assault ship carries half of the troops, vehicles, and 

cargo of a battalion-sized Marine expeditionary unit. These ships are 

sometimes called helicopter carriers because they provide most of the helicopters and all of the fixed-wing aircraft used in Marine operations. Normally, each ship carries, and serves as an operating platform for, about 30 

helicopters and six fixed-wing Harrier jump jets. At times, however, the 

Navy uses an amphibious assault ship as a small aircraft carrier, putting up 

to 20 Harriers on board. In addition, each of these ships carries one to 

three landing craft, which are used to ferry troops, equipment, and materiel to shore. In an expeditionary strike group, one amphibious assault ship 

operates with one amphibious transport dock and one dock landing ship, 

as well as with three surface combatants and one submarine.

The amphibious transport dock, or LPD, originated as a larger version of 

the dock landing ships described below. Like all amphibious ships, transport docks carry some of the troops, vehicles, and material of a Marine expeditionary unit. They carry fewer landing craft than other amphibious 

vessels, but they have a fixed helicopter deck and can provide hangar space 

for four to six helicopters. Maintenance and support on those aircraft, 

however, must be done on an amphibious assault ship. Transport docks of 

the Austin (LPD-4) class are the oldest amphibious ships still in use. They 

are scheduled to be replaced gradually by transport docks of the San Antonio (LPD-17) class, the first of which will be commissioned in 2005. Unlike the two classes of amphibious assault ship (LHA and LHD), which are 

about the same size, the LPD-17 is some 40 percent larger than the LPD4 class, with twice as much vehicle space and more helicopters and landing 

craft. The LPD-4 class, by contrast, has far more cargo space than its replacement.

The dock landing ship, or LSD, is a design that had its origins in World 

War II, when the Navy first developed dedicated amphibious ships. Like 

amphibious assault ships and transport docks, LSDs carry and (via landing 

craft) land troops, vehicles, and material for amphibious operations. Dock 

landing ships have a larger docking well (the area used to transport and deploy landing craft) than other types of amphibious ships do and thus can 

carry more landing craft. They do not have the capability to house helicopters, although they can support helicopter operations with a removable 

landing pad that fits over their docking well. The two classes of LSD in 

the fleet are two variants of the same design. The Harpers Ferry (LSD-49) 

class has 10 times the cargo capacity and slightly more vehicle space than 

the Whidbey Island (LSD-41) class. In exchange, the LSD-41 class has a 

larger docking well that can accommodate more landing craft. 

Wasp Class (LHD)

Tarawa Class (LHA)

Austin Class (LPD)

San Antonio Class (LPD)

Whidbey Island Class (LSD)

Harpers Ferry Class (LSD)
xii THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Summary Table 1.

Schedule for Replacing Existing Amphibious and Maritime

Prepositioning Ships with New Classes

Source: Congressional Budget Office based on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

a. Tarawa, the first LHA to retire, will be replaced by Makin Island, the last of the LHDs.

b. Projected.

c. Through 2004, six of the 12 LPD-17s had already been purchased.

d. Most of these ships will be transferred to the Ready Reserve Fleet to replace cargo ships that will be scrapped.

e. CBO assumes that 16 ships will have sea-basing capabilities and five will be replacement cargo ships.

The Navy’s Plan to Modernize the

Amphibious and Maritime 

Prepositioning Forces 

Under the Sea-Basing Vision

The Navy intends to replace most of its current amphibious and maritime prepositioning ships over the next 30 

years (see Summary Table 1). Its plan for those forces includes:

B Completing the purchase of 12 amphibious transport 

docks of the LPD-17 San Antonio class; 

B Buying 10 amphibious assault ships of a new class, 

designated the LHA(R), which would be similar to the 

existing LHD class but have the ability to carry and 

support more aircraft; 

B Acquiring 12 dock landing ships of a new class, 

known as the LSD(X); and 

B Buying up to 21 new maritime prepositioning ships, 

or MPF(F)s, 16 of which would have capabilities far 

beyond those of today’s maritime prepositioning ships 

in order to support sea basing.

Under that plan, the Navy would have 57 amphibious 

warfare and maritime prepositioning ships by 2035 (see 

Summary Figure 2), compared with 51 in 2004. Those 

ships would be organized into 12 expeditionary strike 

groups and three maritime prepositioning squadrons.

Replacement Ships

Existing Ships

Class

Year First 

Ship Is 

Authorized

Year First 

Ship Is 

Commissioned

Quantity to Be

Purchased 

Class Through 2035

Quantity 

in Service

Year First 

Ship Retires

Amphibious Assault Ships

Tarawa (LHA-1) 5 2007a LHA(R) 2007 2012b 10

Wasp (LHD-1) 7 2027 LHA(R)

Amphibious Transport Docks

Austin (LPD-4) 11 2004 San Antonio 

(LPD-17)

1996 2005 12c

Dock Landing Ships

Whidbey Island (LSD-41) 8 2024 LSD(X) 2020 2024b 12

Harpers Ferry (LSD-49) 4 2032 LSD(X)

Maritime Prepositioning Ships

MPS Cargo Ships 16 2013d MPF(F) 2009 2013b 21e
SUMMARY xiii

Summary Figure 2.

Inventory of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan

Source: Congressional Budget Office based on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

By 2035, each expeditionary strike group would comprise 

one large amphibious assault ship of either the LHD or 

LHA(R) class, an LPD-17, and an LSD(X). Of the maritime prepositioning squadrons, two would consist of 

ships with sea-basing capabilities, and one would consist 

of replacement cargo vessels like those used today. All together, those forces could provide a total lift capacity of 

5.5 MEBs (2.5 MEBs on the amphibious warfare ships, 

2.0 MEBs on the sea-basing ships, and 1.0 MEB on the 

conventional cargo ships).

In the Navy’s and Marine Corps’s vision for sea basing, 

amphibious ships would continue to carry the “assault 

echelons”—the first wave of troops—in any expeditionary operation. The MPF(F) ships would carry most of the 

material needed to sustain that force in the first 20 days 

of operations. They would also hold all of the equipment 

for “follow-on assault echelons”—successive waves of 

troops that would be transported to the theater on aircraft or high-speed surface craft. With sea basing, no land 

base would be necessary for the follow-on forces to assemble themselves and deploy—all of that would occur 

on the ships composing the sea base. Nor would there be 

a large supply depot on land to offer a prime, stationary 

target for attacks by enemy ballistic missiles, cruise missiles, or aircraft. The MPF(F)s are the linchpin of the sea 

base; without them, the Navy and Marine Corps would 

not be able to implement that new approach to amphibious warfare or forcible-entry operations.

Carrying out the Navy’s plan for amphibious and maritime prepositioning forces would require spending an average of $2.4 billion a year (in 2005 dollars) on ship construction between 2005 and 2035, CBO estimates—

more than twice the Navy’s average annual spending to 

build amphibious and maritime prepositioning ships between 1980 and 2004. If costs to operate and support 

those forces were included, the Navy would need to 

spend an average of $5.4 billion per year over the 2005-

2035 period.

That planned increase in spending comes at a time when 

Navy officials are envisioning other modernization programs—for surface combatants, submarines, aircraft carriers, and support ships—that would also require greater 

spending on ship construction. Building the proposed 

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPS Cargo Ships MPF(F) Sea-Basing Ships

LSD(X)
xiv THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Summary Figure 3.

Projected Funding to Construct a 375-Ship Fleet

Compared with Actual Ship Funding

(Billions of 2005 dollars)

Source: Congressional Budget Office.

Note: The data in this figure are roughly analogous to the cost-risk case for ships presented in Congressional Budget Office, The Long-Term 

Implications of Current Defense Plans: Summary Update for Fiscal Year 2005 (September 2004).

375-ship fleet would cost an average of about $19 billion 

annually through 2035, CBO estimates, compared with 

average funding of less than $12 billion a year since 1980. 

Spending on amphibious and maritime prepositioning 

ships would represent about 12 percent of total shipbuilding costs, up from an average of 9 percent between 

1980 and 2004 (see Summary Figure 3). 

Many questions remain about the future size of the 

Navy’s amphibious forces and the viability of the seabasing concept. The Navy may find that modernizing its 

amphibious warfare force and purchasing new MPF(F) 

vessels are difficult to afford simultaneously. Some Navy 

officials have suggested reducing the number of L-class 

ships in order to buy the MPF(F)s. That and other recent 

proposals for reductions in the force structure suggest 

that senior Navy leaders do not think the 375-ship goal is 

viable. If a battle fleet of that size proves too expensive, 

the Navy’s current plans for amphibious and maritime 

prepositioning ships may change. 

In addition, the sea-basing idea is still in its early stages of 

development. Important conceptual issues and technological problems will have to be solved before that idea 

can become a reality. Furthermore, a growing number of 

military leaders and analysts contend that sea basing 

needs to be joint (in other words, that all of the military 

services need to be involved in its development and funding). What role the Army and the Air Force would play 

in that effort, however, is not yet clear.

Lower-Cost Alternatives 

to the Navy’s Plan

CBO constructed four alternative plans for the future of 

amphibious and maritime prepositioning forces that 

would lessen the funding challenge the Navy is facing 

with its shipbuilding budget as a whole and with those 

forces in particular. All of the alternatives would result in 

a smaller amphibious force than exists today, and some 

would result in a smaller prepositioning force as well. 

1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035

0

5

10

15

20

25

30

Actual Projected

Surface Combatants, Aircraft

Carriers, Submarines, and

Support Ships

Amphibious Ships
SUMMARY xv

Each option would take a different approach to modernizing amphibious and maritime prepositioning ships:

B Buying fewer, more-capable ships within the historical 

spending level for construction of those vessels (an average of $1.1 billion per year in 2005 dollars);

B Buying more, less-capable ships within the historical 

spending level;

B Creating a sea-basing force that was more survivable 

(better able to withstand attack) than the force envisioned by the Navy, at a cost below that of the Navy’s 

plan but above the historical level; or 

B Deemphasizing sea basing in favor of forward presence, at a cost below that of the Navy’s plan but above 

the historical level.

CBO found no alternative that could do more with less. 

Saving money on the amphibious warfare and maritime 

prepositioning forces, relative to the Navy’s plan, requires 

buying fewer ships and thus having less capability. Unless 

the Navy can provide a level of resources equivalent to 

that required to implement its current plan, choices will 

have to be made about how to structure those forces in 

the future. Questions include, What should the balance 

be between expeditionary strike groups and maritime 

prepositioning squadrons? Does the Navy need 12 expeditionary strike groups and three maritime prepositioning 

squadrons? What role should sea basing play in the design of the future maritime prepositioning force? Would 

the MPF(F) ships be survivable enough to operate in a 

hostile coastal environment? The options that CBO examined offer different ways to answer those questions.

Option 1A: Buy Fewer, More-Capable Ships 

Within the Historical Spending Level

Since 1980, the Navy has devoted an average of about 

$1.1 billion annually to construction of amphibious ships 

(and the occasional maritime prepositioning ship that it 

has purchased rather than leased). On the assumption 

that the average funding level for those vessels will not increase over the next 30 years, this option would buy the 

new types of ships that the Navy envisions but in much 

smaller numbers than under the Navy’s plan.

This approach would gradually reduce the number of expeditionary strike groups by half (from 12 to six) and the 

number of maritime prepositioning squadrons by onethird (from three to two). To compensate somewhat for 

those cuts, one of the maritime prepositioning squadrons 

would be given sea-basing capabilities. (The other squadron would consist of replacement cargo ships with the 

same capability as today’s maritime prepositioning ships.) 

Under this option, the Navy would buy four of the new 

LHA(R) amphibious assault ships through 2035, instead 

of 10 as under the Navy’s plan; five rather than 12 new 

LSD(X)s that would be larger than today’s dock landing 

ships; and one squadron of eight sea-basing-capable 

MPF(F) ships instead of 16. This option would also purchase seven LPD-17 dock landing ships rather than 12 

and a squadron of five conventional cargo ships. By 

2035, the inventory of amphibious and maritime prepositioning ships would total 31 vessels, compared with 57 

under the Navy’s plan (see Summary Figure 4). Of that 

total, 26 would be L-class ships and sea-basing-capable 

maritime prepositioning ships, versus 52 under the 

Navy’s plan.

Option 1B: Buy More, Less-Capable Ships 

Within the Historical Spending Level

If the Navy was forced to fund amphibious and maritime 

prepositioning ships at the historical level of about $1.1 

billion a year but was reluctant to cut the L-class force to 

the extent envisioned in Option 1A, it could retain a 

larger number of ships by not investing in new designs. 

This option illustrates that approach: it would keep the 

future amphibious warfare and maritime prepositioning 

forces at a greater size than under Option 1A but would 

not pursue the enhanced sea-basing capability sought by 

the Navy and Marine Corps. In other words, for the same 

amount of money, this approach would emphasize quantity over quality, and Option 1A would do the opposite.

In this alternative, the number of expeditionary strike 

groups would gradually be cut by one-quarter, from 12 to 

nine (leaving 50 percent more than in Option 1A). The 

number of maritime prepositioning ships would be reduced with just over half a squadron rather than by a 

whole squadron. Amphibious assault ships would be replaced with ships similar in size and capabilities to existing classes, and maritime prepositioning ships would be 

replaced with modern cargo ships that lacked sea-basing 

capabilities. Thus, the Navy would purchase six LHA(R)s 

over the 2005-2035 period, but those vessels would replicate today’s amphibious assault ships rather than offer enhanced aviation capabilities, as the Navy plans. The 

LPD-17 program would end at nine ships instead of 12. 

Likewise, the Navy would buy nine LSD(X)s rather than 
xvi THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Summary Figure 4.

Inventory of Amphibious and Maritime Prepositioning Ships

Under Alternative Force Structures

Source: Congressional Budget Office based in part on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

12, and those ships would be similar in size and capabilities to existing dock landing ships. By 2035, the total inventory of amphibious and maritime prepositioning vessels would number 39 ships, and the amphibious warfare 

force would number 27 ships.

Option 2: Create a More Survivable 

Sea-Basing Force

To save money, senior Navy leaders have proposed cutting the number of expeditionary strike groups from 12 

to eight—and thus reducing the number of amphibious 

warfare ships—and using the savings to buy two squadrons of sea-basing-capable MPF(F)s. This option follows 

that approach, with one significant difference: it would 

increase the survivability of the MPF(F) ships. As currently planned, those vessels would be much less survivable than amphibious warfare ships. They would have little or no ability to defend themselves from attack and 

would have difficulty continuing to operate if they were 

struck—even though they would be the largest (except 

for aircraft carriers), the most detectable, and thus the 

most targetable Navy ships in a theater of operations. To 

address that issue, this option would build MPF(F)s that 

were closer, though not equal, in survivability to L-class 

amphibious ships. Because a more survivable MPF(F) 

would be more expensive, this option would buy only 

eight, or one squadron’s worth. In all, this approach 

would spend an average of $1.5 billion a year on ship 

construction between 2005 and 2035, compared with 

$2.4 billion under the Navy’s plan.

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60 Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD LPD-17

LHA(R)

MPF(F) Sea-Basing Ships

MPS Cargo Ships

LSD(X)

Option 1A

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60 Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPF(F) Sea-Basing Ships

MPS Cargo Ships

LSD(X)

Option 2

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60 Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPS Cargo Ships

LSD(X)

Option 1B

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60 Total Under the Navy's Plan

LPD-4 LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPS Cargo Ships

LSD(X)

Option 3
SUMMARY xvii

Under this alternative, the LPD-17 program would stop 

at eight ships instead of 12. The LHA(R) program would 

be delayed from 2007 until 2022, and six of those ships 

would be purchased through 2035. The LSD(X) program 

would begin at the same time as in the Navy’s plan 

(2020), but only eight ships would be bought rather than 

12. This option would also purchase eight sea-basing 

MPF(F) ships with enhanced survivability, starting in 

2009. The last of those MPF(F)s would be fully operational by 2021. Under this alternative, the amphibious 

warfare force would decline fairly rapidly through 2024, 

at which time it would level off at 24 ships (eight LPDs, 

eight LSDs, and eight LHA/LHDs). Together, the amphibious and maritime prepositioning forces would total 

32 ships.

Option 3: Deemphasize Sea Basing 

in Favor of Forward Presence

Just as Option 2 represents a slightly more expensive way 

than Option 1A to procure sea-basing capability, this alternative is a slightly more expensive way than Option 1B 

to keep larger amphibious and maritime prepositioning 

forces. Both this approach and Option 1B would forgo 

sea-basing capability, but this alternative would allow for 

greater overseas presence than any of the other options 

that CBO examined. Under this approach, the number 

of expeditionary strike groups would be cut by one-sixth 

(from 12 to 10), and the number of maritime prepositioning squadrons would remain at three, although they 

would consist of new cargo vessels much like today’s 

rather than sea-basing-capable ships. Once implemented, 

this option would provide peacetime forward presence 

and maritime prepositioning capabilities that were similar 

to but slightly less than those of the current force.

The Navy and Marine Corps have not conducted an opposed amphibious assault since the Korean War, but 

in the intervening years, the Navy’s amphibious ships 

have responded frequently to crises around the world. Between 1991 and 2000, for example, amphibious and (on 

occasion) maritime prepositioning ships took part in at 

least 55 operations, ranging from disaster-relief efforts to 

military operations in Iraq, Bosnia, Haiti, and the former 

Yugoslavia. Cutting the crisis-response capability provided by those ships in order to procure the new seabasing capabilities of the MPF(F) might not make sense, 

especially given the challenges involved in making the 

sea-basing concept work. The Navy would need to develop a host of new technologies for MPF(F) ships as well 

as acquire new fleets of aircraft and small ships to keep 

the sea base and the troops it is supporting well supplied, 

at a potential cost of many billions of dollars. As an alternative to investing in sea-basing capabilities, this option 

would keep the amphibious and maritime prepositioning 

forces as large as possible—consistent with saving 

money—to respond to crises.

This approach would end the LPD-17 program at 10 

ships instead of 12. It would delay the start of the 

LHA(R) program from 2007 until 2013 and buy eight 

ships rather than 10 through 2035. The LSD(X) program 

would be delayed by two years (from 2020 until 2022), 

and only 10 ships would be purchased instead of 12. The 

MPF(F) program would consist of three full squadrons’ 

worth of ships, but they would not have sea-basing capabilities. With those changes, building amphibious and 

maritime prepositioning ships would cost the Navy an 

average of $1.5 billion a year between 2005 and 2035. 

The amphibious warfare force would remain at around 

35 ships through 2012 and then quickly level off at 30 

ships—10 LPDs, 10 LSDs, and 10 LHA/LHDs, compared with 12 each under the Navy’s plan. By 2035, the 

total inventory of amphibious and maritime prepositioning ships would number 45.

Measures of Capability 

Under the Options

To evaluate the different alternatives in this study and 

compare them with the Navy’s plan, CBO looked not 

only at total numbers of ships but also at various measures of peacetime and wartime capability. Those measures include the traditional components of amphibious 

lift on L-class ships (such as the total space available for 

carrying troops, landing craft, helicopters, vehicles, and 

cargo); the total amount of lift by all L-class and maritime prepositioning ships; the number of Joint Strike 

Fighters carried by amphibious assault ships; the number 

of expeditionary strike groups that are forward deployed 

(a measure of peacetime forward presence); and the time 

needed to deploy Marine infantry battalions in a wartime 

environment.

Of the approaches analyzed in this study, the Navy’s plan 

would provide the most capability by all of those measures—but at the greatest cost (see Summary Table 2). 

The less expensive alternatives that CBO examined offer 

less capability than that plan and, in many cases, less 
xviii THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Summary Table 2.

The Amphibious and Maritime Prepositioning Forces in 2035

Under Alternative Force Structures

Source: Congressional Budget Office.

Note: MEB = Marine expeditionary brigade; ESG = expeditionary strike group; n.a. = not applicable.

a. Space for troops and vehicles is in relatively short supply on amphibious ships. The Navy has excess capacity in other categories of 

amphibious lift, such as space for cargo, landing craft, and helicopters.

b. The Navy does not employ crew rotation on expeditionary strike groups, although it is planning to experiment with it. This number is 

shown only for comparability.

capability than today’s amphibious and maritime prepositioning forces. However, Options 1A and 2 would provide some of the new sea-basing capability that the Navy 

and Marine Corps desire, and Option 3 would provide 

slightly more lift capacity than today’s force does.

CBO’s analysis suggests that defense officials and lawmakers may have to balance competing priorities. If the 

operational flexibility of sea basing is considered crucial, 

the Navy could procure it without an increase from the 

historical funding level by sharply curtailing the number 

of amphibious warfare ships (Option 1A). With a 36 percent increase in average funding—less than one-third of 

the rise needed to carry out current plans—the Navy 

could achieve some of that capability and also make the 

ships that possess it less vulnerable to attack (Option 2). 

Alternatively, if the size of the force and the amount of 

forward presence it can provide take precedence over seabasing capability, the Navy could have an amphibious 

warfare force of about 27 ships by 2035 (compared with 

35 today) without a rise in funding (Option 1B). With 

the same funding increase as in Option 2, it could retain 

a force of at least 30 L-class ships over the next three

decades. 

Force

Structure

Average 

Annual 

Procurement 

Cost

(Billions

of dollars)

 Lift Capacity

(Number of MEBs) Number of Ships

Number of

Forward-Deployed 

ESGs

Number of Marine Infantry Battalions Ashore 

After

All 

Ships

Amphibious

Ships

Onlya

All

Ships

Amphibious

Ships

Only

Using 

Current 

Crewing

Using Crew 

Rotation

Four 

Weeks

Six 

Weeks

Ten 

Weeks

Navy’s Plan 2.4 5.5 2.3 57 36 2.7 3.6 8 12 15

Option 1A 1.1 3.3 1.3 31 18 1.8 2.4 4 6 9

Option 1B 1.1 4.3 1.8 39 27 2.2 3.0 2 5 12

Option 2 1.5 2.7 1.7 32 24 2.1 2.8 5 7 7

Option 3 1.5 5.0 2.0 45 30 2.4 3.2 2 5 14

Memorandum:

Current Force n.a. 4.9 1.9 51 35 2.7 3.6b 2 6 15
1

Introduction

The U.S. Navy and Marine Corps have conducted 

what they call naval expeditionary operations—operations mounted overseas, often in austere environments, 

from a combination of sea and forward land bases—since 

the Revolutionary War. One type of expeditionary operation is the amphibious assault, an attack mounted from 

the sea against a hostile shore, such as the famous D-Day 

invasion of 1944. Amphibious assaults were perfected 

during the island-hopping campaign in the Pacific in 

World War II and continued during the Korean War, 

when marines stormed ashore at Inchon. However, that 

war marked the last time that the Navy and Marine 

Corps conducted an amphibious assault.

More recently, naval expeditionary operations have emphasized using the sea as a high-speed avenue of maneuver to get marines quickly to a potential hotspot—while 

avoiding defended beaches or coastal approaches—in order to rapidly build up combat power on shore. To accomplish that task, the Navy has maintained a substantial 

number of ships designed to deliver marines ashore and 

to support them from the sea. 

Today’s expeditionary warfare force includes 35 ships of 

various types known collectively as L-class amphibious 

warfare ships. Those vessels are special-purpose warships 

designed to carry Marine Corps units to and across a 

coastal penetration point, even if it is defended—thus 

providing the Navy and Marines with a “forcible-entry” 

capability. Since 1986, amphibious warfare ships have 

been augmented by a special-purpose maritime prepositioning force. The cargo ships that make up that force are 

essentially floating warehouses designed to deliver reinforcements and supplies to assault troops quickly once a 

port and airfield have been seized and secured. The current maritime prepositioning force consists of 16 vessels, 

bringing the size of the expeditionary warfare force to 51 

ships.

Over the next 30 years, the Navy plans to modernize its 

amphibious warfare fleet with a mix of current and new 

ship designs. It also intends to completely replace its maritime prepositioning force with a still-undetermined 

number of new maritime prepositioning ships that have 

advanced capabilities—a class that the Navy refers to as 

the Maritime Prepositioning Force (Future), or MPF(F). 

Carrying out those plans would require more than twice 

as much annual funding as the Navy has devoted to expeditionary warfare ships since 1980, on average, the Congressional Budget Office (CBO) projects. Moreover, that 

funding increase would be needed at a time when the 

Navy wants to expand its overall fleet of battle force ships 

from 293 to 375 (see Figure 1-1).1

This CBO study—the third focusing on the Navy’s longterm shipbuilding plans and the resources they could require—examines the composition, missions, and modernization programs of the Navy’s amphibious and maritime prepositioning forces.2

 It also analyzes four ways to 

reduce procurement costs for those forces to relieve pressure on the Navy’s future shipbuilding budget.

CHAPTER

1. See Department of the Navy, A Report to Congress on Annual LongRange Plan for the Construction of Naval Vessels (May 2003). That 

report, which was mandated by the 2003 defense authorization 

act, advocated building a 375-ship Navy. The authorization act 

ordered the Secretary of Defense to prepare and submit a longterm shipbuilding report to the Congress, and that report was presumably sent with the concurrence of the Office of the Secretary 

of Defense. However, in Congressional hearings in the spring of 

2003, Secretary of Defense Donald Rumsfeld pointedly refused to 

endorse the requirement for 375 ships.

2. The previous studies are Congressional Budget Office, Transforming the Navy’s Surface Combatant Force (March 2003), and Increasing the Mission Capability of the Attack Submarine Force (March 

2002). 
2 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 1-1.

Composition of the Current and 375-Ship Battle Force Fleets

Source: Congressional Budget Office based on data from the Navy.

Notes: Current maritime prepositioning ships are not included in the 293-ship fleet because the Navy does not consider them battle force 

ships. In the 375-ship plan, new, more-capable maritime prepositioning ships are included and are called sea-basing ships.

Attack submarines include four Ohio class ballistic missile submarines that are being converted to carry conventional guided missiles.

a. The Navy’s plan for a 375-ship fleet, submitted in May 2003, included 37 amphibious ships and 18 sea-basing ships. CBO’s analysis, consistent with more-recent information, assumes that the 375-ship fleet would include 36 amphibious ships and 16 sea-basing ships.

Today’s Amphibious and Maritime 

Prepositioning Forces

The ultimate purpose of the Navy’s expeditionary warfare 

force is to transport, insert, and support Marine Corps 

units organized into Marine air-ground task forces 

(known as MAGTFs). Those task forces, which include 

all of the combat and support units necessary for an operation, can be scaled in size from as little as a few hundred 

troops to more than 50,000. However, three generic types 

of MAGTF are common: Marine expeditionary units, 

which are normally the size of a battalion, or around 

2,200 troops; Marine expeditionary brigades (MEBs), 

with about 14,000 troops; and Marine expeditionary 

forces (MEFs), with 40,000 to 50,000 troops. The Marine Corps’s entire force is organized into three MEFs.

The Navy uses two types of ship to deploy those Marine 

units: amphibious warfare ships and maritime prepositioning vessels. Amphibious warfare ships provide the 

Navy’s capability for opposed amphibious assaults 

(forcible-entry operations). Should an assault be required 

in the future, the first wave of attackers would come from 

amphibious warfare ships. Equipment for reinforcements 

would arrive on maritime prepositioning ships.

The Amphibious Warfare Force

The Navy currently has 35 amphibious warfare ships in 

its fleet: 12 LHA or LHD large amphibious assault vessels 

(sometimes called helicopter carriers), 11 LPD amphibious transport docks, and 12 LSD dock landing ships (see 

Figure 1-2). Those ships vary in size and capability, but 

they all carry troops, cargo, and vehicles for Marine expeditionary units as well as landing craft to ferry troops and 

equipment to shore. Some of those ships also carry fixedwing aircraft or helicopters for use in expeditionary operations. Amphibious warfare ships are larger than most 

other Navy vessels. Their displacement (weight) varies 

from 16,000 to about 40,000 tons (see Table 1-1), comLogistics, Mine-Warfare,

and Auxiliary Ships

Amphibious

Ships

Ballistic Missile

Submarines

Attack Submarines

Aircraft Carrier

Surface

Combatants

Current 293-Ship Fleet

70

35

58

14 12

104

Logistics, Mine-Warfare,

and Auxiliary Ships

Attack Submarines Aircraft Carriers

Surface

Combatants

Notional 375-Ship Plan

Sea-Basing

Ships

Amphibious

Ships

Ballistic Missile

Submarines

a

75

37

59

14

12

18

160
CHAPTER ONE INTRODUCTION 3

pared with 4,000 to about 10,000 tons for current surface 

combat ships.3

In the Navy’s practice, classes of vessels are known by the 

name and the letter-and-number designation of the first 

ship in a class. Today, five classes of amphibious warfare 

ships are in active service and one is under construction 

(for more details, see Summary Box 1 on page xi): 

B Tarawa class (LHA-1) amphibious assault ships were introduced in the late 1970s, combining the capabilities 

of several older types of amphibious ships into one. 

They are among the largest amphibious vessels, with a 

displacement of about 40,000 tons, and can carry 

1,700 troops and large amounts of cargo and vehicles. 

They also have a docking well—a large opening and 

ramp to the sea in the back of the ship—to launch 

landing craft and amphibious vehicles. Each LHA carries an air wing comprising 30 CH-46 Sea Knight and 

CH-53 Sea Stallion helicopters, as well as six AV-8B 

Harrier short takeoff and vertical landing jets. In its 

“sea control” configuration, an LHA can carry up to 

20 Harrier aircraft and six helicopters (a more capable 

force than British aircraft carriers deployed during expeditionary operations in the Falklands War). Tarawa 

class LHAs are now about 26 years old, on average. 

Although they have been modernized with new combat systems and other equipment during their service 

lives, they have gotten heavier. That increased weight 

threatens to destabilize the ships’ center of gravity, 

making further improvements virtually impossible.

B Wasp class (LHD-1) amphibious assault ships are based 

on a modified design of the Tarawa class LHAs. They 

carry a similar number of troops but more cargo and 

fewer vehicles. However, they have more space to support aircraft operations as well as a redesigned docking 

well that can accommodate more landing craft than 

the LHAs can. They also have better defensive capabilities than LHAs. The average age of Wasp class LHDs 

is 9; given their intended service life, those ships will 

be a core component of the amphibious warfare fleet 

for the next quarter century. Seven LHDs are operating with the fleet and an eighth is under construction. 

Figure 1-2.

Composition of the Amphibious and 

Maritime Prepositioning Forces

Source: Congressional Budget Office based on data from the Navy.

That ship (LHD-8) is intended to replace the Belleau 

Wood LHA, which is scheduled for retirement in 

2007. Unlike the other ships in its class, the LHD-8 

will have gas turbines and a hybrid electric propulsion 

system instead of being driven by steam. 

B Austin class (LPD-4) amphibious transport docks are the 

oldest ships in the amphibious warfare force, with an 

average age of about 36. They are less than half the 

size of the Tarawa class LHAs and Wasp class LHDs, 

displacing about 17,000 tons. Austin class LPDs can 

carry about 800 troops, a substantial amount of cargo, 

and a moderate number of vehicles. They also have a 

docking well to launch landing craft and amphibious 

vehicles. The principal difference between these amphibious transport docks and the similar dock landing 

ships (described below) is that the transport docks 

have a permanent flight deck to support helicopter operations. However, any deployment of helicopters on 

an Austin class LPD would require the support of an 

LHA or LHD to provide maintenance and other support for the helicopters on a continuous basis.

B San Antonio class (LPD-17) amphibious transport docks, 

which are under construction, are due to replace Austin class LPDs over the next 10 years. They will be 

larger than their predecessors and have more space for 

vehicles and aircraft. (San Antonio class LPDs are discussed in more detail in Chapter 2, along with several

3. See Congressional Budget Office, Transforming the Navy’s Surface 

Combatant Force, Table 1.

Austin Class

Amphibious Transport

Docks (LPD-4) Maritime

Prepositioning Ships

Harpers Ferry Class

Dock Landing Ships

(LSD-49)

Whidbey Island Class

Dock Landing Ships

(LSD-41) Wasp Class

Amphibious Assault

Ships (LHD-1)

Tarawa Class

Amphibious Assault

Ships (LHA-1)

16

5

7

8

4

11
4 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Table 1-1.

Characteristics of Current Amphibious Warfare Ships

Source: Congressional Budget Office.

a. Displacement at full load (including all of the things the ship normally carries).

b. The five categories (or fingerprints) of amphibious lift are the number of troops a ship can carry; its vehicle storage area, measured in 

thousands of square feet (or vehicle square); its cargo storage area, measured in thousands of cubic feet (or cargo cube); the number of 

spots for parking vertical takeoff and landing aircraft (expressed as CH-46 helicopter equivalents); and the number of spots for air-cushion 

landing craft (known as LCACs).

c. An eighth Wasp class ship is under construction and will be commissioned in 2007.

new types of amphibious warfare ships that the Navy 

has proposed.)

B Whidbey Island class (LSD-41) and Harpers Ferry class 

(LSD-49) dock landing ships are two variants of the 

same design. Both types of ship can carry about 450 

troops apiece. They also have slightly larger vehicle 

storage areas than the Austin class transport docks do. 

Harpers Ferry LSDs are considered the cargo variant 

of dock landing ships: they have 10 times the cargo 

storage space of the Whidbey Island class but only half 

the carrying capacity for landing craft in their docking 

wells. LSDs are relatively young ships. The Harpers 

Ferry class is about 8 years old, on average, and the 

Whidbey Island class is about 15 years old.

In the past, amphibious warfare ships were organized into 

12 amphibious ready groups—usually of three ships 

each—that operated independently of other ships in the 

Navy. Each ready group carried one Marine expeditionary unit. Under a plan announced in 2003, the Navy has 

begun reorganizing its fleet so that three surface combatants (a cruiser, a destroyer, and a frigate) and one attack 

submarine operate with each amphibious ready group. 

The resulting task force is called an expeditionary strike 

group, or ESG (see Figure 1-3). 

The Navy says that a combined force of amphibious warfare ships and surface combatants is far more capable of 

responding to a variety of low- to mid-level crises than is 

Fingerprints of Liftb

Class Type of Ship Quantity 

Displacementa

(Tons)

Crew 

Size Troops

Vehicle 

Square

Cargo 

Cube

Helicopter 

Spots

LCAC 

Spots 

Current Ships

LHA-1 

Tarawa

Amphibious

assault ship

5 40,000 1,160 1,713 25.4 105.9 42 1

LHD-1 

Wasp

Amphibious

assault ship

7c 40,500 1,150 1,686 20.9 125.0 45 3

LPD-4 

Austin

Amphibious

transport dock

11 17,000 400 788 11.8 38.3 4 1

LSD-41 

Whidbey Island

Dock landing ship 8 16,000 310 454 13.5 5.1 0 4

LSD-49 

Harpers Ferry

Dock landing ship 4 17,000 330 454 16.9 50.7 0 2

Ships Under Construction

LPD-17 

San Antonio

Amphibious

transport dock

12 25,000 420 720 25.0 36.0 6 2
CHAPTER ONE INTRODUCTION 5

Figure 1-3.

Comparison of an Amphibious Ready Group and an Expeditionary Strike Group

Source: Congressional Budget Office based on information from the Navy.

Amphibious Ready Group

Expeditionary Strike Group

Wasp Class (LHD)

Wasp Class (LHD)

Harpers Ferry Class (LSD)

Harpers Ferry Class (LSD)

Ticonderoga Class (CG)

Oliver Hazard Perry Class (FFG)

Arleigh Burke Class (DDG)

Los Angeles Class (SSN)

San Antonio Class (LPD)

Austin Class (LPD)
6 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

either group of ships alone.4 Surface combatants offer the 

ability to strike targets from long range with Tomahawk 

missiles and the ability to provide air defense for a fleet. 

Amphibious warfare ships provide the means to go ashore 

and conduct operations on the ground.

Together, the Navy’s amphibious warfare ships can carry 

about 35,000 troops. However, because at any time some 

of those ships are in long-term maintenance or the early 

stages of training cycles, not all of them are available to 

deploy and conduct military operations. Within a few 

days, the Navy could respond to a crisis with three to six 

amphibious warfare ships—the two closest forwarddeployed ESGs. In the first six to 10 weeks of a crisis, 

about half of the Navy’s amphibious warfare ships could 

be mustered for combat operations—about six ESGs, or 

six battalions, for a total of about 13,000 troops.

The Maritime Prepositioning Force

In addition to its amphibious warfare ships, the Navy has 

16 maritime prepositioning vessels, organized into three 

squadrons of five or six ships apiece. Each squadron carries enough vehicles, equipment, and supplies to equip 

and sustain a Marine expeditionary brigade for 30 days. 

The ships, most of which are leased cargo vessels, are operated by the Navy’s Military Sealift Command and are 

forward deployed at ports in the Mediterranean Sea, the 

Indian Ocean, and the western Pacific.5

Unlike amphibious warfare ships, maritime prepositioning ships do not carry troops and do not have a forcibleentry capability. They require a secure port at which to 

unload equipment and an airfield where the troops of a 

MEB can fly in from the United States, meet up with the 

equipment, and assemble into a fighting force. Thus, 

maritime prepositioning ships are intended to provide 

follow-on forces that deploy to a theater after the assault 

troops on amphibious warfare ships have secured an area. 

That capability is designed to allow three large Marine 

Corps units to be available for combat operations in a relatively short time.6

 The Marine Corps expects that if a 

port and airfield have to be seized beforehand, the first 

MEB getting its equipment from a maritime prepositioning squadron will not be ready to operate for eight weeks. 

But if the port and airfield are already available, such a 

unit can be ready in two weeks. That was the case early in 

the first Gulf War: because ports, airfields, and an assembly area all existed in Saudi Arabia before the outbreak of 

hostilities, the MEB associated with the maritime prepositioning squadron in Diego Garcia was ready to begin 

military operations within two weeks after the ships of 

the squadron were ordered to leave their berths.

Conducting an Amphibious Assault Today

Although they have not done so for half a century, the 

Navy and Marine Corps retain the capability to mount 

an opposed amphibious assault. Such an operation would 

be complex, involving aircraft carriers, surface combatants, mine-clearing ships, and support ships as well as 

amphibious ships. According to the Marine Corps, the 

minimum force to launch a forcible-entry operation is a 

Marine expeditionary brigade. To muster a force of that 

size, the Navy and Marine Corps would bring at least two 

forward-deployed expeditionary strike groups to the theater of operations, followed by additional ships and marines from ports in the United States. Once assembled, 

the combined group of ships would be called an amphibious task force, and the troops on board those ships 

would be considered the “assault echelon.”

Before troops were sent ashore, enemy forces in the target 

area—particularly ships or missiles that could threaten 

the assault force—would be attacked as much as necessary by the Navy’s carrier-based aircraft and by guns and 

missiles on the surface combatants and submarines.7

 In 

addition, ships capable of conducting mine-clearing operations would need to cut a path through any minefield 

that might prevent the marines from landing on shore.

When the marines were ready to conduct their assault, 

they and their equipment would be transported to the 

4. Gidget Fuentes, “Expeditionary Strike Groups: Combining 

Power, Speed, and Lethality,” Armed Forces Journal (October 

2003), p. 20.

5. Ronald O’Rourke, Navy-Marine Corps Amphibious and Maritime 

Prepositioning Ship Programs: Background and Oversight Issues for 

Congress, CRS Report for Congress RL32513 (Congressional 

Research Service, August 5, 2004).

6. However, two maritime prepositioning squadrons were used early 

in Operation Iraqi Freedom and could require another year or two 

before they are fully reconstituted and available for further operations.

7. Undoubtedly, the other services would contribute to such an operation as well. The Air Force in particular would provide additional 

ground-attack capability with its long-range bombers and shorterrange fighter-bombers if those aircraft had a base within the theater from which to operate.
CHAPTER ONE INTRODUCTION 7

beach with helicopters, air-cushion landing craft (known 

as LCACs), or amphibious assault vehicles (light tanks 

able to “swim” ashore). Helicopters would operate from 

the large flat-deck amphibious assault ships (the LHDs 

and the LHAs) as well as from the amphibious transport 

docks (LPDs). Amphibious assault vehicles and LCACs 

would operate from all types of L-class ships. Although 

the amphibious assault vehicles would go ashore and stay 

there, the LCACs would make repeated trips back and 

forth from the ships to the beach, ferrying whatever 

needed to be brought in for the operation. In addition, 

the short takeoff and vertical landing aircraft carried on 

LHAs and LHDs would provide close air support to the 

marines on the ground. Carrier-based aircraft could also 

perform that role unless they were occupied with other 

tasks.

Current procedures call for the assault echelon of marines 

carried in L-class amphibious ships to either land on enemy territory and seize a lodgment (a piece of territory 

taken to set up a base of operations) or land on allied territory and immediately carry the fight to the enemy. In 

either case, the reinforcements in the “assault follow-on 

echelon” would require a deepwater port and a nearby 

airfield to be landed. Maritime prepositioning ships, carrying equipment and supplies for the reinforcing units, 

would dock at the port and offload their “unit sets” of 

cargo. The marines associated with those sets would fly 

into the nearby airfield, move to the port, prepare the 

equipment coming off the ships, assemble into units, and 

only then launch offensive operations. That process is referred to as reception, staging, onward movement, and 

integration. 

Once in combat, the reinforcing Marine units would receive supplies from shore-based supply depots at the 

lodgment that had been built up from the stores located 

in the ships’ holds. Such depots are known colloquially as 

“iron mountains,” referring to the large amount of military equipment, fuel, food, water, ammunition, and supporting services necessary to conduct a military campaign.

Peacetime Missions of Amphibious and 

Maritime Prepositioning Ships

Because the Navy’s amphibious ships are highly versatile, 

they have been used to respond to a variety of crises, particularly humanitarian operations. Between the end of 

the first Gulf War in 1991 and 2000, amphibious ships 

conducted at least 55 operations, such as providing disaster relief, evacuating U.S. citizens or government personnel from unstable countries, and taking part in military 

operations in Iraq, Bosnia, Haiti, and the former Yugoslavia. Although amphibious ships usually deploy in groups, 

it is common for the ships of a group to separate once 

they reach their forward-deployment area and then conduct simultaneous operations or exercises. That practice—as well as the large size of amphibious ships and the 

supplies and equipment they carry—makes such vessels 

well suited to respond to low-level crises.

The Navy’s maritime prepositioning ships also respond to 

crises, though much less frequently. Such ships spend 

most of their time moored at their ports overseas, but 

they provided support to U.S. troops in Somalia during 

the early 1990s and have furnished bottled water for several disaster-relief operations around the world. The future size and composition of the maritime prepositioning 

squadrons are the subject of much debate within the 

Navy and the Marine Corps. Both services want to expand the capabilities of those squadrons dramatically as 

part of their vision for sea basing (described later in this 

chapter). Such enhanced capabilities could make maritime prepositioning ships even more capable of responding to low-level crises, possibly freeing up amphibious 

warfare ships for other operations.

Requirements for Amphibious and 

Maritime Prepositioning Forces

Although the number of maritime prepositioning squadrons in the Navy has remained constant since they were 

introduced in the 1980s, the number of amphibious warfare ships has declined steadily since the end of the Cold 

War. In the past, the Navy determined the number of Lclass ships it required by the amount of amphibious lift 

(transport capacity on amphibious ships) it considered 

necessary for wartime. More recently, however, the Navy 

has also begun to stress the forward presence provided by 

expeditionary strike groups as the essential measure of capability. That stress appears to reflect, at least in part, the 

Navy’s vision of using its future maritime prepositioning 

ships to provide more forcible-entry capability in conjunction with L-class ships, thus rendering the amount of 

forcible-entry capability on L-class ships alone less significant.

Amphibious Lift 

The most common measure of the capability of the amphibious force is the amount of lift it provides, expressed
8 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

in Marine expeditionary brigade equivalents. That measure focuses on how much force can be delivered on the 

ground in the event of a crisis or conflict. It does not reflect the day-to-day availability of the amphibious force 

in peacetime or its distribution around the globe.

Maritime prepositioning ships are not considered amphibious lift ships—even though together they carry 

enough equipment and supplies for three full MEBs— 

because they do not carry the troops associated with that 

equipment (except for a small security and maintenance 

staff) and cannot conduct amphibious assaults. Instead, 

they are considered sealift ships and are not included in 

the total expeditionary warfare capabilities of the Navy’s 

battle force, which are measured only in terms of amphibious lift. 

The Marine Corps argues today, and has throughout the 

1990s, that its requirement for lift by amphibious warfare 

vessels is 3.0 MEBs. However, resources have not been 

made available to build enough amphibious warfare ships 

to reach that level. The Navy and Marine Corps officially 

say that their “fiscally constrained” goal for amphibious 

lift is 2.5 MEBs. (For more details, see Box 1-1.)

Amphibious lift capacity is determined by more than just 

the number of troops that ships can carry. Because those 

troops operate with trucks, armored vehicles, artillery, 

helicopters, fixed-wing aircraft, landing craft, and supplies, amphibious lift is measured in five categories, or 

“fingerprints”: 

Box 1-1.

The Requirement for Amphibious Lift 

Although the Department of the Navy’s official requirement for amphibious lift has remained steady 

since the 1990s, at three Marine expeditionary brigades (MEBs), it changed frequently before then. 

The war plans of regional combatant commanders 

call for having the capability to mount amphibious 

assaults. In the view of Marine Corps leaders, such 

an assault should be conducted by a force the size of 

a Marine expeditionary force, or MEF (40,000 to 

50,000 troops). Because more than one combatant 

commander has such a requirement, that capability 

should exist in both the Atlantic and Pacific Fleets. 

However, between 1945 and 1990, budgetary pressures forced a continuing reduction in the number of 

amphibious ships in the Navy; consequently, the requirement for amphibious lift declined as well.

The three-MEB requirement was established in 1990 

in the last major study of amphibious-lift needs.1

Three MEBs of amphibious lift along with three 

MEBs of prepositioning sealift would in theory create something close to a two-MEF capability.2 (The 

marines on amphibious warfare ships would provide 

the assault echelons in an amphibious assault, and 

the marines flying in to meet up with equipment 

from prepositioning ships would provide the followon forces.) In the early 1990s, however, the Secretary 

of the Navy reduced the requirement to 2.5 MEBs, 

apparently for budgetary reasons, which is why that 

figure is often referred to as the “fiscally constrained” 

requirement.

1. That study was Department of the Navy, Integrated Amphibious Operations and USMC Air Support Requirements (January 1990), commonly known as DoN Lift 2. 

2. Three MEBs together are a bit larger than one MEF in terms 

of the “fingerprints” of amphibious lift (space for troops, 

vehicles, cargo, helicopters, and landing craft). Conversely, a 

MEF contains elements that three MEBs do not, such as 

headquarters and command-and-control staff. For more 

details, as well as a brief history of the amphibious-lift 

requirement, see Matthew T. Robinson, Integrated Amphibious Operations Update Study (DoN Lift 2+): A Short History 

of the Amphibious Lift Requirement (Alexandria, Va.: Center 

for Naval Analyses, July 2002).
CHAPTER ONE INTRODUCTION 9

B Number of troops;

B Vehicle storage area (expressed in thousands of square 

feet, or “vehicle square”);

B Cargo storage area (measured in thousands of cubic 

feet, or “cargo cube”);

B Number of places (or spots) on the decks and in the 

hangars of amphibious ships to park vertical takeoff 

and landing aircraft, expressed as CH-46 helicopter 

equivalents;8 and

B Number of spots inside the ships for LCACs.

Today, the amphibious warfare force has enough cargo 

cube, helicopter spots, and LCAC spots to meet the Marine Corps’s 3.0 MEB requirement. However, it is substantially short with respect to vehicle square. The force 

can carry enough troops for 2.5 MEBs but only enough 

vehicles for 1.9 MEBs. Thus, the effective capability of 

the force is 1.9 MEBs of amphibious lift. That figure is 

down slightly from the capability in recent years because 

of the decommissioning of some older amphibious ships 

and delays in commissioning their replacements. (As 

noted above, maritime prepositioning ships provide another 3.0 MEBs of sealift, for a total lift capacity of 4.9 

MEBs.)

Expeditionary Strike Groups

The other principal measure used to evaluate how many 

amphibious warfare ships are needed is the number of 

what used to be called amphibious ready groups but are 

now called expeditionary strike groups (see Figure 1-3 on 

page 5). Both the 1997 and 2001 Quadrennial Defense 

Reviews discussed amphibious ships with respect to the 

number of ready groups—rather than the overall amount 

of lift—that they provided. In both reviews, the numerical requirement for amphibious ready groups remained at 

12. In 2000, the Navy released a 30-year shipbuilding report that advocated increasing the number of amphibious 

ships to create 15 ready groups.9

 By contrast, the most recent long-term Navy report, which proposed a 375-ship 

fleet, did not envision increasing the number of amphibious ships from the current level.10 However, legislation 

introduced in the Congress in 2003 would have included 

15 amphibious ready groups in the 375-ship fleet.11

With its existing force, the Navy can keep about 2.7 

ESGs forward deployed at any given time. The group 

that is based in Japan, which includes four amphibious 

ships, is considered to provide full-time forward presence 

by virtue of its being based overseas. The remaining amphibious ships are divided between the Navy’s Atlantic 

and Pacific Fleets into a total of 11 ESGs. Because of the 

time needed for ship maintenance, crew training, and 

transit to deployment areas, those remaining amphibious 

ships are sufficient to keep one ESG forward deployed 

full time and another deployed for six to eight months of 

the year.

Recently, senior Navy officials have discussed reducing 

the number of ESGs to eight and making up the shortfall 

in forward presence by employing a form of crew rotation 

known as Sea Swap. The Navy has experimented with Sea 

Swap on several types of surface combatants: instead of 

having one crew deploy and return home with the same 

ship, the ship remains forward deployed while crews rotate in and out every six months. In between their deployments, the crews train on ships that remain in the 

United States.12

Sea Swap may be more difficult to apply to amphibious 

ships than to surface combatants, however, because of the 

logistical challenges of coordinating predeployment training between the Navy crews and the marines who serve 

8. The number of aircraft that a ship can carry (helicopter spots) differs from the number of aircraft that can operate from that ship 

(operating spots).

9. Department of the Navy, Report on Naval Vessel Force Structure 

Requirements (June 2000).

10. Department of the Navy, A Report to Congress on Annual LongRange Plan for the Construction of Naval Vessels.

11. The National Naval Force Structure Policy Act (H.R. 375 and 

S. 902) asserted that it is “the policy of the United States to rebuild as soon as possible the size of the fleet of the United States 

Navy to no fewer than 375 vessels in active service, to include 15 

carrier battle groups and 15 amphibious ready groups.” That legislation was introduced in the House on January 27, 2003, and in 

the Senate on April 11, 2003, and was referred to the House and 

Senate Armed Services Committees, which had not passed it when 

this study was written. 

12. For more information, see Congressional Budget Office, 

Transforming the Navy’s Surface Combatant Force; and Ronald 

O’Rourke, Navy Ship Deployments: New Approaches—Background 

Issues for Congress, Report for Congress RL21338 (Congressional 

Research Service, August 3, 2004).
10 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

on board an amphibious ship.13 Nevertheless, the Chief 

of Naval Operations, Admiral Vern Clark, has ordered 

Navy analysts to study the issue, and some experimentation is likely to follow.14

If the Navy adapted Sea Swap to its amphibious ships and 

then reduced the number of expeditionary strike groups, 

it would be setting aside the importance of overall amphibious lift on L-class vessels—the traditional measure 

of amphibious capability. (Because amphibious lift is a 

wartime measure, it is determined by the overall number 

of L-class vessels in the fleet, not by whether the Navy 

employs a rotational crewing policy.) No decision has yet 

been made, so in this analysis, CBO did not assume that 

the Navy’s ESGs would use crew rotation to increase forward presence. However, one of the measures discussed in 

Chapter 4 shows what effect Sea Swap would have on the 

forward presence provided by ESGs if the concept was 

applied to amphibious ships.

The Navy’s and Marine Corps’s 

Vision for Sea Basing 

The impetus behind the Navy’s desire to increase its battle force to 375 ships and to expand the capabilities of its 

expeditionary warfare fleet is its “transformation vision,” 

called Sea Power 21.15 That vision rests on three key concepts: Sea Strike, Sea Shield, and Sea Basing. Sea Strike 

represents the Navy’s efforts to support joint campaigns 

by projecting offensive power from and through the 

world’s littoral (coastal) areas. That power could take the 

form of strikes from carrier-based aircraft, from naval 

guns, or from missiles launched from surface combatants 

and submarines; information or electronic attack warfare 

(such as disrupting an enemy’s communications); or 

landings or assaults by Marine Corps ground units.

Sea Shield is the defensive counterpart to Sea Strike. It 

encompasses the capabilities that defend or screen Navy 

ships at sea from attack, protect joint and allied forces operating on shore from air or missile attack, and protect 

the United States from both conventional and unconventional threats. As now conceived, Sea Shield would eventually include theater and perhaps national missile defense systems.

Sea Basing is considered by many defense officials to be 

the most transformational of the three concepts: it envisions that future landings of Marine units ashore will be 

conducted, supported, and sustained from ships at sea. 

Today, such an operation would be supported primarily 

from supply depots on land, located either at an existing 

base provided by a host nation or in a lodgment seized 

during the assault. Future sea-based operations would 

forgo putting “iron mountains” of supplies, fuel, and ammunition ashore and instead keep them at sea, rearming 

and replenishing Marine forces operating on shore only 

when needed. Although the entire fleet would play a role 

in the “sea base,” the most important platforms would be 

the Navy’s amphibious warfare ships and future maritime 

prepositioning vessels.16

Navy and Marine Corps planners hope that under this 

concept, Marine units in the follow-on echelon could 

conduct the major portion of the reception, staging, onward movement, and integration process on board ships 

at sea and thus become operational more quickly. Marine 

units would fly directly to the sea base, assemble into 

combat units, prepare their equipment for combat while 

on board the ships, and launch attacks directly at inland 

targets from the sea base, which would operate over the 

horizon, out of sight of land. No port and airfield would 

need to be taken to support the introduction of either the 

assault or follow-on assault echelons, at least during the 

13. Christopher Munsey, “Sea Swapping Marines is ‘Daunting,’” 

Navy Times, September 20, 2004.

14. Malina Brown, “Expeditionary Strike Groups to Join Naval Sea 

Swap Experiment,” Inside the Navy, March 22, 2004; David 

Brown, “ESGs Could Expand Sea Swap Concept,” Navy Times, 

March 29, 2004; Ron Laurenzo, “Sea Swap Could Become the 

Norm,” Defense Today, April 1, 2004; Lorenzo Cortes, “Navy Surface Chief Would Eventually Like to Swap an Entire ESG,” 

Defense Daily, April 1, 2004; Malina Brown, “LaFleur: Navy 

Working on Applying Sea Swap to an Entire ESG,” Inside the 

Navy, April 5, 2004; Andrew Koch, “U.S. Considers Overhaul of 

Amphibious Forces,” Jane’s Defence Weekly, May 5, 2004; and 

Jason Ma, “LaFleur: Sea Swap Could Keep Amphibious Ship at 

Sea for 12 Months,” Inside the Navy, July 19, 2004.

15. Admiral Vern Clark, “Sea Power 21: Projecting Decisive Joint 

Capabilities,” Proceedings, U.S. Naval Institute (October 2002), 

pp. 32-41, available at www.chinfo.navy.mil/navpalib/cno/

proceedings.html.

16. Officially, the Department of Defense regards sea basing as a joint 

capability. The Army has an interest in developing a sea-basing 

capability, and Air Force bombers and other assets would have to 

be involved to make a forcible-entry operation work. This discussion, however, focuses on the Navy and Marine Corps because 

their conceptual and programmatic efforts to develop a sea-basing 

capability are much farther along than those of the other services.
CHAPTER ONE INTRODUCTION 11

initial “seize the initiative” phase of an attack on enemy 

territory or a defense of allied territory. (Further followon forces would still require an airfield and port.) Moreover, forces ashore could withdraw back to their ships and 

reorganize to attack a new target, again operating solely 

from the amphibious warfare and maritime prepositioning ships of the sea base.

Potential Advantages of Sea Basing

The Marines refer to that new style of naval expeditionary warfare as “operational maneuver from the sea” 

(OMFTS) and “ship-to-objective maneuver” (STOM). 

Those two key concepts implement the Marine Corps’s 

vision of fast and flexible forces. The Marines argue that 

OMFTS and STOM will afford a landing force significant advantages at the operational and tactical levels of 

war, such as:

B Faster deployment and operations;

B More maneuver space and thus greater unpredictability about where U.S. forces might be;

B More uncertainty on the part of the enemy and therefore more disruption to its strategy and operations; 

and

B Faster destruction of enemy forces, either because they 

disperse to cover the wide area where U.S. forces could 

land (and thereby allow themselves to be defeated 

piecemeal by arriving ground forces) or because they 

try to concentrate against U.S. forces (and thus become vulnerable to U.S. air and missile strikes).

The Marine Corps believes that none of those advantages 

are possible without sea basing. The increased speed of 

operations, the greater maneuver space, and the confusion of the enemy are facilitated by keeping the logistics 

support for Marine ground forces at sea. No time is 

wasted in seizing a lodgment and setting up a supply depot. Ground operations against tactical, operational, or 

strategic objectives can proceed almost immediately once 

the sea base has assembled.

In addition to the operational and tactical advantages 

associated with conducting OMFTS and STOM from 

ships, sea basing has two other significant benefits. First, 

it eliminates the need to ask a host nation for permission 

to use a base, thereby giving U.S. combatant commanders greater freedom of action and allowing more-independent operations that do not depend on the politics of 

other countries. Proponents of sea basing argue that such 

independence will be critical in the future because the 

United States will be less and less likely to gain access to 

overseas bases if it must conduct a military operation.17

Those proponents cite several recent examples: Turkey’s 

denial of access to the Army’s 4th Mechanized Infantry 

Division for a northern front against Iraq, and Saudi Arabia’s refusal to let U.S. forces use facilities in that country 

during Operation Enduring Freedom in Afghanistan.18 If 

that trend continues, they argue, sea basing will allow the 

United States to bypass such requests for permission by 

having everything it needs in terms of support at the sea 

base, which (unlike a land base in a foreign country) is 

“sovereign U.S. territory.” The Marine Corps Commandant, General Michael Hagee, has described a sea base 

that would have permitted the military to launch the war 

against Iraq without using Kuwait: “We come into the 

[Persian] Gulf, we do the arrival and assembly, we do the 

reception, staging, onward movement and integration at 

sea.”19

Second, proponents argue that a sea base is less vulnerable 

than a land base to attack from cruise and ballistic missiles. Because ships at sea are constantly on the move, detecting, tracking, and targeting them is inherently more 

difficult than targeting a fixed land base. As cruise and 

ballistic missiles proliferate among potential U.S. adversaries, that advantage of sea basing becomes increasingly 

apparent, supporters say.

17. Richard Mullen, “Seabasing Yields Big Military Advantages: 

Officers,” Defense Today, April 8, 2004, p. 4; Christian Lowe, 

“Attack Platform: Sea Basing Could Render Reluctant Allies Irrelevant,” Armed Forces Journal (April 2004), pp. 36-38; and Nathan 

Hodge, “Iraq War Seen as Test of Sea Basing,” Defense Week, April 

21, 2003, p. 6.

18. Many supporters of sea basing have argued that if the United 

States had had such a capability, it would not have needed to offer 

Turkey a substantial aid package in exchange for allowing the U.S. 

military to launch a division-sized attack on Iraq from the north. 

However, the sea-basing capability being discussed today would 

not be large enough to launch a division-sized attack. Moreover, 

northern Iraq (the part that borders Turkey) is more than 450 

nautical miles from the sea, which would be too far for sea basing.

19. John T. Bennet, “Marine Corps Commandant, DSB Describe 

Visions of Sea Basing Concept,” Inside the Pentagon, October 30, 

2003, p. 16. See also the interview with Rear Admiral John M. 

Kelly, “Kelly: Sea Basing Presents Infinite Number of Problems for 

the Enemy,” Sea Power (June 2004), p. 22.
12 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Potential Drawbacks of Sea Basing

Four counterarguments exist to the points in favor of sea 

basing that proponents cite. First, although supporting 

relatively small military operations from a sea base may 

prove feasible in time, military operations such as the 

division-sized or larger attack on Iraq from Turkey 

planned for Operation Iraqi Freedom may be too big to 

be launched and sustained from a sea base. The Defense 

Science Board, which endorses the sea-basing concept, 

stated in a 2003 report: “Forcible entry from modern seabases . . . represents a substantially greater challenge than 

the amphibious operations of World War II and Korea.”20

Second, although today land bases appear more vulnerable than sea bases to ballistic and cruise missiles, that may 

not always be the case. New short-range ballistic missiles 

with maneuvering reentry vehicles and radar and infrared 

seekers could be accurate enough to attack ships at sea.21

Arguably, sea bases might be at greater risk than land 

bases from ballistic and cruise missiles because they are 

more concentrated, meaning that a missile strike could 

disable or destroy a vastly greater proportion of material 

and capability for a military operation than would be the 

case with a land base. (During the Falklands War, for example, the sinking of the Atlantic Conveyor, which carried 

14 helicopters and all of the tentage for Britain’s landing 

force, “was a crippling blow to British strategic plans for 

the campaign.”)22

As described in the next chapter, current designs for the 

new ships necessary to support the sea-basing concept 

would make those vessels some of the largest and most 

detectable ships in a theater of operations as well as the 

least survivable if hit by enemy fire. The Government 

Accountability Office (formerly the General Accounting 

Office) has also reported that the Navy may be underestimating the threat posed by cruise missiles and may be 

overly optimistic about its ability to defend against that 

threat.23 In addition, if an enemy is sophisticated enough 

to have cruise and ballistic missiles in sufficient quantities 

to threaten a land base, it is also likely to have the weapons and ability to severely disrupt the continuous airlift 

of supplies from a sea base to troops on land.

Third, opponents of sea basing might question the likelihood that the U.S. military would attempt an amphibious assault in the future when it has not done so since the 

Korean War. Although maintaining current amphibious 

capabilities—which can be used for various purposes 

other than opposed amphibious assaults—may be advantageous, it is less clear that all of the Navy’s amphibious 

forces should be prepared to fight from a sea base. 

Finally, sea basing might prove to be too expensive for 

what in the end could be a modest capability. The total 

amount of resources needed to carry out the sea-basing 

concept is highly uncertain. Because that concept has not 

been fully fleshed out, CBO has not attempted to estimate the total cost of building a sea-based amphibious 

force. However, implementing that concept would involve developing a variety of new technologies, ships, and 

aircraft, some of which would require technological advances whose feasibility is not yet clear (see Box 1-2). The 

Defense Science Board has stated that fully realizing the 

sea-basing vision could potentially cost tens of billions of 

dollars.24

The Possible Scope of Sea Basing

Some supporters of the overall concept of sea basing argue for more-modest capabilities. They state that rather 

than try to conduct multiple battalion- or brigade-sized 

operations from a sea base, the military could use such a 

base for seizing a lodgment that would serve as a base for 

more forces brought ashore to conduct larger operations. 

One or two battalions could be deployed by air behind an 

enemy’s shore defenses and then move toward the sea in 

conjunction with supporting operations from U.S. forces 

at sea. That approach differs from a more traditional amphibious operation in which marines assault a beach directly and try to seize a lodgment head-on. The more 

modest approach to sea basing would simply enhance the 

traditional amphibious assault capability in which the 

20. Department of Defense, Office of the Under Secretary of 

Defense for Acquisition, Technology, and Logistics, Defense

Science Board Task Force on Sea Basing (August 2003), p. iv, 

available at www.acq.osd.mil/dsb/reports/seabasing.pdf.

21. Office of Naval Intelligence, Worldwide Maritime Challenges 

(2004), p. 22. That may be especially true of China’s growing 

arsenal of ballistic missiles.

22. Max Hastings and Simon Jenkins, The Battle for the Falklands

(New York: W.W. Norton, 1983), p. 229.

23. General Accounting Office, Defense Acquisitions: Comprehensive 

Strategy Needed to Improve Ship Cruise Missile Defense, NSIAD00-149 (July 11, 2000).

24. Department of Defense, Defense Science Board Task Force on Sea 

Basing, p. 85.
CHAPTER ONE INTRODUCTION 13

Marine Corps specializes. It would not try to fundamentally change the way Marine forces operate and fight. 

As described by many senior Navy leaders, the sea base 

would comprise the entire fleet. For example, Admiral 

Clark has written that “sea bases will consist of numerous 

platforms, including nuclear-powered aircraft carriers, 

multi-mission destroyers, submarines with Special Forces, 

and maritime pre-positioned ships.”25 That would be 

true inasmuch as carriers, destroyers, and submarines 

would continue to perform many of the missions that 

they do today, such as projecting power ashore from the 

sea through the use of carrier-based aircraft, Tomahawk missiles, naval gunfire, and the insertion of specialoperations forces. But, as discussed above, the transforBox 1-2.

Sea and Air Connectors for the Sea Base

One of the most important examples of the new 

technologies and equipment necessary to make sea 

basing a reality involves what are called the sea and 

air connectors. To put troops ashore and sustain 

them requires having the means to get troops from 

the continental United States to a theater of operations quickly. The Navy and Marine Corps are still 

studying the best way to do that. One option would 

be to purchase fast sealift ships capable of ferrying 

troops from the United States directly to the sea base 

at high speeds. Such a ship does not exist in the 

Navy’s inventory or even on the drawing boards; at 

the moment, it is just a “concept ship.” Another alternative for getting troops to the sea base would be 

to fly them to an advanced base some 200 to 2,000 

nautical miles away from the theater of operations 

and then ferry them to the sea base using shorterrange high-speed vessels. Ships of that type do exist, 

and the Navy, Marine Corps, and Army have been 

experimenting with commercial off-the-shelf variants. Using such ships as sea connectors would require scaling up their designs to make them bigger 

and then funding their construction, but the Navy 

does not believe those to be insurmountable obstacles. The distance from the advanced base to the

theater will in part drive the requirements for those 

high-speed ferries.

The Navy and Marine Corps may need other types 

of vessels to help deploy troops and equipment. A 

larger air-cushion landing craft than now exists in 

the inventory may be necessary to get everything 

ashore within the timelines that the Marine Corps 

desires. To speed up the assault, the Navy and Marine Corps are looking at buying a small number of 

flow-on/flow-off (flo/flo) ships to bring four or five 

landing craft at a time near the shore. (Existing flo/

flo ships, such as the one chartered to bring the 

U.S.S. Cole back to the United States after it was attacked by terrorists in Yemen, are very large. The flo/

flo ships that the Navy and Marine Corps have in 

mind would be much smaller.) Such ships would not 

be difficult to design and build, but they would require additional funding.

The Marine Corps has stated that it will need to replace its large CH-53 helicopters to provide the 

heavy lift necessary to support troops operating from 

a sea base. Joint requirements may envision developing and procuring an even larger heavy-lift aircraft 

than the CH-53’s replacement, such as a quad-tilt 

rotor, capable of carrying 20 tons at a time as far as 

110 nautical miles.1

 Such an aircraft is only in the 

early design stages and could prove costly if bought 

in significant numbers. 

The Navy and Marine Corps are still refining their 

sea-basing concepts. Ideally, one outcome of a clearer 

vision of sea basing would be a tally of what kinds of 

sea and air connectors would be required to make 

the concept work, how many would be necessary, 

and how much they would cost. So far, those issues 

have not yet been resolved.

1. The Marine Corps Commandant, Michael Hagee, has 

endorsed the need for such an aircraft. See Jason Sherman, 

“U.S. Seeks Ship-Based Airlifter,” Defense News, April 26, 

2004, p. 16.

25. Clark, “Sea Power 21,” p. 37.
14 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

mational character of sea basing lies in how it would 

change the way the Marine Corps assembles and projects 

forces from the sea and the way the Navy supports and 

sustains those forces. The most important ships involved 

in those changes would be existing and future amphibious warfare ships and especially the proposed Maritime 

Prepositioning Force (Future) ships.26

At the moment, proponents of the more expansive view 

of sea basing hold sway, primarily because of the strong 

advocacy of that concept by senior Marine Corps and 

Navy leaders. The strength of that advocacy is reflected in 

the Navy’s future plans for its amphibious warfare and 

maritime prepositioning forces. 

26. Colonel Art Corbett and Colonel Vince Goulding (ret.), “Sea Basing: What’s New?” Proceedings, U.S. Naval Institute (November 

2003), pp. 34-39.
2

The Navy’s Plan for Modernizing the 

Amphibious and Maritime Prepositioning Forces

Impelled by the Sea Power 21 vision in general and the 

sea-basing concept in particular, the Navy intends to replace most of its amphibious warfare ships and all of its 

maritime prepositioning ships over the next 30 years. 

Specifically, the Navy plans to replace all of its current 

amphibious transport docks with the LPD-17 class now 

under construction; begin a new class of amphibious assault ship, the LHA(R); and replace all of its dock landing 

ships with the still-conceptual LSD(X) (see Table 2-1). 

That modernization program would keep the size of the 

L-class force at 36 ships through 2035 (see Figure 2-1), at 

which point the force would be slightly younger, on average, and slightly more capable than it is today. More dramatically, the Navy plans to replace its mostly chartered 

maritime prepositioning ships with new Maritime Prepositioning Force (Future) ships, which would substantially alter the way the Navy and the Marine Corps conduct operations on shore. 

Under those plans, the Navy’s amphibious lift capability 

would slowly increase. It would rise from 1.9 Marine expeditionary brigade equivalents now to 2.1 MEBs by the 

end of 2005, with the arrival of the first LPD-17 in the 

fleet, and reach the fiscally constrained goal of 2.5 MEBs 

in 2015, when the Navy commissioned the last LPD-17. 

(As noted in Chapter 1, the amount of amphibious-lift 

capability is determined by the size of the smallest category of amphibious lift, which is currently square footage 

for vehicles; see Figure 2-2 on page 18). However, the 

Marine Corps’s 3.0-MEB requirement would never be 

met under the Navy’s long-term shipbuilding plans.

Overall, that modernization program would keep the 

goal for the total lift capability of the amphibious and 

maritime prepositioning forces the same as it is now— 

5.5 MEBs—but would change its distribution. Instead of 

the current goal of approximately 2.5 MEBs of amphibious lift and 3.0 MEBs of sealift, the Navy would have 2.5 

MEBs of amphibious lift on L-class ships, 2.0 MEBs of 

sea-based lift on sea-basing-capable MPF(F) ships, and 

another 1.0 MEB of sealift on replacement prepositioning cargo ships. Because MPF(F) sea-basing ships would 

be able to equip and support full Marine combat units, 

they would be considered operational fleet assets and 

would be counted along with amphibious warfare ships 

in the Navy’s overall battle force.

Much uncertainty surrounds what capabilities—and thus 

what costs—future amphibious and maritime prepositioning ships would have. Even allowing for that uncertainty, however, the Congressional Budget Office estimates that the Navy’s modernization plan will require 

much higher funding than the service has devoted to the 

amphibious and maritime prepositioning forces in the 

past 20 years. 

The quantities and timing of ship purchases discussed in 

this chapter are based on the long-term shipbuilding report that the Navy issued in May 2003—A Report to Congress on Annual Long-Range Plan for the Construction of 

Naval Vessels—updated from various selected acquisition 

reports (documents on major procurement programs that 

the services are required to submit regularly to the Congress). That combination of sources represents the most 

authoritative statement of the Navy’s long-term shipbuilding plans available to CBO. Overall, the Navy intends to buy 28 amphibious ships and, CBO assumes, 21 

maritime prepositioning ships over the next 30 years.

CHAPTER
16 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Table 2-1.

Schedule for Replacing Existing Amphibious and Maritime Prepositioning Ships 

with New Classes

Source: Congressional Budget Office based on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

a. Tarawa, the first LHA to retire, will be replaced by Makin Island, the last of the LHDs.

b. Projected.

c. Through 2004, six of the 12 LPD-17s had already been purchased.

d. Most of these ships will be transferred to the Ready Reserve Fleet to replace cargo ships that will be scrapped.

e. CBO assumes that 16 ships will have sea-basing capabilities and five will be replacement cargo ships.

The LPD-17 Amphibious 

Transport Dock

The program to develop the San Antonio class amphibious transport dock began in 1990, and construction of 

the first ship was authorized in 1996. These ships are intended to replace the Austin class LPD-4 transport docks, 

which will reach the end of their notional 40-year service 

lives in the next 10 years.1

 The Navy plans to procure 12 

LPD-17s—one for each of the 12 expeditionary strike 

groups. So far (through fiscal year 2004), it has ordered 

six of those ships. Thus, the Navy plans to buy six more 

between 2005 and 2010, at a rate of one per year (see 

Figure 2-3 on page 19).

The LPD-17 class is designed to be a substantial improvement over the LPD-4 class in terms of lift capacity, 

accommodations for personnel, electronics, and selfdefense capabilities. The ship will be more than 45 percent larger than its predecessor, displacing about 25,000 

tons at full load, compared with almost 17,000 tons for 

Replacement Ships

Existing Ships

Class

Year First 

Ship Is 

Authorized

Year First 

Ship Is 

Commissioned

Quantity to Be

Purchased 

Class Through 2035

Quantity 

in Service

Year First 

Ship Retires

Amphibious Assault Ships

Tarawa (LHA-1) 5 2007a LHA(R) 2007 2012b 10

Wasp (LHD-1) 7 2027 LHA(R)

Amphibious Transport Docks

Austin (LPD-4) 11 2004 San Antonio 

(LPD-17)

1996 2005 12c

Dock Landing Ships

Whidbey Island (LSD-41) 8 2024 LSD(X) 2020 2024b 12

Harpers Ferry (LSD-49) 4 2032 LSD(X)

Maritime Prepositioning Ships

MPS Cargo Ships 16 2013d MPF(F) 2009 2013b 21e

1. The Navy describes the LPD-17 class as the replacement for 41 

older ships: 11 LPD-4s, five LSD-36 dock landing ships, 20 tank 

landing ships (LSTs), and five amphibious cargo ships (LKAs). 

However, three of the LSDs and all of the LSTs and LKAs have 

already been retired.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 17

Figure 2-1.

Inventory of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan

Source: Congressional Budget Office based on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

the LPD-4 class (see Table 2-2 on page 20).2 It will carry 

fewer troops and less cargo than the LPD-4 class but have 

twice as much space for vehicles and landing craft as well 

as two additional spots for helicopters. The crew and marines aboard the new ship will have more-spacious bunks 

than those found on previous classes of amphibious ships. 

The LPD-17 will also be equipped with computers and 

systems for cooperative engagement capability, part of the 

Navy’s effort to integrate the electronics and computers 

on its ships into one fleetwide warfare system. Finally, the 

LPD-17 will carry two rolling air-frame missile launchers 

with 42 ship-defense missiles. (Space and weight have 

also been reserved to install vertical launch system cells 

for the Evolved Sea Sparrow Missile defensive system, although those cells were eliminated from the design early 

on to save money.)

The construction program for the LPD-17 has been a 

troubled one. The 1996 selected acquisition report estimated that a 12-ship program would cost an average of 

about $830 million per ship. Eight years later, that cost 

had grown by more than 50 percent—to an average of 

about $1.3 billion per ship, CBO estimates. (The Navy’s 

2004 selected acquisition report estimated that a 12-ship 

program would cost about $1.2 billion per ship, on average.) 

Although CBO does not provide an explanation for the 

cost growth, the Navy attributes it in part to mistakes by 

the service and by the contractor, Avondale Industries 

(now owned by Northrop Grumman). Those mistakes 

included computer design tools that initially were not up 

to the complex task of designing a Navy warship, insufficient research and development spending to design a 

complicated weapon system, and a lack of understanding 

of the costs of many new features that the Navy wanted 

the ship to have. As a consequence, the program suffered 

substantial delays, which themselves led to higher costs, 

including additional years of inflation in material and 

labor costs. Costs for labor and materials also proved 

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPS Cargo Ships MPF(F) Sea-Basing Ships

LSD(X)

2. A ship’s light load reflects the displacement of the ship itself, not 

including its weapons (such as aircraft), fuel, personnel, or other 

types of cargo. The full load refers to a ship’s displacement including all of the things it normally carries.
18 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 2-2.

Amphibious Lift, by Category, Under the Navy’s Plan

(Marine expeditionary brigade equivalents)

Source: Congressional Budget Office based on data from the Navy.

Note: The five categories (or fingerprints) of amphibious lift are the number of troops a ship can carry; its vehicle storage area, measured in 

thousands of square feet (or vehicle square); its cargo storage area, measured in thousands of cubic feet (or cargo cube); the number 

of spots for parking vertical takeoff and landing aircraft (expressed as CH-46 helicopter equivalents); and the number of spots for aircushion landing craft (known as LCACs).

greater than originally estimated apart from the effects of 

inflation. Overall, the Navy attributes 14 percent of the 

cost growth to additional inflation, 28 percent to the restructuring of the procurement schedule, 29 percent to 

the complexity of the design and to higher labor and 

overhead rates, 25 percent to the challenges of integrating 

the ship’s systems and the materials used, and 4 percent to 

additional outfitting costs.

The LHA(R) Amphibious Assault Ship

The LHA(R) class of amphibious assault ship is intended 

to replace the current aging LHA Tarawa class. It may 

eventually replace the LHD Wasp class as well. Officially, 

the Navy has selected a design for only the first LHA(R), 

called Flight 0; the design for subsequent ships is still to 

be determined. According to the 2005 Future Years Defense Program, the first LHA(R) will be authorized in 

2007, with all others of the class coming after 2009. The 

ship will displace 45,000 tons at full load or 30,000 tons 

at light load—12 percent more than the latest amphibious assault ship, the LHD-8, which is now under construction.

The design of the LHA(R) remains the subject of considerable controversy within the Department of the Navy. 

The department conducted an analysis of alternatives for 

the ship, considering six different designs—ranging from 

one that would be essentially the same as the LHD-8 to 

one (called the Dual Tram) that, among other things, 

would weigh 70 percent more than existing amphibious 

assault ships and have two separate flight decks so that 

fixed-wing and rotary-wing aircraft could operate simultaneously (something that cannot be done on LHAs and 

LHDs).3

 The President’s budget for 2005, submitted 

2005 2010 2015 2020 2025 2030 2035

0.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Cargo Cube

LCAC Spots

Helicopter Spots

Troops

Vehicle Square

3. According to the Navy’s analysis of alternatives, the Dual Tram 

design would have a displacement of 69,000 tons (as large as the 

Navy’s former Midway class aircraft carriers) and cost an average 

of about $3 billion apiece. CBO estimates the cost of those ships 

at closer to $4 billion apiece.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 19

Figure 2-3.

Annual Purchases of Amphibious and Maritime Prepositioning Ships

Under the Navy’s Plan

Source: Congressional Budget Office based on data from the Navy.

Note: The steady-state requirement is the annual purchases needed to keep the amphibious and maritime prepositioning forces at the 

Navy’s planned level of 57 ships indefinitely. MPF(F) = Maritime Prepositioning Force (Future).

in February 2004, indicated that the Navy had selected a 

design for the first LHA(R) called the “LHD plus plug,” 

which would have a somewhat longer and wider hull than 

the LHD class and displace about 50,000 tons. That design was a slight modification of one of the midrange designs in the analysis of alternatives and was intended to 

balance cost and capability. The first LHA(R) was estimated to cost $3.7 billion to procure, including $800 

million for design and engineering.4

Since the 2005 budget was submitted, however, concerns 

about the affordability of that LHA(R) have caused the 

Navy to change the design to one that is essentially a repeat of the LHD-8—except that it would have enhanced 

aviation capabilities. However, it would not have a docking well to transport and deploy the landing craft that 

move large equipment ashore. That design was not one 

considered in the analysis of alternatives.

If constructed as currently proposed, the “LHA(R) aviation variant” would be the first amphibious ship in decades built without a docking well. Eliminating the docking well allows more space and weight to be devoted to 

the hangar area and to facilities that support aviation. For 

example, the LHA(R) would carry 600 fewer troops and 

have 9,000 fewer square feet of vehicle space than the 

LHD-8, but it could carry two to three times as much 

aviation fuel as well as more and larger aircraft—including helicopters and Harrier aircraft today, or V-22 tiltrotor aircraft and Joint Strike Fighters (JSFs) when those 

are fielded in coming years.

The Navy has budgeted about $3 billion for the first 

LHA(R), or about $800 million more than for the 

2005 2010 2015 2020 2025 2030 2035

0

1

2

3

4

LPD-17 LHA(R) MPF(F) LSD(X)

Steady-State

Requirement

4. Ronald O’Rourke, Navy-Marine Corps Amphibious and Maritime 

Prepositioning Ship Programs: Background and Oversight Issues for 

Congress, CRS Report RL32513 (Congressional Research Service, 

August 5, 2004), pp. 7-8.
20 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Table 2-2.

Characteristics of Current and Proposed Amphibious and

Maritime Prepositioning Ships

Source: Congressional Budget Office.

Note: MPF(F) = Maritime Prepositioning Force (Future); n.a. = not available.

a. Displacement at full load (including all of the things the ship normally carries).

b. The five categories (or fingerprints) of amphibious lift are the number of troops a ship can carry; its vehicle storage area, measured in 

thousands of square feet (or vehicle square); its cargo storage area, measured in thousands of cubic feet (or cargo cube); the number of 

spots for parking vertical takeoff and landing aircraft (expressed as CH-46 helicopter equivalents); and the number of spots for air-cushion 

landing craft (known as LCACs).

c. An eighth Wasp class ship is under construction and will be commissioned in 2007.

d. Many of the characteristics of these ships are estimates published in Navy briefings or CBO’s assumptions based on conversations with 

Navy officials.

e. Officially, the program quantity is four ships. However, CBO assumes that the LHA(R) will also replace the LHD-1 class as those ships reach 

their retirement age of 40 years. In CBO’s analysis, only 10 of the 12 ships are bought through 2035.

f. Depending on the final design of these ships, the Navy could buy as few as 15 (three squadrons of five conventional cargo ships) or 24 

(three squadrons of eight sea-basing ships). CBO’s analysis assumes that the Navy will buy 21 (one squadron of five conventional cargo 

ships and two squadrons of eight sea-basing ships). 

Fingerprints of Liftb

Class Type of Ship Quantity 

Displacementa

(Tons)

Crew 

Size Troops

Vehicle 

Square

Cargo 

Cube

Helicopter 

Spots

LCAC 

Spots 

Current Ships

LHA-1 

Tarawa

Amphibious 

assault ship

5 40,000 1,160 1,713 25.4 105.9 42 1

LHD-1 

Wasp

Amphibious 

assault ship

7

c 40,500 1,150 1,686 20.9 125.0 45 3

LPD-4 

Austin

Amphibious 

transport dock

11 17,000 400 788 11.8 38.3 4 1

LSD-41 

Whidbey Island

Dock landing 

ship

8 16,000 310 454 13.5 5.1 0 4

LSD-49 

Harpers Ferry

Dock landing

ship 

4 17,000 330 454 16.9 50.7 0 2

Ships Under Construction

LPD-17 

San Antonio

Amphibious

transport dock

12 25,000 420 720 25.0 36.0 6 2

Proposed Shipsd

LHA(R) Amphibious 

assault ship

12e 45,000 1,852 1,102 12.0 125.0 45 0

LSD(X) Dock landing ship 12 22,000 ~350 590 22.0 5.1 0 4

MPF(F) Maritime

prepositioning 

ship

21f n.a. n.a. n.a. n.a. n.a. n.a. n.a.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 21

LHD-8. That estimate, however, is based on the larger 

LHD-plus-plug design. Ten LHA(R)s of the aviationvariant design would cost an average of about $2.4 billion 

each, CBO estimates. That figure is consistent with the 

costs of both the LPD-17 and the LHD-8 when measured per thousand tons. (For more details about how 

CBO calculated its cost estimates for individual ships, see 

Box 2-1.) The Navy has not yet decided on the configuration of future LHA(R) ships. Various designs are still 

under consideration, with one candidate being a ship 

similar to the first LHA(R) but somewhat larger and capable of carrying more aircraft.

The Navy’s decision to build a smaller amphibious assault 

ship than it had originally planned (or than other designs 

that it had considered) has been criticized as not adequately supporting future Marine Corps warfighting requirements, including the new sea-basing strategy. A 

larger design is needed to support that strategy, some critics argue.5

 Other Marine Corps officials have maintained

Box 2-1.

Developing Cost Estimates for Amphibious and Maritime

Prepositioning Ships

In estimating the costs of various amphibious and 

maritime prepositioning ships for this analysis, the 

Congressional Budget Office (CBO) relied mainly on 

a cost-per-thousand-tons methodology. Using data 

on the Navy’s costs to build the LPD-17 class of amphibious transport docks and the LHD-8 amphibious assault ship, CBO estimated that the Navy pays 

about $80 million per thousand tons to construct an 

amphibious warship. That number is based on the 

ships’ light loads (the displacement of the vessels 

themselves without their crew, materiel, weapons, 

and fuel).

For new amphibious warfare ships, CBO’s cost estimates were consistent with that approach. New ship 

designs tend to be more expensive on a per-ton basis 

than older designs because of higher labor and materials costs and the costs of incorporating new technology. However, the similarity between existing ships 

and the proposed designs for new amphibious ships 

suggests that extrapolating from the cost per thousand tons of amphibious ships now under construction provides the most likely predictor of the cost of 

those future ships.

For prepositioning and sea-basing ships, CBO used 

the initial cost estimates that the Center for Naval 

Analyses (CNA) developed in its analysis of alternatives for the Maritime Prepositioning Force (Future), 

or MPF(F), program. CNA estimated that replacement cargo ships for that force would cost about $20 

million per thousand tons, which is consistent with 

the cost of the T-AKE combat logistics ships that the 

Navy is building today. Consequently, CBO used 

that $20 million per thousand tons estimate for all of 

the MPF(F) replacement cargo ships in this analysis. 

CNA estimated that the first MPF(F) sea-basing ship 

would cost $1.6 billion, or about $40 million per 

thousand tons, but that successive ships would cost 

less. Those estimates suggest that the average price tag 

for a squadron of eight sea-basing ships would be 

about $1.3 billion per ship. In this analysis, CBO 

used the $40 million per thousand tons estimate for 

the first sea-basing ship because it did not have 

enough information about that vessel or an appropriate historical analogy to produce a completely independent estimate. For succeeding ships of the class, 

however, recent experience suggests that optimism 

about reducing costs may not be warranted. For example, the Navy’s experience with cost growth in its 

Virginia class submarine and LPD-17 programs suggests that sea-basing ships could actually cost substantially more than CNA estimates. Thus, CBO estimated that eight sea-basing ships would have an 

average cost of $1.6 billion apiece, which is consistent 

with a cost of $40 million per thousand tons. Conversely, some Navy officials hope that competition 

among potential shipbuilders can reduce the cost of 

the MPF(F) ships below what CNA estimated.

5. See, for example, Department of Defense, Office of the Under 

Secretary of Defense for Acquisition, Technology, and Logistics, 

Defense Science Board Task Force on Sea Basing (August 2003), 

available at www.acq.osd.mil/dsb/reports/seabasing.pdf.
22 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

that the Navy needs an expeditionary strike ship, though 

it is not clear what such a ship would entail in terms of 

size, capabilities, or cost.6

Conversely, other officials, including many in the Marine 

Corps, have argued that very large designs for the new 

amphibious assault ship are unnecessary. In their view, 

the LHA(R) aviation variant is the right ship because, 

when operating in conjunction with new maritime prepositioning ships, its helicopters would fly off and operate from the prepositioning ships. At the same time, additional fixed-wing aircraft (Joint Strike Fighters) would be 

flown in and operated from the LHA(R), making that 

ship in effect a small aircraft carrier. Reportedly, as many 

as 23 JSFs could operate from the first LHA(R). The 

Navy hopes that subsequent versions of that ship will accommodate up to 30 JSFs, but for this analysis, CBO assumed that all members of the LHA(R) class bought by 

the Navy would have the same capabilities as the first 

one. CBO has few details about what a future LHA(R) 

might look like or cost.

The LSD(X) Dock Landing Ship 

Little is known about the LSD(X) other than that it is intended to replace the LSD-41 Whidbey Island and LSD49 Harpers Ferry classes of dock landing ships. The first 

LSD(X) will not be authorized until 2020, with an expected commissioning date of 2024, when the first LSD41 will reach the end of its notional 40-year service life. 

Development and procurement of the LSD(X) are too far 

in the future for the Navy to have considered in any detail 

what characteristics and capabilities it wants the ship to 

have. The Navy’s long-term shipbuilding report envisioned procuring 12 of the ships between 2020 and 2031 

at an average cost of about $750 million. CBO does not 

know what characteristics, such as dimensions or displacement, were used in making that estimate. 

For the purposes of this analysis, CBO assumed that the 

LSD(X) would reflect the growth in size that new amphibious ships have exhibited over the past several years 

relative to previous classes. A weighted average of the 

growth in ship displacement from the LHD-8 to the 

LHA(R) and from the LPD-4 class to the LPD-17 suggests that the LSD(X) would be about 30 percent larger 

than the LSD-41 and LSD-49 classes. Thus, CBO assumed that the LSD(X) would displace about 15,000 

tons at light load and 22,000 tons at full load (versus 

12,000 tons at light load and 16,000 to 17,000 tons at 

full load for the LSD-41 and LSD-49 classes).

CBO assumed that the Navy would use the additional 

space in the LSD(X) to carry 30 percent more troops and 

vehicles than on the LSD-41 class, to compensate for the 

Navy’s shortages of lift in those categories relative to the 

amphibious-lift goal. The LSD(X) would carry the same 

amount of cargo and the same number of landing craft as 

the LSD-41 class. (In comparison, the LPD-17’s displacement is more than 45 percent greater than that of the 

LPD-4 class and results in twice the vehicle square and 

LCAC spots as well as in six air spots instead of four.) 

The average cost for 12 LSD(X)s would be about $1.2 

billion each, CBO estimates, based on the cost per thousand tons of the LHD-8 and the LPD-17 class. 

One of the difficulties, however, in determining the 

Navy’s and Marine Corps’s plans for dock landing ships is 

that the services are still developing concepts for the future composition and employment of amphibious forces. 

For example, current plans would have each expeditionary strike group include a large amphibious assault ship 

(such as an LHD or LHA(R)), an LPD-17, and an LSD 

class ship. But the Navy is also considering a formation in 

which each expeditionary strike group would include an 

LHD, an LHA(R), and an LPD-17. In that case, the 

LSD(X) program would never be started, and existing 

LSDs would be retired without replacement. The Navy 

and Marine Corps are still debating the merits of that formation. One problem is that unless the Navy cut the 

number of expeditionary strike groups, using such a formation would cost more than the Navy’s existing plan.

The Future Maritime 

Prepositioning Ship

The MPF(F) represents the greatest departure from past 

practice in the Navy’s plan for amphibious and maritime 

prepositioning vessels. It is an important ship in the service’s vision of the future of expeditionary warfare, but it 

is also the ship about which the Navy has released the 

fewest details. The prospective fleet of MPF(F) ships 

would, at a minimum, carry all of the equipment and 

material necessary for three Marine expeditionary brigades to operate for 20 days. Beyond that, the ships 

would have various sea-basing capabilities that current 

prepositioning cargo ships lack, such as the ability to: 

6. Malina Brown, “Naval Services May Develop New Class of ‘Expeditionary Strike Ships,’” Inside the Navy, April 12, 2004, p. 14.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 23

B Operate and support rotary-wing aircraft; 

B Have equipment and supplies off-loaded selectively, 

depending on what a military operation required, 

without the entire ship needing to be unpacked; and

B Transfer troops, military equipment, fuel, and supplies 

to aircraft and smaller surface craft at sea—rather than 

at a pier in a port—in conditions at least equal to “sea 

state three” (waves four feet high and wind speeds of 

15 knots). Those aircraft and surface craft would then 

transport the troops and equipment to shore.

Because the Navy has not yet spelled out its requirements 

for MPF(F) ships in much detail, the capabilities—and 

costs—of the ships could vary widely.

Possible Designs for MPF(F) Ships

The Center for Naval Analyses, a federally funded research and development center that serves as the Navy’s 

research arm, has conducted an analysis of alternatives for 

the design of the future maritime prepositioning ship. 

The three main MPF(F) options in the analysis are: 

B A modified large, medium-speed roll-on/roll-off 

(LMSR) cargo ship, which would essentially replicate 

the capabilities of today’s maritime prepositioning 

ships, with no sea-basing features. Five ships—at an 

average cost of $700 million each, CBO estimates—

would constitute a squadron capable of supporting a 

Marine expeditionary brigade.

B A “constrained design” sea-basing ship, capable of operating rotary-wing and tilt-rotary-wing aircraft. The 

design is constrained in the sense that the ship’s size is 

limited so it could be built in several of the private 

shipyards that construct Navy vessels.7 The Center for 

Naval Analyses estimated that eight of these ships 

would make up a squadron and that the lead ship of 

the class would cost about $1.6 billion.

B An “unconstrained design” sea-basing ship, capable of 

operating Joint Strike Fighters. This ship would be 

very large (displacing 83,000 tons at full load) and 

could only be built by Ingalls or Newport News Shipbuilding, both of which are owned by Northrop 

Grumman. Six ships would be needed to form a 

squadron and the first one would cost about $2.2 billion, according to the Center for Naval Analyses.

The last two alternatives would be logistical and aviation 

support ships, capable of conducting a variety of seabasing operations in support of different military objectives. In addition, the analysis of alternatives looked at 

families of specialized ships that would perform different 

functions in support of the sea-basing concept.

The analysis of alternatives suggested that total procurement costs for the MPF(F) program could range from 

$9 billion to $30 billion. If history is a guide, the Navy’s 

cost estimates for those ships could prove too low. A 

RAND study found that, on average, costs for Navy ship 

programs grew by 11 percent from the original estimates.8

 Moreover, during the past five years, the Navy’s 

Virginia class attack submarine program and LPD-17 

class amphibious ship program have experienced cost 

growth of 20 percent and 40 percent, respectively.

The Navy has not yet decided which design or designs for 

the MPF(F) it wants to buy. Over a year ago, Navy officials seemed to indicate that they would like to have three 

maritime prepositioning squadrons equipped with seabasing capabilities. More recently, the Chief of Naval Operations appeared to imply that he wanted only two seabasing squadrons, neither of which would use the large 

unconstrained design. (The fate of the third squadron 

was not clear.)

On the basis of that information, CBO assumed for this 

study that the Navy would buy two squadrons—or a total 

of 16—of the smaller constrained-design sea-basingcapable ships. A third squadron would be composed of 7. The most likely yards that could build this ship would be National 

Steel and Shipbuilding Company in San Diego and Bath Iron 

Works in Maine (although it has no recent experience in constructing support ships), which are owned by General Dynamics, 

and Avondale Industries in Louisiana and Ingalls Shipbuilding in 

Mississippi, which are owned by Northrop Grumman. 

8. See J.M. Jarvaise, J.A. Drezner, and D. Norton, The Defense System Cost Performance Database: Cost Growth Analysis Using Selected 

Acquisition Reports, MR-625-OSD (Santa Monica, Calif.: RAND, 

1996).
24 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

five LMSRs to replace existing cargo ships.9 Thus, CBO 

assumed that the Navy would buy a total of 21 MPF(F) 

ships, out of a possible 15 to 24 depending on the design 

that could be selected.

Press reports indicate that the ongoing debate within the 

Department of Defense about the capabilities of the 

MPF(F) has superseded the results of the analysis of alternatives.10 Partly in response to the continuing uncertainty about the proposed ship, the conference report 

accompanying the 2005 defense appropriation act states 

that “none of the funds provided for the MPF(F) may be 

obligated or expended until the Secretary of the Navy 

submits to the congressional defense committees a detailed report on the MPF(F) mission, operational requirements, analysis of alternatives, expenditure plans, and 

overall program congruence with ongoing forcible entry 

studies.”11 Nevertheless, CBO used the information in 

the MPF(F) analysis of alternatives to establish a baseline 

for this study. Even if the final design is not identical to 

one of those considered here, CBO’s analysis illustrates 

the force-structure and budgetary issues associated with 

decisions about the future of the maritime prepositioning 

force.

Survivability of MPF(F) Ships

Besides the ship’s capabilities, quantity, and cost, another 

critical characteristic of the MPF(F) that has not been finalized is its survivability in the event of attack. Navy 

ships are built to one of three levels of survivability: Level 

I is for ships, such as ammunition resupply vessels, that 

operate in the least demanding wartime environment, 

whereas Level III is for ships, such as major surface combatants, that operate in the most demanding environment. Amphibious warfare ships are built to Level II, 

which falls between the other two standards. (For more 

information about the concepts underlying the Navy’s 

survivability levels, see Box 2-2.) Thus far, the design 

specifications for the MPF(F) ships appear to require only 

an “enhanced commercial standard,” which is something 

less than a Level I survivability standard. That means the 

ships would have little, if any, capability to defend themselves from attack and no ability to “fight hurt” if they 

were attacked.

Nevertheless, the Navy and the Marine Corps envision 

having the MPF(F) operate along with, and in proximity 

to, L-class amphibious warfare ships. That could include 

operating in environments where it was subject to attack 

from cruise missiles, submarines, mines, small boats, or 

aircraft—the full array of littoral threats that concern 

Navy officials. Further, to perform its mission of providing continuous logistics support to troops on shore, the 

MPF(F) would probably have to operate far closer to the 

shore (within 25 nautical miles) than would an aircraft 

carrier, for example. In that environment, surface combatants protecting an MPF(F) would have only about a 

minute to detect, track, target, and destroy an antiship 

cruise missile traveling at twice the speed of sound. Moreover, since the MPF(F)s would probably be the largest 

ships in the littoral environment and the most visible to 

sensors, they would be the most likely target within a 

group of ships for ballistic or antiship cruise missiles.12

Building the MPF(F) ships to Level II survivability specifications could mitigate those concerns, but it would also 

substantially increase the cost of the ships. It might also 

lessen the ability of the MPF(F) to perform the sea-basing 

mission as the Navy and Marine Corps would like. To 

allow for selective off-loading of cargo, a substantial portion of the MPF(F)’s internal capacity would need to operate like a modern, floating warehouse with large, open 

spaces. But making the MPF(F) more survivable would 

involve, among other things, increasing the compartmentalization of its design. (Notably, in discussions during 

the late 1980s about the specifications of what was to become the LPD-17, alternative designs similar to the ones 

being considered for the MPF(F) were proposed. Those 

designs were rejected, however, because of concerns about 

9. In a few years, the Navy must decide whether to exercise an option 

to buy its existing leased maritime prepositioning ships. If it does 

not buy them, it will need to sign new leases so those ships can 

remain in the maritime prepositioning force until the new 

MPF(F)s are deployed. When that happens, the existing maritime 

prepositioning ships will be transferred to the Ready Reserve Fleet 

to replace sealift ships that will be scrapped.

10. Christopher J. Castelli, “Meeting of Top Naval Officials Sheds 

Light on Prepositioning Ships,” Inside the Navy, September 6, 

2004, p. 1.

11. House of Representatives, Making Appropriations for the Department of Defense for the Fiscal Year Ending September 30, 2005, and 

for Other Purposes, Conference Report 108-622 (July 20, 2004), 

p. 360.

12. For a similar discussion, see Robert Work, “The Department of 

the Navy and Assured Access: A Critical Risk Assessment,” in 

Andrew Krepinevich, Barry Watts, and Robert Work, Meeting the 

Anti-Access and Area-Denial Challenge (Washington, D.C.: Center 

for Strategic and Budgetary Assessments, 2003), pp. 52-56.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 25

Box 2-2.

The Survivability of Surface Ships in the Navy

The concept of survivability as it relates to Navy 

ships rests on three features: susceptibility, vulnerability, and recoverability.1

 Susceptibility is a ship’s 

ability to avoid an enemy strike, or its probability of 

being hit. Vulnerability is the ship’s ability to withstand the strike, or its probability of being destroyed 

if hit. Recoverability is the ability of the crew to restore a ship’s systems so the ship can carry out its 

missions while damaged. Key determinants of survivability include, among other things, a ship’s defensive systems, the way it is constructed, and the resources on board the ship to redress damage. 

In designing and building ships, all three of those 

concepts must be balanced. For example, a vessel 

that had zero susceptibility when its defensive systems were engaged but that had had little attention 

paid to reducing its vulnerability would be subject to 

crippling attack when its defenses were down, such 

as when it was on a nonalert status in a foreign port. 

Conversely, a ship that was built to withstand almost 

any kind of attack would most likely be too heavy, 

costly, and slow to be effective in combat situations.

The Navy divides its surface ships into three broad 

survivability categories that reflect the environments 

in which they are expected to function: Level I, Level 

II, and Level III. Ships built to Level I are expected 

to operate in the least severe environment, away 

from the area where a battle group is operating or the 

general war-at-sea region. Those vessels should be 

able to maintain good handling in bad weather and 

should have systems for fighting fires on board the 

ships, hardening against electromagnetic pulses, and 

protection against chemical, biological, or radiological contamination. However, they are not expected 

to “fight hurt,” as the Navy puts it. Such ships include material support ships, mine-warfare vessels, 

and patrol combatants. 

Ships built to Level II are expected to operate in a 

more severe environment, such as in support of a 

battle group in the war-at-sea region. Level II survivability should include the capacity to continue fighting even if the ship is hit by enemy weapons. Such 

ships would have all of the features of Level I but 

more redundancy in their primary and support systems, better structural integrity and compartmentalization (such as being built with numerous watertight sections), protection against conventional and 

nuclear blasts, and a smaller signature (meaning they 

have a smaller radar cross-section, make less noise 

when passing through the water, and are less susceptible to mines). Ships built to Level II include the logistics support ships that supply materials, fuel, and 

ammunition to carrier battle groups and amphibious 

warfare ships during combat. 

Level III is the most severe environment envisioned 

for surface warships. Vessels designed to withstand 

that environment should have all of the features of 

ships designed to Level II as well as better defensive 

systems and more ability to deal with the degrading 

effects of hits from antiship cruise missiles, torpedoes, and mines (through better damage-control systems and greater structural integrity). Ships built to 

Level III specifications include aircraft carriers and 

major surface combatants, such as Aegis-capable 

cruisers and destroyers.

1. This discussion comes almost entirely from Department of 

the Navy, Chief of Naval Operations, Ship Safety and Survivability Office, Survivability Design Handbook for Surface 

Ships (September 2000).
26 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

the ship’s survivability and therefore about the risk to the 

marines it would carry.)

How MPF(F) Ships Might Be Used

Another source of uncertainty about the design and capabilities of sea-basing maritime prepositioning ships is the 

fact that the Navy envisions using them in four different 

ways—individually, in an MPF(F) squadron, in conjunction with one expeditionary strike group, or in conjunction with two. MPF(F) ships would be capable of some 

independent operations, although the environment 

would have to be fairly benign, given the low level of survivability those ships are likely to have.

Designing MPF(F) ships so they bring the optimal mix of 

capabilities to an operation when used in any of those 

ways is the central issue that the Navy and Marine Corps 

are examining today. For example, this study assumes—

on the basis of the analysis of alternatives—that an 

MPF(F) squadron will be composed of eight similarly designed ships. But the Navy is now looking at whether a 

squadron should be composed of nine ships plus an additional conventional cargo ship. If such a squadron became the choice of the Navy and Marine Corps, it could 

be more expensive than the estimates that CBO reports 

in this study—depending on the final design of the 

MPF(F) ship itself. Moreover, the Navy is considering 

other compositions for MPF(F) squadrons, such as using 

nine to 10 vessels per squadron, with two or three different types of ship. A squadron in which all of the ships 

were more or less the same would allow more flexibility in 

the ships’ use. Conversely, a squadron in which the ships 

were more specialized could be less expensive because not 

every vessel would need to have aviation capabilities.

Budgetary Implications 

of the Navy’s Plan

Assessing the resources necessary to implement the Navy’s 

plan for modernizing amphibious and maritime prepositioning forces requires dealing with uncertainty about the 

design of the MPF(F), the LSD(X), and even to some degree the LHA(R). But even allowing for that uncertainty, 

CBO’s analysis indicates that the Navy’s plan will cost 

substantially more than what the service has spent on amphibious and maritime prepositioning ships over the past 

20 years.

Between 1980 and 2004, the amphibious warfare force 

received an average of about $1.1 billion a year (in 2005 

dollars) for ship construction, or about 9 percent of the 

Navy’s total shipbuilding budget.13 With that funding, 

the Navy built an average of slightly less than 0.9 ships a 

year—almost enough annual production to keep the amphibious warfare force at 36 ships indefinitely.14

In all, modernizing the amphibious warfare force as the 

Navy plans to do and acquiring 21 new maritime prepositioning ships would cost an average of $2.4 billion a 

year between 2005 and 2035, CBO estimates—more 

than twice the average historical funding level (see 

Table 2-3). Even if the MPF(F) was excluded, costs 

would still average $1.5 billion per year. Moreover, the 

highest spending would occur in the next 10 years, when 

costs for amphibious and maritime prepositioning ships 

would average $3.1 billion a year. Although annual costs 

would be substantially smaller in succeeding decades, at 

no point in CBO’s projection would they be at or below 

the historical average level.

Senior Navy leaders appear to recognize the funding challenge posed by that modernization program. Because of 

the high value those leaders place on acquiring a seabasing capability, they want to free resources to pay for 

the MPF(F) program.15 Consequently, they are considering reducing the number of expeditionary strike groups 

to eight, in conjunction with employing crew rotation for 

ships in those groups. If such a reduction occurred—and 

led the Navy to cut the number of LPD-17s to eight, delay the first LHA(R) by 15 years, and buy only eight 

LSD(X)s in the 2020s—the result would be substantial 

savings relative to the current plan. Construction costs for 

both L-class and maritime prepositioning ships would average $1.8 billion a year between 2005 and 2035 instead 

of $2.4 billion (see the section labeled “Reduced Navy 

Plan” in Table 2-3). Over the next 10 years, construction 

costs would average $2.0 billion annually instead of $3.1 

billion.

13. Even during the 1980s, a decade that included the Reagan 

Administration’s defense buildup, the Navy still spent an average 

of $1.1 billion a year on amphibious ships.

14. That steady-state production level is calculated by dividing the 

total number of ships by their service life. In this case, 36 amphibious ships divided by a 40-year service life equals a production rate 

of 0.9 per year.

15. Christopher J. Castelli, “Navy Wants to Cut Number of Strike 

Groups, Slash LPD-17 Shipbuilding,” Inside the Navy, April 26, 

2004, and “Navy May Cut Number of Expeditionary Strike 

Groups to Fund MPF(F),” Inside the Navy, July 12, 2004.
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 27

Table 2-3.

Average Annual Construction Spending and Procurement for Amphibious

and Maritime Prepositioning Ships, 2005 to 2035

Source: Congressional Budget Office.

Note: n.a. = not applicable (because most current maritime prepositioning ships are leased by the Navy from private firms).

a. CBO assumed that if the Navy reduced the number of expeditionary strike groups to eight, it would end the LPD-17 program at eight ships 

instead of 12, delay the LHA(R) program until 2022, and buy eight LSD(X)s instead of 12.

Although the increases in spending discussed above may 

seem modest relative to the Navy’s entire budget of $120 

billion, they should be considered in the context of other 

shipbuilding needs. To maintain today’s 293-ship fleet in 

a steady state, the Navy would have to spend an average 

of about $12.8 billion annually on ship construction, 

CBO estimates. However, between 1990 and 2004, the 

Navy spent an average of about $8.9 billion a year on 

shipbuilding (see Table 2-4), including conversions and 

nuclear-refueling overhauls of existing ships as well as 

construction of new ones. As a consequence, it built up a 

cumulative shortfall of about $58 billion and 16 ships relative to the amounts needed to keep the fleet at the current size. Thus, if the Navy wants to have at least 293 

ships at the end of the 35-year period that began in 1990 

—because the average service life of the entire fleet is 

about 35 years—it must make up that shortfall in ship 

construction over the next two decades. 

Average spending on ship construction has risen in recent 

years, to about $9.3 billion a year from 2001 to 2005 (excluding overhaul and conversion programs), although it 

remains far below the steady-state requirement. If that 

level of spending continued for the next two decades, the 

Navy would face an additional shortfall of $58 billion, for 

a total of $116 billion over the 1990-2025 period. That 

shortfall would result in 44 fewer ships’ being bought 

Historical

Average,

1980-2004

Projected Average

2005-

2014

2015-

2024

2025-

2035

2005-

2035

Navy Plan

Construction Spending (Billions of 2005 dollars)

Amphibious warfare ships 1.1 1.5 1.2 1.8 1.5

Maritime prepositioning ships n.a. 1.6 1.2 0 0.9

Total 1.1 3.1 2.3 1.8 2.4

Procurement Quantity

Amphibious warfare ships 0.9 0.9 0.7 1.1 0.9

Maritime prepositioning ships n.a. 1.0 0.9 0 0.6

Total 0.9 1.9 1.6 1.1 1.5

Reduced Navy Plana

Construction Spending (Billions of 2005 dollars)

Amphibious warfare ships 1.1 0.3 0.7 1.6 0.9

Maritime prepositioning ships n.a. 1.6 1.2 0 0.9

Total 1.1 2.0 1.9 1.6 1.8

Procurement Quantity

Amphibious warfare ships 0.9 0.2 0.4 0.9 0.5

Maritime prepositioning ships n.a. 1.0 0.9 0 0.6

Total 0.9 1.2 1.3 0.9 1.1
28 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Table 2-4.

Shortfalls in Sustaining a 293-Ship Navy, 1990 to 2025

Source: Congressional Budget Office.

a. The annual purchases and spending required to maintain the fleet at a certain size (in this case, the current size, 293 battle force ships). 

To determine steady-state purchases, CBO divided the Navy’s inventory of ships by the service life of each type of ship. To determine 

steady-state spending, CBO multiplied those annual purchases by its estimate of the unit (per-item) cost of each type of ship.

b. “Recent plans” refers to average construction spending and purchases between 2001 and 2005.

c. Money spent for construction of new ships and for major conversions and nuclear-refueling overhauls of existing ships.

d. The Navy does not buy fractional ships, of course, but showing the data to one decimal place provides greater understanding of historical 

and future trends.

during that period than the number needed to maintain 

the fleet at 293—implying that the Navy’s battle force 

would total around 250 ships by 2025, far short of the 

375-ship goal espoused in recent years.

Thus, in the context of past funding levels, the Navy’s 

plans for amphibious and maritime prepositioning ships 

and for a larger overall force appear daunting. The Navy’s 

proposal to build a 375-ship fleet would cost an average 

of about $19 billion a year through 2035, CBO estimates 

(see Figure 2-4).16 Spending on amphibious and maritime propositioning ships would make up about 12 percent of the total—up from the average share of 9 percent 

that they have consumed since 1980.

Type of Ship

Annual 

Average, 

1990-

2004

Steady-State 

Requirementa

Historical Cumulative 

Surplus or Shortfall (-) 

Relative to SteadyState Requirement,

1990-2004

Projected Cumulative 

Surplus or Shortfall (-) 

Relative to Recent

Shipbuilding Plans, 

2005-2025b

Total Cumulative 

Surplus or

Shortfall (-),

1990-2025

Construction Spending 

(Billions of 2005 dollars)c

Surface Combatants 3.7 3.4 4.7 2.8 7.5

Attack Submarines 1.9 4.0 -39.9 -31.9 -71.9

Ballistic Missile

Submarines 0.3 1.0 -8.6 -19.0 -27.6

Aircraft Carriers 1.4 2.3 -15.2 -6.9 -22.1

Amphibious Ships 1.1 1.3 -0.2 0.7 -0.5

Other 0.5 0.7 -0.8 -3.6 -2.8

Total 8.9 12.8 -58.3 -57.9 -116.3

Quantityd

Surface Combatants 3.4 3.1 4.3 -2.6 6.8

Attack Submarines 0.6 1.8 -17.4 -13.9 -31.2

Ballistic Missile

Submarines 0.1 0.3 -3.0 -6.7 -9.7

Aircraft Carriers 0.1 0.2 -1.6 -1.0 -2.6

Amphibious Ships 0.9 0.9 -0.1 0.4 0.3

Other 2.1 2.0 2.2 -10.0 -7.9

Total 7.3 8.3 -15.6 -28.5 -44.2

16. That figure is roughly analogous to the cost-risk estimate for ships 

in Congressional Budget Office, The Long-Term Implications of 

Current Defense Plans: Summary Update for Fiscal Year 2005

(September 2004).
CHAPTER TWO THE NAVY’S PLAN FOR MODERNIZING THE AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 29

Figure 2-4.

Projected Funding to Construct a 375-Ship Fleet

Compared with Actual Ship Funding

(Billions of 2005 dollars)

Source: Congressional Budget Office.

Note: The data in this figure are roughly analogous to the cost-risk case for ships presented in Congressional Budget Office, The Long-Term 

Implications of Current Defense Plans: Summary Update for Fiscal Year 2005 (September 2004).

The Navy could address those funding issues in myriad 

ways. The next chapter examines four alternatives to the 

Navy’s current plan for the amphibious and maritime 

prepositioning forces. Two of the options would keep 

spending on those forces at its historical level, and the 

other two would require spending increases, though not 

to as great an extent as the Navy’s plan would. Chapter 4 

compares the capabilities of the forces that would result 

from those alternatives.

1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035

0

5

10

15

20

25

30

Actual Projected

Surface Combatants, Aircraft

Carriers, Submarines, and

Support Ships

Amphibious Ships

3

Lower-Cost Alternatives

to the Navy’s Plan for Amphibious 

and Maritime Prepositioning Forces

As Chapter 2 described, the Navy faces a funding 

challenge with its plans for shipbuilding as a whole and 

for amphibious and maritime prepositioning ships in particular. The Navy could ameliorate that situation in many 

ways. To illustrate some of them, the Congressional Budget Office constructed four alternative plans for modernizing those ships at a lower cost than under the Navy’s 

plan. All of the alternatives would result in a smaller amphibious force than exists today. 

The first two alternatives would modernize the amphibious and maritime prepositioning forces within historical 

spending levels—an average of $1.1 billion a year, in 

2005 dollars—by purchasing either fewer but morecapable ships (Option 1A) or more but less-capable ships 

(Option 1B). Those approaches represent the most drastic change from the Navy’s plan. The other two alternatives would cost about 36 percent more (an average of 

$1.5 billion a year). Option 2 would reduce the number 

of expeditionary strike groups from 12 to eight but make 

those eight capable of conducting sea-basing operations, 

in conjunction with Maritime Prepositioning Force (Future) ships, by 2035. Option 3, by contrast, would abandon the sea-basing concept and focus on providing forward presence with ESGs. Under that alternative, the 

amphibious warfare and maritime prepositioning forces 

in 2035 would look much like they do today, though 

somewhat smaller.

This chapter describes in detail the different force structures that would result from those approaches. Chapter 4 

examines how capable the alternative force structures 

would be in peacetime and wartime compared with today’s expeditionary warfare fleet and with the one envisioned in the Navy’s plan.

These options focus only on issues related to shipbuilding. None would change the number or size of Marine 

Corps units or the total end strength of the Corps (now 

175,000 active officers and enlisted personnel). Consequently, they would not alter the quantities of air and 

ground equipment that the Marine Corps plans to procure in coming years.1

 Nor would any of the alternatives 

adopt rotational crewing concepts, such as Sea Swap. 

(Chapter 4, however, describes the effect that Sea Swap 

would have on maintaining forward-deployed expeditionary strike groups.)

Option 1A: Buy Fewer, 

More-Capable Ships Within 

Historical Spending Levels

The first two options that CBO considered are driven 

mainly by funding issues. Since 1980, the Navy has devoted an average of about $1.1 billion annually to constructing amphibious ships. (It has devoted little to constructing maritime prepositioning ships because most of 

those vessels are leased from private firms.) CBO estimates that the Navy’s plan would require spending an average of $2.4 billion over the next 30 years to build amphibious and maritime prepositioning ships. The service 

faces funding challenges in other areas as well. Its programs for attack submarines, surface combatants, and aircraft carriers all require more spending than has been 

available in recent years. (In particular, the Navy wants to 

buy large numbers of a new small, fast surface combatant 

CHAPTER

1. For details about those plans, see Congressional Budget Office, 

The Long-Term Implications of Current Defense Plans: Detailed 

Update for Fiscal Year 2005 (September 2004).
32 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

called the littoral combat ship. Admiral Vern Clark, the 

Chief of Naval Operations, has called that ship the Navy’s 

“most transformational effort and number one budget 

priority.”)2 Since the Navy cannot buy all of the ships it 

would like at its current level of funding, CBO developed 

two options to show the implications of modernizing amphibious and maritime prepositioning forces within the 

$1.1 billion historical funding level—or about half of 

what the Navy’s plan would cost.

Option 1A would continue to pursue the transformational vision of sea basing while reducing the size of the 

amphibious warfare and maritime prepositioning forces. 

This approach would gradually cut the number of expeditionary strike groups by half (from 12 to six) and the 

number of maritime prepositioning squadrons by onethird (from three to two). One of those squadrons would 

be configured to support sea-based operations, and the 

other would consist of conventional cargo vessels along 

the lines of today’s maritime prepositioning ships. Although ship purchases would be smaller in this option 

than in the Navy’s plan, the same types of new, morecapable ships would be procured: the LHA(R) amphibious assault ship, the LSD(X) dock landing ship, and the 

sea-basing-capable MPF(F) ship (as well as replacement 

cargo ships).

Thus, in modernizing the amphibious and maritime 

prepositioning forces within the historical funding level, 

this approach emphasizes quality over quantity. (Option 

1B, which is discussed in the next section, takes the opposite tack.) The L-class force, although much smaller 

than today’s, would be replaced with modern and morecapable ships. The maritime prepositioning force would 

also be cut (though less dramatically) but would include 

one squadron with new aviation and sea-basing capabilities.

Shipbuilding Under Option 1A

Overall, this alternative would construct an average of 0.7 

amphibious and maritime prepositioning ships a year between 2005 and 2035—less than half the 1.6-ship average under the Navy’s plan. For L-class amphibious warfare vessels only, the shipbuilding rate would be 0.3 per 

year under this option, compared with 0.9 under the 

Navy’s plan, which is also the historical rate.

With an approach such as this, in which the level of resources is the driving factor, the Navy could choose 

among many different programs resulting in different 

compositions for the amphibious and maritime prepositioning forces. A key factor in determining the potential 

mix of ships would be the balance between L-class vessels 

and MPF(F) ships and between the types of ship within 

each of those categories. With respect to L-class ships, 

this alternative tries to take a balanced approach, maintaining relatively equal numbers of LPDs, LSDs, and 

LHA/LHDs. Likewise, with respect to the second category, it buys both MPF(F) ships with sea-basing capabilities and conventional maritime prepositioning ships.

Specifically, Option 1A would shrink the LPD-17 program from 12 to seven ships. It would delay the start of 

the LHA(R) program until 2025, 18 years later than under the Navy’s plan, and would buy only four of those 

ships by 2035 instead of 10 (see Figure 3-1). The LSD(X) 

program would be delayed until 2023 and then only five 

ships would be purchased, compared with 12 under the 

Navy’s plan. The MPF(F) program would be split between buying one squadron’s worth (eight ships) of the 

“constrained” sea-basing-oriented design, which is capable of operating and supporting helicopters and tilt-rotor 

aircraft, and purchasing one squadron (five ships) of conventional prepositioning cargo vessels, similar to the ones 

in the force today. 

Under this option, the total number of amphibious warfare and maritime prepositioning ships would decline 

from 51 in 2004 to 31 in 2035 (see Figure 3-2). The 

number of L-class vessels would remain at the planned 

level of 36 through 2010 but then fall steadily until 2035, 

when the force would settle into its new steady-state size 

of 18 ships—seven LPDs, five LSDs, and six LHA/LHD 

class ships (compared with 12 of each under the Navy’s 

plan). The number of maritime prepositioning ships 

would decline from 16 now to 13, although eight of 

those 13 would be sea-basing ships.

2. Scott C. Truver, “Navy Plans to Develop LCS Fleet with ‘Lightening Speed,’” Sea Power (May 2003). For more details about that 

ship, see Congressional Budget Office, Transforming the Navy’s 

Surface Combatant Force (March 2003); and Ronald O’Rourke, 

Navy Littoral Combat Ship (LCS): Background and Issues for Congress, Report for Congress RS21305 (Congressional Research Service, July 30, 2004), and Navy DD(X) and LCS Ship Acquisition 

Programs: Oversight Issues and Options for Congress, Report for 

Congress RL32109 (Congressional Research Service, September 

3, 2004).
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 33

Figure 3-1.

Annual Purchases and Costs of Amphibious and Maritime Prepositioning Ships 

Under Option 1A

Source: Congressional Budget Office based in part on data from the Navy.

Note: The steady-state requirement is the annual purchases or spending needed to keep the amphibious and maritime prepositioning forces 

at the planned level (in the case of Option 1A, 31 ships) indefinitely. MPF(F) = Maritime Prepositioning Force (Future).

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

Purchases Under the Navy's Plan

Steady-State

Requirement

Number of Ships Purchased Under Option 1A

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

5

6

LHD-8 LPD-17 MPF(F) LSD(X) LHA(R)

Costs Under the

Navy's Plan

Steady-State

Requirement

Shipbuilding Costs Under Option 1A

(Billions of 2005 dollars)
34 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 3-2.

Inventory of Amphibious and Maritime Prepositioning Ships Under Option 1A

Source: Congressional Budget Office based in part on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

Lift Capability Under Option 1A

As described in Chapter 2, the Navy’s plan would eventually provide enough lift for the equivalent of 5.5 Marine 

expeditionary brigades: 2.5 MEBs of amphibious lift, 2.0 

MEBs of lift on sea-basing ships, and 1.0 MEB of sealift 

on cargo ships. By comparison, this option would provide 

3.25 MEBs of lift overall: 1.25 MEBs of amphibious lift, 

1.0 MEB of sea-based lift, and 1.0 MEB of sealift. 

Costs of Option 1A

Under this alternative, the Navy would spend an average 

of $1.1 billion a year on ship construction from 2005 to 

2014, $1.1 billion from 2015 to 2024, and $1.2 billion 

from 2025 to 2035—for an annual average of $1.1 billion over CBO’s projection period (see Table 3-1). Including operation and support (O&S) costs for those 

ships, Option 1A would require an average of $3.4 billion 

in annual spending during that period. Those costs are 

much lower than under the Navy’s plan, which would 

spend $3.1 billion on ship construction between 2005 

and 2014, $2.3 billion between 2015 and 2024, and $1.8 

billion between 2025 and 2035—for an overall average of 

$2.4 billion a year, or $5.5 billion including O&S costs. 

As another point of comparison, if the ships in this option were bought at a steady-state rate (the number of 

ships in the force divided by their 40-year service life), 

this approach would require slightly more than $1.1 billion in annual funding (see Figure 3-1).

Option 1B: Buy More, 

Less-Capable Ships Within 

Historical Spending Levels

If the Navy is forced to fund amphibious ships at the historical average of about $1.1 billion a year but is loath to 

cut the L-class force to the extent envisioned in Option 

1A, it can maintain a larger number of ships by not investing in any new designs. This option illustrates that 

approach: it would keep the future amphibious warfare 

and maritime prepositioning forces at a greater size than 

under Option 1A but would not pursue the enhanced 

sea-basing capability sought by the Navy and Marine 

Corps. In other words, for the same amount of money as 

Option 1A, this alternative would emphasize quantity 

over quality.

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPF(F) Sea-Basing Ships

MPS Cargo Ships

LSD(X)
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 35

Table 3-1.

Projected Average Annual Spending

for Construction and Operation and

Support, 2005 to 2035

(Billions of 2005 dollars)

Source: Congressional Budget Office.

Notes: O&S = operation and support.

By comparison, between 1980 and 2004, the Navy spent an 

average of about $1.1 billion per year (in 2005 dollars) on 

construction of amphibious warfare ships. (It mainly leased 

rather than built maritime prepositioning ships.)

In this alternative, the number of ESGs would gradually 

be cut by one-quarter, from 12 to nine (leaving 50 percent more ESGs than in Option 1A). The number of 

maritime prepositioning ships would be reduced by a little more than half a squadron. Amphibious warfare ships 

would be replaced by ships similar in size and capabilities 

to existing classes, and maritime prepositioning ships 

would be replaced by modern cargo ships with no seabasing capabilities. 

Shipbuilding Under Option 1B

Overall, this alternative would construct an average of 1.0 

amphibious warfare or maritime prepositioning ship a 

year between 2005 and 2035, compared with 0.7 ships 

under Option 1A and 1.6 under the Navy’s plan. The 

shipbuilding rate for only L-class vessels would be 0.6 per 

year under this approach—twice the rate in Option 1A 

but one-third less than in the Navy’s plan.

With respect to specific programs, this option would terminate the LPD-17 program at nine ships. It would delay 

the start of the LHA(R) program by six years, until 2013 

(see Figure 3-3). Six of those ships would be purchased 

through 2035—twice as many as in Option 1A. The 

LSD(X) program would start in 2020, and a total of nine 

ships would be purchased. This option would also buy 12 

conventional MPF(F) ships, enough for about 2.5 maritime prepositioning squadrons. Unlike in Option 1A, 

those squadrons would not have any sea-basing capabilities. With those changes, the steady-state amphibious 

warfare force would number nine LPDs, nine LSDs, and 

nine LHA/LHD class ships (compared with 12 each under the Navy’s plan and seven, five, and six, respectively, 

under Option 1A).

The total size of the amphibious warfare and maritime 

prepositioning forces would decline throughout the 

2005-2035 period under this option (see Figure 3-4), 

though not as precipitously as under Option 1A. The 

number of L-class vessels would drop from 36 in 2005 to 

27 by 2035, although it would hover in the low 30s 

through most of that period, falling to the steady-state 

level only near the end. The maritime prepositioning 

force would decline from 16 ships now to 12 ships by the 

2020s. Thus, the overall force would number 39 ships in 

2035, compared with 31 under Option 1A and 57 under 

the Navy’s plan. 

Lift Capability Under Option 1B

This approach would result in about 30 percent more lift 

capability than Option 1A: a total of 4.2 MEBs (1.8 

MEBs of amphibious lift and about 2.4 MEBs of sealift) 

rather than 3.25 MEBs. However, that figure would still 

fall short of the Navy’s planned total of 5.5 MEBs (2.5 

MEBs of amphibious lift, 2.0 MEBs of sea-based lift, and 

1.0 MEB of sealift). Because this alternative would not 

procure any ships with sea-basing capability, it would not 

provide any sea-based lift.

2005-

2014

2015-

2024

2025-

2035

Total,

2005-

2035

Navy’s Plan

Ship Construction 3.1 2.3 1.8 2.4

Ship Construction and O&S 6.0 5.5 5.0 5.5

Option 1A:

Buy Fewer, More-Capable Ships

Ship Construction 1.1 1.1 1.2 1.1

Ship Construction and O&S 3.8 3.3 3.0 3.4

Option 1B: 

Buy More, Less-Capable Ships

Ship Construction 1.1 1.2 1.0 1.1

Ship Construction and O&S 3.9 3.7 3.4 3.6

Option 2:

Create a More Survivable Sea-Basing Force

Ship Construction 1.6 1.3 1.6 1.5

Ship Construction and O&S 4.3 3.5 3.5 3.8

Option 3:

Deemphasize Sea Basing 

in Favor of Forward Presence

Ship Construction 1.4 1.3 1.8 1.5

Ship Construction and O&S 4.2 3.8 4.4 4.1
36 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 3-3.

Annual Purchases and Costs of Amphibious and Maritime Prepositioning Ships 

Under Option 1B

Source: Congressional Budget Office based in part on data from the Navy.

Note: The steady-state requirement is the annual purchases or spending needed to keep the amphibious and maritime prepositioning forces 

at the planned level (in the case of Option 1B, 39 ships) indefinitely. MPF(F) = Maritime Prepositioning Force (Future).

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

Purchases Under the Navy's Plan

Steady-State

Requirement

Number of Ships Purchased Under Option 1B

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

5

6

LHD-8 LPD-17 MPF(F) LSD(X) LHA(R)

Costs Under the

Navy's Plan

Steady-State

Requirement

Shipbuilding Costs Under Option 1B

(Billions of 2005 dollars)
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 37

Figure 3-4.

Inventory of Amphibious and Maritime Prepositioning Ships Under Option 1B

Source: Congressional Budget Office based in part on data from the Navy.

Note: MPS = maritime prepositioning squadron.

Costs of Option 1B

As in Option 1A, the cost of building L-class vessels and 

maritime prepositioning ships would average $1.1 billion 

a year over the 2005-2035 period under this alternative—

the same amount that the Navy spent, on average, between 1980 and 2004 and much less than the $2.4 billion annual average needed to fund the Navy’s plan (see 

Table 3-1 on page 35). During the first 10 years of the 

projection period, construction costs would average a bit 

less than $1.1 billion. They would vary slightly in succeeding decades, averaging $1.2 billion between 2015 

and 2024 and a little less than $1.0 billion between 2025 

and 2035. Those procurement costs compare reasonably 

well with the steady-state spending level of about $1.3 

billion a year required to keep the amphibious and maritime prepositioning force at 39 ships indefinitely (see Figure 3-3). 

Because this approach would operate more ships than 

Option 1A, it would entail larger operation and support 

costs. With both O&S and construction included, this alternative would cost an average of $3.6 billion annually 

over 30 years, versus $3.4 billion under Option 1A.

Option 2: Create a More Survivable 

Sea-Basing Force

As noted in Chapter 2, the Navy is considering not only 

modernizing the amphibious warfare force but also 

shrinking it as part of a reduction in the number of expeditionary strike groups from 12 to eight. To illustrate 

some of the implications of such a decision, this option 

also cuts the number of ESGs to eight. 

At the same time, this alternative attempts to address the 

issue of the survivability of MPF(F)s that was raised in 

Chapter 2. The Navy plans to build those ships to an enhanced commercial standard (apparently something less 

than Level I survivability), which is equivalent to the survivability of the Navy’s cargo ships, but it intends to use 

the sea-basing-capable MPF(F)s in potentially demanding wartime environments. This option would instead 

build those ships to a higher level of survivability than the 

Navy plans, although less than that of amphibious warfare ships (Level II).3

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPS Cargo Ships

LSD(X)

3. For an explanation of the Navy’s survivability standards for ships, 

see Box 2-2 on page 25.
38 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Under this approach, the Navy would modernize both 

the amphibious warfare force and the maritime prepositioning force but would cut the number of ESGs by onethird and the number of maritime prepositioning squadrons by two-thirds (from three to one). The remaining 

squadron would be composed of MPF(F)s of the constrained sea-basing design, built to enhanced levels of survivability and capable of operating and supporting helicopters and tilt-rotor aircraft. Because both this option 

and the next one are meant to emphasize issues other 

than funding pressures, CBO did not constrain them to 

the historical level of spending on amphibious ships. Instead, it chose simply to keep costs substantially below 

the level that the Navy’s plan would require.

One of the arguments that the Navy and Marine Corps 

use to justify the need for sea basing is that, in the future, 

ballistic and cruise missiles could pose too great a threat 

to a land base in a theater of operations. In time (or perhaps at the same time), however, those missiles could 

prove just as threatening to MPF(F) ships. Such vessels 

would be the second largest ships in the theater (if one of 

the Navy’s large aircraft carriers was also operating there) 

but would have the lowest level of survivability. Moreover, MPF(F) ships would be some of the most detectable 

and thus targetable ships in the fleet and would operate 

much closer to shore than aircraft carriers would. 

The Navy argues that Sea Shield—the network of defensive capabilities provided by its ships, aircraft, and sensor 

and electronic warfare systems—would protect MPF(F) 

ships from threats posed by missiles, mines, small boats, 

and submarines. However, an important component of 

employing Sea Shield would be destroying the sites of 

ballistic and cruise missiles early, before the missiles could 

be launched to threaten U.S. forces. Doing that would 

give an advantage not only to U.S. sea-based forces but 

also to the land base that sea basing is supposed to replace. The issue, then, seems to rest on whether “leakers” 

—any surviving missiles that were not destroyed at the 

point of origin—would pose a greater threat to a land 

base than to a sea base. As noted in Chapter 2, a strike by 

a single conventional missile against a land base would 

probably do less damage to ongoing military operations 

than would the same strike against an MPF(F), which 

would represent one-eighth of all of the capabilities of a 

sea-basing squadron. In addition, land bases, once established, would not be threatened by any mines or submarines that might have escaped the notice of Sea Shield.

Shipbuilding Under Option 2

This alternative would construct an average of 0.8 amphibious and maritime prepositioning ships per year 

between 2005 and 2035—half as much as under the 

Navy’s plan. The building rate for L-class vessels would be 

0.5 ships per year—versus 0.9 under the Navy’s plan. 

The LPD-17 program would end at eight ships instead of 

12 under this approach. The LHA(R) program would be 

delayed from 2007 until 2022, with six ships purchased 

through 2035 (see Figure 3-5). The LSD(X) program 

would begin at the same time as in the Navy’s plan 

(2020), but only eight ships would be bought rather than 

the 12 now envisioned. This option would also purchase 

eight constrained-design MPF(F) ships, with sea-basing 

capabilities and enhanced survivability, starting in 2009. 

(The potential cost of upgrading the survivability of the 

MPF(F) is discussed below.)

Under this alternative, the amphibious warfare and maritime prepositioning forces would reach their steady-state 

sizes—24 L-class ships (eight LPDs, eight LSDs, and 

eight LHDs/LHAs) and eight MPF(F) ships—between 

2022 and 2024 (see Figure 3-6). That overall force of 32 

ships would be 24 less than in the Navy’s plan.

Lift Capability Under Option 2

This approach would result in 1.7 MEBs of amphibious 

lift, 1.0 MEB of sea-based lift, and no sealift, for 2.7 

MEBs overall. That total is only half of the level in the 

Navy’s plan: 5.5 MEBs overall (2.5 MEBs of amphibious 

lift, 2.0 MEBs of sea-based lift, and 1.0 MEB of sealift).

Costs of Option 2

Although it would require more spending on ship construction than either Option 1A or 1B, this alternative 

would cost substantially less than the Navy’s plan, particularly in the next 20 years (see Figure 3-5). Between 2005 

and 2035, this option would spend an average of $1.5 

billion on ship construction, or $3.8 billion with O&S 

costs included. By comparison, annual costs under the 

Navy’s plan would average $2.4 billion and $5.5 billion, 

respectively. 

Average construction spending would vary in each succeeding decade of the projection period: $1.6 billion 
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 39

Figure 3-5.

Annual Purchases and Costs of Amphibious and Maritime Prepositioning Ships 

Under Option 2

Source: Congressional Budget Office based in part on data from the Navy.

Note: The steady-state requirement is the annual purchases or spending needed to keep the amphibious and maritime prepositioning forces 

at the planned level (in the case of Option 2, 32 ships) indefinitely. MPF(F) = Maritime Prepositioning Force (Future).

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

Purchases Under the Navy's Plan

Steady-State

Requirement

Number of Ships Purchased Under Option 2

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

5

6

LHD-8 LPD-17 MPF(F) LSD(X) LHA(R)

Costs Under the

Navy's Plan

Steady-State

Requirement

Shipbuilding Costs Under Option 2

(Billions of 2005 dollars)
40 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 3-6.

Inventory of Amphibious and Maritime Prepositioning Ships Under Option 2

Source: Congressional Budget Office based in part on data from the Navy.

Note: MPS = maritime prepositioning squadron; MPF(F) = Maritime Prepositioning Force (Future).

from 2005 to 2014, $1.3 billion from 2015 to 2024, and 

$1.6 billion from 2025 to 2035. Those averages compare 

well with a steady-state funding requirement of $1.4 billion per year for a 32-ship force.

Because the MPF(F) ships in this option would be built 

to higher survivability standards than the Navy intends, 

they would have a higher price tag than their counterparts in the other options. L-class ships, which are built 

to Level II survivability, cost about $80 million per thousand tons (see Table 3-2). The estimates for lead ships in 

the analysis of alternatives conducted by the Center for 

Naval Analyses—which CBO used for its options—suggest that sea-basing MPF(F) ships would cost about $40 

million per thousand tons. To illustrate what a more survivable version might cost, CBO priced the MPF(F) ships 

in this option at about $60 million per thousand tons. At 

that price, eight ships of that class would cost about $2.2 

billion apiece, on average—comparable with the LHD-8 

and the LHA(R). CBO did not analyze or estimate specific survivability enhancements to the MPF(F) designs 

proposed in the analysis of alternatives. Rather, the higher 

price per ton is intended to illustrate the potential effect 

on the Navy’s budget of addressing concerns about survivability.

CBO cannot show in any measurable way how much 

more survivable these MPF(F) ships would be than the 

less expensive ships purchased under the other options 

and the Navy’s plan. More-survivable ships clearly cost 

more, but not all survivability features of L-class vessels 

could be incorporated into the MPF(F), even if the Navy 

wished to do so. For example, design elements that increase a vessel’s survivability include greater compartmentalization and watertight doors. However, because an 

MPF(F) would need to serve, at least in part, as a floating 

warehouse, it could not easily be designed and built with 

numerous watertight compartments. Nevertheless, the 

combat logistics ships that operate with carrier battle 

groups are built to a Level II survivability standard and 

thus are able to “fight hurt.” CBO envisions that the 

MPF(F) ships in this option will have a greater ability to 

fight hurt, depending on the actual level of damage, than 

their counterparts in any other option or in the Navy’s 

plan.

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD

LPD-17

LHA(R)

MPF(F) Sea-Basing Ships

MPS Cargo Ships

LSD(X)
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 41

Table 3-2.

Estimated Costs of New Amphibious and Maritime Prepositioning Ships

Source: Congressional Budget Office.

a. Rounded to the nearest $100 million.

b. Rounded to the nearest $10 million.

c. Based on the aviation-variant design.

d. CBO’s estimate.

e. Estimate from the Center for Naval Analyses’ analysis of alternatives for the MPF(F) program.

f. Derived from the sea-basing-capable version.

Option 3: Deemphasize Sea Basing 

in Favor of Forward Presence

Under this approach, the Navy would modernize both 

the amphibious warfare force and the maritime prepositioning force but with none of the sea-basing capability 

envisioned in the Navy’s plan. The number of ESGs 

would be cut by one-sixth (from 12 to 10), and the number of maritime prepositioning squadrons would remain 

at three, although they would not be designed for sea basing. Once implemented, this option would provide much 

the same peacetime forward presence and maritime prepositioning capabilities as today’s fleet.

The logic behind this approach is that the Navy’s and 

Marine Corps’s desire to develop a sea-basing capability 

could prove too expensive or difficult (or both) to 

achieve. In the most ambitious vision of sea basing, the 

military would have the ability to launch Operation Iraqi 

Freedom without using Kuwait as a staging area.4 A more 

modest version would involve the ability to deploy two 

reinforced infantry battalions 110 nautical miles from 

their supporting ships. As noted in Chapter 2, that would 

require a large investment in sea-basing-capable MPF(F) 

ships—which, according to the Center for Naval Analyses, would cost two to four times more than a conventional replacement cargo ship. A host of new technologies 

would also be required to make sea basing work, including potentially costly heavy-lift rotary-wing aircraft and 

other ship-to-shore support craft (see Box 1-2 on page 

13). Even if the investments necessary to produce those 

Light-Load

Displacement

(Thousands of tons)

Average Unit Cost

(Billions of dollars)a

Cost per

Thousand Tons 

(Millions of dollars)b

Ships Under Construction

LPD-17 17.0 1.3 80

LHD-8 28.3 2.2 80

Proposed Ships

LHA(R)c 30.5 2.4 80

LSD(X) 15.0d 1.2 80

Maritime Prepositioning Force (Future) 

Replacement-cargo-ship version 

(Navy’s plan and Options 1A, 1B, and 3) 32.0 0.7 20

Sea-basing-capable version (Navy’s plan and

Option 1A) 38.0 1.6e 40e

More-survivable version (Option 2) 38.0 2.2f 60f

4. According to Marine Corps Commandant Michael Hagee, “We 

come into the [Persian] Gulf, we do the arrival and assembly, we 

do the reception, staging, onward movement and integration at 

sea.” Quoted in John T. Bennett, “Marine Corps Commandant, 

DSB Describe Visions of Sea Basing Concept,” Inside the Pentagon, October 30, 2003, p. 1.
42 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

craft were made, it is not clear from current analyses that 

Marine Corps units could be deployed and adequately 

sustained from the sea in a variety of operating environments. In addition, although the likelihood of mounting 

an opposed amphibious assault in the future is unclear, it 

appears limited. 

For all of those reasons, this approach emphasizes the 

peacetime crisis-response capabilities of the Navy and 

Marine Corps rather than their ability to conduct an opposed amphibious assault. The Navy’s amphibious ready 

groups (now expeditionary strike groups) have responded 

frequently to crises around the world. Between 1991 and 

2000, amphibious and (occasionally) maritime prepositioning ships took part in at least 55 operations, ranging 

from wars to various humanitarian operations. Cutting 

the crisis-response capability provided by amphibious 

ships in order to buy the new sea-basing capabilities of 

the MPF(F) may not make sense.5

 The Navy and Marine 

Corps would argue that the new MPF(F) ships would 

also be able to perform crisis-response missions, either 

independently or in conjunction with L-class amphibious 

ships, although that ability would depend on the design 

and operating concept of MPF(F) ships, which are still 

undetermined. Nevertheless, the ships of an expeditionary strike group are more versatile than the proposed seabasing ships, can respond more quickly, and are far better 

equipped to handle unexpected problems or threats. Sacrificing the sea-basing capabilities of maritime prepositioning ships in exchange for a larger L-class force may 

therefore represent a viable alternative to the Navy’s 

approach.

Shipbuilding Under Option 3

This alternative would construct more amphibious and 

maritime prepositioning ships than any of the other options that CBO examined: 1.2 per year between 2005 

and 2035, compared with 1.6 under the Navy’s plan. The 

building rate for L-class vessels would be 0.7 per year, 

which is close to the historical rate of 0.9 ships per year 

that the Navy’s plan would provide.

With respect to specific programs, this option would end 

the LPD-17 program at 10 ships instead of 12. It would 

also delay the start of the LHA(R) program until 2013 

and buy eight rather than 10 of those ships through 2035 

(see Figure 3-7). The LSD(X) program would be delayed 

until 2022 and, as with the LPD-17, only 10 ships would 

be bought instead of 12. The MPF(F) program would include enough ships for three full squadrons, but they 

would be prepositioned cargo ships along the lines of today’s vessels.

This option represents a smaller decline in fleet size relative to the Navy’s plan of 57 ships than any of the other 

options examined in this study. The total expeditionary 

warfare fleet would remain at around 50 ships through 

2013 and then decline to its steady-state level of 45 ships 

in 2023 (see Figure 3-8). That steady-state fleet would 

comprise 30 L-class ships—10 LPDs, 10 LSDs, and 10 

LHA/LHDs (instead of 12 each under the Navy’s plan)—

and 15 conventional maritime prepositioning ships.

Lift Capability Under Option 3

This alternative would result in nearly as much lift capability as the Navy’s plan and about the same as exists today: 5.0 MEBs overall (2.0 MEBs of amphibious lift and 

3.0 MEBs of sealift) compared with the Navy’s planned 

total of 5.5 MEBs overall (2.5 MEBs of amphibious lift, 

2.0 MEBs of sea-based lift, and 1.0 MEB of sealift). Like 

Option 1B, this approach would not provide any seabased lift because it would not procure any ships with 

sea-basing capability.

Costs of Option 3

With respect to average annual costs, this alternative 

would be much less expensive than the Navy’s plan, but 

its costs would be higher than the historical funding level 

for amphibious ships. Between 2005 and 2035, this option would require spending an average of $1.5 billion a 

year to build new amphibious and maritime prepositioning ships. That spending would average $1.4 billion over 

the next 10 years, $1.3 billion from 2015 to 2024, and 

$1.8 billion from 2025 to 2035 (compared with $3.1 billion, $2.3 billion, and $1.8 billion, respectively, under the 

Navy’s plan). With operation and support costs included, 

the Navy would need to spend an average of $4.1 billion 

a year on its expeditionary warfare force under this option 

(see Table 3-1 on page 35).

Effects of the Options 

on the Industrial Base

Any change in production plans for amphibious ships 

would have implications for the industrial base that 

5. See, for example, Jason Ma, “Admiral Touts ESG’s QuickResponse Capability for War on Terror,” Inside the Navy, 

October 11, 2004.
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 43

Figure 3-7.

Annual Purchases and Costs of Amphibious and Maritime Prepositioning Ships 

Under Option 3

Source: Congressional Budget Office based in part on data from the Navy.

Note: The steady-state requirement is the annual purchases or spending needed to keep the amphibious and maritime prepositioning forces 

at the planned level (in the case of Option 3, 45 ships) indefinitely. MPF(F) = Maritime Prepositioning Force (Future).

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

Purchases Under the Navy's Plan

Steady-State

Requirement

Number of Ships Purchased Under Option 3

2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 2031 2033 2035

0

1

2

3

4

5

6

LHD-8 LPD-17 MPF(F) LSD(X) LHA(R)

Costs Under the

Navy's Plan

Steady-State

Requirement

Shipbuilding Costs Under Option 3

(Billions of 2005 dollars)
44 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 3-8.

Inventory of Amphibious and Maritime Prepositioning Ships Under Option 3

Source: Congressional Budget Office based in part on data from the Navy.

Note: MPS = maritime prepositioning squadron.

builds those vessels. Assessing the precise impact over the 

next 10 years is difficult in the absence of data about how 

many man-hours would be needed to build the different 

MPF(F) designs. However, some studies have shown that 

overcapacity exists in the shipbuilding industrial base, in 

that today’s 293-ship Navy could be supported with 

fewer than the six private shipyards that make up that 

base.6

Two shipyards—Bath Iron Works (owned by General 

Dynamics) and Avondale Industries (owned by Northrop 

Grumman)—are capable of building LPD- or LSD-sized 

amphibious ships. However, under a recent agreement 

brokered by the Navy, Bath will not receive any LPD-17 

work; instead, it will build all of the remaining DDG-51 

destroyers, the last three of which were authorized in the 

2005 budget. Bath also anticipates receiving orders for 

the new DD(X) destroyer to provide it with work after 

the DDG-51s are completed. Under current plans, the 

second DD(X) is to be awarded to Bath (the lead ship of 

that class was awarded to Northrop Grumman), but that 

will not happen until 2007 or possibly later, depending 

on the progress of the program. In the case of Avondale 

Industries, reductions in LPD-17 work could lead the 

shipyard to cut its workforce by 2,000 people—and fall 

below the level it considers necessary to maintain its viability—by 2007 unless it receives new orders to take the 

place of the reduced LPD-17 work.

Ingalls Shipbuilding (also owned by Northrop Grumman) argues that the Navy’s plan, which would authorize 

the LHA(R) in 2007, will reduce its workload in 2007 

and 2008 below what it considers viable. Delay or cancellation of the LHA(R) program could prolong that period, 

depending on the final status of other ship programs, particularly the DD(X). 

2005 2010 2015 2020 2025 2030 2035

0

10

20

30

40

50

60

Total Under the Navy's Plan

LPD-4

LSD-41 and LSD-49

LHA/LHD LPD-17

LHA(R)

MPS Cargo Ships

LSD(X)

6. See Industrial College of the Armed Forces, ICAF Industry Studies 

2003: Shipbuilding (Washington, D.C.: National Defense University, 2003), p. 8, available at www.ndu.edu/icaf/industry/IS2003/. 

In addition to the four shipyards mentioned below—Bath Iron 

Works, Avondale Industries, Ingalls Shipbuilding, and National 

Steel and Shipbuilding Company—Electric Boat Corporation 

(owned by General Dynamics) and Newport News Shipbuilding 

(owned by Northrop Grumman) also build Navy vessels.
CHAPTER THREE LOWER-COST ALTERNATIVES TO THE NAVY’S PLAN FOR AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES 45

The MPF(F) could provide additional work to any of 

those shipyards, but the first ship of that class is not 

scheduled to be authorized until 2009, and major production on it would not ramp up until 2010. Moreover, 

none of those yards has built logistics ships for the Navy 

in recent years. National Steel and Shipbuilding Company (owned by General Dynamics) is one of the Navy’s 

traditional suppliers of sealift-type ships and hopes to 

participate in the MPF(F) program. That shipyard currently builds the T-AKE logistics ship, the last of which is 

scheduled to be authorized in 2007. However, it may receive or share in orders for the four T-AOE(X) combat logistics ships planned for 2009 and 2010.

4

Measures of Capability Under the Options

The different approaches to structuring the amphibious warfare and maritime prepositioning forces described 

in Chapter 3 would provide differing capabilities. To 

evaluate how those force structures would compare with 

each other and with the Navy’s plan, the Congressional 

Budget Office used various measures of both peacetime 

and wartime capability:

B The total number of amphibious warfare and maritime prepositioning ships in the Navy;

B The amount of amphibious lift available on L-class 

amphibious warfare ships, measured in terms of five 

traditional components: the number of troops, landing craft, and helicopters that can be carried as well as 

the amount of space for vehicles and cargo;

B The total amount of lift (amphibious lift, sea-based 

lift, and sealift) provided by amphibious warfare and 

maritime prepositioning ships;

B The total number of Joint Strike Fighters carried by 

amphibious assault ships;

B The number of expeditionary strike groups deployed 

in forward areas; and

B The time needed to deploy Marine infantry battalions 

in a hostile environment.

The Navy’s principal mission in peacetime is to maintain 

a combat-credible forward presence. Thus, the most important measure of how well the amphibious force performs during peacetime is arguably the capabilities it provides on-station in three overseas theaters of operations: 

Europe, the Indian Ocean, and East Asia. In wartime, a 

better measure is how much actual combat capability the 

force can bring to bear in a particular period. The measures that CBO chose capture aspects of both the peacetime and wartime missions.

The strength of those measures is that they provide a clear 

picture of the kinds of capabilities that each option sacrifices in order to save money. Relative to today’s capabilities, every alternative examined in this study would reduce forward presence by ESGs and decrease the number 

of Marine battalion landing teams that could be deployed. Those changes would take place fairly gradually: 

for example, under all of the options, the first reduction 

in the number of ESGs would occur in 2012.

The measures of capability used in this analysis have limitations, however. Probably the most important shortcoming is that, if sea basing can be made to work, it will fundamentally alter the way the Navy and Marine Corps 

conduct military operations. Only the last measure—the 

speed with which Marine battalion landing teams can be 

put ashore—captures some of that effect. But none of the 

measures demonstrate the operational maneuverability 

that sea basing would provide to the amphibious forces 

that were equipped for it. The ability to move quickly 

and unpredictably is highly prized by today’s Navy and 

Marine Corps leadership. Unfortunately, CBO could not 

find an effective way to quantify that ability.

Number of Amphibious Warfare and 

Maritime Prepositioning Ships

The total inventory of amphibious warfare and maritime 

prepositioning ships under the Navy’s plan and the four 

alternatives that CBO examined measures the overall capacity of the force. (In no situation, however, would the 

entire force ever be available to deploy to a conflict, because at any one time some ships would be undergoing 

long-term maintenance and some units would be in 

training.)

CHAPTER
48 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 4-1.

Total Number of Amphibious and Maritime Prepositioning Ships

Under Alternative Force Structures

Source: Congressional Budget Office based in part on data from the Navy.

As with all of the measures used here, the Navy’s plan 

would provide the largest number of amphibious warfare 

and maritime prepositioning ships: 57 by 2035 (see Figure 4-1). The less expensive alternatives would provide 

substantially fewer ships. Of those alternatives, Option 3 

would produce the largest force, with 45 ships, followed 

by Option 1B, with 39 ships, because they would not buy 

the more expensive sea-basing maritime prepositioning 

ships. Options 1A and 2, which would invest in seabasing capabilities, would result in much smaller forces: 

31 and 32 ships, respectively. However, those two options 

differ in the speed with which they would reduce the 

force. Option 1A draws down the force less quickly than 

Option 2 does, so it results in more ships between 2016 

and 2034 (even though it ends up with fewer ships than 

Option 2 by the end of CBO’s projection period).

Amount of Amphibious Lift 

on L-Class Ships 

As noted in Chapter 1, for decades the traditional measure of capability for the amphibious force was its ability 

to carry Marine expeditionary brigades or some equivalent unit. Amphibious-lift capability is measured by five 

components: the amount of cargo space (called cargo 

cube) available; the number of troops that can be transported; the amount of space for vehicles such as tanks and 

trucks (referred to as vehicle square); the number of spots 

for carrying rotary-wing aircraft (expressed as CH-46 

helicopter equivalents); and the number of spots for carrying air-cushion landing craft (or LCACs). 

Since the early 1990s, the Marine Corps’s official requirement for lift has been 3.0 Marine expeditionary brigades. 

The Navy has been unable to afford enough amphibious 

ships to provide that amount of lift, so it has adopted the 

“fiscally constrained” goal of 2.5 MEBs. However, actual 

amphibious-lift capacity is measured by the smallest component. Today, the amphibious force has enough vehicle 

square for only 1.9 MEBs (although it has excess capacity 

in the other components of amphibious lift), so that 

number is the current capability. It is set to rise to 2.1 

MEBs by the end of 2005 with the arrival of the first 

LPD-17 class ship. Under the Navy’s plan, amphibiouslift capability would grow to nearly 2.5 MEBs by 2025 

and remain there through 2035 (see Figure 4-2).

2005 2010 2015 2020 2025 2030 2035

0

30

40

50

60

Navy's Plan

Option 3

Option 1B

Option 1A

Option 2
CHAPTER FOUR MEASURES OF CAPABILITY UNDER THE OPTIONS 49

Figure 4-2.

Components of Amphibious Lift on L-Class Ships Under Alternative Force

Structures

(Marine expeditionary brigade equivalents)

Source: Congressional Budget Office based in part on data from the Navy.

Note: The five components of amphibious lift are the number of troops a ship can carry; its vehicle storage area, measured in thousands of 

square feet (or vehicle square); its cargo storage area, measured in thousands of cubic feet (or cargo cube); the number of spots for 

parking vertical takeoff and landing aircraft (expressed as CH-46 helicopter equivalents); and the number of spots for air-cushion landing craft (known as LCACs).

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Cargo Cube

Helicopter Spots LCAC Spots

Troops

Vehicle Square

Navy's Plan

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Cargo Cube

LCAC Spots Helicopter Spots

Troops

Vehicle Square

Option 1A

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Cargo Cube

LCAC Spots Helicopter Spots

Troops

Vehicle Square

Option 1B

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Cargo Cube

LCAC Spots

Helicopter Spots Troops

Vehicle Square

Option 2

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Cargo Cube

LCAC Spots

Helicopter Spots

Troops

Vehicle Square

Option 3
50 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

All of the alternative approaches in this study would result in less amphibious lift than the Navy’s plan would. 

Option 1A would produce the greatest decline because it 

would cut the number of L-class vessels the most. By 

2035, it would provide only enough amphibious lift for 

1.3 MEBs. By contrast, Option 3, which would sacrifice 

sea-basing capability to maintain a larger L-class force, 

would provide enough amphibious lift for 2.0 MEBs—

only slightly more than the amount available today. Options 1B and 2 would provide lift for 1.8 and 1.7 MEBs, 

respectively.

As is the case today, vehicle square would be the limiting 

component of amphibious lift under all four of the options for most of the period covered by this analysis. 

Troop space would also be in relatively short supply by 

2035. (Figure 4-3 provides more detail about how the 

Navy’s plan and the alternatives in this study compare in 

terms of those two key components.)

Total Amount of Lift on 

Amphibious Warfare and 

Maritime Prepositioning Ships

Amphibious lift is only one aspect of transporting and 

sustaining Marine Corps units in naval expeditionary operations. A broader measure of capability is the total lift 

for troops and equipment provided by the amphibious 

warfare and maritime prepositioning forces. Currently, 

that total is 4.9 MEBs—1.9 on amphibious warfare ships 

and 3.0 on conventional maritime prepositioning ships—

although the Navy’s goal is a total lift capacity of 5.5 

MEBs. By introducing sea basing, the Navy’s plan would 

achieve that goal but would change its composition—to 

2.5 MEBs of lift on L-class ships, 2.0 MEBs on new seabasing maritime prepositioning ships, and 1.0 MEB on 

conventional cargo ships similar to the maritime prepositioning vessels in the fleet today.

Of the alternatives examined in this study, Option 3 

would provide the largest amount of lift: 5.0 MEBs in 

2035 (see Figure 4-4)—less than under the Navy’s plan 

but more than exists now. That higher capacity results because Option 3 would retain the largest number of conventional maritime prepositioning ships and forgo the 

Navy’s and Marine Corps’s sea-basing initiative. At the 

other end of the scale, Option 2 would provide the least 

amount of total lift—2.7 MEBs by 2035—because the 

goal of procuring more-survivable sea-basing maritime 

prepositioning ships would come at the expense of a 

larger overall lift force. Options 1A and 1B would provide 3.3 MEBs and 4.4 MEBs, respectively, by 2035, 

while keeping the amount spent on procuring the new 

ships that provide that lift at the historical funding level.

Number of JSFs Carried on Large 

Amphibious Assault Ships

Comparing the number of Joint Strike Fighters that the 

Navy’s amphibious assault ships can carry highlights the 

importance of that aircraft, in the eyes of many Marine 

Corps officials, for future amphibious operations. The 

JSF is designed to have the range and payload to provide 

close air support to distant Marine operations ashore. 

The more JSFs available on amphibious ships, the better 

able the force will be to perform the close-air-support 

mission. 

The JSF’s importance is also reflected in the Navy’s decision to design the new LHA(R) amphibious assault ship 

to support more flight operations by such aircraft. The 

first LHA(R)—what is being called Flight 0—is being designed to carry 23 JSFs. The Navy hopes that future versions of the ship—Flight 1—will carry up to 30 of those 

fighters. (For the purposes of this analysis, however, CBO 

assumed that all subsequent LHA(R)s would carry the 

same number of JSFs as the first one.) In addition, the 

Navy expects existing LHA and LHD class amphibious 

assault ships to carry 20 JSFs when the ships are configured in a carrier role. As a result, the Navy’s plan would 

produce an amphibious assault fleet capable of carrying a 

total of 264 JSFs by 2035.

Of the alternatives, Option 3 would come closest to the 

Navy’s plan because it would retain the largest number of 

big amphibious assault ships. By 2035, that option would 

provide the capacity to carry 218 Joint Strike Fighters, 

followed by Option 1B with 195, Option 2 with 172, 

and Option 1A with 126 (see Figure 4-5).

Number of Forward-Deployed 

Expeditionary Strike Groups

Although amphibious-lift capacity has long been the traditional measure of capability for the Navy’s amphibious 

forces, the amount of forward presence provided by expeditionary strike groups has grown in importance. Amphibious ships are often called on to respond to smallscale crises around the globe. For example, they are the 
CHAPTER FOUR MEASURES OF CAPABILITY UNDER THE OPTIONS 51

Figure 4-3.

Lift Capacity for Troops and Vehicles on L-Class Ships 

Under Alternative Force Structures

(Marine expeditionary brigade equivalents)

Source: Congressional Budget Office based in part on data from the Navy.

Note: Vehicle square is vehicle storage area measured in thousands of square feet.

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

Option 2

Option 1A

Option 1B Option 3

Navy's Plan

Vehicle Square

2005 2010 2015 2020 2025 2030 2035

0.0

1.0

1.5

2.0

2.5

3.0

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan

Troops
52 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 4-4.

Total Lift Provided by the Amphibious and Maritime Prepositioning Forces 

Under Alternative Force Structures

(Marine expeditionary brigade equivalents)

Source: Congressional Budget Office based in part on data from the Navy.

Note: Total lift comprises amphibious lift on L-class ships, sea-based lift on sea-basing-capable Maritime Prepositioning Force (Future) 

ships, and sealift on conventional maritime prepositioning ships.

military’s tool of choice for evacuating U.S. personnel 

from a country or providing humanitarian aid because 

the Marine Corps units on those ships have the skills and 

equipment to transport goods and people between ship 

and shore. In many cases, amphibious ships do not operate together when they are forward deployed. A group of 

three amphibious ships will often split up to cover two or 

three locations and thereby extend those ships’ unique capabilities to a broader area.

Under current practices for crewing, maintenance, and 

training, an average of about 2.7 ESGs are forward 

deployed at any given time out of the 12 in the fleet. 

Recently, senior Navy leaders, including Chief of Naval 

Operations Vern Clark, have suggested that the Navy experiment with rotating crews and marines to forwarddeployed amphibious ships (rather than having a ship 

and its crew and marines return home between deployments) in order to provide more presence with fewer 

ships. A similar policy, called Sea Swap, is being used on 

some types of surface combatants. The Navy has found 

that Sea Swap allows Arleigh Burke class destroyers to 

provide about 35 percent more presence than ships of the 

same class not using crew rotation. If the Navy achieved 

the same results with ESGs and maintained 12 such 

groups, it could keep an average of 3.6 ESGs forward deployed. (As a practical matter, however, Admiral Clark 

has indicated that he hopes the use of crew rotation will 

allow the Navy to reduce the size of the amphibious force 

and still maintain roughly the current level of overseas 

presence.)

With current operating practices, the Navy’s plan would 

provide the highest level of forward presence by ESGs 

(see Figure 4-6). Because all four options would cut the 

number of ESGs, they would provide less overseas coverage. Option 3 would put an average of 2.4 ESGs onstation by 2035—slightly less than under the Navy’s 

plan—and Option 1B would provide 2.2 ESGs. Option 

2, which, with respect to L-class vessels, is consistent with 

proposals to reduce the amphibious force to eight expedi2005 2010 2015 2020 2025 2030 2035

0.0

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan
CHAPTER FOUR MEASURES OF CAPABILITY UNDER THE OPTIONS 53

Figure 4-5.

Total Number of Joint Strike Fighters Carried by Amphibious Ships

Under Alternative Force Structures

Source: Congressional Budget Office based in part on data from the Navy.

tionary strike groups, would keep 2.1 ESGs forward deployed, on average. Option 1A would keep only 1.8 

ESGs on-station because it would make the deepest cuts 

to the L-class force.

If the Navy could successfully rotate crews to amphibious 

ships, along the lines of Sea Swap, that picture would be 

brighter. Three of the alternatives would provide more 

forward presence than today’s larger amphibious force, 

which does not yet employ rotating crews. By 2035, Option 3 would keep an average of 3.2 ESGs forward deployed, followed by Option 1B with 3.0 ESGs and Option 2 (which maintains a total of eight strike groups) 

with 2.8 ESGs. Only Option 1A would provide less than 

the current level of forward presence, with an average of 

2.4 ESGs forward deployed at any one time.

Time Needed to Deploy Marine

Infantry Battalions to a Conflict

The Navy and Marine Corps use the speed with which 

Marine battalion landing teams can be put ashore in a 

hostile environment—more than any other measure—to 

demonstrate the potential effect of sea basing. Today, 

with a total force structure of 12 expeditionary strike 

groups and three maritime prepositioning squadrons, the 

Navy believes it could insert 15 Marine infantry battalions into a theater of operations within 10 weeks (see the 

top panel of Figure 4-7). That estimate assumes that no 

land base on friendly territory would be available in the 

theater; instead, the marines on L-class ships would have 

to seize a beachhead and secure it before the battalions 

supported by the maritime prepositioning squadrons 

could be assembled and begin operating. The first battalions to arrive would come from the two ESGs that would 

be forward deployed at any given time. Another four battalions would come from amphibious ships surged from 

bases in the United States and would start operating by 

the fifth week. The nine battalions supported by the maritime prepositioning squadrons could begin operating (a 

few battalions at a time) in weeks eight, nine, and 10.

According to the Navy and Marine Corps, sea basing 

would accelerate that process by at least three weeks. 

With a force structure of 12 ESGs (including 36 am2005 2010 2015 2020 2025 2030 2035

0

100

120

140

160

180

200

220

240

260

280

300

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan
54 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

Figure 4-6.

Average Number of Expeditionary Strike Groups Forward Deployed

Under Alternative Force Structures

Source: Congressional Budget Office based in part on data from the Navy.

Note: Sea Swap is the Navy’s plan to rotate crews every six months to forward-deployed ships in order to increase the amount of forward 

presence they provide.

2005 2010 2015 2020 2025 2030 2035

0.0

1.5

2.0

2.5

3.0

3.5

4.0

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan

With Current Crewing

2005 2010 2015 2020 2025 2030 2035

0.0

1.5

2.0

2.5

3.0

3.5

4.0

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan

With Sea-Swap Crew Rotation
CHAPTER FOUR MEASURES OF CAPABILITY UNDER THE OPTIONS 55

Figure 4-7.

Time Needed to Deploy Marine Infantry Battalions in a Hostile Environment 

Under the Navy’s Plan

(Number of battalions)

Source: Congressional Budget Office based on data from the Navy.

Notes: Under the current timeline, the amphibious assault would begin in week 5 or 6. Under sea basing, operations could begin as early as 

week 2. MPF(F) = Maritime Prepositioning Force (Future).

1 2 3 4 5 6 7 8 9 10

0

2

4

6

8

10

12

14

16

Current Timeline

Weeks

1 2 3 4 5 6 7 8 9 10

0

2

4

6

8

10

12

14

16

Expeditionary Strike Groups

Sea-Basing MPF(F) Ships

Surged Amphibious Ships

Conventional Maritime Prepositioning Ships

Timeline in 2035 with Sea Basing

Weeks

Sources of Battalions:
56 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

phibious ships), two squadrons of sea-basing-capable 

MPF(F)s, and one squadron of conventional maritime 

prepositioning ships, the time needed to get 12 battalions 

deployed would drop from nine weeks to six weeks under 

the Navy’s plan (see the bottom panel of Figure 4-7).

Put another way, sea basing would allow twice as many 

Marine infantry battalions to be in place by week six 

(12 battalions instead of six) as would be the case today, 

the Navy and Marine Corps say. Four of those battalions 

would be deployed by the second week: one from the first 

forward-deployed ESG to arrive and three from the first 

MPF(F) squadron to arrive. By the fourth week, four 

more battalions would be deployed, one from a second 

forward-deployed ESG and three from the second 

MPF(F) squadron. As would be the case today, additional 

battalions arriving on amphibious ships from the United 

States would deploy by the fifth week. Finally, by week 

10, the three battalions supported by the conventional 

maritime prepositioning squadron would deploy. Thus, 

the Navy and Marine Corps would have the same total 

number of battalions operating after 10 weeks as they 

would today, but the bulk of those units would enter the 

conflict more quickly.

All of the alternative force structures analyzed in this 

study, because they would be smaller and less capable 

than the Navy’s planned force, would deploy fewer battalions, sometimes less quickly, in 2025 or 2035 (see Figure 

4-8). CBO compared the results for both years because 

the alternatives vary in the pace at which they would reduce the number of amphibious ships over time. In 2025, 

Options 1B and 3 would deploy fewer Marine infantry 

battalions to a conflict through week seven than the other 

alternatives or the Navy’s plan because they lack seabasing-capable MPF(F) squadrons. After that, however, 

they would deploy more battalions than Options 1A and 

2 because of their larger conventional maritime prepositioning forces. (Option 1B diverges from Option 3 

after week nine because it has one fewer Marine infantry 

battalion to deploy.)

The same general pattern would hold true in 2035. Options 1A and 2 would get four Marine infantry battalions 

into the conflict by the second week, compared with only 

one battalion under Options 1B and 3. By week 10, however, Option 3 would deploy more battalions than any 

other option—a total of 14, compared with 12 for Option 1B, nine for Option 1A, and only seven for Option 

2. However, this measure does not capture the investment 

in survivability that Option 2 would explicitly make. 

Theoretically, its single MPF(F) squadron would be better able to sustain operations in the event that antiship 

threats had not been completely eliminated from the 

theater of operations.

Implications of the Analysis

The central conclusion of CBO’s analysis is that with respect to amphibious warfare and maritime prepositioning 

forces, less money spent on the force structure will mean 

less overall capability than exists today.1

 CBO found no 

alternative that would allow the Navy and Marine Corps 

to have substantially more overall capability than the current fleet but at a price significantly below what the Navy 

plans to spend on its amphibious forces.

Some important questions for the Congress (which CBO 

did not attempt to answer) arise from this analysis. Are 

the strategic, operational, and tactical benefits of sea basing worth their monetary cost? And if procuring those 

benefits means reducing the number of L-class amphibious ships, are they worth the loss of other capabilities? 

For example, the Chief of Naval Operations has stated 

that he considers speed one of the most important—if 

not the most important—criterion for determining what 

capabilities the Navy should procure. If a given capability 

allows the Navy to bring force to bear in a conflict faster 

than it can today, he favors investing in it rather than in 

programs that do not further that aim. Is the ability to 

advance the timeline of Marine amphibious operations 

by several weeks worth the many billions of dollars that a 

sea-basing capability will require or worth a cut of onethird in the number of expeditionary strike groups—a 

trade-off that senior Navy leaders are explicitly considering? Are the freedom of action and operational flexibility 

that might be gained with sea basing worth those costs? 

(As stated at the beginning of this chapter, CBO’s measures of capability cannot capture the value of independent action or operational flexibility.)

The four options described in this study represent ways to 

defer significant increases in spending on amphibious 

1. By contrast, CBO’s analysis of the surface combatant force found 

that several alternatives costing less than the Navy’s plan would 

leave the force larger and more capable than the current fleet of 

surface combatants. See Congressional Budget Office, Transforming the Navy’s Surface Combatant Force (March 2003).
CHAPTER FOUR MEASURES OF CAPABILITY UNDER THE OPTIONS 57

Figure 4-8.

Time Needed to Deploy Marine Infantry Battalions in a Hostile Environment 

Under Alternative Force Structures

(Number of battalions)

Source: Congressional Budget Office based in part on data from the Navy.

1 2 3 4 5 6 7 8 9 10

0

2

4

6

8

10

12

14

16

Option 2

Option 1A

Option 3 Option 1B

Navy's Plan

Timeline in 2025

Weeks

1 2 3 4 5 6 7 8 9 10

0

2

4

6

8

10

12

14

16

Option 2

Option 1A

Option 1B

Option 3

Navy's Plan

Timeline in 2035

Weeks
58 THE FUTURE OF THE NAVY’S AMPHIBIOUS AND MARITIME PREPOSITIONING FORCES

forces for the next 30 years. In the meantime, the Navy 

could use the money not devoted to amphibious or maritime prepositioning ships to pay for other transformational efforts, ship programs, or needs. However, deferring that spending would have significant consequences 

for the size and composition of amphibious forces. 

Whether the Navy should make that trade-off is a matter 

for defense officials and lawmakers to decide.