Expeditionary advanced base operations (EABO) have changed the Marine Corps’ amphibious shipping requirements. The service has stated it needs at least 31 “L-class” ships to support current obligations. It also needs between 18 and 35 of a new class of ships, the medium landing ship (LSM), formerly the light amphibious warship, to support EABO.1
There is a good chance the Marine Corps will get neither the amphibious transport docks (LPDs) nor LSMs in the numbers it needs, leaving it unable to conduct traditional expeditionary operations or deploy distributed forces. The Navy needs to stop buying LPDs and LSMs. Instead, it needs more of the already fielded expeditionary transfer dock (ESD) and expeditionary sea base (ESB) ships.
The LSM is Ill Suited for Its Mission
The second edition of the Tentative Manual for EABO states, “Littoral maneuver will rely heavily on surface platforms such as the Medium Landing Ship. . . . The range, endurance, and austere access of LSMs enable the littoral force to deliver personnel, equipment, and sustainment across a widely distributed area.”2
An LSM survives by hiding in plain sight among commercial shipping.3 It might be seen but not recognized as a warship, receiving little attention, especially during peacetime or gray zone operations. But once the enemy identifies the LSM, he can follow it and know where the Marines it carries have been inserted.
Any ship of sufficient capacity can position forces before a conflict. The difficulty comes once hostilities start. Then, successful operations require self-defense capability beyond crew-served weapons. As small ships based on commercial designs, LSMs have neither sufficient defenses nor the excess size, weight, and power to add adequate protection.
An LSM will probably travel at around 15 knots with a range of 3,500 nautical miles (nm).4 Depending on start point and destination, an LSM could need to refuel while inside China’s weapons engagement zone. Underway replenishment exposes fleet oilers and other support ships to increased risk. Likewise, using fuel from commercial or other sources ashore puts an LSM at the mercy of partners, some of whom may not be resolute in the face of Chinese intimidation.
A single LSM is expected to cost roughly $150 million.5 While cheaper than the alternatives, it does far less, less well.
LPDs Are Unaffordable
In addition to the LSM, the Marine Corps wants at least one more LPD every other year, starting in fiscal year 2024.6 The San Antonio class are capable amphibious ships. Their well deck can launch amphibious combat vehicles (ACVs), landing craft air cushion (LCACs), ship-to-shore connectors (SSCs), and landing craft utility (LCUs). They have a robust aviation capability, with up to four deck spots and a hangar for rotorcraft.
For survivability, LPDs incorporate the SeaRAM (rolling airframe missile) close-in weapon system (CIWS) and can be equipped with the Evolved Seasparrow Missile (ESSM). The ships have naval damage control features integrated into the design. All that goes a long way toward explaining the LPD’s nearly $2 billion unit price.7
Still, an LPD would be hard-pressed to survive in a high-intensity conflict unescorted by surface combatants. Unlike a commercially derived design, it cannot hope to hide among commercial shipping.
Marine Corps leaders advocate for more LPDs based on their ability to support contingency and crisis response operations, such as humanitarian assistance and disaster relief, often performed by Marine expeditionary units. But few of these missions require specialized naval vessels, only the ability to deploy Marines and materiel.
The LPD is caught in between: too much ship for most missions; too light to survive the most demanding without escort; and too expensive to buy in sufficient quantities.
The Solution Already Exists
The Navy’s expeditionary transport dock ships and expeditionary sea bases could replace LSMs in EABO while reducing the need for additional LPDs for contingency operations. They could accomplish this with lower programmatic risk, lower cost, and greater versatility than LSMs and LPDs.
Current ESDs and ESBs are derivatives of the Alaska-class commercial tanker, manufactured by General Dynamics NASSCO. Both are 785 feet long with beams of 164 feet, displacing up to 78,000 and 90,000 tons, respectively.8 They travel as fast as an LSM at 15 knots but have considerably greater range—9,500 nm.9
There are two ESDs currently in the fleet, albeit in reduced operating status. They use a semisubmersible midship section to support float-on, float-off operations for three LCACs, although they have sufficient capacity to support many other types of watercraft and amphibious vehicles. The ESD has 25,000 square feet of vehicle/cargo stowage and 380,000 gallons of fuel capacity.10 Though they are built primarily to conduct at-sea transfer from roll-on/roll-off maritime prepositioning ships to LCACs and SSCs, a portion of their cargo stowage could be repurposed for Marine berthing.
The ESB has similar provisions to the ESD, but, instead of accommodations for LCACs, incorporates a flight deck with four spots able to accommodate large rotorcraft, such as CH-53s or V-22s, plus deck storage for two more and a maintenance hangar. The ships have a mission deck from which its crane can lift cargo to the flight deck or lower it to the waterline. It has 250 berthing spaces for mission personnel (beyond ship’s company) and could carry more by adding supplemental berthing in the cargo spaces or mission deck.11
Like the LSM, ESDs and ESBs are derivatives of a commercial design. But size matters—these ships’ large displacement provides inherent resiliency against damage, with a bigger crew for damage control. In addition, the Alaska class has a double hull, originally meant to hold oil but also helpful in keeping projectiles and water out. The ESB also incorporates the N-30 fire-protection system. While not equal to the survivability measures of a ship built from the keel up for naval service, the ESD and ESB are hardly sitting ducks.
In addition, the 70,000-plus ton ESBs and ESDs have a lot more space, weight, and power trade space than the 4,000-ton LSM or even the 25,000-ton San Antonio class. They have excess capacity to add defensive weapons, sensors, and other systems, whether integrated into the ship or strapped onto the deck.
Added systems could include CIWS, SeaRAM, and ESSM. The ESB’s large flight deck and ESD’s semisubmersible deck also offer space for defensive weapons to be employed on an ad hoc basis. For example, embarked Marine low-altitude air-defense elements could use their Medium Air Defense Integrated System and Medium Range Intercept Capability antiair systems from the ships’ decks.
More Range Equals More Options
The 9,500 nm range of the ESD and ESB allows them to deploy unrefueled from the continental United States to the second and first island chains. This also would allow rapid response to crises in other theaters.
These ships even have the capacity to transport 380,000 gallons of JP-5 fuel, so they could help fill EABs ashore and fuel bunkers afloat, mitigating some of the daunting fuel resupply problems for EABO.
In peacetime or gray zone operations, an ESD or ESB could transit largely unnoticed in sea lanes among similar commercial shipping. Unlike the LSM, neither the ESD nor ESB needs to beach to deploy Marines.
Instead, the ESD can deploy Marines ashore via LCAC or sea-shore connector at ranges greater than 200 nm. If equipped with LCUs, which originally were proposed for integration on the ESD, that range could extend to more than 1,000 nm.12 All can carry the personnel and vehicles necessary for a reinforced platoon with the Navy/Marine Corps Expeditionary Ship Interdiction System (NMESIS) or similar launchers. Surface transport gives the ESD the ability to land larger launchers for weapons such as ground-launched Tomahawks, Standard Missiles, and future systems.
The ESB can support an aviation detachment of up to six large rotorcraft. A mix of CH-53Ks and MV-22Bs could deliver vehicles and personnel associated with a reinforced platoon from a Marine littoral regiment (MLR) with Naval Strike Missile (NSM) capability at range.
Both the ESD and ESB can deploy small surface craft, such as rigid-hull inflatable boats (RHIBs) and unmanned surface vessels (USVs), allowing either ship to seed the battlespace with reconnaissance/counterreconnaissance teams and sensors.
Whether by sea or by air, either of these ships could access thousands of potential landing sites in the Indonesian or Philippine archipelagos. Even if the enemy spotted the ships, a deception plan with multiple feints and false insertions would make locating the actual positions of Marines ashore challenging.
Specialized Ships Are Unaffordable
The “Gator Navy” has never been a top priority for the Navy writ large. Even capable ships such as LPDs are not prioritized for acquisition or sustainment. The program viability of LSMs, like that of other small, specialized ships, would likely resemble the Avenger-class mine-countermeasure (MCM) ships and Cyclone-class patrol boats—championed at first, then bought in small quantities, and eventually shunted aside.
In many ways, ESDs and ESBs are more versatile than LPDs and LSMs, able to perform a wide range of additional missions. For example, the ESB already has demonstrated MCM and special operations support missions operationally.
With cranes, mission and flight decks, and a submersible deck, ESDs can deploy an array of unmanned aerial systems (UASs), unmanned underwater vessels (UUVs), and USVs. General Dynamics has proposed additional modifications to enhance these capabilities, including adding a UUV deployment system below the ESB’s waterline and dedicated UAS pads on their fantails.13
There are ample opportunities for novel employment of offensive weapons from both ships. Weapons such as the High Mobility Artillery Rocket System already have been fired from ship decks.14 The same launcher can also fire the longer-range Army Tactical Missile System.
While study is necessary, the NSM likely could be fired from embarked vehicles. The ships also could employ many containerized weapons, ranging from NSMs and High Speed Antiradiation Missiles to Valkyrie UASs.15,16
The versatility of ESDs and ESBs offers incredible value for both the Marine Corps and the Navy. These ships have immense capacity to embark personnel and equipment to support EABO. They have an organic capability to support surface and air insertion at vast distances. They both can support multiple modes of reconnaissance and counterreconnaissance. With the right packages on board, they could even be formidable strike platforms. Cumulatively, these capabilities present a significant dilemma for the enemy.
For example, an ESB could steam from Hawaii into the first island chain loaded with two reinforced platoons of Marines armed with NMESIS and their supporting reconnaissance detachments. Its MV-22Bs could patrol well ahead of the ship’s advance, dropping sonobuoys and other sensors, including expendable UASs, to protect the ship and assist in the intelligence preparation of the battlefield.
While still more than a day’s steaming from the intended sites for the NMESIS, MV-22s could insert reconnaissance elements to assess locations. Later, after multiple false insertions, the CH-53Ks could deploy Marines and their vehicles from ranges of 100 nm or more.
Turning back toward friendly lines, the ESB might transfer much of its remaining JP-5 to a larger expeditionary advanced base enroute to Guam. Once in port, the ship could offload its CH-53Ks to free deck space for multiple containerized weapons.
The ESB could retain its MV-22Bs, outfitting them to launch air-to-surface missiles via parachute deployment. USVs and UUVs could be loaded on the ESB’s mission deck, with an assortment of strike and sensor packages. Navy SEALs might be embarked along with their boats. Finally, the ESB could reload fuel to help slake the thirst of other aircraft and ships operating near the first island chain.
This ability to reconfigure for every stage of competition and conflict—from deterrence and competition to combat operations—distinguishes the ESB and ESD from the LSM and, to some extent, the LPD.
Build a Different Fleet
The current acquisition strategy for amphibious ships will result in inadequate numbers of both L-class ships and medium landing ships. ESDs and ESBs, on the other hand, would provide off-the-shelf solutions the Navy and Marine Corps need.
Ten additional ESBs and ESDs should replace the desired additional San Antonio–class LPDs and the 35 LSMs. The first two are simple—return the USNS John Glenn (ESD-2) and Montford Point (ESD-1) to active status.17 Then add two more ESDs and eight ESBs on top of the six currently slated. That mix of 4 ESDs and 14 ESBs would allow continuous ESB coverage in support of Marine expeditionary units and contingency operations in addition to EABO support. ESDs would support maritime prepositioning in the Pacific to support EABO and the transport of large weapon systems.
If all surged toward the Pacific, with two reinforced platoons on board each, that would be up to 36 units of missile shooters—greater than what could be carried by a fleet of 35 LSMs. Ten ESDs/ESBs at $550 million save roughly $1.65 billion compared with 35 LSMs at $150 million each and one LPD at $1.9 billion.18 Those savings could be invested to enhance the ships’ mission packages and survivability or toward other service priorities.
Building more ESDs and ESBs would provide a more capable and versatile fleet, more quickly and at lower risk and cost than acquiring LSMs and L-class amphibs. In an unstable world with even less Department of Defense budget stability, that is a far more prudent use of taxpayer dollars.
1. Sam LaGrone, “House Bill Backs Marines’ 31-ship Requirement, Over Navy’s 25-ship Level,” USNI News, 10 May 2022.
2. Tentative Manual for Expeditionary Advanced Base Operations, Second Edition (Washington, DC: Headquarters, U.S. Marine Corps) May 2023.
3. Jane Edwards, “Lt. Gen. Karsten Heckl on Light Amphibious Warship Program,” ExecutiveGov, 6 October 2022.
4. Congressional Research Service, “Landing Ship Medium (LSM) (formerly Light Amphibious Warship [LAW]), Background and Issues for Congress,” 7 August 2023.
5. Congressional Research Service. “Landing Ship Medium.”
6. Mallory Shelbourne, “FY2024 Budget: Navy Won’t Buy Any More San Antonio Amphibs in the Next Five Years,” USNI News, 9 March 2023.
7. Mallory Shelbourne, “Navy and Marine Debate Amphibious Ship Costs as Clash Over LPD-17 Flight II Line Continues,” USNI News, 16 March 2023.
8. “Expeditionary Transfer Dock (ESD)/Expeditionary Mobile Base (ESB) Fact Sheet,” Naval Sea Systems Command.
9. “Expeditionary Sea Base Selected Acquisition Report 2021,” Department of the Navy, 31 December 2021.
10. “Expeditionary Sea Base Selected Acquisition Report 2021.”
11. CAPT Daryl Cardone, CDR Ben Coyle, and LCDR Daniel Murphy, USN, “Assessing the Expeditionary Sea Base,” U.S. Naval Institute Proceedings 148, no. 1 (January 2023).
12. “The U.S. Navy’s Mobile Landing Platform Ships,” Defense Industry Daily, 10 February 2015.
13. Aaron-Matthew Lariosa, “NASSCO Pitches ESB Mothership to US Navy,” Naval News, 16 January 2023.
14. Gidget Fuentes, “Marines Fire HIMARS From Ship in Sea Control Experiment With Navy,” USNI News, 24 October 2017.
15. Tyler Rogoway, “Northrop Grumman Shows Off Shipping Container-Launched Anti-Radiation Missile Concept,” The Warzone, 8 October 2018.
16. Joseph Trevithick, “This Containerized Launcher for the XQ-58A Valkyrie Combat Drone Could be a Game Changer,” The Warzone, 16 October 2019.
17. The Navy’s FY2025 budget request proposes to retire the USNS John Glenn (ESD-2). See Mallory Shelbourne, “New Navy Budget Seeks 6 Battle Force Ships, Decommissions 19 Hulls in FY 2025,” USNI News, 11 March 2024.
18. “Expeditionary Sea Base Selected Acquisition Report 2021.”