Amphibious Operations in a Brave New World
Editor’s Note: This article is adapted from a new report published by the Center for Strategic and Budgetary Assessments entitled Advancing Beyond the Beach: Amphibious Operations in an Era of Precision Warfare.
Last month, Houthi rebels in Yemen twice fired anti-ship cruise missiles (ASCMs) at the guided-missile destroyer USS Mason, forcing the ship to take defensive measures. In September, the same rebel group attacked a former U.S. high-speed vessel, burning it to the waterline. These events highlight the ease with which potential adversaries, including stateless terrorists, can obtain and use capable long-range weapons. In the words of Vice Adm. Joseph Mulloy, deputy chief of naval operations for the integration of capabilities and resources, “in the next few years, everywhere the Navy goes, if you’re not in a submarine, you better watch out because every…country will be able to launch high-speed missiles at you.”
Traditional amphibious operations will be particularly vulnerable to ASCMs and surface-to-air missiles (SAMs) that can reach hundreds of miles away. A large assault like Iwo Jima or Guadalcanal would involve capital ships operating close to hostile shores for hours to offload Marines and their equipment using helicopters, short-range armored vehicles, and unprotected hovercraft and boats. These kinds of large-scale operations will likely not be viable in future conflicts.
Moreover, big amphibious assaults may not be necessary in the future, thanks to the same precision weapons technologies. Much smaller ground units and capabilities dispersed over wide areas can themselves use surface-to-air missiles (SAMs), ASCMs, and other weapons to achieve outsized effects. This increases the importance of amphibious raids against enemy weapons installations and the value of small expeditionary bases for U.S. forces to employ SAMs and ASCMs to contest the enemy’s access and constrain its options.
Over the last two decades, the Marine Corps and Navy acquired a slew of new platforms to improve their amphibious capabilities in recognition of these trends. The Corps introduced both the MV-22 Osprey tilt-rotor aircraft and the F-35B Joint Strike Fighter (JSF), while the Navy commissioned new classes of small-deck and big-deck amphibious ships.
Despite these new acquisitions, U.S. naval forces today remain unable to execute amphibious operations in contested environments, since they lack the defensive capacity to protect themselves against the large number of adversary weapons they would likely face as they close on an enemy’s shores. Amphibious forces will also have difficulty reducing their vulnerability by conducting landings from farther away because almost all Marine equipment is too heavy to be lifted by helicopters, and current surface connectors such as landing craft and hovercraft cannot safely conduct a transit long enough to grant amphibious ships the range they need. Although troops could be moved longer distances by air for small raids, the six F-35Bs in a Marine Expeditionary Unit (MEU) will be too few to provide enough long-range fires to degrade ground defenses and provide close air support to troops conducting the raid.
New Ways to Fight
To fix this shortcoming, we need to go back to the starting point: operating concepts. These concepts form the basis for new system and platform requirements, inform strategies for how to prioritize investments, and help guide doctrine and tactics for how to integrate new and existing capabilities. New methods of operating can help mitigate the Corps’ most severe limitations, such as surface connector survivability and long-range fires capacity, by using planned or existing capabilities in new ways or by enabling new systems to perform in a less sophisticated and costly manner.
One such concept is the expeditionary advance base. The potential adversaries U.S. forces will be expected to deter or defeat are fielding weapons and targeting capabilities designed to delay and reduce the effectiveness of U.S. or other forces that may attempt to intervene on behalf of allies. These enemy systems are optimized to engage ships and aircraft, which are significant threats to an adversary and have identifiable signatures against the relatively plain backgrounds of sea and sky. They are not as effective at attacking ground units, which are composed of smaller, less concentrated capabilities than ships or aircraft and are able to blend into the busy background of terrain, trees, and structures.
Amphibious forces can exploit this targeting challenge by establishing expeditionary advance bases in littoral areas near enemy forces, targets, or potential objectives. These bases would be small expeditionary outposts for elements composed of 100 to 1,000 personnel. Because they are harder to find and engage than ships, expeditionary advance bases can be established closer to the enemy and for longer periods of time. Their proximity and persistence could enable forces at these bases to constrain the enemy’s freedom of action by threatening anti-air or anti-ship attacks, denying or confusing enemy sensors, or launching unmanned systems that interfere with or interdict enemy forces. If several expeditionary advance bases were positioned along a littoral area, they could act as a barrier to enemy ships and aircraft attempting to reach open water. For example, against an adversary such as China, these bases could transform Japan’s Ryukyu Islands and the Philippines into barriers to Chinese power projection.
Marines and amphibious forces could leverage expeditionary advance bases to support forward arming and refueling of short take-off and vertical landing (STOVL) aircraft, such as the F-35B. The Marine Corps concept of distributed STOVL operations would enable counter-air operations, strikes, and raids to be conducted from these bases well inside a contested area.
Amphibious raids are a traditional Marine Corps mission, but their purpose and the manner in which they are conducted will have to change to accommodate contemporary threats. Historically, raids have been executed as part of power projection operations, such as amphibious assault. In the future, they will likely be conducted more often to support sea control in littoral areas by degrading or destroying enemy anti-air and anti-ship missile batteries and associated sensors. Due to the threat to amphibious ships from ASCMs, torpedoes, and mines, raids will need to be conducted from farther away than today.
Amphibious operations can also support efforts by U.S. forces to fight a protracted campaign. One such approach would be to deny the adversary the imported materials and exported goods to support or fund the war effort. Mounting a blockade, however, requires more than sea control ships. Surface combatants enable U.S. forces to stop vessel traffic at a chokepoint and attack ships that do not comply. Vessels would then need to be boarded, inspected, and quarantined if they contain banned materials or goods. Amphibious forces, with their large complements of small boats and marines, would be an essential component of the boarding element of a blockading force.
These new operating concepts will require changes to Navy and Marine Corps systems, platforms, and processes. One key area for improvement is the heaviness of vehicles. The Marine Corps’ ability to quickly move troops over the horizon has been hampered by the steadily growing weight of its vehicles. Lighter vehicles, such as the Internally Transportable Vehicle (ITV), which can be lifted internally by an Osprey, would enable the Corps to take full advantage of the MV-22’s 400-nautical mile combat radius and move beyond a reliance on vulnerable surface connectors to move larger weapons and systems.
The Marines Corps will also need to change its priorities for surface connectors. The Corps spent decades in a fruitless quest to develop and procure the Expeditionary Fighting Vehicle (EFV), a platform conceived with the goal of being able to carry 17 marines 25 miles to shore at a speed of more than 20 knots. Today, the niche the EFV was designed to fill — an armored vehicle that can swim ashore from over the horizon — has become irrelevant. As threat capabilities have increased, 25 miles is no longer a sufficient standoff distance for an amphibious warship.
Instead of attempting to build a better EFV, the Navy and Marines should optimize their surface connectors for ocean transit. Minimizing on-land requirements for connectors could reduce cost while retaining a high water speed and the ability to carry large payloads. Further, by reducing the swimming requirements for ground vehicles, the Marines could purchase a system optimized for land warfare without having to accept tradeoffs to provide amphibious capability.
Amphibious ships at sea and, more importantly, Marines ashore in expeditionary advance bases, will need higher-capacity defenses to persist in contested environments. At sea, smaller amphibious ships should be equipped with Vertical Launch System (VLS) magazines that could carry medium-range air defense SAMs in relatively large numbers. Marines ashore should field air defenses such as the Army Indirect Fire Protection Capability (IFPC) Increment 2-1 and employ camouflage and electronic warfare systems to defeat enemy targeting sensors.
To exploit the ability of expeditionary advance bases to threaten enemy ships, aircraft, and forces ashore, the Marine Corps should expand the fires capabilities of ground units by fielding more High Mobility Rocket Artillery System (HIMARS) launchers. The HIMARS launcher can carry several surface-to-surface missiles, including the Army Tactical Missile System (ATACMS), which will soon field an anti-ship variant. The Marines would then benefit from other improvements made to ATACMS, as well as the introduction of replacement weapons to support Army cross-domain operations.
Naval forces will need more and longer-range fires to support widely distributed ground units that could be hundreds of miles from their host ship. Amphibious ships with VLS magazines as described above could carry anti-ship and strike weapons in addition to SAMs, enabling them to launch attacks in concert with long-range raids by marines in MV-22s. In addition, the MEU air element could be expanded to increase the number and frequency of long-range air strikes and close air support operations.
The composition of ARGs should change to enable this increased priority on aviation. The Marine Corps should move from its current three-ship formation to a four-ship formation that includes an additional small-deck amphibious platform. A four-ship ARG would enable the Marine Corps to field a force with between 70 and 100 percent more strike aircraft while sacrificing little airlift capacity. It would also refocus large-deck amphibious ships on strike aviation and include more small-deck amphibious ships to enable a more distributed amphibious force while carrying rotary-wing aircraft that are displaced by the addition of extra attack fighters on the LHAs/LHDs.
If the Navy’s amphibious fleet remains at its target of 33 ships, a shift to 4-ship ARGs will reduce the number of complete ARGs deployed at any one time even if the total number of amphibious ships deployed remains the same. Because amphibious forces will likely continue to operate in a disaggregated manner, the new configuration is not likely to affect day-to-day operations. Perhaps more importantly, the deployment of aviation-centric LHAs/LHDs will provide an alternative to large nuclear carriers in some situations and reduce the stress on the carrier fleet, which needs more time for training and maintenance between deployments.
Potential adversaries will continue to improve their ability to contest the sea and air around their territory, increasing the range at which amphibious operations must occur and making amphibious ships and marines more vulnerable. The United States must adopt new operating concepts and new or modified capabilities for amphibious operations that address these trends and enable the U.S. Navy and Marine Corps team to continue supporting American efforts to deter aggression, respond to crises, and exploit its maritime superiority as an asymmetric military advantage.
Bryan Clark is a Senior Fellow at the Center for Strategic and Budgetary Assessments (CSBA). He is a retired submarine officer and studies naval warfare, electromagnetic spectrum warfare, and military innovation.
Jesse Sloman is an Analyst at CSBA. He is a former Marine and studies naval warfare, military readiness, and the future of warfare.