The Navy needs a new, 21st-century landing craft utility (LCU)—the kind of flexible, shallow-draft, fast-moving cargo-carrier required for putting Marine Corps tanks and armored vehicles ashore during a modern-day amphibious landing.
To be sure, technological breakthroughs have given warfighters a wide array of options for transporting personnel and equipment during the first wave of an amphibious landing. The LCAC (landing craft, air cushion) and the MV-22 tiltrotor aircraft are the newest additions. The Navy is modernizing many of the older workhorses in its amphibious fleet, from the AAV (amphibious assault vehicle) to the LHD-1, LHA-6 and LPD-17. And tactics such as vertical envelopment using large numbers of helicopters have proved effective for limited operations. Indeed, no other navy can match the United States’ for numbers, technology, or breadth of experience.
Under current doctrine, amphibious assaults are carried out by a Marine Expeditionary Unit (MEU) embarked as part of a Navy Amphibious Ready Group (ARG) consisting of an amphibious assault ship, multipurpose (LHD), and two amphibious transports—an amphibious dock landing ship (LSD) or amphibious transport dock (LPD). Skeptics may well ask, why do we need anything more?
New Threats, New Challenges
But the picture isn’t quite so comforting if you compare the capabilities of the current choices against the Marine Corps’ needs for launching amphibious operations. While U.S. forces haven’t mounted any large-scale amphibious attacks in recent decades, they have been called on repeatedly for missions ranging from combat to disaster relief, deploying a wide array of equipment and payloads. In this capacity, they are facing new asymmetric warfare threats from rogue states and hostile insurgent forces, many of which now have access to precision-guided rockets, artillery, mortars and missiles, along with short- and mid-range antiship weapons that provide them with anti-access and area-denial (A2/AD) capabilities. In 2006, for example, non-state actor Hezbollah fired an Iranian-built C-802 against an Israeli Sa’ar 5 corvette. The possibility of being hit by such weapons is pushing our large amphibious support ships farther out to sea—and in the process making the job of getting from the ships to the beach even more daunting and precarious.
Moreover, whether a Marine Expeditionary Unit (MEU) faces regulars or irregulars, the vehicles most likely to survive on the battlefield ashore typically are the heaviest—armored tracked and wheeled vehicles such as tanks and personnel carriers. Yet, the increasing weight of our new armored vehicles often exceeds the ability of our air- and landing-craft to carry them from the support ships to the beach. The plodding speed of the AAV-7 Amphibious Assault Vehicle and the high fuel consumption of the 40-knot LCAC and the limited 15,000-pound external lift of the combat-loaded MV-22 Osprey tiltrotor aircraft are all significant tactical limitations.
The Marine Corps thought it had a partial solution in the high-technology Expeditionary Fighting Vehicle (EFV), but the Defense Department canceled the project in 2011 in favor of refurbishing the AAV and procuring a cheaper Amphibious Combat Vehicle (ACV). As a result, today’s heavy-lift capability depends primarily on the 50-year-old 1610-class LCU and related landing craft, which are slow and aren’t designed to make the most of in the support ships’ 50-foot-wide well decks. The current LCU measures 135 feet by 30 feet, carries 160 tons to 180 tons at just under 11 knots and requires a nine-foot depth to operate.
Replacing the LCAC and 1610-Class LCU
Planners have long considered replacing the LCAC and the LCU-1610 with updated designs such as planing monohulls or enlarged, high-powered air-cushion technology. The LCAC’s presumed replacement, the Ship-to-Shore Connector (SSC), is similar to the LCAC in speed and carrying capacity, with slightly better fuel consumption. And the successor to the LCU-1610 reportedly offers the same hull, the same speed, and the same capability as the current model, with updated electronics and stronger steel. But neither design capitalizes on the kind of breakthrough concepts and technologies that would make the successor landing craft more effective and affordable. And even with the MV-22 Osprey, the Navy and Marine Corps still lack the kind of fast, heavy-lift capability needed to transport a modern-day assault force ashore.
We propose a Landing Craft Utility-Folding (LCU-F). The innovative design would provide the higher speed, larger payload capacity, greater fuel efficiency and better beach-landing ability needed to fulfill today’s amphibious force requirements, yet the LCU-F could be folded up to fit neatly into the standard well decks of the major amphibious transport ships. The new LCU-F would be based on a novel concept—a folding landing craft—developed by the team of the late small-boat designer Phil Bolger and Susanne Altenburger of Phil Bolger & Friends. The unorthodox configuration is designed to take advantage of age-old hull-speed geometry to provide a modern-day landing craft that, when expanded to its fold-out length, can get more speed for the horsepower than conventional LCUs.
Like a Swiss Army Knife
In drawings illustrating the folding process, the proposed LCU-F prototype looks something like a Swiss Army knife—with its ends folding both outward and inward. When the boat goes into the water, the mostly empty bow and stern modules are folded out to extend the length of the vessel (see drawing on next page) and increase her maximum hull speed. With a boat length of 270 feet, a beam of 22 feet, and a draft of 4.5 feet, the LCU-F could carry up to 200 tons of personnel and equipment at a speed up to almost 20 knots—a far better performance than the current LCU–1610–class craft (see table on page 64). Besides adding to the length of the new landing craft, the hinged modules provide a wave-piercing bow and a stern ramp for the LCU-F and give it added displacement to support the weight of the vessel’s cargo.
When the LCU-F is stowed aboard a well-deck ship, with its bow and stern modules folded back over the main hull, it measures 143 feet long, 22 feet wide and 20.5 feet high—a package that fits neatly (in multiples) into the standard well decks of the Navy’s existing amphibious ships. Indeed, most of the support ships could carry at least two LCU-Fs in their well decks, and the recently modernized LSD-41-class vessels could pack six LCU-Fs in their 440-foot wells. (By contrast, the current LCU–1610–class craft is awkwardly sized, and ends up wasting valuable space aboard amphibious transport ships.)
Here’s how the LCU-F would work:
Pre-loading the LCU-F for combat. In anticipation of a hot landing—i.e., not a training cruise—the MEU’s vehicles and equipment are pre-loaded onto the LCU-F from a shore-side base or one of the new mobile landing platforms (T-MLPs). The unfolded landing craft eases its stern into position, and the combat vehicles are backed over the LCU-F’s stern-deck into its cargo bay, so they will face its stern-ramp ready to roll when the Marines reach the beach. Once the LCU-F is loaded and its cargo bays are locked tight, the end modules are folded over on top of its main hull, and the LCU-F powers itself onto the amphibious landing ship for transport and into its assigned stowage position by using its flush and stern-thrusters. Pre-loading the LCU-F in preparation for the assault mission frees up precious combat-vehicle stowage capacity aboard each of the ARG’s amphibious landing ships.
Getting under way. Once the folded LCU-F clears the amphibious ship’s stern gate, it extends a set of gyro-controlled sponsons, temporarily increasing its beam (and thus its stability). Then it unfolds its stern section and each of two half-bow sections to reach its full operational length. Once that’s accomplished, the crew retracts the sponsons and lowers two twin-propeller drives to a draft of about 11 feet. Now its two diesels can propel a full combat load at about 19 knots for a range of more than 1,500 nautical miles. All drive components can be purchased right off the shelf.
Armament. Each LCU-F would carry amidships one modified Marine Corps Avenger 2x4-Stinger antiaircraft mount and one AH-1 attack-helo Vulcan cannon 20/30-mm turret system, both of them as bolt-on roof–surface–mounted units that would provide a two-mile self-defense range. Additional protection would come from shipboard antiaircraft weapons systems in the rear, from surrounding helicopters, and from carrier-based fixed-wing aircraft.
Landing. Because of its unusual configuration, the LCU-F would require an unconventional landing. Just over the horizon from the beach, the LCU-F would turn its stern-ramp to the beach and accelerate stern-first, with its vehicles and weapons now facing the shore. Before entering the surf-zone, the estuary, or the salt-marsh tidal river, it retracts its prop-drives and moves at up to ten knots using a set of flush 360-degree main and stern thrusters, drawing just 4.5 feet.
On the beach. Once the LCU-F reaches the shore, it drops its stern ramp, and opens its cargo gate and rear-bay roof-hatch, and personnel and equipment use the stern ramp to get ashore. With its bow already facing seaward, the LCU-F uses its two thrusters to move off the beach until the prop-drives can be lowered again for the run back to the LHD or other amphibious transport ship.
Return to the ARG. Back offshore, the LCU-F remains unfolded, retracts the prop-drives and enters the amphibious support ship’s well-deck stern-first under its two flush thrusters to receive the next load of MEU combat and support equipment and troops. The medium tactical vehicle replacement (MTVR) 6x6 with 20-foot container, or the 14–foot–tall rough terrain container handler protrude through the after-cargo-bay’s sliding roof. Longer and higher vehicles, such as 8-by-8s and 10-by-10s, ride outside on its stern.
Admittedly, the innovative concept requires some compromises: Designing the LCU-F to head toward the beach at 20 knots means equipping it with a wave-piercing bow and forgoing the traditional bow-ramp that has become an icon in World War II-era movies. So the new landing craft wouldn’t be capable of drive-through operation. But its ability to back onto the beach and use its stern-ramp more than makes up for that.
Single First Wave
An ARG that comprises one LHD (with three LCACs on board) and two LSD-41s (carrying a dozen LCU-Fs) could deploy its forces to 15 shore-side insertion points. The combination would enable the MEU’s full ground-combat complement of Marines, along with their tanks and personnel carriers, to arrive together as a single first wave and proceed inland immediately without waiting for each other on or near the shore.
The addition of the LCU-F also would pave the way for significant changes in the planning and execution of amphibious assault landings. The new vessel’s high heavy-lift speed, range, and number of hulls available would vastly expand dusk-to-dawn maneuvering-distances. The amphibious support ships could stay offshore at much safer distances—100, 150 and even 200 nautical miles from shore—far enough to evade adversaries’ missiles. With such a large assault-radius, the Marine units would be better able to hide their intentions from enemy forces.
At the same time, however, distances closer to 100 nautical miles would pose difficulties for the combat-loaded AH and UH helicopters, which typically can’t carry enough fuel to make such trips and take part in the battle also. One possible solution would have the helos fly off the LHD and for one of them to land on the stabilized stern-deck of each LCU-F right at the end of its unfolding process. The LCU-F could thus carry one AH or UH helo until the force is much closer to shore—a plan that would leave the helos with enough fuel to carry out their assault actions. Another is to keep one or two LCU-Fs near the shore to serve as forward refueling platforms for the helos until shore-based refueling facilities are in place. These concepts require further study and experimentation.
Distances of more than 100 nautical miles from the beach would exceed the capability of LCACs and SSCs as well, since both vessels consume large amounts of fuel and have shorter ranges than the LCU-F would. In such cases, the LCU-Fs could be assigned to carry the heavier loads and possibly provide partial refueling for the LCACs and SSCs.
As everyone in the amphibious operations community knows, there are plusses and minuses to all landing craft. Whatever its other advantages, the LCU-F can’t possibly match the 40-knot speed of the LCAC and its unique over-the-beach capability. But the LCAC and SSC can’t carry as much for as long a distance as the LCU-F can.
Part of a Family
We suggest that to provide the most flexibility and the highest likelihood of mission success the Navy establish an SSC and LCU-F “family of amphibious lighterage” (FOAL) that includes landing craft with complementary capabilities. A FOAL of SSCs and LCU-Fs (or any analogous LCU-X of medium speed, heavy load capability) would provide both full amphibious capability and substantial first-wave capability at various ranges. Neither is as good as the other in their specific strengths, but each easily mitigates the other’s weakness.
Another advantage: Once the first wave of the amphibious assault is over, the LCU-F could quickly be reconfigured to serve as a 55,000-gallon combat tanker or as an inshore fire-support platform for several six-tube Marine Corps HIMARS rocket artillery systems or its related 12-tube MLRS. Beyond amphibious operations LCU-F could deploy as a helo- and small–craft–equipped mother ship for special forces operations, or engage in piracy-interdiction—all dramatically increasing its tactical utility to the Navy.
Pairing the LCU-F with the high-speed air-cushion LCAC/SSCs would give the Navy-Marine Corps Team an unparalleled capability for fast amphibious lift from well over the horizon. Amphibious assault capability remains one of the distinguishing advantages of the United States maritime forces, but it can no longer be single-purpose, exotic, or expensive. The LCU-F is one potential solution.
Commander Bosworth is deputy group director of the Chief Technology Office of the Naval Sea Systems Command. Previously, he was program manager of Ship and Force Architecture Concepts (SFAC), an advanced research and development program managed by NavSea. SFAC chartered the study on this topic.
Captain Junge is a professor of joint military operations at the Naval War College. He served as commanding officer of the USS Whidbey Island (LSD-41).