Online open-source information on the UHAC is dated, and Wikipedia provides the most details.
The U.S. Defense Advanced Projects Agency (DARPA) created the Captive Air Amphibious Transporter (CAAT) as a test prototype vehicle with treads and foam flotation pads.
The U.S. Marine Corps Warfighting Laboratory used CAAT to create the half-scale UHAC demonstrator, which was, according to Wikipedia,
“42 ft (13 m) long, 26 ft (8 m) wide, 17 ft (5 m) high, weighed 38 tons, and traveled at 4–5 knots (7.4–9.3 km/h) knots on water; the hull was made of aluminum, with a small pilothouse mounted on the bow. Using track feet fitted with dense air-impregnated foam blocks makes it buoyant in the water and propels it on land, allowing it to traverse through mud, sand, and marshland when ashore. This made the demonstrator’s ground pressure about 1 PSI, compared to 9.7 PSI for the Amphibious Assault Vehicle.
The full-size UHAC is planned to be 84 ft (26 m) long and up to 34 ft (10 m) high. The UHAC is primarily aimed at potentially replacing the Landing Craft Air Cushion hovercraft, but it could also supplement it and replace the Landing Craft Utility. Compared to the LCAC, the UHAC is planned to have a heavier payload of 150 tons (standard) to 190 tons (overload) compared to 65 tons, a longer range of 200 nmi (230 mi; 370 km) compared to 86 nmi (99 mi; 159 km), has the advantage of using its tracks to move inland from the beach and over 10 ft (3.0 m) sea walls, and is estimated to cost less than half as much to build and maintain per unit; the LCAC has a faster water speed of over 30 knots compared to 20 knots for the UHAC, and a smaller area of 1,800 sq ft (170 m2) compared to 2,500 sq ft (230 m2).
The UHAC would be faster on water than the AAV and could even transport them to get closer to shore or carry up to three M1 Abrams tanks. A production version would be survivable with a lower profile, armor, and armament. The concept for the UHAC began in 2008 with the goal to design an amphibious vehicle with low PSI. The Office of Naval Research accepted the design from Navatek, and three prototypes have been constructed since (a one-fifth scale model, a one-quarter scale model, and the half-scale model). Currently, the UHAC effort is a collaborative effort between the U.S. ONR and the Singapore Ministry of Defense Science and Technology department. No decision has been made on taking the final steps necessary to produce the full-scale version.”
Remember that Wikipedia’s UHAC information dates back to the Rim of the Pacific (RIMPAC) Exercise 2014. Thus, Naval News contacted the U.S. Marine Corps Public Affairs and Navatek, the original manufacturer of the UHAC, for answers and information updates. Naval News learned that Navatek ceased business operations around 2020 and became another company under another name. The Marine Corps Communication Strategy and Operations, Combat Development and Integration, Quantico, Virginia, replied to Naval News on August 1, 2024:
“Force Design, our Concept for Stand-In Forces, and our Tentative Manual for Expeditionary Advanced Base Operations provide clear direction on how we will operate now and in the future. The Marine Corps serves as the Nation’s premier crisis response force and simultaneously serves as a persistent presence within contested areas as the leading edge of a maritime defense. We seek the technologies, platforms and systems that are light, mobile, versatile, and more easily deployable and sustainable to best support the expeditionary nature of our Service. We have no information on the status of the company that built the UHAC prototype.”
Marine Corps Combat Development and Integration Department
The Marine Corps Combat Development and Integration Department chose not to answer the list of Naval News questions on the Ultra Heavy-Lift Amphibious Connector regarding its status, fate, future testing expectations, desires for a full-scale demonstrator, or forthcoming visions for the UHAC concept.
Naval News also received a reply in August 2024 from someone who remembers the out-of-business Navatek. This is his response.
“Navatek was very proud of the company’s advanced naval architecture and marine engineering that culminated in our patented half-scale Ultra Heavy Lift Amphibious Connector. It incorporated many never-before-tried approaches to amphibious vehicles. Its ability to operate in the surface zone, in mud flats, climb large vertical seawalls, and have extremely low ground pressure to maneuver across soft sand was unprecedented. Additional work included interface equipment such as a very lightweight ramp structure put in pretension using the company’s inflatable products.
Several models of different scales were produced over the life of the program, culminating with the half-scale prototype. At the conclusion of the program, the Navy and Marine Corps had no further use of the half-scale prototype, and the vehicle was eventually scrapped. A small-scale vehicle has been used as a surrogate amphibious vehicle in other ONR [Office of Naval Research] programs and is in existence.
You would have to ask ONR and Marine Corps on their desire to further this work, but Navatek is not aware of any plans to fund further work in this area.”
The U.S. Navy’s Office of Naval Research did not respond to Naval News’ request for information.
Naval News Comments
Naval News contacted Mark Cancian, Senior Adviser, International Security Program at the Center for Strategic and International Studies (CSIS) and a retired U.S. Marine colonel, about his thoughts and whether he believes the UHAC could be revived. Cancian wrote:
No question it is a cool-looking machine, and it might have worked. It’s sensible for the Marine Corps to try all kinds of technologies to see what might be suitable. The Marine Corps seems to have opted with the Navy to extend the life of LCACs. That might have been cheaper. I think there is no likelihood that the Marine Corps will revive this program. Its new concept, Force Design 2030, sees smaller, lighter forces and less need for large-scale amphibious operations.”
Mark Cancian, Senior Adviser, CSIS
