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US Marines demonstrate Ultra Heavy-lift Amphibious Connector prototype


July 16, 2014

The US Marines have demonstrated a half-scale version of their proposed amphibious vehicle during maritime warfare exercises

The US Marines have demonstrated a half-scale version of their proposed amphibious vehicle during maritime warfare exercises

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In a recent demonstration carried out during RIMPAC 2014, the US Marines displayed and tested a fully-functional, half-scale prototype of its new amphibious transport vehicle. In its proposed full-size version the Ultra Heavy-Lift Amphibious Connecter (UHAC) concept is designed to power across the water with a payload of nearly 200 tons (180 tonne) at up to 20 knots (23 mph/37 km/h) and be capable of driving up on to the shore and over the top of obstructions up to 10 ft (3 m) high.

As the proposed next generation of amphibious lander, the full-scale version of the UHAC is set to boast triple the carrying capacity of the Landing Craft Air Cushion (LCAC) vehicles currently used to provide ship-to-shore transport for the US Navy by offering a payload capacity of up to 190 tons (172 tonne). Even though the demonstrator is just a half-scale version, it is still a substantial vehicle in itself at 42 ft (13 m) long, 26 ft (8 m) wide, and 17 ft (5 m) high.

Developed from its previous incarnation as a one-third scale Captive Air Amphibious Transporter (CAAT) concept, the land-sea capability of the UHAC is provided buy a set of tracks – similar to a tank – fitted with captured-air foam cells that provide buoyancy, act as paddles when in the water, and behave as track-driven pads when on the land. This system provides a very low ground pressure footprint that helps make the UHAC truly amphibious, at it is also able to traverse through mud, sand and marshland equally well.

The RIMPAC demonstration involved the UHAC leaving the Marine Corps Training Area Bellows and traversing the ocean to the USS Rushmore, where it entered the ship’s amphibious landing dock (or well deck), picked up an assault vehicle, and successfully transported it back to the shore.

"Showcasing the UHAC during RIMPAC is a big deal," said Dave George, project officer at the Marine Corps Warfighting Lab. "This is a great way to let people know that this new technology is being developed and this is a great way to show what it can do. Today went quite well. We had much better seas then we anticipated and we were still able to get onto the well deck of the USS Rushmore."

The next stage of the UHAC's development remains unclear at present and no mention has been made of taking the final steps necessary to produce a full-scale version. But given the apparent success of the RIMPAC demonstration and the obvious advantages of the captured-air foam cell track design, it is likely that we may well see more developments on this vehicle in the not too distant future.

Originally created by Navatek Ltd – a hydrodynamic research and naval architecture company based in Honolulu – the project was funded and carried out by the Office of Naval Research (ONR).

RIMPAC (Rim of the Pacific) is the world's largest international maritime warfare exercise and runs from June to July every two years. It takes place in and around the Hawaiian Islands with the US inviting military forces from the Pacific Rim and beyond to participate.

The short video below shows the UHAC in action.

Source: US Navy

About the Author
Colin Jeffrey Colin discovered technology at an early age, pulling apart clocks, radios, and the family TV. Despite his father's remonstrations that he never put anything back together, Colin went on to become an electronics engineer. Later he decided to get a degree in anthropology, and used that to do all manner of interesting things masquerading as work. Even later he took up sculpting, moved to the coast, and never learned to surf. All articles by Colin Jeffrey

I assume that the foam paddles can cope with having a short log or pointed stake trapped between them whwn the track leaves the drive wheel as part of its operation.

Mel Tisdale

I think that is way cool. It would be neat to see a smaller version for civilian use.


M I C..K E Y.. Mouse. .. This looks way too fragile, and susceptible to rip currents,winds or like Mel T mentioned debris in its path, land or water. Bet it looked good on paper though.

Jay Finke

This thing looks like a grade school science project... Any 3rd world country would have taken it out before it got out...of the water! Looks like another U.S. bridge to nowhere.

Tom Bimble

There's no reason to think this vehicle will be any more vulnerable to debris, currents, or winds than existing vehicles of the same size. The piece implies the air-foam cells lower the ground pressure. That comes from the width of the tracks, not the cells. What would be the result of separating the propulsion on land from the propulsion on water from flotation? In other words, a very large amphibious tractor to transport other vehicles from ship to shore?


resembles WW1 tank from side., Apps for Rescue, MedEvac, Tug, Tow, Dozer, Fire Support, CP

Stephen Russell

They probably will do a fair amount of testing under different conditions before ordering a hundred thousand of them.

Snake Oil Baron

Frighteningly large. Seems to be a couple skeptics in here that think a small log is going to stop this from landing on a beach... im not sure you realize how big 42 ft (13 m) long, 26 ft (8 m) wide, and 17 ft (5 m) high is or that as the article stated, this is the HALF SIZE version. unless your mounting the beaches off the coast of BC i doubt your going to find a twig thats going to stop an 84ft long 52ft wide 34ft tall MONSTER.

I could see this machine backing into a beach or sitting out in the water with a tank/artillery pointed up the wrong way and just laying waste before landing. Im not sure a 3rd world country is going to deal with an modern tank sitting a couple KMs off their shore, likely with a miniature carrier/dessy sitting behind that.

Shane Berg

Third-world countries can and do use first-world weapons.

I'd wonder about it's vulnerability to explosive projectiles rather than obstcles.


@theotherwill " There's no reason to think this vehicle will be any more vulnerable to debris, currents, or winds than existing vehicles of the same size '' unless you account for drag and lack of propulsion, and just a splash of poor design. . so yes it's the same as any other ship on land.

Jay Finke

Interesting idea. Certainly a lot simpler and quieter than the standard air cushion hovercraft landing vehicles with their multiple lift and thrust engines. The biggest problem I see here is the tracks have very little "bite" while in the water. You can see in the video the vehicle's forward speed is about 1/5 of the ground speed of the tracks, they just slip along the water's surface. Once on land the tracks slow down significantly to keep the vehicle from lurching forward. To do "20 knots" the tracks look like they'd need to turn at 100kts. That's quite fast and centrifugal forces will start having significant effect.

Seems like current, wind or even waves will be able to push this vehicle around or even prevent forward progress with strong off-shore winds and there's no way to move this craft sideways or perform stationkeeping very accurately.

I'm guessing in the end the top section of tracks will be enclosed to make alongside operations possible.

In all this looks like a 5th grader's science fair presentation who just had to produce a "looks cool" project without thinking about the real-world operations of the thing.

Gerard Jeronowitz

3rd world or not, land mines are still very effective against amphibious incursions.


It would work so much better to have the floatation separate from the tracks.

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