The U.S. Marine Corps' New Sea Taxi Prototype Has Cold War Origins

Last month the U.S. Marine Corps demonstrated its new Ultra Heavy-Lift Amphibious Connector prototype in Hawaii. The UHAC’s basic concept is similar to vehicles the Marines and the Army experimented with in the 1960s.

The company completed the Airoll Test Platform in 1959. The design was “track-laying” like a normal tank but—used air-filled tires attached to chains instead of metal links.

The inflated orbs meant the prototype floated more readily than the jardheads’ existing amphibious tractors. The wheels also acted as paddles in the water.

The system had additional benefits on land, as well as when entering and exiting the water. The prototype traveled faster on solid ground than many regular tanks and armored personnel carriers because the free-spinning tires could build up added momentum.

But the platform could also use those rubber wheels to paddle out of soft sand or deep mud. These kinds of terrain still pose big problems for traditional tracks.

The Marine Corps saw promise in the new concept for amphibious operations. The Army also had an interest in the basic design for missions on deep, soft snow.

However, Vietnam provided the biggest boost for the Airoll setup. Southeast Asia’s river deltas, swamps and tidal marshes were major natural barriers for heavy armor.

The South Vietnamese relied on bridge-laying vehicles to cross canals and soft terrain. Army photo

American troops experienced the same problems. Recovery vehicles with powerful cranes and tanks capable of placing temporary bridges over soft ground were always in high demand.

The Pentagon felt that the Airoll system might be the solution for everyone. By early 1960s, the Marines were testing new variants of their testbed, while the Army was experimenting with another design called the Plenum Air Tread Amphibian—or PATA.

The various prototypes ran tests in the Mississippi bayous and the jungles of Thailand. The PATA—also known as the XM-759 Marginal Terrain Vehicle—went through significant changes in the process.

In the end, the tires—central to the basic concept—turned out to be one of the biggest problems. The air-filled cells were susceptible to damage from both enemy fire and everyday use.

Defense contractor LTV ran the XM-759 project and continued to improve the vehicle into the 1970s. Unfortunately, the whole project became one of the many victims of post-Vietnam budget cuts.

Still, the final designs had flatter, paddle-shaped airbags that look very much like smaller versions of the new UHAC’s floats. This new prototype likely owes a lot to Borg-Warner’s Airoll and LTV’s PATA.

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