Marine Corps’ Monster Sea Taxi Paddles to Shore

It’s a tank! It’s a landing craft! It’s both!

Marine Corps’ Monster Sea Taxi Paddles to Shore Marine Corps’ Monster Sea Taxi Paddles to Shore
The Marines are paying a lot more attention to the Pacific as the war in Afghanistan draws to a close for American troops. That... Marine Corps’ Monster Sea Taxi Paddles to Shore

The Marines are paying a lot more attention to the Pacific as the war in Afghanistan draws to a close for American troops. That means new amphibious toys for the Marines to play with.

On July 11, the Marine Corps Warfighting Lab rolled its Ultra Heavy-Lift Amphibious Connector into the waters just east of Bellows Air Force Station in Hawaii. Big, floaty and ugly, the UHAC is a giant taxi designed to move troops and tanks from warships miles from a coastline.

The Marines have other vehicles that do the same job, namely LCAC hovercrafts and LCU landing ships. But the tracked, 42-foot-long and 38-ton UHAC is designed to move around on land that’s too difficult for hovercrafts to reach.

Instead of parking on the beach, this vehicle can keep going.

During the windy, early-morning demonstration, the UHAC chugged and paddled its way onto the beach outside Bellows. Then it headed toward a sand berm and climbed right over. The monster crossed a road into a clearing before wheeling back out to sea.

It’s still a very early prototype, developed with help from Singapore.

Brig. Gen. Kevin Killea, the Warfighting Lab’s chief, says almost everything about it will be different if the Marines and Singapore turn UHAC into a full-fledged program. It’ll be more than twice as big, with a bigger engine capable of traveling around 20 knots while hauling up to 190 tons. That’s enough for three main battle tanks.

The main purpose of last week’s test is to study how the tracks—known as captive air cells—keep the craft buoyant. The trick is using a non-absorptive foam, like giant air cushions.

“Basically, it allows you—if you spread out the weight and have that many captive air cells—to carry an enormous amount of weight literally almost on top of the water as opposed to being submerged and having to plow through the surf,” Killea said.

Right now the UHAC can travel up to 15 miles off a shore. But one priority is expanding the range much farther out.

The growing threat from anti-ship missiles proliferating around the world may force the Navy to park its big, heavy base ships up to 100 miles from a hostile coast. The landing craft have to be able to make the trip.

But can it survive?

There’s also a dilemma about how to armor the UHAC.

The prototype is unarmored and unarmed. The Marines also don’t intend to use an operational UHAC to assault a defended beach. Better to use something like it on a friendly beach—or after the Marines have already secured one.

“We understand the context of how we’re using something like this—a connector from ship to shore like today’s LCAC,” Killea said. “We don’t necessarily plan on LCACs going against a [defended] shore.”

However, the UHAC still has to be armored. It still has to be able to defend itself. It also has to be able to transport slow-moving armored AAV amphibious vehicles into a position where they can assault a beach, potentially exposing the UHAC to deadly enemy fire.

But the more armor, the more weight … and the slower it goes.

“In future phases and obviously in the final design, all the abilities will have to be there,” Killea said. “Survivability, lethality and support ability. Survivability will be key in the fact that you will want something with a low profile. You will want something that can move quickly.”

About an hour later farther up the beach, another demonstration served as a good comparison.

A U.S. and Indonesian Marine assault group composed of four AAVs—three American and one Indonesian—and two U.S. LCACs carried out a simulated shore assault launched from the landing ship USS Rushmore.

As the AAVs approached the beach, the vehicles spewed out a white smoke screen that obscured their location. The tracked vehicles then emerged onto the warm Hawaiian sand still partially obscured. A moment later, the AAVs sped through a breach in a tree-lined embankment before rushing to a staging area just inside Bellows.

Two LCAC hovercrafts followed, hitting the beach but intentionally deflating just short of the embankment. It all went quite faster than the chugging UHAC. But the UHAC went farther—and that’s something the Marines are counting on.