The future LCAC will be a central element of the sea basing concept

By MATT HILBURN, Associate Editor

The Navy hopes to have a Landing Craft, Air Cushion (LCAC) replacement ready by 2015 that will provide substantially more lift capability and reliability than the 72 1980s-vintage LCACs now in the fleet. Whether it will be given the name LCAC(X), Seabase-to-Shore Connector or the currently en vogue designator, Joint Maritime Assault Connector (JMAC), the new vehicle is destined to be a vital linchpin in the Navy’s sea basing concept because of its speed and increased cargo capacity.

The essence of sea basing is that U.S. forces responding to international crises would no longer establish beachheads containing mountains of materiel, huge headquarters and troop staging areas similar to those created in Kuwait in support of Operation Iraqi Freedom. Beginning in about 2015, those functions would be moved offshore to a sea base comprised in part by the Maritime Prepositioning Force (Future), a planned squadron of 14 vessels including amphibious ships and transport vessels.

A planning objective of the sea basing concept is to move two battalions totaling 2,400 Marines to an objective ashore overnight.

“The Navy wants to carry roughly twice as much cargo,” said Clay Moise of Textron Marine and Land Systems, the prime contractor of the LCAC, a title it would like to keep for the JMAC.

But he added that other capabilities and requirements are still being developed.

Current LCACs, which hover on a cushion of air, are able to carry 60-75 tons of cargo at speeds of up to 40 knots for 200-300 miles. They are 88 feet long and have a beam of 47 feet. When first deployed in the early 1980s, they were considered a revolution in how Marines reached shore objectives, most notably because they are able to access 70 percent of the Earth’s coastline as opposed to 15 percent for more traditional landing craft.

LCACs are transported in the well decks of large amphibious ships and can maneuver on and off of the ships via beach-like ramps, thus foregoing long recovery operations. Their primary function is to carry cargo that is too big for air transport. Even with a 75-ton cargo capacity, however, the current LCACs have their limits. The Marine Corps’ M1 Abrams Main Battle Tank, for example, weighs nearly 70 tons.

According to Capt. Richard Hooper, advanced warfare program manager at Naval Sea Systems Command, the JMAC will most likely be based on air cushion technology, but other ideas have been, and continue to be, studied.

“We looked at using a displacement craft with wheeled ability,” he said citing the Marine’s Expeditionary Fighting Vehicle as a working example of that kind of technology. “You’re talking about doing that on a much bigger scale, and that would be very difficult.”

The Navy’s current LCAC fleet is undergoing a service-life extension that will take them from the 20 years for which they were designed to function to 30 years, but at that point, roughly 2015, they will need to be replaced.

While the aging LCAC fleet is certainly a driving force behind the JMAC, according to Hooper, reliability and cost savings are also high on the list of reasons the Navy is looking to upgrade.

“I would say that the LCAC, when it was fielded, was definitely a revolution in how the Marine Corps did its mission,” said Hooper. “Do you get it absolutely perfect the first time? No.”

Hooper said the JMAC will be more reliable, easier to maintain and have the same, if not less, number of crew members and maintainers.

To this end, he said the JMAC might incorporate the use of new composite materials being developed at the Office of Naval Research to be used in areas where the LCAC experiences high rates of erosion such as propulsion shrouds and lifting bands. Hooper added that the Navy is investing some research money into improving the lifespan of the skirting material, which serves to capture the air underneath the craft.

Budget constraints are a factor in the new design and how the Navy ultimately addresses the requirements the JMAC will have in terms of speed, range, payload and ability to operate in high sea states.

“We’ve got to find the sweet spot of an affordable craft that can meet the minimum requirements, but do it most affordably because our whole procurement budget is constrained today, and it’s probably not going to be much improved over time,” Hooper said.

Both the Navy and Textron agree JMAC probably will not look radically different than the current LCAC, but the one area where the notional JMAC might differ from its forefather is length.

“They have to be transported in well decks of existing amphibs,” said Moise. “That gives you a beam and height restraint, not so much a length constraint.”

He said the JMAC could be up to 130-140 feet long.

Design challenges for the JMAC, according to Textron, are very similar to those faced by LCAC engineers in the late 1970s and early ’80s. These include the drive train, lift system, propulsion system and, perhaps to a larger extent than with the LCAC, the hull design.

“The more you can save in the hull structure, the more you can put on the deck,” said Moise.

The Navy said that, to date, there have been no tests on a prototype JMAC, but that it “will be doing testing of technology that will employed on the craft to reduce risk in the intermediate years between now and when we start construction of the craft,” Hooper said.

The current LCAC runs with a crew of five, but as the JMAC takes shape, Textron officials said it will be fully digitalized and, at some point in the future, possibly fully autonomous.

“[What’s] come across loud and clear in our dialog with the fleet is that making the JMAC or the Seabase-to-Shore Connector more reliable and maintainable so that the overall manning requirements for the unit at worst the same if not less for the same number of craft,” Hooper said.

He was quick to underscore, however, that JMAC development is in the very early stages of a long process.

“My vision today about what the craft is going to be may be tempered by time and that process,” Hooper said. “I’ll just underline that.”