Maneuvering the LCAC into the 21st Century

By Lieutenant Colonel Mel R Jones, U.S. Army (Retired)

In the Mediterranean, ACU-4 has participated in successful joint amphibious operations with the Hellenic Navy. Dubbed Alexander the Great, this major exercise is conducted annually, and has focused on demonstrating the LCAC's versatility in the Aegean Sea.

Meanwhile, ACU-5, through its forward-deployed Western Pacific (WestPac) Alpha Detachment at Sasebo, carries its motto "No beach out of reach" from the Korean Peninsula in the north to Australia in the south. According to Captain Robert D. Liggett, commanding officer of ACU-5, LCAC crews and craft are swapped out every 6 months and 18-24 months, respectively. In addition, a permanent maintenance detachment is assigned to the Germantown (LSD-42) in support of WestPac Alpha.

In 1995, the forward-deployed support system got its first real test, when a propeller shroud had to be replaced on one of the LCACs. Captain Liggett obtained parts from the supply system and from stocks at ACU-5, and the shroud itself was flown to Japan in an Air Force C-5A Galaxy. Because the alignment of the shroud with the propeller and propulsion system was beyond ACU-5's capability, Textron Marine & Land Systems, the LCAC manufacturer, sent technical representatives over, and ACU-5 sent a team of extra maintenance personnel. They had the craft back in service in short order.

With a carrier battle group and an amphibious ready group operating from Japan, WestPac Alpha has to be ready to provide LCAC support almost around the clock. The few maintenance problems are taken care of on the spot, and crew proficiency is maintained by rotating ACU-5 LCAC personnel back to Camp Pendleton, where they are unhampered by host-nation operational restrictions. But the forward-deployed LCACs still get a brisk workout during regional exercises, under way in areas of strategic importance to the United States. A recent exercise off the coast of South Korea is a prime example.

According to participants, the exercise included one of the most intensive LCAC operations in recent memory. Over a four-day period in February 1996, as part of a Seventh Fleet exercise, four LCACs from Sasebo operated "at the very top of the envelope."

Operations Specialist Chief Steven Green was one of the craft masters. "We were trying to test the LCACs and just see exactly what they can do," he explained. "The sea state was extremely high; the winds were 30-35 knots constant. We did some nighttime operations. We were testing all our equipment, the craft, and the capabilities of the craft, so we could learn and then pass our experiences on to others."

Chief Green, also a veteran of Arctic demonstration/evaluation exercises, said the LCAC performs superbly over both ice and mud, although it handles differently in each case. "One of the biggest differences was fuel. Up in the Arctic, we used diesel fuel marine, and when we were in Korea, we used JP5, which burns cleaner. It's just a lot better fuel for the craft," he observed.

Operations Specialist Chief Danny Bold, another LCAC craft master, noted that even in Korea the crews had to operate in subzero temperatures. "We hit the beach and ice would cover the craft. In a lot of cases, we had to beat ice off to continue with our mission."

He said that he had never seen tidal conditions like those encountered in Korea, but that the LCACs and crews were equal to the challenge.

Part of the problem was the bamboo poles Korean fishermen use to ground their nets. These and other obstacles had to be negotiated during the second leg of the mission over the mud flats, which extended as far as seven miles at low tide. Crews were careful to preserve the fishermen's economic stake, and the LCAC gave them the flexibility to negotiate such widespread obstructions and still accomplish the mission.

When the LCACs returned to the Fort McHenry (LSD-43) and the Belleau Wood (LHA-3) with their final load of Marine equipment for the voyage back to Japan, exhausted crews expressed satisfaction with the mission. "The exercise gave our crews the opportunity to operate in an environment they rarely see," said Chief Green, "and the LCACs held up great considering the amount of weight we were carrying and the sea state. We had a greater than 90% reliability rate. We ran them pretty much around the clock at one point, switching off crews."

A pressing concern from the standpoint of sustaining these high readiness levels is how soon SLEP will get under way. In fiscal year 1996, $37 million was appropriated for the design and validation phase. According to Naval Sea Systems Command, this action followed a study conducted in May 1995 and forwarded to the Office of the Chief of Naval Operations in February 1996. Among other things, the study was to consider linkage between recommended improvements and operational requirements, replacement of obsolete equipment, and changes that would cut operating and support costs.

These objectives could be accomplished by replacing the current skirt, communications, and navigation systems and upgrading the gas turbine engines. The key element in the SLEP is a more aggressive corrosion control program that will support the extension of LCAC life to 30-plus years while reducing operating cost and maintenance workload and improving readiness.

"I think the area where we had the biggest problem with corrosion was underneath the engine modules," Captain Liggett explained. "Saltwater would get in there, and it was hard to get out. Under the SLEP, that portion of the deck will go from aluminum to carbon graphite for corrosion control." Other areas both under the hull and topside will receive improved corrosion protection. Using lessons learned from more than 70,000 hours of operational experience, the SLEP can incorporate modifications that will have a real impact on cost maintenance.

Relative to capabilities, Captain Liggett said, "Hopefully, we'll have all the craft on a baseline, and so the difference between one craft and another after SLEP should be almost indiscernible to the user, the user being the amphibious ready group commander." In light of the LCAC's past performance and its evolution as a multimission craft, the Navy probably will continue to review SLEP schedule options for maximum efficiency. For example, if SLEP were to get under way in fiscal year 1998, ACU-5 could induct three craft into the program that year.

Another factor affecting the timing of SLEP is maintaining industrial capability at the nation's only large aircushion vehicle manufacturer. By transitioning from a mid-life availability (MLA) program to SLEP in 1998, when LCAC-91 is scheduled for delivery as the Navy's last new-construction craft, Textron Marine & Land Systems can execute all the basic SLEP statement of work improvements, with minimal interruption of the production line. As other craft return to the New Orleans facility, the transition from MLA to SLEP would be seamless.

LCAC development also must keep pace with new-construction amphibious ships scheduled to enter the fleet at the turn of the century. For example, without state-of-the-art LCACs in her well deck, LPD-17 forfeits a great deal of her effectiveness. SLEP would be a cost-effective hedge against this happening.

The LCAC's original mission was the transport of wheeled and tracked vehicles, equipment, and supplies from ships at sea to the beach, but two additional missions recently have evolved. The first is carrying people. Following a number of humanitarian missions, the Marines cited a need to conduct noncombatant evacuation operations. Combined with their requirement to move a greater number of troops more safely ashore by LCAC during combat operations, this led to the development of the personnel transport module (PTM).

There are two PTM prototypes operational today, and there are contracts to deliver eight more. They will be pre-staged on the East and West Coasts, with one or two in WestPac Alpha. Capable of moving 180 people with small amounts of equipment, they can be erected in five to six hours and can be used as the operational commander dictates. They have not yet been called on to evacuate noncombatants or combat wounded (they have stretcher capacity), but they were used to move troops in Desert Storm.

The second mission, capitalizing on the LCAC's ability to skim across a variety of surfaces, is deploying surf zone clearance tools such as the shallow water assault breaching (SABRE) and distributed explosive technology (DET) systems, both of which are under development by the U.S. Navy. A new fire-and-forget fuse design is common to each system, but the SABRE launches a 405-foot explosive line, while DET fires a 180-foot by 180-foot explosive net that detonates once it has reached a safe standoff from the LCAC. For the LCAC, the success of this mission relies on a much improved navigation system for precise positioning. The SLEP program is designed to achieve this objective.

At Eglin Air Force Base, Florida, an LCAC participating in joint Navy and Air Force signature testing was outfitted with an Air Force 30-mm Gatling gun (GAU-13), self-contained in the GPU-5 pod and fired against hardened beach obstacles. The LCAC and the GAU-13 proved a potent combination, destroying concrete cubes, Jersey barriers, and hedgehogs at a rate of 2,400 rounds per second. The success of this direct fire demonstration encouraged the Navy to examine existing weapon systems that could be employed on board LCACs in support of the Marine expeditionary unit.

At the U.S. Marine Corps Combat Development Center, the LCAC is such a key element in the Sea Dragon program that planners use the craft as a starting point for practically every project. Potential applications for the LCAC include direct and indirect fire support, logistical support, surf zone mine clearing, and special operations. And while the Marines, primary LCAC users, may wonder how far the mission can extend for a craft at the mid-point of a 20-year service life, they have to take heart that SLEP will keep it around well into the 21st century.


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