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Amphibious Assault Landing Craft (AALC)

Concept Design of the present day LCAC began in the early 1970s with the full-scale Amphibious Assault Landing Craft (AALC) test vehicle. During the advanced development stage, two prototypes where built. JEFF A was designed and built by Aerojet General in California. JEFF B was designed and built by Bell Aerospace in New Orleans, Louisiana. These two developmental prototype air-cushion landing craft, JEFF-A (Aerojet) and JEFF-B (Bell) soon attracted vigorous Marine Corps support. These two craft confirmed the technical feasibility and operational capability that ultimately led to the production of LCAC. JEFF B was selected as the design basis for today's LCAC. In March 1979, management of Landing Craft, Air Cushion (LCAC) and Amphibious Assault Landing Craft (AALC) programs was transferred to PMS377 from PMS300 and SEA 03, respectively.

From the 1960s onward, the Navy and Marine Corps looked for ways of quickly moving vehicles, supplies, equipment, and troops from ship to shore during amphibious assaults. Indeed, this was the main objective of the Navy's Amphibious Assault Landing Craft (AALC) program established in 1968. This effort ultimately led to the introduction of the first Landing Craft, Air Cushion (LCAC), into Navy service in December 1984. LCACs - along with the Advanced Amphibious Assault Vehicle and the MV-22 Osprey tilt-rotor aircraft - will comprise the tactical mobility triad, a vital enabler of the Navy-Marine Corps over-the-horizon amphibious assault plans.

As part of the AALC program, the Navy issued contracts to Aerojet General and Bell Aerospace, Textron for the preliminary design of two so-called JEFF craft, vehicles that could ride a cushion of air over water, land, or ice; carry a payload of approximately 60 tons; and do so at speeds of 40-50 knots. These craft would operate from Navy amphibious warships equipped with well decks.

Reviewing each company's designs, Navy program managers determined that neither design had a clear margin of superiority, so in 1971 the service contracted with the two companies to build prototypes. Aerojet's air-cushion vehicle was dubbed JEFF (A), while Bell's was designated JEFF (B).

Extruded aluminum decking has been used on various Navy craft including the prototype Amphibious Assault Landing Craft (AALC) JEFF(B). However, combining aluminum with steel can present significant corrosion problems due to electrolysis. These problems can be overcome with special treatments of the aluminum and isolation of the aluminum panels from the steel structure with special sealing compounds.

Both firms experienced some difficulties translating their designs into advanced, working vehicles. Aerojet took until 1976 to complete its JEFF (A); JEFF (B) was not completed until 1977. However, the latter craft "flew" first that same year while JEFF (A)'s first test did not occur until October 1978. For several years thereafter, both craft underwent a series of rigorous tests.

By then, Navy and Marine Corps planners had many reasons for wanting to bring the type of capability inherent in the JEFF designs into fleet operation. The AALC program had emphasized the need for the fast and efficient movement of men and supplies, sometimes in the face of inhospitable surf or terrain, to rapidly build up combat power ashore during an assault. As the program progressed, other factors - such as the need to initiate amphibious assaults over the horizon from a defended coastline - became just as salient.

Emerging anti-ship and other weapons were making the tactics and procedures associated with traditional amphibious operations increasingly untenable. No longer could amphibious forces assemble and begin operations within visual or sensor range of coastal defenders, as they had done since the advent of amphibious operations. Naval leaders realized that future attacks on a defended shore would have to be launched from over the horizon, 25 miles or more out to sea. This extra sea space would complicate enemy targeting, give U.S. naval forces additional time to detect and defend against an attack, and preserve the element of tactical surprise as to where a landing would actually occur.

However, if amphibious forces were to remain farther offshore, they would have to develop a faster means of moving the ground combat forces ashore. Helicopters carried by aviation-capable amphibious warships offered one means of moving men and some lighter equipment ashore at these extended ranges. However, helicopters could not transport bulkier or heavier items in the Marine Corps inventory, nor could they move vehicles such as trucks or the Corps' M-60 main battle tanks. Surface transport would be needed to get this heavier equipment ashore, but prior to the LCAC, landing craft had a top speed of approximately 8-10 knots.

This is why the Navy and Marine Corps' selection of a modified JEFF (B) - which became the LCAC that entered service in 1984 - was a critical step forward for U.S. amphibious warfare capability. LCACs in service today can carry a 60-ton payload (75 tons in an overloaded condition) at speeds of up to 40 knots (in sea state 2) and have a nominal range of 200 nautical miles. Additionally, with its air cushion technology, the LCAC can access over 70% of the world's coastlines, in comparison to the 17% for older, "displacement"-type landing craft. It is used to transport equipment and supplies, and sometime personnel, directly to an assigned craft landing zone inland from the beach.

The LCACs achieved initial operational capability in 1986, and the Navy approved full production of the craft in 1987. The first LCAC will reach the end of its expected service life in 2004. An ongoing Service Life Extension Program will extend the service life of each LCAC to 30 years.



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Page last modified: 22-07-2011 17:33:34 ZULU