deploying military hovercraft. During the Cold War, it built several types of amphibious assault hovercraft for the Northern, Baltic, and Black Sea fleets. Their planned targets were rocky coasts where conventional landing craft have little or no utility. But with hovercraft able to cross something like 70 % of the worlds coastlines (versus 17 % for conventional landing craft), they became a natural choice for Soviet Naval Infantry. Large troop- and vehicle- carrying hovercraft, known by NATO reporting names like
Early Western hovercraft were smaller, like the British-designed SR.N5 (called the PACV-series, when built by Bell for U.S. service), carrying an infantry squad or platoon. Field trials included combat deployments to Vietnam and Malaysia, with mixed results. The plus side was their speed and agility across rivers, swamps, and bays. The downside was vulnerability, especially their rubber skirts and propulsion systems. Despite this, Great Britain and Iran (under the last Shah) purchased many patrol hovercraft. Several factors kept hovercraft from entering Navy service as quickly — mainly money. The war in Vietnam was a huge financial drain in the 1960s and 1970s. The Navy and Marine Corps only began developing an amphibious hovercraft in the 1970s.
In late 1976 the Navy formalized a requirement and opened the competition for a Landing Craft, Air Cushioned (LCAC). Two contractors, Aerojet-General and Bell Aerospace (now Bell-Textron Land-Marine Systems in New Orleans, Louisiana), designed and built prototypes in the hope of winning a production contract for a planned fleet of over one hundred LCACs. The requirement included specifications for payload (up to 150,000 1b/68,182 kg), speed (greater than 50 kt/ 91 kph), and range (up to 200 nm/365 km at cruising speed). The Aerojet-General prototype was called JEFF-A; the Bell entry was JEFF-B. They looked similar when placed side by side. The competition was fierce, with both designs showing advantages and faults. In the end, Bell's JEFF-B design won, entering production as the Navy's new LCAC. JEFF-B's shorter length (87 ft/26.5 m versus 100 ft/30.5 m for the JEFF-A) and lower displacement (160 tons versus 162.5 tons) were decisive factors. In 1982, the Navy issued the first production contract for three LCACs. First delivery came in 1984, followed by ship compatibility trials. Lockheed Shipbuilding (later acquired by Avondale Shipbuilding) was certified as a second-source contractor, but Bell-Textron has built the majority of the craft.
By the late 1980s, several dozen LCACs were in service with the Navy, aboard a dozen amphibious ships in the Pacific and Atlantic fleets. Seventeen LCACs served on six LSDs during Desert Shield and Desert Storm, providing much of the lift during those operations. Though they did not conduct any assault landings, the amphibious forces offshore tied down over seven Iraqi divisions in coastal defenses around Kuwait City. The LCACs maintained a 100 % availability rate throughout nine months of operations in the Persian Gulf, giving ARG commanders great confidence in their reliability. Since that time, the fleet has shifted the bulk of landing craft duty to the LCACs. In humanitarian and peacekeeping operations in Bangladesh, Haiti, and Somalia, and regular operations in ARGs, the LCACs again proved their worth. The total force of 91 LCACs was nearly complete by early 1996. More were planned, but the Navy's drawdown cut the original target of 107 units. The force of 91 LCACs is a national treasure which is being used hard.
To understand the LCACs, you need to visit one of two bases constructed to service them. I visited the LCAC facility at the Naval Amphibious Base at Little Creek, near Norfolk, Virginia. This is the home of Assault Craft Unit (ACU) 4, the core unit for Atlantic Fleet-based LCACs. A similar facility services ACU 5 (the Pacific Fleet unit) at Camp Pendleton, California. ACU 4 operates roughly forty LCACs, providing detachments of hovercraft to Atlantic Fleet amphibious ships. The size of these detachments varies according to ship type. The following table summarizes the LCAC capacity of various ships:
Given the mix of ships within an ARG, a MEU (SOC) commander might have between six and nine LCACs in his well decks. That is a lot of capability to project Marines and firepower in just a few small packages. The ARG commander must manage this handful of LCACs carefully.
As you walk up to an LCAC on the ramp at Little Creek, the first thing you notice is that it looks much more like an aircraft or spacecraft than a warship. Much of the design for the LCAC was based on aircraft structures and technology to reduce weight and maximize payload. The LCAC is basically a platform with lift fans underneath, and twin deckhouses and engines along the sides. There are ramps at both ends, and a large rubber skirt running around the sides. Most of the structure is aluminum alloy, with some ceramic splinter armor. LCAC has to be able to survive hits when it works inshore. The threats range from artillery to anti-tank guided missiles. The four Avco- Lycoming TF-40B gas-turbine power plants provide a total of 12,444 shp/11,800 kw, and are mounted in pairs. Two engines drive the four 5.25-ft/1.6-m-diameter lift fans. The other pair drive the two 11.75-ft/3.6-m-diameter propulsion fans. Steering is done with variable-pitch propellers, aerodynamic rudders, and a pair of rotatable bow thruster nozzles. With a nominal load of fuel and a sixty-ton payload, LCAC can sustain up to 50 kt/91 kph in seastate 2 (a light chop) for a range of up to 328 nm/607 km. By cutting the payload, longer ranges can be obtained.
As you walk up the bow ramp, you enter a large (67-by-27-ft/20.4-by-8.2 m) cargo stowage area. Cargo tie-down points stud the decking, and there is a decided 'crown' (or hump) to the deck to drain off any seawater. A nominal load of 119,980 1b/54,421 kg can be spread over 1,809.5 ft/168.1 m of space. If necessary, this can be raised to an overload of 149,978 lb/68,027 kg as long as the seastate is moderate (the pounding of the waves in a high seastate can cause structural damage). Along with the deck cargo, there is room in the deckhouses for twenty-three passengers. Passenger accommodations are decidedly austere and very noisy when the LCAC is underway.
On the starboard side is the control cab, where the crew of five is located. This includes the LCAC commander, pilot, engineer, and navigator. U.S. Navy landing craft are commanded by a chief petty officer instead of a commissioned officer. This tends to make life aboard the landing craft a bit more relaxed and earthy than what you find aboard large amphibs; but don't think the enlisted crews of landing craft are lax about their responsibilities. On the contrary, they are highly professional, and over the last five decades, have won their share of Medals of Honor and Navy Crosses. Accommodations on the LCACs are spartan, with few of the 'homey' amenities that we would find in the LCUs. Crews live on-board the ships where they are based, since LCACs lack galley and berthing facilities.
The control cab is laid out like an aircraft cockpit, which makes sense when you consider that an LCAC is more an aircraft than a surface craft. In fact, LCAC missions are listed on the daily ARG/MEU (SOC) air tasking order, to avoid interference with flight operations by helicopters and V/STOL aircraft. The control stations for the navigator, engineer, and pilot are laid out left to right. In addition to the throttle controls for the four TF-40B gas- turbine engines, there is a helm control station with instruments to assist in steering and navigation. These include a modified LN-66 navigation radar (to detect surface targets and land masses); an inertial system, known as the Attitude Heading and Reference Unit (AHRU); and a speedometer known as the High-Speed Velocity Log (HSVL). Like the Doppler sensing systems used on helicopters, described
The LCAC's role makes good communications a mission-critical feature. The LCAC is much faster than any previous landing craft. Speeds of up to 50+ kt/91 + kph are common, depending on load and seastate. This capability means that the big amphibious ships that operate LCACs no longer need to stand a few thousand yards/meters off of an enemy coastline, vulnerable to enemy fire. In fact, LCAC-EQUIPPED ships can stay up to 50 nm/91 km offshore and still be able to put a wave of loaded LCACs onto a beach every three hours. This three-hour cycle time is the normal turnaround used by Navy and Marine planners in landing operations. It assumes an hour each way for transit time, plus a half hour on each end for loading and unloading. This is what 'standoff' really means, and LCAC is the first of three new systems (LCAC, the MV-22B, and the AAAV) that makes standoff amphibious assault possible.
You may wonder why so many navigational systems are necessary. If you have ever tried to navigate a boat 50 nm/91 km offshore, you would understand! As you approach a coastline, the reference points you use to determine your course and position are slow to appear, and even easier to miss. Now add in fog, rain, spray,
