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Landing Craft Air Cushion (LCAC)

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Presentation on theme: "Landing Craft Air Cushion (LCAC)"— Presentation transcript:

1 Landing Craft Air Cushion (LCAC)
By David Dearie

2 Landing Craft Air Cushion (LCAC)
History Characteristics Maintenance Crew Mission Operational Success

3 Landing Craft Air Cushion (LCAC)
Maintenance Planned Maintenance System Corrected Preventative Packages Operational Costs Welding Man-hours expended

4 Landing Craft Air Cushion (LCAC)
Craft Crew Cabin Crew Qualification Process Ratings

5 Landing Craft Air Cushion (LCAC)
Mission Ready for Tasking Ship to Shore Over The Horizon (OTH) Direct USMC Support Non-Military utilization

6 Landing Craft Air Cushion (LCAC)
Operational Success Navy and Marine Corp Humanitarian Katrina Tsunami Los Angeles Fire Department Special Operations

7 Landing Craft Air Cushion (LCAC)
History Original hovercraft concept Early years JEFF A/B Hovercraft around the globe War and Peace Take Quiz and answer.

8 History A hovercraft is a craft capable of traveling over relatively smooth surfaces supported by a cushion of slow moving, high-pressure air, ejected against the surface below, and contained within a “skirt.” Although supported by the air, they are not usually considered to be an aircraft. The idea of using an air-cushion as a means or aid to acceleration and reduction in (hydrodynamic) drag was first explored by Sir John Thornycroft, a British engineer, who, in the 1870's built some experimental models on the basis of an air cushion system that would reduce the drag of water on boats and ships. In 1877 he successfully patented the idea and his theory was that if a ship's hull was given a concave bottom, which could be filled - and replenished - with air, it would create significant additional lift. And so the air cushion effect was born. Decades later scientists and inventors were still busy with his ideas but without any practical applications. With the coming of the airplane however, it was noticed that additional lift was obtained if the plane flew closer to land or water, creating a "funnel effect", a cushion of air. The next two decades saw little interest in air cushion development. World War 1 saw a huge increase in the development of the airplane as a military weapon and even though the ground effect was known, airplanes were designed for speed and maneuverability in the air rather than close to the ground

9 Early Years Lighter Air Cushioned Vehicle - an air cushion vehicle craft that travels over water, beaches, soft or firm ground, snow or ice at speeds of up to fifty miles per hour. The craft has an open deck space with a total payload capacity of thirty tons. The LACV-30 is approximately 40 ft wide by 80 ft long, weighs about 65,000 lbs empty, can carry up to 60,000 lbs of cargo, utilizes gas turbines to power its twin propellers, and can cruise at speeds of up to about 60 mph. A major Army mission is to ensure the adequate flow of supplies and materiel to the various field elements deployed worldwide. With commercial shippers converting to containerized cargo, the Army realized that some of its then current watercraft would inhibit fast turnaround of container ships and thereby reduce productivity. The Army concluded that the air cushion vehicle concept should be developed for use in an over-the-shore logistics operation.

10 Early Years The successful use of the air cushion effect was not lost on engineers after World War 2 was over and in the early 1950's British, American and Swiss engineers started to rethink Sir John Thornycroft's problem. The Englishman Christopher Cockerell, commonly seen as the father of the hovercraft, being retired from the army, settled into boat building where he soon got captivated by Thornycroft's problem of reducing the hydrodynamic drag on the hull of a boat by using some kind of air cushion. His theory was that, instead of using the plenum chamber - an empty box with an open bottom as Thornycroft had devised - air was instead pumped into a narrow tunnel circumnavigating the entire bottom, it would flow towards the center and form a more effective air cushion. This peripheral jet would cause the air to build up enough pressure to equal the weight of the craft and, as it would have nowhere to go, the pressure would force the craft up, clearing it off the ground altogether. Cockerell successfully tested his theory and filed his first patent in The year after he formed a company called Hovercraft Ltd. He further envisioned and partially worked out other problems of the hovercraft principle that still have to be fully exploited by modern hovercraft builders. One of these was to re-use the air for greater overall efficiency. Thinking that his air cushion vehicles would be eminently suitable as amphibious craft he approached the British Ministry of Supply, the government's defense equipment procurement authority with his findings. Soon after, in 1956, the air cushion vehicle was classified as "secret" and a construction contract was placed with a British aircraft and seaplane manufacturer. The result was the SR.N1 in 1959. The first SR.N1 weighed four tons and could carry three men. Its maximum speed was 25 knots (1 knot = 1.15 miles or 1.85 kilometres per hour) on calm water. It had a 6-inch (15 cm) rubberized skirt to make it easier to contain the air cushion on uneven ground. By this time the Americans, the French, Japanese and Swedes had begun to be interested in the air cushion vehicle and its possibilities and companies sprang up the world over.

As far as experimental vehicles were concerned the Soviets, in their race for technological supremacy, were as prolific as the Americans in building craft of all sizes, shapes and types. Nothing was too weird or technologically theoretical but it was built. Especially after World War 2, during the 1950's and 1960's did experimental constructions reach extraordinary proportions.

11 It took 25 charges to sink me!
Jeff A/B It took 25 charges to sink me! Jeff A Jeff B

12 Around The Globe Russian Swede China

13 Russian This is the world’s largest military hovercraft and it belongs to the Russian army. It is armed with missiles, artillery and anti-aircraft defense guns and can carry a few heavy tanks at once. After approaching to the enemy coastline it can give a burst of fire to tear of such fierce force that can tear big military ship apart, then without any slowing down start moving on the shore advancing deep inside to unload the tanks and infantry.

14 China The 540-ton Zubr LCAC, the world’s largest amphibious assault hovercraft, can reach speeds in excess of 60 knots, can travel 300 nautical miles and can shoulder various large loads: 130 tons of cargo, 500 troops, three 50-ton medium battle tanks, 10 BTR-70 armored personnel vehicles or eight BMP-2 infantry fighting vehicles.

15 Sweden Hovercraft 2000, which is the Swedish name of the vehicles, will perform the same function as defense Light Faith boats and so called Stridsbåt 90. First task is therefore transportation of troops. Hovercraft 2000 takes up to 50 troops / passengers, compared with Stridsbåt 90, which holds up to 16 people. Floats can easily be converted to freight traffic.

16 Christopher Cockerell
A fan draws air from the ambient atmosphere at pressure pa and compresses it to a stagnation pressure po in the reservoir inside the vehicle.  The air then exhausts downward through a narrow slot of width w at the periphery of the vehicle (w<<R), creating a condition that maintains a positive gage pressure (an "air cushion") underneath the vehicle. This allows the vehicle to float at a height h above the ground. Air Flow 4 Tons 3 man crew 25 Knots (1 knot = 1.25 mph: 25knots=28.8mph First Hovercraft Military Transportation

17 War and Peace Hovercraft serve different missions depending the country and the climate. We have seen many countries have a flavor of hovercraft. The USA uses hovercraft routinely during war and peace. Vietnam. This hovercraft was used to clear areas of Vietnam in a matter of hours that would normally take weeks. Often traveling at speeds greater than 60 MPH, they carried both offensive and defensive weapons. Today. The hovercraft today are primarily used to transport troops and equipment to the beach and return to the “mother ship.” Not equipped to fight, their speed and agility are their only defense.

18 Landing Craft Air Cushion (LCAC)
Characteristics of an LCAC Specifications Differences Comparisons Take Quiz

19 Characteristics LCAC General Characteristic
Builder: Textron Marine and Land Systems/Avondale Gulfport Marine. Date Deployed: 1982. Propulsion: Legacy 4-Allied-Signal TF-40B gas turbines (2 for propulsion / 2 for lift); 16,000 hp sustained; 2-shrouded reversible pitch airscrews; 4-double-entry fans, centrifugal or mixed flow (lift)SLEP 4–Vericor Power Systems ETF-40B gas turbines with Full Authority Digital Engine Control Length: 87 feet 11 inches (26.4 meters). Beam: 47 feet (14.3 meters). Displacement: 87.2 tons (88.60 metric tons) light; tons ( metric tons) full load. Speed: 40+ knots (46+ mph; kph) with full load. Range: 200 miles at 40 kts with payload / 300 miles at 35 kts with payload. Crew: Five. Load: 60 tons / 75 ton overload (54.43/68.04 tonnes) Armament: mm MGs. Gun mounts will support: M-2HB .50 cal machine gun; Mk-19 Mod3 40mm grenade launcher; M-60 machine gun. Electronics: Radars, Navigation: Marconi LN 66; I band / Sperry Marine Bridge Master E.

20 Characteristics Legacy – Original craft from 1983
SLEP – Service Life Enhancement Program FMP – Fleet Modernization Plan LACV – Light Air Cushion Vehicle

21 Characteristics Comparisons of LCAC – Travel in excess of 50 knots
Fuel of 300 NM Capable of carrying 60 – 75 ton payload Crew of 5 LCU – Landing Craft Utility Self-sustaining with accommodations and galley 2 Detroit Diesel engines 11 knots, 1200 NM range, carry 170 ton payload Crew of 14


2. Presentation C. LCAC Characteristics/Systems (III) Components Skirt System Identify all parts of the skirt system.

24 Propeller System There are two 11 foot, 9 inch diameter propellers on the stern of the craft Major components consist of Shroud - 14 ft outside diameter Propeller spinner Drive adapter Propeller assembly Propeller controls Hydraulic system 360 degree FOD screen The propellers are controllable as far as the pitch angle is concerned. The angle can be changed from +40 degrees forward to -35 degrees reverse pitch


DISCUSSION POINT RELATED INSTRUCTOR ACTIVITY 2. Presentation D. LCAC Capabilities and Limitations Discuss LCAC minimum operational temperature and cold weather kit. Refer to SEAOPS Volume I, page 1-7 and to 1-70. -30° FAHRENHEIT (-34.4° CELSIUS)

27 120 ° FAHRENHEIT (48.8° CELSIUS)
DISCUSSION POINT RELATED INSTRUCTOR ACTIVITY 2. Presentation D. LCAC Capabilities and Limitations Discuss LCAC maximum operational temperature and hot weather operations. Refer to SEAOPS Volume I, page 1-7. (48.8° CELSIUS)

28 Landing Craft Air Cushion (LCAC)
Maintenance (UNDER CONSTRUCTION) Planned Maintenance System Packages Corrective and Preventative Operational Costs Welding Man-hours expended

29 Maintenance Packages

30 Maintenance Corrective and Preventive

31 Maintenance Corrosion

32 Maintenance Man-hours expended

33 Craft Crew Cabin Crew (Starboard) Cabin Crew (Port)
Craftmaster – Senior Enlisted Sailor who drives or “pilots” the LCAC. Engineer – Petty Officer Second or above with an engineering source rating. Navigator - Petty Officer Second or above with a Quartermaster or Operations Specialist. Cabin Crew (Port) Loadmaster – Typically a Petty Officer Third Class or above with a Boatswain mate source rating. Deck Mechanic – Junior Sailor with an engineering rate background.

34 Craft Crew Qualification Process
Initial Program Entry Qualification Process – Minimum aptitude Five year program commitment No conviction at Non-Judicial Punishment (i.e., Captain’s Mast) in past 12 months. Medical screening Initial and Follow-up Training Craftmaster, Engineer, Navigator (Starboard Cabin Crew) – six month school to include classroom, simulator, and hands-on and and night flight training. Must maintain proficiency of 20 hours a quarter, 10 must be night hours. Load Master and Deck Mechanic – 50 flight hours plus six weeks of classroom study.

35 Craft Crew Ratings

36 Landing Craft Air Cushion (LCAC)
Mission Ready for Tasking Ship to Shore Over The Horizon (OTH) Direct USMC Support Non-Military utilization

37 Mission Over the Horizon (OTH) Ready for Tasking (RFT) Ship to Shore
Requirements for LCAC operations is derived from multiple operation plans (called “O Plans). These classified documents direct military insertion into hostile territories over a period of time. Minimum LCAC requirements within these O Plans dictate quantity of LCAC inventory should be RFT on a daily basis. However, because of equipment casualty and maintenance, actual RFT numbers may be below O Plan tasking, an average of 80% is realistic, if not higher. Ship to Shore LCAC’s success stems from time and distance more than payload. As learned earlier there are other waterborne craft that can carry more resources longer distances but in a greater amount of time (LCU for example). For resupply after establishing base camp this is acceptable. LCAC’s provides immediate and rapid responses of Marines and cargo into a hostile landing zone in a fraction of the time. Over the Horizon (OTH) Benefit of LCAC speed and agility is OTH tasking. Naval ships can sit just OTH from shore, approximately 26 miles, and deliver troops and cargo to the beach. This keeps the enemy from engineering an attack on the delivery ships.

38 Mission Direct USMC Support Non-Military utilization LCAC Delivery
LCAC’s main mission, deliver Marines and cargo to the beach. The slogan, “No Beach Out of Reach” is a testimony of our mission and success. LCAC’s can transport tons of payload to include weapons systems, equipment, cargo and personnel of the assault elements of the Marine Air-Ground Task Force from ship to shore and across the beach. LCAC can also carry heavy payloads, such as an M-1 tank, at high speeds. The air cushion allows the LCAC to reach more than 70% of the world's coastline. Conventional landing craft can land at only 15% of coasts. To launch and recover conventional landing craft, the ship can ballast over 15,000t of seawater to allow these craft to float into and out of the well deck. Non-Military utilization Los Angeles fire department entered into a memorandum of agreement to have LCAC’s delivery fire fighting vehicles throughout the coast, including Catalina Island, to reach difficult or impossible areas to access. LCAC Delivery LCAC’s must be delivered via ship to their ultimate location. The following ships are designed to carry, repair, and fuel LCAC’s. LSD LHA LPD 1 LPD 17

39 Mission LHD/LHA LPD/LSD
WASP/TARAWA Class. Off the beach, landing craft are launched and recovered through the very large stern gate, which opens the well deck to the sea. This well deck is 267ft long, 50ft wide and is designed specifically for the fly-in / fly-out capabilities of the air-cushioned landing craft (LCAC). LPD/LSD AUSTIN/SAN ANTONIO Class. The LPD 4 Austin class of ship combines the functions of three different classes of ships; the landing ship (LSD), the tank landing ship (LST), and the attack cargo ship (LKA). The LPD 17 class program will be the replacement for three classes of amphibious ships that have reached the end of their service life – LPD 4, LSD 36, LST 1179.

40 LSD 36 CLASS 2 LCAC Anchorage class 2 LCAC for normal ops
can carry 3 if mezzanine ramp removed (not done on West coast) 2 LCAC

41 LSD 41 CLASS 4 LCAC Whidbey Island class 3-4 LCAC for normal ops
5 LCAC for admin load Note: Spot 1 has wave guard 4 LCAC

42 LSD 49 CLASS Harpers Ferry class 2 LCAC for normal ops 2 LCAC

43 LHA 1 CLASS Tarawa class 1 LCAC 1 LCAC

44 LHD 1 CLASS Wasp class 3 LCAC for normal ops 3 LCAC

45 LPD 1 CLASS 1 LCAC emergency haven 1 LCAC

46 LPD 17 CLASS 1 LCAC emergency haven 2 LCAC

47 Operation Success Navy and Marine Corp
LCAC’s are used throughout the world. Since the first LCAC deployment in 1986, only one craft of the 91 inventory experienced a collision with injuries. The craft was later destroyed. Humanitarian Katrina Tsunami Los Angeles Fire Department Special Operations

48 Operation Success Tsunami Sumatra END Video

49 Operation Success Final Video from years ago: Part 1 Part 2 To The

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