Saturday, August 9, 2008

More History...


Civil commercial hovercraft

The British aircraft manufacturer Saunders-Roe which had aeronautical expertise developed the first practical man-carrying hovercraft, the SR-N1, which carried out several test programmes in 1959 to 1961 (the first public demonstration in 1959), including a cross-channel test run. The SR-N1 was powered by one (piston) engine, driven by expelled air. Demonstrated at the Farnborough Airshow in 1960, it was shown that this simple craft could carry a load of up to 12 marines with their equipment as well as the pilot and co-pilot with only a slight reduction in hover height proportional to the load carried. The SR.N1 did not have any skirt instead using the peripheral air principle that Sir Christopher has patented. It was later found that the craft's hover height was improved by the addition of a 'skirt' of flexible fabric or rubber around the hovering surface to contain the air. The skirt was an independent invention made by a Royal Navy officer, C.H. Latimer-Needham, who sold his idea to Westland (parent company of Saunders-Roe), and who worked with Sir Christopher to develop the idea further.

The first passenger-carrying hovercraft to enter service was the Vickers VA-3, which in the summer of 1962 carried passengers regularly along the North Wales Coast from Moreton, Merseyside to Rhyl. It was powered by two turboprop aero-engines and driven by propellers.

During the 1960s Saunders-Roe developed several larger designs which could carry passengers, including the SR-N2, which operated across the Solent in 1962 and later the SR-N6, which operated across the Solent from Southsea to Ryde on the Isle of Wight for many years. Operations by Hovertravel commenced on 24 July 1965 using the SR-N6 which carried just 38 passengers. Two modern 98 seat AP1-88 hovercraft now ply this route, and over 20 million passengers have used the service as of 2004.

In 1966 two Cross Channel passenger hovercraft services were inaugurated using hovercraft. Hoverlloyd ran services from Ramsgate Harbour to Calais and Townsend Ferries also started a service to Calais from Dover, which was soon superseded by that of Seaspeed.

As well as Saunders-Roe and Vickers (which combined in 1966 to form the British Hovercraft Corporation (BHC)), other commercial craft were developed during the 1960s in the UK by Cushioncraft (part of the Britten-Norman Group) and Hovermarine (the latter being 'Sidewall Hovercraft', where the sides of the hull projected down into the water to trap the cushion of air with 'normal' hovercraft skirts at the bow and stern).

The world's first car-carrying hovercraft made their debut in 1968, the BHC Mountbatten class (SR-N4) models, each powered by four Rolls-Royce Proteus gas turbine engines. These were both used by rival operators Hoverlloyd and Seaspeed to operate regular car and passenger carrying services across the English Channel. Hoverlloyd operated from Ramsgate, where a special hoverport had been built at Pegwell Bay, to Calais. Seaspeed operated from Dover, England to Calais and Boulogne in France. The first SR-N4 had a capacity of 254 passengers and 30 cars, and a top speed of 83 knots (154 km/h/96 mph). The Channel crossing took around 30 minutes and was run rather like an airline with flight numbers. The later SR-N4 MkIII had a capacity of 418 passengers and 60 cars. These were later joined by the French-built SEDAM N500 Naviplane with a capacity of 385 passengers and 45 cars, of which only one example entered service and was used intermittently for a few years on the cross-channel service until returned to SNCF in 1983. The service ceased in 2000 after 32 years, due to competition with traditional ferries, catamaran, the advancing age of the SR-N4 hovercraft and the opening of the Channel Tunnel.

In 1998, the US Postal Service began using the British built Hoverwork AP.1-88 to haul mail, freight, and passengers from Bethel, Alaska to and from eight small villages along the Kuskokwim River. Bethel is far removed from the Alaska road system, thus making the hovercraft an attractive alternative to the air based delivery methods used prior to introduction of the hovercraft service. Hovercraft service is suspended for several weeks each year while the river is beginning to freeze to minimize damage to the river ice surface. The hovercraft is perfectly able to operate during the freeze-up period; however, this could potentially break the ice and create hazards for villagers using their snowmobiles along the river during the early winter.

The commercial success of hovercraft suffered from rapid rises in fuel prices during the late 1960s and 1970s following conflict in the Middle East. Alternative over-water vehicles such as wave-piercing catamarans (marketed as the SeaCat in Britain) use less fuel and can perform most of the hovercraft's marine tasks. Although developed elsewhere in the world for both civil and military purposes, except for the Solent Ryde to Southsea crossing, hovercraft disappeared from the coastline of Britain until a range of Griffon Hovercraft were bought by the Royal National Lifeboat Institution.

In Finland small hovercraft are widely used in maritime rescue and during the rasputitsa ("mud season") as archipelago liaison vehicles. In England, hovercraft of the Burnham-on-Sea Area Rescue Boat (BARB) are used to rescue people from thick mud in Bridgwater Bay. Also Avon Fire and Rescue Service became the first fire service in the UK to operate a hovercraft. It is used to rescue people from thick mud in the Weston-super-Mare area and during times of inland flooding.

The Scandinavian airline SAS used to charter an AP. 1-88 Hovercraft for regular passengers between Copenhagen Airport, Denmark and the SAS Hovercraft Terminal in Malmö, Sweden.

An experimental service was operated in Scotland across the Firth of Forth (between Kirkcaldy and Portobello, Edinburgh), 16-28 July 2007. Marketed as Forthfast, the service used a craft chartered from Hovertravel Ltd and achieved 85% loadings. The possibility of establishing a permanent service is now under consideration. [3]

Following the abandonment of hovercraft use across the English Channel, and pending any reintroduction on the Scottish route, the United Kingdom's only public hovercraft service is that operated by Hovertravel between Southsea (Portsmouth) and Ryde, on the Isle of Wight.

From 1960s, several commercial lines were operated in Japan, without much success. In the country, the only commercial line still available is the one that links Ōita Airport and the central Ōita.


Military hovercraft


A US Navy LCAC hovercraft assigned to USS Iwo Jima (LHD-7).First applications of the hovercraft in military use was with the SR.N1 through SR.N6 craft built by Saunders-Roe in the Isle of Wight in the UK and used by the UK joint forces. To test the use of the hovercraft in military applications the UK set up the Interservice Hovercraft Trials Unit (IHTU) base at Lee-on-the-Solent in the UK (now the site of the Hovercraft Museum). This unit carried out trials on the SR.N1 from Mk1 through Mk5 as well as testing the SR.N2, 3, 5 and 6 craft. Currently the Royal Marines use the Griffon 2000TDX as an operational craft. This craft was recently deployed by the UK in Iraq.

In the US, during the 1960s, Bell licenced and sold the Saunders-Roe SRN-5 as the Bell SK-5. They were deployed on trial to the Vietnam War by the Navy as PACV patrol craft in the Mekong Delta where their mobility and speed was unique. This was used in both the UK SR.N5 curved deck configuration and later with modified flat deck, gun turret and grenade launcher designated the 9255 PACV. The United States Army also experimented with the use of SR.N5 hovercraft in Vietnam. Three hovercraft with the flat deck configuration were deployed to Dong Tam in the Mekong delta region and later to Ben Luc. They saw action primarily in the Plain of Reeds. One was destroyed in early 1970 and another in August of that same year after which the unit was disbanded. The only remaining U.S. Army SR.N5 hovercraft is currently on display in the Army Transport Museum in Virginia. Experience led to the proposed Bell SK-10 which was the basis for the LCAC-class air-cushioned landing craft now deployed.

The Soviet Union was one of the first few nations to use a hovercraft, the Bora, as a guided missile corvette.

The Finnish Navy designed an experimental missile attack hovercraft class, Tuuli class hovercraft, in the late 1990s. The prototype of the class, Tuuli, was commissioned in 2000. It proved an extremely successful design for a littoral fast attack craft, but due to fiscal reasons and doctrinal change in the Navy, the hovercraft was soon withdrawn.

The Hellenic Navy operates four Russian-designed Zubr class LCAC. This is the world’s largest military air-cushioned landing craft.

Credit to wikipedia
site can be viewed with links at;http://en.wikipedia.org/wiki/Hovercraft

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