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A Hovercraft is a craft that travels while hovering on a cushion of high pressure air.

The hovercraft as we know it is a relatively modern invention. The first working model was made in 1955, and the first full size hovercraft in '59. But the idea of using a cushion of air to support, or partial support, a vehicle is not new.

When anything moves through a fluid, such as air, water, or tea, ******** The denser the fluid, ***** This is true when a boat moves through water. Now, there are many ways that this ***** can be reduced, such as designing the craft to be well streamlined; but even on the most streamlined boats, the **** is considerable. But moving through air causes much less ***** than moving through water, so the idea was proposed to lift the hull of the ship partially, or fully, out of the water. This would reduce friction, as more of the craft would be moving through air, and less through water.

The earliest reference to this idea was in 1716 by Emanuel Swedenbørg.¹ As he hadn’t got a sufficiently powerful engine, he couldn't build his plans. Many other efforts were made, with much of this work was carried out by Thorneycroft technical name pending in the Victorian era. ( Thorneycroft would, after merging with Vospers, go on to make some real hovercraft in the 60's and 70's. )

But the real problem was with air leakage. Lift any weight above a surface, and the air just flows away. You can lift a craft up a few feet with little difficulty, but completely lifting a craft above the surface is a different matter unless you are going to use vast, and uneconomical, quantities of power.

A solution to this problem was found by Christopher Cockerell, ( later knighted, ) who discovered that by directing a ring of air at a surface, the moving air forms a 'momentum curtain', a virtual wall, trapping a cushion of high pressure air within itself.

As was the custom, he took his design to the Government. The politicians saw it's potential, and put it on the official secrets list. But the Navy said it was an aeroplane, the RAF said it was a boat, and the Army weren’t interested either. Thus it needlessly remained classified for about 3 years, but as the forces had no need for the hovercraft, it was de-listed. Fortunately for Cockerell, he was living in the middle of Harold Wilson's White Heat of Technology. Vast quantities of money were available to be spent on research. When the hovercraft design was handed to the NRDC², who, in the Autumn of ‘58, contracted Saunders Roe Ltd. to build a prototype.

Working at brake neck speed, they had finished within a year. They named it the SR·N1Saunders Roe Nautical One, ) it was first 'flown' on the 11th of June. ***** On the 25th of July, ‘59, after being shipped over to France, it crossed the ‘Channel, in 2 hours and 3 minuets. It was 50 years to the day after the first aeroplane crossing by Louis Blériot.

However, although this ‘momentum curtain’ worked, it just wasn't enough. The SR·N1 hovered only 23cm above the ground - enough for it to operate in fair weather, but even then, small waves started to be a problem.

The next improvement was made by Cecil Hugh Latimer-Needham who invented the 'skirt' - two rubber sheets attached to the base of the hovercraft. The air would be blow through it, and the same momentum curtain would be formed, only it would flex in sympathy with the surface which it travelled over. Saunders roe built the skirt, and installed it on their SRN1, but unfortunately the design was found to be flawed. When the hovercraft flew over an obstacle, the outer sheet would bend in more than the inner ring, meaning that the flow of air was reduced, and the hovercraft would drop at that point, causing the hovercraft to ‘plough in’,

It was Denys Bliss, who was at the time working at HDL, who solved this problem. His design used a single rubber sheet bent into a U shape. **** When air was blown into the skirt, it would expand out to form a large 'bag'. This time, when demonstrated on the SR·N1, the ’craft flew over an obstacle, the entire skirt bent, but as the flow of air wasn’t hindered, and the hovercraft would continue smoothly on.

Over in France, Jean Bertin had been developing a diferent solution to the same problem. On his 'craft, he used multiple, but smaller, skirts. It was easier to change a single skirt should it become damaged, but as the skirt leaked more air, the craft was less economical to run.

Sauders and Roe wern't no launch their second craft, the SR·N2 until '62. During that time, they developed the SR·N1. But others were at work. The CC·1 from Britten Norman was launched in '60, and the VA·1 from Vickers Armstrong in '61

In Xx, ‘60, Britten Norman Ltd.‘s first hovercraft, CC1, was first trialed, becoming the second hovercraft to fly.

After the CC1, Cushioncraft built the CC2. This could carry 11 passengers, and was the first hovercraft to be put on the comercial market. Three were made over the next several years, two were sold to the Ministry of Technology, and the other was ******.

The SRN2 was launched in January, ‘62. It was a passenger hovercraft, originally taking xx passengers. ( It was later adapted to take ‘52. ) Public Service started on the 11th of August that year, taking passengers over the Solent. It was a hefty 10' each way, but they still managed to get xx passengers over that summer. ( They stopped in winter because the hovercraft couldn‘t cope with the weather. ) By this time, Wesland Aerocraft had taken over Saunders Roe hovercraft department.

By now, the hovercraft was receiving enormous public attention. Their futuristic feel made them popular, and they were shown at the ‘expos of the time.

In May ‘62, Vickers Armstrong launched their third hovercraft, the VA3. It was, like the SRN2, designed for passenger service. It was launched later than the SRN2, but they still managed to start public service first, operating across the Dee Estuary between Ryle, Wales, and Wallasea, near Liverpool. The service started on the 20th of July, and was planned to run 12 services a day for a 59 day trial. Due to technical problems and Bad weather, 23 days of the service had to be canciled. It‘s use as a passenger craft ended on the 17th of September, when it broke lose during extreme weather. The craft was still operatable even though no longer fit for passenger use. It ended life with the IHTU, being blown up during mine tests.

An Experimental service was run by P & A Campbell Ltd. over the Bristol Channel between the 23rd of July to the 30th of August. The service ran between Weston-super-Mare and Penarth, Wales

That same year, Westland Aerocraft’s laid down a production line to produce the SRN5 and SRN6 ‘craft. The SRN6 was a longer version of the SRN5. First launched on the 11th of April, ‘64, the SRN5/6 became Westland Aerocraft‘s most popular model. They were put into use all other the globe. Although they did make the hovercraft affordable to many non-spesialist operators, they received a lot of critisism, due to the high noice levels, the low efficiency, and the tendance to capsise in bad weather. In fact, their tendancy to capsise was so bad, that Westland started including an emergence exit in the floor of the craft!

From the 11th of April to the 31st of October, Hovertravel operated a service across the Solent Using the first SRN5. After the first two weeks, the SRN2, which had been modified, joined the SRN5. 30,000 passengers were carried on the service.

Meanwhile, in Scotland, William Denny and Brothers Limited were building their first hovercraft, the D1, the first sidewall.

The idea of a sidewall was to provide a compramise between the speed of a hovercraft and the efficiency of a ferry. By effectively having two hulls on either side of the hovercraft, no air would be able to excape, cutting down air leakage to only a third or less. This greatly improved fuel consumption, but it meant that one of the hovercraft main advantages, that of being ampiphibious, was lost. But for the many situations that the hovercraft was used as a ferry, this didn‘t really matter.

Another advantage of the sidewall was that traditional ‘water screws’ could be used, unlike fully ampiphibious hovercraft, which had to use propelors. This was quiter and more efficient.

Denny launched their second hovercraft, the D2, in ‘63. It could carry about 70 passengers. The ‘craft was origionaly designed for the Navy, but it was rejected by the IHTU. William Denny and Brothers Ltd. had been Liquidated by then, but Denny Hovercraft Ltd. was still going. As the Navy had no use for the craft, they launched a hoverbus service on the Thames. The D2 002 travel 600 miles down to London for this purpose. The service was expensive, charging £1 a time. Four of the D2s were made.

In March, ‘66, Wesland aerocraft and Vickers Armstrong mearged their hovercraft interests to form the British Hovercraft Corperation. The shares were owned by Westland Aerocraft, Vickers Armstrong, and the NRDC. In 1970, Wesland Aerocraft bought out the other shareholders.

BHC launched their first SRN4 on the 4th of December, ’67. It is perhaps the most famous hovercraft in the world, used exclusively on the cross ‘Channel routes. The original specification was designed to carry 254 passengers and 30 cars, later models carried many more. This SRN4, the Princess Margeret, was the first of six to be built. Two were sold to Seaspeed, and four to Hoverlloyd.

In January of the next year, Hovermarine launched a sidewall craft - the HM2. In it’s different models, over 100 were sold for use as anything from high speed ferrys to fireboats. They had a much lower length:beam ratio than the D2, and were faster. A few suvive, but most have gone. A number were converted to house boats.

The Company later lanched their HM5 range which could carry upwards of 500 passengers.

BHC launched the first BH7 on the 31st of October, ‘69. A number were built, designed for use by navies worldwide. They could carry 72 passengers and 7 cars. Six were sold to the Iranian Navy; they are belived to be in storage.

Some indesision was reached over wether a hovercraft should be classified as a boat or as an aeroplane. In the US, hovercraft were declared to be a type of boat, however in the UK, hovercraft were registered as aerocraft. However, the proposed Hovercraft Act, and the following Hovercraft ( General ) Order 1972, desired to change this and classify them as a seperate vehicle. This raised certain interesting situations in law, where ships and aerocraft had both been mentioned, which had to be changed to mention hovercraft.

In the early 80’s, Hovertravel, which operated hovercraft over the Solent, was looking for a replacement for their aging, and uneconomical SRN6s. The resulting Hovercraft was AP188 was a joint project with the NRDC, BHC, and Hoverwork, the manufacter associated with Hovertravel. It carried more passengers, travelled faster, used less fuel, and was much more safe. It used Diesel engines, a first for BHC, which was quite unusual : at the time, most hovercraft used gas turbine engines. Thirteen were built, ( another one has been ordered, ) and many are still in use today.

By ‘84, BHC had effectively ceased hovercraft production., and so the Company was renamed Westland Aerospace. Hoverwork continued producing the AP188.

Hovercraft were being used increasingly by the military. The SRN6 were used in both the Falklands War and the First Gulf War. ******

IHTU

In ‘86, the US Navy developed the LCAC³ as a hovering landing craft. The craft has rear and bow loading ramps, based much on the SRN6 Mk. 5a., but much larger. 91 were built from ‘86 to ‘01, 80 are still in service with the US Navy and the Japan Maritime Self-Defense Force. The ‘craft will be phased out from ‘19, from when the SSC⁴ will be used.

The Nineties was a lean time for hovercraft : economic resesion and increasing fuel prices were to blame.

On the 1st of June, ‘99, the world heard that Sir Christopher Cockerell, the hovercraft‘s inventor, had sadly died. He was survived by his two daughters, Francis and Anne

On the 30th of September, the last SRN4 service ran across the ‘Channel. The high cost of Fuel and competition from the ‘Channel Tunnel ment that the service was no longer comercialy viable. Two of the SRN4s are on perniment display at the Hovercraft Museum. All of the others have been broken up.

|||move||| In the early days, the hovercraft received enormous attention by the media, and many considered the hovercraft to be the future of all transport. However this has not happened. After the Suez crisis, the price of oil rose so much that the hovercraft became uneconomical in many situations. With the use of deisel engines, economity has been inproved, but the hovercraft is now mainly used in niché rôles by the military and hobbyist users.

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The last remaining European hovercraft service runs between Ryde, on the Isle of Wight and Southsea, in Portsmouth, although some other services remain in other parts of the world.

The SR·N1 is now preserved at the RAF Wroughton branch of the National Science Museum, in Swindon. Many of the other early hovercraft are preserved at the National Hovercraft Museum in St. Daedalus, near Portsmouth.

Historic Craft

Saunders Roe SR·N1

The SR·N1 ( Saunders Roe Nautical One ) was the first full sized hovercraft. Commissioned in the Autumn of '58 by the NRDC, it was finished in under a year and first flown on the 11th of June '59. Little more that a month later, in was shipped over to Calais, and on the 25th of July, it crossed the 'Channel, with Christopher Cockerell, piloted by Peter Lamb and Navigated by John Chaplin⁵. For many years, it was used as the test bed for hovercraft development, being used to trial both the original skirt and the bag skirt. It is now preserved at a branch of the Science Museum.

Cuchioncraft CC·1

The CC·1 ( Cushioncraft 1 ) was built by Britten Norman Limited as an experimental craft. It was registered as G APYH on the 9th February '60, although it wasn't flown until XX⁶.

Cushioncraft CC·2

3 CC·2 craft were made, the first ( G ARSM ) was flown XXX. Britten Norman then made the CC·2 available to purchase, at £25,000 each. It could carry 11 passengers, and was originally designed for the banana grower XXX.⁷

Vickers Armstrong VA·3

Vickers-Armstrong' VA·3 was the first hovercraft to operate a commercial service. Starting on the 20th of July '62, the service ran between Rhyl, North Wales and Morton, nr. Liverpool until the 17th of September, when it got damaged during extreme weather. In was then used mainly for demonstrations, until sometime after June '66 when it was blown up in mine testing by the IHTU⁸.

Westland Aerospace SR·N2

The SR·N2 was built to test the use of a hovercraft as a ferry. It was launched in January '62, but didn't start passenger service until 11th of August, when it operated over the Solent from Ryde, IOW to Eastney, Portsmouth. The trip was a hefty 10' each way, but ended on the 24th, after carrying over 1,500 passengers. The hovercraft was later used on many trial services across the country.

BHC SR·N3

The SR·N3 was a longer version of the SR·N2 capable of carrying several cars as well as passengers. Launched on the 9th December '63, it was mainly aimed at the military. After being taken on by the IHTU, it was given the Military aerocraft registration X6655.⁹

SR·N5 Warden and SR·N6 Winchester Classes

The SR·N5 and SR·N6 were both put into mass production at the same time. The first one, SR·N5 001 was launched on the 11th of April '63. The SR·N6 was effectively a longer version of the SR·N5¹⁰. They were used for passenger and military róles across the world¹¹; but although they were good hovercraft, being long and narrow made them prone to capsising. For this reason, an emergency trap door was installed in the floor of the craft.¹²¹³

BHC SR·N4 Mountbatten Class

The SR·N4 were the largest civilian hovercraft, the mark 3 model being able to carry 418 passengers and 61 cars¹⁴. Six were made over the years and they were used exclusively on cross 'Channel services. The first, Princess Margaret, was ordered by Seaspeed, the hovercraft department of British Rail, in '6X. It was first tested on the 5th of December '67, but didn't go to sea until the 4th of February '68. It was much larger that any other hovercraft built before, carrying 174*** passengers and 34 cars. At first there were many problems with it. Hoverlloyd, who were already using the SR·N5/6 hovercraft on their cross 'Channel routes, ordered two. They were to be named Swift and Sure. Seaspeed then ordered their second craft, Princess Margaret, followed by two more hovercraft, Sir Christopher and the Prince of Wales, for Hoverloydd.

The hovercraft themselves used gas turbine engines - light and reliable, but very inefficient. After the Suez Crisis, the cost of fuel was to expensive to justify burning over 4 tonnes of fuel per hour. So in '83, after years of discussion, Hoverloydd and Seaspeed finally merged. They had both been losing money for some time, and they hoped that not having to operate two sets of terminals would allow them to survive. The service continued until September 2000, when the service finally stopped.

The Princess Margaret and Princess Anne survive, and can be seen on static display at the Hovercraft Museum. All of the others were cut up for spares.¹⁵.

SEDAM N500

Only two N500 were built; Ingenieur Jean Bertin and Côte d'Argent, which got destroyed after only seven flying hours. It was intended to be the French response to the British SR·N4s, which were in operation on cross 'Channel services. The company, SEDAM, was in financial trouble, having had little commercial success with their earlier craft, the N102 and N300. The French government subsidised the N500s in an effort to make them compete with the SR·N4. The craft was the first to have two decks, to try and allow the craft to accommodate double decker busses, something the SR·N4 couldn't do. However, the SR·N4's four propellers could independently rotate to improve handling, but the N500's three, equally powerful propellers were fixed. This meant that the craft was less monovable, less powerful, and heavier than the SR·N4s. Only two were ordered, one by Seaspeed, and one by Hoverlloyd; but when Hoverlloyd saw how bad Seaspeed's one was, they soon cancelled their order. Even after alterations, the craft was still out of service 30% of the time, and eventually the craft was returned to SEDAM, to be broken up.

BHC AP1·88/100

The AP1·88 was designed by Hoverwork as a replacement for the SRN·5/6 hovercraft in use all over the globe. It had either 88 or 100 seats which was much more that the previous SRN·5/6. 12 have been built, with o0ne being manufactured, most are still in use.

Hoverwork BHT·130

Built in '05 to ‘07, the only BHT·130 built so far Gh2142 operates across the Solent with Hovertravel.

Spin Offs

The Hovercraft has proven to be one of the most versatile form of transport arround, but high costs mean that in is now only used in nîche rolés, mainly military. But the hovercraft principle has been used elsewhere.

Flymo Lawn Mowers

The famous orange hovering lawn mowers was invented in '64, and went into production the next year. Origionaly, they were blue and white; they didn't get their distinctive orange colour until '77.

See www.flymo.com

Hover Pallet

The Idea of the Hover Pallet was to create a device that could carry large loads over surfaceses that wouln't otherwise be able to carry the load. By spreading evenly over a large area, the hover pallet allowed heavy weights to be carried over terain which wouln't normally be up to the load.

Hover Trucks

Hover Landrover

Hover Beds

the Hover Bed was designed to speed up burns patients' recovery. By blowing the patient off the bed, the patient wouldn't be in contact with bed, hence speeding up their recovery.

Air Hockey

Aair hockey doesn't exactly run on the same principle as the hovercraft, as it doesn't use a momentum curtain.

Tracked Hovercraft

The Tracked Hovercraft Project in England, and the Aërotrain Project in France both investigated the possibility of a 'hover train'. They both showed great promise, but both eventualy got the axe: the French decided to go for the TGV, and the British decided to go for the APT¹⁸. The APT was also eventualy axed, leaving the UK without high sped ground transport.

Future

The hovercraft is now mainly used by the military, rescue and hobbyists. In the UK, the Hovercraft Club of Great Britain has many members involved in 'cruising' and 'racing' hovercraft. The RNLI¹⁹ use several Griffon hovercraft across the UK for 'mudflat rescue'.

Bibliograpy

• Angela Croome - Hovercraft ( 1960 - ‘84 )
• Anthony Watts - A source Book of Hovercraft and Hydrofoil ( xx )
• Chris Potter - www.hovercraft-museum.org
• Anthony Barton - www.bartiesworld.co.uk/hovercraft
• James Rowson - www.jameshovercraft.co.uk
• British Pathé - www.britishpathe.com
• Mark Porter - www.btinternet.com/mark.e.porter
• Various Authors - www.ferryfantastic.webs.com
• Hansard, 16th May ‘68
• www.dft.gov.uk
• www.ssa.nls.uk

Links

• James' Hovercraft - www.jameshovercraft.co.uk
• Bartie's World Hovercraft - www.bartiesworld.co.uk/hovercraft
• Mark Porter's Hovercraft Histories - www.btinternet.com/mark.e.porter
• The Hovercraft Museum - www.hovercraft-museum.org
• Hovercraft Club of Great Britain - www.hovercraft.org
• Ferry Fantastic - www.ferryfantastic.webs.com
• www.srn4.co.uk - A DVD on the SR·N4 available to purchase.
• www.britishpathe.com - British Pathé have a large collection of films of hovercraft.
• www.hovercraft.org.uk - Hovecraft Club of Great Britain
• Hovercraft Act '68