When I was a kid, living in East Kent, I would sometimes go down to Dover Cliffs with my Dad to watch the cross-Channel ferries go in and out, but an alternative outing was to Pegwell Bay, near Ramsgate. This was then a potential jump-off point for a continental holiday, unlikely as that seems now. The bay is, after all, no-one's idea of a port, what with those crumbly cliffs fronting on to a wide flat beach.
Pegwell Bay in the mid-19th century
But in the 1970s, after parking the car at the top of the cliffs near the replica Viking longboat which was sailed over from Denmark in 1948, and was subsequently presented to Britain ...
"Hugin"
... one could wander over to look down on the terminal buildings and apron of the Hoverlloyd operation based there, because the vessels operated from Pegwell Bay were not ordinary ships, but large passenger hovercraft. The flat beach was an advantage for such vehicles, as it meant an easy transition from water to concrete apron.
The Pegwell Bay terminal in the 1970s
The hovercraft shown in the picture was an SR.N4, capable of carrying over 250 people and 34 vehicles; there were 4 of these, and they had replaced the much smaller SR.N6 vehicles, whose capacity had been only 58 passengers and which could not accommodate cars.
1970s amateur cine-film of Ramsgate hoverport
The "air cushion vehicle", as a concept, seems first to have been proposed by Emanuel Swedenborg in the 18th century, but the first serious attempt to harness high pressure air to lift a boat body was in 1915, when the Austrian Dagobert Muller constructed a fast motor-torpedo boat using an aircraft engine to force air under the bow in an attempt ot increase its speed. This wasn't a true hovercraft, however, and the idea never caught on.
Further theoretical work was done in the Soviet Union, including by Konstantin Tsiolkovsky - better known for his pioneering work in rocketry - during the 1920s, while 1931 experiments by the Finnish engineer Toivo Kaario first introduced the use of a flexible envelope to contain the pressurised air. The Soviet research continued after the war, but headed in a direction which would lead eventually to the ekranoplan, rather than the hovercraft. Research in the 1950s-1960s at Avro Canada by John Frost, utilising pressurised air to generate lift, was used in unsuccessful attempts to produce VTOL vehicles such as the AvroCar, rather than what we would now call hovercraft.
The AvroCar; not a hovercraft, only a hovering craft.
The development of the hovercraft was to fall to Christopher Cockerell, whose researches were initially classified owing to their military potential; he failed to gain interest from the armed forces, however, and instead focussed on civilian applications. Working with the flying boat manufacturer Saunders-Roe, based on the Isle of Wight, he built the SR.N1 in 1958, and this craft carried out a successful crossing of the English Channel in 1959.
An SR.N1 under trial by the Royal Navy c.1963.
Though the various versions of the SR.N1 were useful testbeds, they were not practical vehicles, hovering too close to the surface to deal well with even small waves (something demonstrated by the Duke of Edinburgh during a visit to Saunders-Roe - allowed to fly the SR.N1, he went too fast and damaged the vehicle's bow). The design was then improved by the addition of a rubber skirt to contain the layer of pressurised air, a development which allowed the vessel to hover further from the surface and pass over small obstacles.
As Saunders-Roe moved towards commercial produciton, they joined with Supermarine to create the British Hovercraft Corporation, who would manufacture the SR.N4's and 6's used on the Pegwell Bay to Calais route, and also between Dover and Boulogne.
There were other companies interested in the hovercraft, however, with the English Channel crossing looking especially promising for a craft which was substantially faster than conventional ferries. The French inventor Jean Bertin produced a number of designs, including a very large commercial hovercraft, the N500 Naviplane, for Seaspeed to use on the cross-channel route. With a capacity of 400 passengers and 55 cars this was bigger even than the SR.N6, but it was dogged by problems. The first model was destroyed by a fire at the production facility on the Gironde, only a couple of weeks after its initial flight. The second went into operation on the Dover-Boulogne route, but was found unreliable and eventually returned to the manufacturer, ultimately to be broken up.
Bertin's monster, the N500, during its troubled time with Seaspeed.
The SR.N4's were more successful, both on Hoverlloyd's Pegwell Bay route and on the Dover service operated by Seaspeed (a joint venture by British Rail and SNCF); they were refurbished in 1976, with an extended middle section inserted to give a capacity of 418 passengers and 60 cars. The smaller SR.N6's contiued to operate on shorter, passenger-only routes, such as Cowes-Southampton, Portsmouth-Ryde and Portsmouth-Cowes.
One niche application of air-cushion technology was in the so-called Hovertrain designs which for a while vied with magnetic levitation in the attempt to supplant conventional railways. Jean Bertin, the designer of the ill-fated N500 Naviplane, was a leader in this field, and tested his "Aerotrain" concept extensively in the 1960s.
A fantastically retro Aerotrain prototype.
But Aerotrain, like maglev, failed to take root as a means of mass transport, and the French government killed off Bertin's concept when it elected to build the TGV network using traditional wheel-on-rail technology.
Meanwhile the cross-channel operators, Hoverlloyd and Seaspeed, were facing increasing commercial pressures and escalating fuel prices. In 1981 were allowed to merge as Hoverspeed. The Pegwell Bay operation was closed down in 1982 and its vehicles reassigned to the Dover run, though the facility remained as a maintenance and admin hub for some years afterwards. It was also in the 1980s that the only serious accident on the Channel run occurred, when the SR.N6 "Princess Margaret" ran into the Dover breakwater during poor weather, killing four people.
The British Hovercraft Corporation was also in trouble, having produced only one new design since the merger, and in 1984 changed its name to Westland Aerospace, to concentrate on composites manufacture. This in turn made the maintenance of the existing Hoverspeed vessels increasingly expensive, and once the Channel Tunnel opened the writing was on the wall for the cross channel hovercraft route. The Dover-Boulogne hovercraft link, by this time reduced to two vessels, closed down in 2000.
A Hovertravel AP1-88 coming ashore at Southsea.
A handful of passenger hovercraft services remain, including one in Britain. Hovertravel operate services across the Solent from Southsea to Ryde, using not only older British Hovercraft Corporation vehicles but a 2007 vintage Hoverworks BHT130, built at St Helens on Merseyside.
The Hovertravel BHT130 departing from Ryde.
This same model of hovercraft is also used as a passenger, freight and mail transport serving various remote communities in Alaska. A number of attempts to run regular commercial hovercraft services in Japan foundered, however, with the last one (serving Oita airport) closing in 2009.
Various militaries use or have experimented with air-cushioned vehicles in either amphibious landing or littoral combat roles; but outside of a few niche contexts, most of what a hovercraft can do may be done as effectively, but cheaper, by more conventionally hulled (or catamaran) vessels with less outrageous fuel consumption figures. The relative heyday of the passenger hovercraft has come and gone. If one goes to Pegwell Bay now, the Viking longship is still there, but the hovercraft have long vanished, along with the associated buildings. The apron, and the bare foundations of the old terminal, are still clearly visible on a Google Maps satellite view, however...
And here is the rather sorry view from ground level...
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