They were once known as the Concordes of the Seas, mighty flying boats that used
to ferry their passengers with speed and style. Hovercraft were a symbol of
national innovation and represented the future of Transport in the 20th century
and yet like the Concorde, the huge iconic mountbatten class hovercraft
that once traversed the 22 mile English Channel from England to France carrying
hundreds of passengers and cars are no longer with us.
But today the technology still attracts investment from the world military's,
industry and rescue services. These versatile machines have been used in the
most inhospitable terrain defying friction and coasting over obstacles
that would be unpassable in other vehicles or ships. Hovercraft are capable
of travelling up fast flowing rivers, over ice caps, on marshes or reclaimed
land. 60 years after their invention they are still found working in the most
remote corners of the world. The name "hovercraft" was originally a
trademark held by the British engineering company saunders-roe which
produced some of Britain's largest and most successful rotor propelled vehicles.
To avoid the trademark other manufacturers used for designation ACV
or air-cushion vehicles, whatever name they go by their distinctive shape is a
result of a common principle to trap a cushion of air beneath the craft to
reduce friction with the ground or waves and achieve high speeds. The man credited
with the invention of the hovercraft was the Cambridge born engineer Christopher
Cockerel who worked on radio technology during the second world war for the
Marconi company. After leaving Marconi he bought a small boat hire business and
immediately applied these engineering skills to explore ways of making these
boats go faster. High-speed watercraft were all over the news at the time as
Donald Campbell's Bluebird had broken the world water speed record four times
by 1958 hydroplaning on the calm lakes of Cumbria at 202mph then 216mph, 225mph and
finally 239 miles an hour 395 km/h. These speeds were
possible as a result of surface effects that bounced the Bluebird on top of the
water like a skimming stone. Cockerel had a different approach. By funneling a
curtain of air around the perimeter of the boats underside his craft could ride
on a cushion of trapped air. The unique advantage of this innovation was that
the hovercraft was able to float above the ground even as it was traveling
slowly or stopped. Cockerel first tested the concept in his home workshop
channeling air from a vacuum cleaner between two concentric plates, then
scaling up a test with a series of larger radio-controlled models. In the
autumn of 1958 he sent in design for the world's first prototype hovercraft to
the factory at Saunders-Roe. The first working hovercraft was the Saunders-Roe
nautical one or SR-N1. This first prototype lacked of a skirt of the later
models, so as it zoomed across the water it was often hidden behind a huge wall
of spray. Regardless the media were amazed by the new technology and gave
it the nickname the "Flying Saucer". On the 25th of July 1959, 50 years to the day
after Louis Blériot made the first crossing of the English Channel in a
heavy than airplane, the SR-N1 set off from Calais to make the first-ever
hovercraft crossing. As part of a three-man crew, Cockrell himself was on
board, his job to provide dynamic ballast by moving himself around on the top of
the hovercraft. With a moderate swirl and no following winds the SR-N1 arrived at
Dover in two hours and three minutes. With this success engineers went to work
on refining the design. As on the first channel crossing the SR-N1 struggled
with high winds or over variable slopes, pilots though to use considerable skill
to compensate for the poor steering response. These issues were mitigated
with the addition in 1961 of the hovercraft distinctive skirt which gave
it greater clearance over the ground or waves by more effectively containing the
cushion of air. the SR-N1 could now operate with twice its original weight
this improved carrying capacity also allowed
a turbojet engine to be fitted aft of the SR-N1 increasing the maximum speed from
35 to 50 knots is 57 miles an hour 92 km/h. A series of lightweight
hovercraft were developed in the next few years including the SR-N5 which was
licensed to be built by the US military and saw service in the swamps and
jungles of Vietnam. The largest hovercraft built at the
Saunders-Roe Factory was the SR-N4 the "Mountbatten class" which was four times
larger than any of a preceding hovercraft the first SR-N4 called the
"Princess Margaret" was originally designed to carry 254 passengers and 30
cars. The four steerable propellers on the roof were the largest in the world
each 19 feet or 6.1 meters across these were powered by Rolls-Royce Proteus
turboprop engines each using a ton of fuel per hour. The SR-N4 was refitted and
expanding twice growing to a capacity of 60 cars and 418 passengers as as many as
a 747 airliner. The main ferry route was between Dover and Boulogne, a 22 mile trip
which took on average just 35 minutes. However when unloaded the SR-N4 could
go even faster and the unofficial record for a cross-channel crossing was a
blistering 15 minutes and 23 seconds however as the speed limit only English
Channel is 70mph (112km/h) this was never officially recognized. The
Princess Margaret was also immortalized in the 1971 James Bond film "Diamonds are
forever" in which Sean Connery embarked from Dover aboard the new Mountbatten
ferry. The channel's hovercraft service had its peak year in 1986 when three
million passengers made the crossing however by October 2000 the route was
closed, in part due to competition from the new Channel Tunnel rail service but
by other accounts it was the end of the duty-free service in 1999 but made the
hovercraft uneconomical. At this point sales from tax-free
products on board were making more profit than the ticket receipts and
when spare parts ran out the SR-N4 was retired. A petition in 2016 to save and
SRM for the Princess Anne for display in the hovercraft museum near Portsmouth in
the UK was successful and the progress of restoring one of the giant
Mountbatten hovercraft continues this year. Christopher cockerel envisioned a
future where we would cross the Atlantic in huge nuclear-powered hovercraft,
however this wasn't to be. Rising oil prices in the 1970s that meant on many
routes, more economical hydrofoils and catamarans offered better profit
margins. However in rough terrain and inhospitable environments the hovercraft
still can't be matched and has been developed for the world's elite and
amphibious units. The largest ever hovercraft is a thoroughly modern
military vessel the "Zubr class" air-cushioned landing craft.
Zubr is 57 meters long or 187 feet one metre longer than the SR-N1 but can
carry a much greater load up to 555 tons this means that it can land three tanks
or eight armored personnel carriers with 375 troops onto a beach. Zubr was
designed in the 1980s by the Soviet regime to match the capabilities of the
American LCAC military hovercraft. It comes equipped with an active system for
hiding its magnetic field a kind of stealth mode for avoiding magnetic
influence mines. In the case of a nuclear or chemical strike the crew can seal off
their living quarters and continue their operations.
In 2009 China announced that they would purchase four of the "Zubr class" boats for
for $350 million dollars each and since then they have been granted a license to
build further derivatives themselves. With Chinese interests in the disputed
territories in the South China Sea huge hovercraft like the Zuber set to remain
front and center in the world stage for years to come. So thanks for watching and
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