This video was made possible by CuriosityStream. Watch thousands of high-quality documentaries
and get access to my streaming service, Nebula, using the link in the description. Fifty years ago, giant hovercraft were the
pride of Britain. They were a new kind of machine that could
go almost anywhere, on land, water, or just about any other surface. And they were fast, capable of reaching one
hundred and thirty kilometers an hour. The largest could transport sixty cars and
as many passengers as a jumbo jet. These giants once promised to revolutionize
the way we travel. But today, they’ve all but disappeared. To understand what made hovercraft so revolutionary,
consider that they're not like any other vehicle. In fact, they share more in common with aircraft
than boats. That’s because hovercraft are essentially
airborne. They work using the principles of lift and
thrust. To lift off and hover, fans trap a cushion
of air, while propellers generate thrust to move forward. And what it all means is that friction and water
resistance are significantly reduced, allowing a hovercraft to hit speeds well beyond that
of any ship. But speed isn’t the only advantage. Because no other vehicle can match a hovercraft’s
versatility. Out at sea, in shallow water, on ice, or in
a swamp, they can go where no other vehicle can. Where’s there’s no harbor, a hovercraft
can simply crawl out of the water where a ship would run aground. Hovercraft were a brilliant innovation. And in the 1960s, a hover transport revolution
seemed just over the horizon. When the first hovercraft debuted in the summer
1959, it stunned the world as it appeared to almost magically float over any surface. Its designer, a brilliant British engineer
named Christipher Cockerell, wasn't the first to dream up the idea of a hovercraft. But modern hovercraft wouldn't be possible
without Cockerell’s key innovation, called the Momentum Curtain. Earlier attempts at building hovercraft involved
blowing air into an open hull, which didn't work very well and required a lot of power. Cockerell’s innovation was to direct a ring
of air towards the outer edges of the hull, trapping high pressure air. Which allowed the craft to hover much higher
off the ground. In 1959, Cockerell and two others piloted
the first practical hovercraft all the way across the English Channel. But it would take another key innovation to
truly unlock the hovercraft’s potential. In 1961, another British engineer proposed
fitting the craft with a flexible skirt, which would allow it to hover much higher off the
ground to better handle uneven surfaces With the flexible skirt, hovercraft could
become a much more versatile machines. And it sent British Aircraft builders racing
to develop their own designs. Almost overnight, the first small scale hovercraft
transport services began popping up throughout Britain. In just few short years, hovercraft would
go from small prototypes, to enormous craft that could carry hundreds of passengers By the mid-1960s a hovercraft craze had swept
the world. And countries like the United States and France
poured millions into their development. But the British were at the forefront, and
the leading company in the world was Saunders-Roe They had not only built Cockerell’s original
prototype, but also a series of civilian and military designs. And in 1963, Saunders Roe set out to build
a new kind of hovercraft. One that would be four times larger than previous
designs, and built to compete against conventional ferries. On the English Channel, a ferry needed about
an hour and half to make a crossin. A hovercraft would cut the trip down to just
half an hour, allowing for twice as many daily crossings. The new giant hovercraft would be designated
as the SR.N4. And it would operate more like an airliner
with a crew that would include a captain, flight engineer and navigator, along with
a deck and cabin crew of eleven. In standard configuration, it would carry
30 cars and 254 passengers, or configured for 609 passengers No one had ever attempted to build a hovercraft
this large. The engineering and economic risks were enormous. The world’s largest hovercraft debuted in
the summer of 1968 with service connecting Britain and France on the English Channel. On board, high profile guests included Princess
Magaret and Christopher Cockerell himself. Passengers marveled at the all-British achievement
as the 165-ton machine built up speed. But what no one yet realized, was that the
SR.N4’s rubber skirt was literally tearing apart beneath them. Attachments designed to contour to waves,
were damaged or torn right off by rough seas, sending repair crews scrambling to replace
them after almost every trip. And just three days into service a large wave
damaged the craft, putting it out of commission for nearly a week. And was really just the start of problems. Crossings were regularly canceled due to mechanical
issues like hydraulic and gearbox failures. But an even bigger issue was the weather. The SR.N4 was rated for waves of just two
and a half meters. And on the English Channel, it didn’t take
much to stir up those kind of conditions. In its first three months of service, more
than a third of the scheduled trips were canceled. The debut hadn’t gone well. And in October of 1968, the SR.N4 was pulled
from service altogether to undergo extensive modifications. Unreliable and seemingly unsuitable for open
water travel, the future of large passenger hovercraft was in doubt. Despite the disastrous debut, cross-Channel
hovercraft proved incredibly popular with the traveling public. And by the time the SR.N4 was put back into
service, many of the earlier issues had been solved. And the skirt had been redesigned to better
withstand waves. By mid-1970, there were two carriers operating
iconic hovercraft on the English Channel. And, they could barely keep up with demand,
with trips fully booked weeks out in advance. But there was still a problem. Neither carrier, was actually making money. Because the SR.N4’s burned a thousand gallons
of aviation grade fuel every hour. And maintenance costs were astronomical compared
to conventional diesel ferries. To offset high operating costs, both carriers
had to modify their hovercraft to increase passenger and vehicle capacity by widening
and lengthening their hulls. By 1978, the largest hovercraft could carry
up to 418 passengers and 60 cars. The increased capacity helped make giant hovercraft
more competitive. By the end of the decade, hovercraft were
carrying nearly a third of cross-Channel passenger traffic. But as the 1980s approached, large civilian
hovercraft would face a challenge that no engineer could solve. If the iconic hovercraft were in operation
today, they would still be the fastest way to cross the English Channel. Faster than conventional diesel ferries, or
high speed catamarans introduced in 1991. Faster than even the Channel Tunnel which
opened in ‘94. But it wouldn't have mattered. The hovercraft as a form of transport, really
was doomed from the start. In the early 1960s, they had captivated the
public’s imagination with their incredible speed. But that speed came at the cost of just about
everything else. Compared to conventional ferries, hovercraft
were less reliable, less efficient, less capable in rough weather, and less comfortable. And it meant that by the end of the 1960’s,
excitement over hovercraft had largely worn off. And Britain's once booming hovercraft industry
fell into recession. To make matters worse, fuel prices skyrocketed
in the 1970s. Putting a final nail in the coffin, ensuring
that fuel-thursty hovercraft could never be widely adopted as transport. And it meant that the enormous SR.N4’s would
represent the pinnacle of passenger hovercraft design. But in the 1980’s they would face increasingly
stiff competition from conventional ferries, which had wide enough profit margins to continually
lower fares and win back customers. Giant hovercraft could no longer compete,
especially after the Channel tunnel opened in 1994. But no vehicle can match a hovercraft’s
versatility. Which is why these awesome machines remain
relevant today with the world’s militaries, industry, and rescue services, even as the
iconic SR.N4’s were entirely phased out by the year 2000. But many argue that hover technology never
reached its full potential. And in the 1960s, Cockerell and British engineers
had a much bigger vision for a new form of transport that would hover on a cushion of
air and reach speeds of five hundred kilometers an hour. They were called Tracked Hovercraft, and they
would’ve been faster than any train in the world, even to this day. By 1972, engineers had developed the necessary
technologies and even constructed a test track and prototype train. They were seemingly on the cusp of reinventing
railways. But their efforts have almost entirely been
forgotten. You can learn more about the incredible story
of the tracked hovercraft in my latest video available right now on Nebula. Nebula is where you can watch a growing number
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