Speaker 1: Welcome to tech Stuff, a production from iHeartRadio. Hey there,
Speaker 1: and welcome to tech Stuff. I'm your host, Jonathan Strickland.
Speaker 1: I'm an executive producer with iHeart Podcasts and how the
Speaker 1: tech are you? So y'all already know what this episode
Speaker 1: is about, because it's right there in the title for
Speaker 1: the episode. The title itself is a reference to a
Speaker 1: nineteen ninety five Jackie Chan film called Rumble in the Bronx.
Speaker 1: So in the climax of that film spoiler alert, there's
Speaker 1: a scene in which a hovercraft goes absolutely ape through
Speaker 1: the city. It crashes into cars, it absolutely destroys Lamborghini,
Speaker 1: and it interrupts a rock band that's playing outside on
Speaker 1: the street. And it's at this point in the film
Speaker 1: where the drummer of the rock band stops playing mid song,
Speaker 1: stands up, points and yells hover aft, which is my
Speaker 1: favorite part of the whole movie, even with all the
Speaker 1: amazing fight sequences taken into account. And this is the
Speaker 1: sort of stuff that inspires tech Stuff episodes, because that's
Speaker 1: how my brain works now anyway, Yeah, Jackie Chan films
Speaker 1: from the nineties really a source of inspiration. So I
Speaker 1: thought it would be fun to do an episode tracing
Speaker 1: the history of hovercraft and to talk a little bit
Speaker 1: about how they actually work. And I also think this
Speaker 1: is the type of topic where you have one concept
Speaker 1: in your head when you first hear about it, Like
Speaker 1: when you first hear the word hovercraft, you might have
Speaker 1: a vision in your head of what that might be,
Speaker 1: and then ultimately you could be disappointed when you see
Speaker 1: it in the real world. That was my reaction anyway,
Speaker 1: because as a kid, when I heard the word hovercraft,
Speaker 1: I thought of some sort of semi magical vehicle that
Speaker 1: could levitate above the ground, probably something closer to what
Speaker 1: drones are, but without the rotors, right, Like there's some
Speaker 1: unseen force that makes the thing floatt. So I was
Speaker 1: kind of thinking of something similar to like the hover
Speaker 1: boards that are featured in the documentary Back to the
Speaker 1: Future too, But of course that's not how your typical
Speaker 1: hovercraft works. Hovercraft, by the way, are also called air
Speaker 1: cushion vehicles, and that air cushion gives a huge indication
Speaker 1: of how these things work. And arguably my whole perception
Speaker 1: or misperception of hovercraft isn't really fair. I mean, it's
Speaker 1: not the hovercraft's fault that I had an overactive imagination
Speaker 1: and unrealistic expectations. It is a fascinating invention, and it
Speaker 1: traces its history really back to the nineteenth century, when
Speaker 1: you had people sort of theorizing about it, but effectively
Speaker 1: for talking about making something that actually works. It's more
Speaker 1: like the middle of the last century. And I was
Speaker 1: born in the last century, and saying that way hurts
Speaker 1: a little bit. But the inventor of the hovercraft, the
Speaker 1: person that we credit as the inventor, so so I
Speaker 1: guess you could say sort of inventor of the hovercraft
Speaker 1: was a gentleman by the name of Christopher Sidney Cockrell.
Speaker 1: Now I say sort of because, as we will find
Speaker 1: out later in this episode, there was another person who
Speaker 1: came up with the same concept a decade earlier, but
Speaker 1: due to a technicality, this person had no ownership of
Speaker 1: this idea. But we'll get back to why that happened.
Speaker 1: So Cockrell's parents were both distinguished members of English society.
Speaker 1: His mother was Florence Kingsford cockerl. She was known for
Speaker 1: her artistic talents in calligraphy, illumination, illustration, and costuming. When
Speaker 1: I say illumination, I mean manuscript illumination, think of the
Speaker 1: stuff that monks used to do back in the Middle Ages.
Speaker 1: So way back in my college days, I focused my
Speaker 1: studies in medieval literature and medieval history, and after looking
Speaker 1: at Florence's work, I'm really amazed at how her evokes
Speaker 1: those ancient texts. Cockrell's father was Sir Sidney Cockrell, who
Speaker 1: came from a coal mining family. Like it astonishes me.
Speaker 1: He came from a family that worked coal mines, but
Speaker 1: he found himself thrust into the social circles of influential
Speaker 1: people who were in the artistic and literature worlds in England.
Speaker 1: So Old sid served as a personal secretary to British
Speaker 1: author and artist William Morris, and Sydney eventually became the
Speaker 1: director of the Fitzwilliam Museum in Cambridge, England, where he
Speaker 1: had a bit of a reputation for having an incredibly
Speaker 1: effective method to convince hoity toity rich people to hand
Speaker 1: over some of their filthy lucre to support the museum.
Speaker 1: So Christopher Cockrell came from, if not blue blood, at
Speaker 1: least light blue blood Lemmelson Mit, which bills itself as
Speaker 1: the quote national leader in advancing in vention education in
Speaker 1: The quote says that Sidney Cockroll wasn't entirely sold on
Speaker 1: the idea of his son going into engineering, but that's
Speaker 1: exactly what young Christopher Cockroll wanted to do. And I
Speaker 1: find this notion rather like a money python sketch, because
Speaker 1: you have a man who comes from a coal mining family.
Speaker 1: He's defied the odds, he's become a director of a
Speaker 1: prestigious museum, and now he is concerned that his son
Speaker 1: wants to be an engineer. In fact, there is a
Speaker 1: money python sketch in which you have a family of
Speaker 1: It sounds like lower class English folk who are authors,
Speaker 1: who are a shame that their son wants to go
Speaker 1: into being a coal miner, flipping the old narrative on
Speaker 1: its head. So this is reminding me of that fictional sketch,
Speaker 1: you know, very silly stuff. But yeah, he didn't want
Speaker 1: Christopher to become an engineer. But whether he had reservations
Speaker 1: or not, ultimately Sydney agreed to support his son's pursuit
Speaker 1: of an education in engineering. In fact, according to the Guardian,
Speaker 1: Sydney offered Christopher the princely sum of ten pounds for
Speaker 1: every patent his boy would receive. This was back when
Speaker 1: old Chris was still a teenager. Sidney would call an
Speaker 1: end to that deal later on because it would get
Speaker 1: pretty deep, deep, pretty expensive. Christopher attended Petterhouse College at
Speaker 1: Cambridge University. In his obituary Cockrell passed away in nineteen
Speaker 1: ninety nine, by the way, in his obituary in The Guardian,
Speaker 1: Christopher Cockrell was said to have spent much of his
Speaker 1: spare time in college quote taking motorcycles to pieces or
Speaker 1: racing them end quote, and that this gave him the
Speaker 1: experience of practical background in basic mechanics and engineering, which
Speaker 1: is kind of cool, like the idea of learning by
Speaker 1: doing something you're already interested in. So that was already
Speaker 1: neat of course. Christopher by this point, by the time
Speaker 1: he was going to university, had already expressed a deep
Speaker 1: interest in engineering. Upon graduation, Christopher Cockerrell took a position
Speaker 1: with the Radio Research Company. This was in nineteen thirty five,
Speaker 1: so still relatively early in the days of radio. I
Speaker 1: mean radio had been around for a while, but still
Speaker 1: a fairly young science. And he joined the Marconi Wireless
Speaker 1: Telegraph Company and worked in an R and D department
Speaker 1: that largely focused on radar and he made numerous contributions
Speaker 1: to radio and radar technology. Many of those contributions were
Speaker 1: put to use by Allied forces during World War Two. Now,
Speaker 1: Christopher Cockrell made a career change in nineteen fifty, so
Speaker 1: the war hit was over. He continued to work in
Speaker 1: radio for a few years, but in nineteen fifty his
Speaker 1: father in law had left his wife a big sum
Speaker 1: of money, and together Christopher and his wife decided that
Speaker 1: they wanted to purchase a boat business in Norfolk, England,
Speaker 1: and Cockroll devoted his attention to managing this boat business.
Speaker 1: And it was to shift when I was reading up
Speaker 1: on his life that this actually gave me a little
Speaker 1: bit of whiplash, because here's someone who was instrumental in
Speaker 1: advancing technology and radio and radar, and now he's switching
Speaker 1: over to manage a boat business. But it was as
Speaker 1: a manager of this boat company that led him to
Speaker 1: start thinking about a solution to a really tricky problem
Speaker 1: and ultimately would lead him to inventing the hovercraft. So
Speaker 1: Cockrell got to thinking that there must be a way
Speaker 1: for heavy watercraft to travel much faster across bodies of water,
Speaker 1: and it would be possible if only you could get
Speaker 1: the boat out of the water. If you could remove
Speaker 1: it from contact with the water itself, if the craft
Speaker 1: could somehow float above the surface of the water, then
Speaker 1: that would eliminate all the friction that it otherwise would
Speaker 1: encounter as it moves through the water, and it would
Speaker 1: be able to move much more quickly than it could otherwise.
Speaker 1: But you just had to figure out a way to
Speaker 1: minimize or eliminate contact with the water. And if you
Speaker 1: could get it to lift up above the surface of
Speaker 1: the water entirely, technically you actually would have an aircraft,
Speaker 1: not water craft. But that was his starting point. He thought,
Speaker 1: how can I create a vessel that would minimize or
Speaker 1: eliminate contact with the water so that it can move
Speaker 1: much more quickly and efficiently. So Cockrell imagined a craft
Speaker 1: with a cushion of air underneath it. That cushion of
Speaker 1: air would provide a barrier between the vessel itself and
Speaker 1: the water or land underneath. If you could blow out
Speaker 1: enough air, it could skim right across the surface, whether
Speaker 1: it's water, land, or some mixture like mud or swamp
Speaker 1: or whatever, and it could potentially cut travel times significantly,
Speaker 1: at least as far as water goes maybe not with land,
Speaker 1: because as it turns out, if you're going across solid
Speaker 1: land and you've got yourself a road and you have
Speaker 1: a wheeled vehicle, you can zip along that pretty darn fast,
Speaker 1: and it would probably be difficult and very dangerous to
Speaker 1: operate a hovercraft at those speeds, because you've got to remember,
Speaker 1: hovercraft typically for propulsion's sake, is using wind power as well. Right,
Speaker 1: you've got a fan that points backward and you're blowing
Speaker 1: out airs and you know, obviously equal opposite reaction time.
Speaker 1: That means you're moving forward as a result with a
Speaker 1: proportional force, but that doesn't mean that you can easily
Speaker 1: do things like stop, and that turning is more of
Speaker 1: a gradual process as well. So moving at high speeds
Speaker 1: across land where you could occasionally encounter obstacles probably not
Speaker 1: the best idea. But anyway, in Cockrell's spare time, he
Speaker 1: started to tinker to see if this idea he had
Speaker 1: could be made practical. He wondered, first is it plausible
Speaker 1: and then is it practical? So early on, as a
Speaker 1: store where he goes, he used some tubes from an
Speaker 1: old vacuum cleaner as well as the vacuum cleaner's motor,
Speaker 1: and he used a pair of empty cans. The types
Speaker 1: of cans, it depends on which version you read. Like
Speaker 1: some say it was a couple of coffee cans. One
Speaker 1: was slightly smaller than the other. One was like, no,
Speaker 1: it's a coffee can, and then a cat food can.
Speaker 1: Some call them tin cans, some call them aluminum cans.
Speaker 1: I think what's important to know is he used a
Speaker 1: pair of cans. One was larger than the other one.
Speaker 1: He put the smaller one inside the larger one. He
Speaker 1: blew air so that it would go underneath the smaller one,
Speaker 1: which was turned face down I imagine, like open side down,
Speaker 1: and the air would create an air cushion, and the
Speaker 1: smaller one would end up hovering inside the larger one
Speaker 1: and just kind of bang around a little bit. So
Speaker 1: he saw that this was possible. It could create lyft,
Speaker 1: and that lift could be enough to counteract the weight
Speaker 1: of the vessel, in this case the little small can.
Speaker 1: So his concept had validity, and Cockrell got to work
Speaker 1: building on a prototype, an actual sort of small hovercraft
Speaker 1: that would be more substantial than just a pair of
Speaker 1: aluminum cans and some tubes. And it took him a
Speaker 1: while to build it, but by nineteen fifty five he
Speaker 1: had a working prototype, and he then had to decide
Speaker 1: what was he going to do with it. And he
Speaker 1: could have tried to create like a private business based
Speaker 1: off this, but the story goes that instead he thought,
Speaker 1: I'll show local officials, I'll see if I can get
Speaker 1: some investment in this and turn it into something viable.
Speaker 1: In that way, I'm not just sinking money into something
Speaker 1: that may never pan out. So he arranges a demonstration
Speaker 1: for his hovercraft prototype with some local officials, and the
Speaker 1: story goes that the local officials were astonished and more
Speaker 1: than a little frightened as Cockrell's prototype skimmed around inside
Speaker 1: an office that he had brought it into this office
Speaker 1: of the the local officials. He had fired up the
Speaker 1: engine that would drive the fan. So you got to remember,
Speaker 1: this is an internal combustion engine. It is burning fuel
Speaker 1: and letting out fumes, and it's very loud, and it's
Speaker 1: turning this fan, and the fan is making this hovercraft
Speaker 1: skim above the surface of the ground. And then there's
Speaker 1: not really a way of steering the hovercraft at this point.
Speaker 1: It's just showing a proof of concept. It's kind of
Speaker 1: bumping around like a bumper car all over the office.
Speaker 1: People are jumping up on chairs and desks and trying
Speaker 1: to get out of the way. And meanwhile, like I said,
Speaker 1: it's noisy and it's smelly. It made a real impression
Speaker 1: and it makes me think of that scene in Rumble
Speaker 1: in the Bronx where there's just a hovercraft gone wild.
Speaker 1: So the officials weren't quite ready to devote funding to
Speaker 1: Cockrell's invention at this point. There was this general perception
Speaker 1: in the nineteen fifties that England was not really that
Speaker 1: interested in investing in innovation. There was this perception that
Speaker 1: England was kind of backward at this point. They were
Speaker 1: focused more on things like, well, we're doing it this
Speaker 1: way because that's how we've always done it. Whether that
Speaker 1: was an accurate representation of what was going on in England,
Speaker 1: I can't say, but that was the perception. So consequently,
Speaker 1: the nation was starting to feel like it was falling
Speaker 1: behind some of the rest of the world. More than that,
Speaker 1: the officials who saw this demonstration decided, rather than fund
Speaker 1: Cockrell's idea, they would put it on a so called
Speaker 1: secret list, which effectively meant they were classifying his invention.
Speaker 1: They were putting it under classified information, and Cockrell would
Speaker 1: be legally prohibited from talking about it or finding some
Speaker 1: other means to fund his work that that would be
Speaker 1: against the law. Maybe he could find a way to
Speaker 1: fund it if he could somehow convince people to give
Speaker 1: him money without actually talking about the invention itself. But
Speaker 1: really it just meant that the officials were really hamstringing him.
Speaker 1: Now we're going to take a quick break, and when
Speaker 1: we come back, we'll talk about what happened next and
Speaker 1: how Cockroll was able to get some progress despite this
Speaker 1: initial setback. But first let's take a break to hear
Speaker 1: from our sponsors. Okay, we're back. So before the break,
Speaker 1: I talked about how Cockrell does this demonstration. Officials are
Speaker 1: taken aback and they decide to classify Cockroll's invention, which
Speaker 1: effectively makes it impossible for him to do any real
Speaker 1: work on it. This is despite the fact that Cockrell
Speaker 1: had demonstrated to them that his hovercraft could potentially solve
Speaker 1: a lot of problems like not only could it glide
Speaker 1: over water, it could go over land, it could go
Speaker 1: over lots of icky stuff that other vehicles actually have
Speaker 1: a lot of trouble with so marshes and muddy sections
Speaker 1: and stuff. You know, if you had a boat, you
Speaker 1: wouldn't be able to go through these because there's not
Speaker 1: enough water to keep the boat floating right. The boat
Speaker 1: would just get beached or mired. Same with vehicles that
Speaker 1: are on treads or wheels, they would eventually get stuck
Speaker 1: in really nasty muddy situations. But the hovercraft would float
Speaker 1: above all this. It could get you through to places
Speaker 1: that other vehicles couldn't unless you were using something like
Speaker 1: say a helicopter or an airplane. So Cockrel was really
Speaker 1: making a case for how this could be a really
Speaker 1: useful vehicle for all sorts of different applications, and none
Speaker 1: of that seemed to really matter to these officials. However,
Speaker 1: he did receive a patent for his invention in nineteen
Speaker 1: fifty six because he had filed for this patent before
Speaker 1: the officials had put the hovercraft on the secret list,
Speaker 1: so ironically, his invention was already public because patents are public, right,
Speaker 1: that's one of the elements of patents. When you file
Speaker 1: for a patent, your description of your invention is made public,
Speaker 1: but in return, you receive government protection for your idea,
Speaker 1: at least for a certain amount of time. So this
Speaker 1: is why we call him the inventor of the hovercraft,
Speaker 1: because Cockrell actually secured patents relating to his invention, although
Speaker 1: as I mentioned earlier in this episode, and we'll get
Speaker 1: back to it, there was someone else who had built
Speaker 1: something similar a decade before Cockroll did. In nineteen fifty eight,
Speaker 1: the UK government declassified his work and this gave Cockroll
Speaker 1: the chance to actually pursue funding. The UK's National Research
Speaker 1: and Development Agency or NRDA, was really impressed with his
Speaker 1: invention and they commissioned a company called Saunder's Row to
Speaker 1: build a test hovercraft based on Cockrell's design. So Sunder's
Speaker 1: Row was already an established business. It specialized in building boats,
Speaker 1: and they produced a vehicle that was called the SR
Speaker 1: in one. SR standing for Saunder's Row, and it was
Speaker 1: really only big enough to hold its own crew. It
Speaker 1: wasn't designed for passengers. But here's the thing. It did work,
Speaker 1: and on July twenty fifth, nineteen fifty nine, Saunder's Road
Speaker 1: demonstrated its capabilities by having the SR in one cross
Speaker 1: the English Channel. The hovercraft left Dover in England and
Speaker 1: landed in Calais in France. Ou La Lain. Cockrell himself
Speaker 1: was aboard of the hovercraft for this demonstration. According to
Speaker 1: The Guardian, he served as ballast very dignified. This demonstration
Speaker 1: convinced UK authorities to invest more heavily into the hovercraft technology,
Speaker 1: and the NRDA created a company called Hovercraft Development Limited
Speaker 1: with the purpose of creating hovercraft for commercial purposes such
Speaker 1: as ferrying cargo and passengers across various rivers and channels
Speaker 1: like the English Channel. The organization oversaw the work of
Speaker 1: five different companies that were all dedicated to this purpose,
Speaker 1: so there was five different boating companies that all began
Speaker 1: building hovercraft vehicles. Christopher Cockrell landed a gig as the
Speaker 1: director for Hovercraft Development Limited, and he was also the
Speaker 1: technical advisor to the company and he stayed on in
Speaker 1: that capacity until nineteen sixty six. Also in recognition of
Speaker 1: his contributions, he would ultimately receive a knighthood in nineteen
Speaker 1: sixty nine, just like his dear old dad. So you
Speaker 1: had Sir Sidney and now you had Sir Christopher. The
Speaker 1: first of the passenger hovercraft was the Vickers VA three,
Speaker 1: which was an experimental vehicle it wasn't meant to be
Speaker 1: built for full commercial use. It was more like, again
Speaker 1: a proof of concept. It launched in nineteen sixty two.
Speaker 1: British United Airways ran the service because again hovercraft were
Speaker 1: thought of as an aircraft not a boat, right, because
Speaker 1: these fans would end up creating this air cushion that
Speaker 1: made the vehicle hover, sometimes several feet above the surface
Speaker 1: that it traveled across. So as such it was more
Speaker 1: of an aircraft than a watercraft. So the initial route
Speaker 1: passed over an estuary between Liverpool and North Wales. The
Speaker 1: hovercraft would hold up to twenty four passengers per trip,
Speaker 1: and it was intended to take twelve trips per day.
Speaker 1: And like I said, this was kind of an experiment.
Speaker 1: It was a pilot program. And originally the concept was
Speaker 1: that it would go for fifty nine days and then
Speaker 1: they would evaluate does this make sense, like can we
Speaker 1: turn this into a reasonable and viable transportation option. But
Speaker 1: while it was meant to go for fifty nine days,
Speaker 1: it only made it to thirty six. The reason for
Speaker 1: that was not entirely the fault of the actual vehicle,
Speaker 1: although there were some engine problems that turned out to
Speaker 1: be a bit of an issue, and in fact that
Speaker 1: would become a thing for a lot of hovercraft. It's
Speaker 1: not that the design was bad, it's that sometimes the
Speaker 1: equipment that was being used wasn't the most reliable. The
Speaker 1: other issue was that there was a lot of bad
Speaker 1: weather during that stretch. Now I think that you should
Speaker 1: just anticipate that, because as far as I'm concerned, bad
Speaker 1: weather is kind of a constitutional requirement in the UK,
Speaker 1: at least every time I've been there. So anyway, because
Speaker 1: of this combination of issues, the experiment was cut short.
Speaker 1: The VA three would retire as a passenger vehicle, but
Speaker 1: the British government would continue to use the VA three
Speaker 1: vessel to conduct some other kinds of tests, including a
Speaker 1: very extreme one. Namely, the test they wanted to really
Speaker 1: check out was could a hovercraft pass safely over a
Speaker 1: zone in the sea that happened to be occupied by
Speaker 1: marine mines? Right? Like? These are those mines you see?
Speaker 1: You know, typically I almost only see them in things
Speaker 1: like cartoons, where it's the giant globe with lots of
Speaker 1: little pressure sensors on it that are connected by chains
Speaker 1: and anchor to the seafloor. And the ideas that a
Speaker 1: boat which will pierce the surface of the water. If
Speaker 1: it were to make contact with these would cause it
Speaker 1: to explode. Well, the thought was, well, hovercraft, they don't
Speaker 1: pierce the surface of the water, they hover above it.
Speaker 1: So is it possible that a hovercraft could safely glide
Speaker 1: over an area that is filled with marine mines and
Speaker 1: not trip them? And they tested it and the VA
Speaker 1: three done blowed up real good, which answered that question
Speaker 1: rather definitively. Passenger hovercraft would tackle the English Channels starting
Speaker 1: in nineteen sixty six, with one of the most famous
Speaker 1: being a class of hovercraft called the SRN four. Again
Speaker 1: back to the Saunders Row and this was also known
Speaker 1: as the mount Batten class of hovercraft, and the very
Speaker 1: first one that made the trip across the English Channel
Speaker 1: was called Princess Margaret. This was in nineteen sixty eight.
Speaker 1: These vessels could make the trip between England and France
Speaker 1: in about half an hour. Typically we're talking like Dover
Speaker 1: to Calais, but sometimes a different port in France. But
Speaker 1: the interesting thing is if you contrast this with the
Speaker 1: traditional ferries that were making this trip between England and France,
Speaker 1: that journey would typically take an hour and a half.
Speaker 1: So three times as long. So the fairies had some advantages, right,
Speaker 1: You could build a ferry large enough to carry much
Speaker 1: more cargo and many more passengers than your typical hovercraft could.
Speaker 1: You know, hovercraft was usually carrying around two dozen people,
Speaker 1: maybe a little bit more, and maybe like as many
Speaker 1: as twenty cars initially. With these larger hovercraft and fairies
Speaker 1: could carry much more than that. However, hovercraft could make
Speaker 1: three trips in the same amount of time that the
Speaker 1: ferry took to do one, so there was a way
Speaker 1: of you know, kind of figuring that out and balancing
Speaker 1: it between the two. For a while, hovercraft would factor
Speaker 1: into Britain's transportation infrastructure. In fact, some would call hovercraft
Speaker 1: a quintessentially British form of transportation because there were lots
Speaker 1: of places around Britain where you could grab a hovercraft
Speaker 1: to go from one port city to another, whether it
Speaker 1: was to cross a river or an estuary or a
Speaker 1: channel or whatever it might be. But as I mentioned earlier,
Speaker 1: there's some slight dispute as to whether we should even
Speaker 1: call Cockrell the father of hovercraft in the first place,
Speaker 1: and that maybe thinking of hovercraft as a really British
Speaker 1: type of technology is misleading because, as it turns out,
Speaker 1: a Yank came up with a very similar methodology a
Speaker 1: decade earlier. And again, the actual theory for hovercraft predated
Speaker 1: both of these guys by decades, like almost a century,
Speaker 1: so let's keep that in mind. But the Yank was
Speaker 1: a guy named Charles Joseph Fletcher who was born in
Speaker 1: nineteen twenty two in New jer the United States. So
Speaker 1: Cockrell was born in nineteen ten. Fletcher was born in
Speaker 1: nineteen twenty two, so he's twelve years younger than Cockrell.
Speaker 1: During World War Two he served as an officer in
Speaker 1: the US Navy, and while doing so, sometime around that
Speaker 1: same time period. The details, to me are are a
Speaker 1: little bit hazy because a lot of the sources just
Speaker 1: don't have things like specific dates, But sometime around then,
Speaker 1: he sketched out a design for a vessel that would
Speaker 1: use a cushion of air to glide. You know, you
Speaker 1: could almost say hover above the surface below, whether that
Speaker 1: was land or sea, which sounds pretty familiar right now.
Speaker 1: He called his invention a glide mobile, so he had
Speaker 1: hovercraft and glidemobiles. So the story goes that Fletcher actually
Speaker 1: built a prototype of his design and tested it in
Speaker 1: New Jersey and showed it off to the Navy, and
Speaker 1: the War Department said, say that can be useful and
Speaker 1: then swooped in to take charge. So the War Department
Speaker 1: classified the project, similar to what happened to Cockrell when
Speaker 1: he showed it off to those local officials over in
Speaker 1: the UK. By making it a classified project, it prevented
Speaker 1: Fletcher from being able to seek a patent for it.
Speaker 1: He did not file a patent before showing it off,
Speaker 1: so the Glidemobile didn't really go much further as a result,
Speaker 1: because it just became the property of the War Department,
Speaker 1: and the War Department apparently didn't do very much with it. However,
Speaker 1: eventually some British companies were making a patent claim against
Speaker 1: the glidemobile design. This is after World War Two, it's
Speaker 1: in the nineteen fifties, and the hovercraft companies are saying, hey,
Speaker 1: you are infringing upon a patented technology. And then Fletcher
Speaker 1: was able to defend the position of the glidemobile by
Speaker 1: pointing out that no his designs predated Cockrell's patent and
Speaker 1: that it served as sort of prior art and meant
Speaker 1: that they weren't infringing upon a patent because they were
Speaker 1: building upon a design that actually pre dated the patent.
Speaker 1: Presumably Fletcher was able to prove this concept predated Cockrell's
Speaker 1: patent and he was able to move forward. I don't
Speaker 1: know for sure, because again the details are pretty scarce.
Speaker 1: But anyway, you didn't see hovercraft become a favored form
Speaker 1: of transportation here in the United States, whereas again in
Speaker 1: the UK, particularly in like the sixties and seventies, it
Speaker 1: really was like it became a kind of common form
Speaker 1: of transportation for folks who were trying to get across
Speaker 1: bodies of water quickly. Now, even though they were really
Speaker 1: famous in those days, there's only one commercial hovercraft service
Speaker 1: that is still in business today in the world, and
Speaker 1: it happens to be in the UK. It's a route
Speaker 1: that goes between the city of Ride, which is on
Speaker 1: the Isle of Wight, and south Sea in Portsmouth. So
Speaker 1: you might wonder what the heck happened? Why did this
Speaker 1: form of transportation, which was fairly enthusiastically embraced in the sixties,
Speaker 1: why did it peter out by the time you get
Speaker 1: to modern day, to the point where now there's only
Speaker 1: one commercial route still in business. Well, I'll tell you,
Speaker 1: but before I do, we're gonna take another quick break
Speaker 1: to thank our sponsors. Before the break, I mentioned that,
Speaker 1: you know, for a while, hovercraft were enjoying a moment
Speaker 1: in the spotlight, but then a few decades later they
Speaker 1: have all but disappeared, at least as far as commercial
Speaker 1: travel goes. I don't want to say that there are
Speaker 1: no hovercraft anymore. There certainly are, and in fact, there
Speaker 1: are a lot of hovercraft that are meant for very
Speaker 1: specific purposes. It's just you don't see them as cargo
Speaker 1: and passenger travel solutions these days, not that much anyway.
Speaker 1: And there are a few reasons for this. And it
Speaker 1: is kind of crazy because even if you go back
Speaker 1: to like the nineteen seventies, there's a James Bond movie
Speaker 1: in which there's a big hovercraft sequence. And again there's
Speaker 1: the bit in the ninety five movie Rumble in the
Speaker 1: Bronx where there's a big hovercraft sequence. But there are
Speaker 1: reasons why it's no longer a reliable and widespread travel solution.
Speaker 1: One is that hovercraft, especially older hovercraft, are really really noisy.
Speaker 1: I mean they make a huge amount of noise. They
Speaker 1: use these massive engines to turn the fans. The mount
Speaker 1: Batten class that I mentioned earlier used these enormous turbo
Speaker 1: gas engines that were made by Rolls Royce, and these
Speaker 1: engines make a whole lot of noise. They also generate
Speaker 1: a lot of exhaust, but they're very, very loud. The
Speaker 1: fans also generate a good deal of noise as well.
Speaker 1: So if you were a company and you're proposing building
Speaker 1: out a hovercraft to run a route between two particular cities,
Speaker 1: chances are you're going to have residents of those cities say,
Speaker 1: come on, we don't want that. We do not want
Speaker 1: to have this kind of noise pollution in our communities.
Speaker 1: Most folks aren't keen to have their days punctuated with
Speaker 1: extremely loud traffic from all sorts of places. And as
Speaker 1: someone who lives right across from a freight train line,
Speaker 1: I can understand this is not thrilling to hear that
Speaker 1: freight train go by. So that made expansion a little tricky, right.
Speaker 1: It's a lot of not in my backyardism, but understandable
Speaker 1: because that noise pollution is serious stuff. But another issue
Speaker 1: is that while hovercraft can have a big advantage in
Speaker 1: that you don't have to use a peer or anything
Speaker 1: like that. Like, you don't need a peer or a
Speaker 1: dock in order to secure the craft. You can just
Speaker 1: drive the hovercraft from the water up to the land
Speaker 1: as long as the land is relatively clear. You still
Speaker 1: need a space where the hovercraft can go, right, you
Speaker 1: can't just plow through like woods or whatever. You can't
Speaker 1: go wreaking havoc through a marina. You need to have
Speaker 1: a dedicated space where the hovercraft can beach itself, like
Speaker 1: can go up onto the land and then descend so
Speaker 1: that people can get off the vehicle. So you do
Speaker 1: need to have some physical space available for the hovercraft,
Speaker 1: and not every place had that as an option. Then
Speaker 1: there's the issue of maintenance and repair. Hovercraft need these
Speaker 1: really big engines to work. Like if you're looking in
Speaker 1: the grand scheme of things the fans used in hovercraft,
Speaker 1: they don't need to generate the same amount of lift
Speaker 1: that a helicopter would, right, they don't have to work
Speaker 1: as hard as the rotors of a helicopter, but they
Speaker 1: still have to work. And these really really big hovercraft,
Speaker 1: while they can be very efficient, still need a great
Speaker 1: deal of power in order to generate that lift. So
Speaker 1: you need these really large engines. If those engines are
Speaker 1: in disrepair, then you're not going to go anywhere. And
Speaker 1: as I've already said, like some of the engines that
Speaker 1: were used in hovercraft, especially in the early days, weren't
Speaker 1: terribly reliable, and that meant that hovercraft could be down
Speaker 1: just as frequently as they could be in operation, and
Speaker 1: this gets expensive to do maintenance and repair all the time.
Speaker 1: There's also the matter of fuel. Those engines require a
Speaker 1: lot of fuel in order to operate, and fuel is expensive.
Speaker 1: And remember, in the nineteen seventies, the world went through
Speaker 1: an oil crisis and fuel prices skyrocketed in the nineteen seventies.
Speaker 1: This was due to a political crisis in the Middle
Speaker 1: East that spawned from some military conflicts in the Middle East.
Speaker 1: So this was not a natural oil crisis, it was
Speaker 1: a man made one. But it's still meant that fuel
Speaker 1: prices around the world, especially in the UK and the
Speaker 1: United States and in Japan, went crazy high, and so
Speaker 1: operating a transportation system that was fuel hungry was kind
Speaker 1: of a losing proposition as far as money goes. So
Speaker 1: eventually it just got to a point where the return
Speaker 1: on investment wasn't really that good. It became too expensive
Speaker 1: to operate a hovercraft service. Most hovercraft are fairly modest
Speaker 1: in size. They might carry a couple of dozen passengers
Speaker 1: at a time, maybe a few cars. The Mount Batten
Speaker 1: class was different by the time we get to its
Speaker 1: later refittings because of the Saunders Row would end up
Speaker 1: upgrading this class of hovercraft over and over again. By
Speaker 1: the end of it, they could carry more than four
Speaker 1: hundred passengers and around sixty cars at a time, which
Speaker 1: is pretty impressive, but I imagined that the profit margins were
Speaker 1: still fairly thin when you look at how expensive it
Speaker 1: was to keep the vehicles in operation versus how much
Speaker 1: you can make in ticket sales to customers. Because eventually
Speaker 1: you're going to get to a point where a customer
Speaker 1: is going to say, I'm not willing to spend that
Speaker 1: much money just to save an hour's worth of time
Speaker 1: while I'm crossing the English Channel, for example, Like I'll
Speaker 1: spend less money and it'll take me an hour and
Speaker 1: a half to get there, rather than spend five times
Speaker 1: as much in order to get there in half an hour.
Speaker 1: So it just meant that there really became fewer and
Speaker 1: fewer financial reasons to keep a hovercraft operation going. So
Speaker 1: by the year two thousand, most hovercraft services commercial ones
Speaker 1: had shut down, and as I said, the only one
Speaker 1: that remains now goes between the Isle of Wight and Portsmouth.
Speaker 1: Occasionally you will see hovercraft of various sizes doing other
Speaker 1: types of jobs. There are some military hovercraft, there are
Speaker 1: some other ones that are used for you know, recreation purposes,
Speaker 1: but when it comes to commercial transportation, it's really mostly
Speaker 1: a thing of the past. Now that we've covered the
Speaker 1: history of the craft, let's talk about what's actually making
Speaker 1: them hover because it's just a tiny bit more complicated
Speaker 1: than fan points down and air pushes hovercraft up, but
Speaker 1: only a tiny bit more complicated than that. Ultimately, that
Speaker 1: is what is making the hovercraft work. So you could
Speaker 1: just walk away with fan points down. It pushes air down,
Speaker 1: hovercraft goes up because equal and opposite reaction and whatnot.
Speaker 1: So the original hovercraft design used two layers of a
Speaker 1: shell or hull. Think of it like a channel, like
Speaker 1: it was a channel through which air could flow, and
Speaker 1: the underneath the hovercraft is a hollow section that would
Speaker 1: be called a plenum. In fact, the original version of
Speaker 1: a hovercraft that little ten can version. You could think
Speaker 1: of that as a plenum based hovercraft, where you're just
Speaker 1: pumping air through the plenum. That's enough to generate lift,
Speaker 1: but only generates a little left. You aren't able to
Speaker 1: get very much height using that. So this other version,
Speaker 1: the one that Cockroll had designed, used this channel of
Speaker 1: air that would direct air to flow down along the
Speaker 1: periphery of the hovercraft's bottom, So you have a vertically
Speaker 1: oriented fan it's blowing air downward. That air flows through
Speaker 1: this channel, which then is directed toward the outer section
Speaker 1: of the hovercraft. It creates a ring of air. That
Speaker 1: air is effectively flowing inward toward the inside of the hovercraft,
Speaker 1: that plenum, that hollows section underneath the hovercraft, and that
Speaker 1: ring of air also serves as a kind of curtain
Speaker 1: or barrier, so it's not allowing air to escape out
Speaker 1: the sides of the hovercraft, or at least not a
Speaker 1: lot there escaping out the sides of the hovercraft. And
Speaker 1: this creates the lift. It allows the hovercraft to levitate up,
Speaker 1: not levitate, but to hover up, and you can get
Speaker 1: a hover of around several inches up to a couple
Speaker 1: of feet, but you couldn't get much higher than that. However,
Speaker 1: later on, engineers developed a flexible skirt for hovercraft. So
Speaker 1: imagine that you have this flexible material, typically made out
Speaker 1: of rubber, that goes around the periphery of the hovercraft.
Speaker 1: So it's got a little skirt that goes all the
Speaker 1: way around. When you're directing air downward, perhaps in the
Speaker 1: same style as you were before, which was actually called
Speaker 1: a peripheral jet approach, maybe you're using a combination of
Speaker 1: the skirt and a peripheral jet. Then it keeps the
Speaker 1: air in more effectively than just the peripheral jet by itself.
Speaker 1: The rubber contains the air there. It creates this air cushion,
Speaker 1: and theft actually get much more height this way. You
Speaker 1: can get maybe up to like six or seven feet
Speaker 1: of height using this. So the skirt makes it look
Speaker 1: like the hovercraft is still keeping contact with the ground,
Speaker 1: but the actual bottom of the hovercraft itself is several
Speaker 1: feet above that, and this is how hovercraft typically work.
Speaker 1: A secondary fan is usually used to provide propulsion. I
Speaker 1: mentioned this earlier. You got a fan that points like
Speaker 1: backward from the hovercraft, and when you turn that on,
Speaker 1: it's shooting air. Out the back, and then you get
Speaker 1: the equal but opposite reaction. The hovercraft will move forward.
Speaker 1: You usually have a rudder or some other method to
Speaker 1: redirect that fan so that you can make turns. Those
Speaker 1: turns can be pretty gradual, and you still have momentum.
Speaker 1: You know, you have the loft conservation of motion. You're
Speaker 1: still moving. So that's why it's difficult to pilot these things.
Speaker 1: It's challenging. You can't just slam on brakes with a hovercraftft.
Speaker 1: You can stop the fan and you will come to
Speaker 1: a stop gradually, but you can't just slam the brakes,
Speaker 1: so tight turns and sharp stops are not really possible,
Speaker 1: which is why hovercraft are typically a little easier to
Speaker 1: operate on the water than they are on the land.
Speaker 1: If you come up to an obstacle on land, you
Speaker 1: might be bumping into something. One thing that Cockrell figured
Speaker 1: out was that, perhaps counterintuitively, the larger the hovercraft was,
Speaker 1: or more precisely, the larger the area of the air
Speaker 1: cushion or cushions that provide the lift, the more efficient
Speaker 1: the hovercraft became. Here's how he put it in his patent,
Speaker 1: and it does get technical. So here we go quote.
Speaker 1: In such vehicles, the lift or load carrying capacity is
Speaker 1: proportional to the plan area of the gas cushion or cushions.
Speaker 1: The energy required to contain the cushion or cushions is
Speaker 1: proportional to the peripheral dimension of the cushion or cushions. Thus,
Speaker 1: for an increase in size of a vehicle, the lift
Speaker 1: increases proportionally to the area of the cushion or cushions,
Speaker 1: whilst the energy requirements increase linearly with the periphery of
Speaker 1: the cushion or cushions. So, in other words, the larger
Speaker 1: the hovercraft is, or the larger the surface area of
Speaker 1: the air cushion is, the easier it is to achieve
Speaker 1: greater lift with only a smaller increase in actual power.
Speaker 1: So you're getting greater returns for just a smaller investment
Speaker 1: in power, and thus it's more efficient to build larger
Speaker 1: hovercraft than it is to build smaller hovercraft. I guess
Speaker 1: you could still just say that pointing a fan downward
Speaker 1: provides the lift needed to hover the vehicle, and you
Speaker 1: could just leave it at that, but you do need
Speaker 1: some other design elements to make the vehicle stable and useful,
Speaker 1: Like I said, hovercraft are still a thing, They're just
Speaker 1: not typically used for commercial transportation. They are not commonplace,
Speaker 1: but similar technologlogies related to hovercraft have found their way
Speaker 1: into designs since then. You might know that the original
Speaker 1: concept for the hyperloop train system included a train running
Speaker 1: through a tube where you had pumped out most of
Speaker 1: the air, and the train would hover above the floor
Speaker 1: of that tube through the use of air ball bearings.
Speaker 1: So Elon Musk described it as sort of like an
Speaker 1: air hockey table, only facing downward instead of facing upward.
Speaker 1: That's not that different from a hovercraft, or a glidemobile,
Speaker 1: or an air cushioned vehicle, however you want to call it.
Speaker 1: The methodology described in the hyperloop concept is a bit
Speaker 1: different from what you'd see in a hovercraft, but the
Speaker 1: gist is similar. As it would turn out, the various
Speaker 1: companies that sprung up in the wake of Musk's proposal would,
Speaker 1: by turns, choose a different approach. Some went with magnetic levitation,
Speaker 1: some would dispense with the idea of suspending the train
Speaker 1: above the track entirely and thus embrace a more traditional
Speaker 1: train design. But initially the hyperloop was meant to have
Speaker 1: an air cushion under it. Of course, you could argue
Speaker 1: that these days the hyperloop concept has been all but
Speaker 1: abandoned because several of the companies that pursued the goal
Speaker 1: of making it a reality have since gone out of business.
Speaker 1: You can, of course, build your own hovercraft. There are
Speaker 1: websites describing how to make a sample hovercraft using like
Speaker 1: a balloon and an old CD or a DVD. I
Speaker 1: would suggest use one you don't plan on ever playing again.
Speaker 1: Maybe maybe a kid rock album would be suitable. There
Speaker 1: are also kits to build an actual hovercraft. You know,
Speaker 1: you can kind of build a sort of personal pan
Speaker 1: pizza sized vehicle. I've seen diy hovercraft on YouTube of
Speaker 1: varying degrees of safety and reliability, and there are lots
Speaker 1: of ones for things like radio controlled hovercraft. Right. There
Speaker 1: are a lot of toy versions of hovercraft that work
Speaker 1: on the same principle, but they're obviously at a much
Speaker 1: smaller scale, and that way you can learn how challenging
Speaker 1: it is to direct a vehicle that works on momentum
Speaker 1: and has a lack of breaks. It can really be
Speaker 1: easy to get moving in a particular direction and a
Speaker 1: real challenge to you know, stop doing that. But that's
Speaker 1: our look at hovercraft, a technology that I think is
Speaker 1: pretty interesting, pretty cool. I have never written on one.
Speaker 1: I've never been on a hovercraft. I kind of wish
Speaker 1: that I had had that experience. Maybe one day I'll
Speaker 1: make a trip out to the Isle of Wight simply
Speaker 1: so that I could say I wrote on a hovercraft,
Speaker 1: which means that I'll be walking around Isle of Wight
Speaker 1: and probably lamenting how many places have closed down. I've
Speaker 1: watched some videos recently of that area of Isle of
Speaker 1: Wight and it was looking a little grim, although I
Speaker 1: should say that was also in the off season, so
Speaker 1: maybe that's it, you know, Maybe it's just that, Oh,
Speaker 1: these are things that are usually working in the more
Speaker 1: popular seasons. It's just in the off season they shut
Speaker 1: down because there's no sense in running it. Then maybe
Speaker 1: that's the case, I hope. So, but that is our
Speaker 1: look at hovercraft. I hope you enjoyed this episode. You
Speaker 1: learned a bit about Sir Christopher Cockrell and his mission
Speaker 1: to create a new form of transportation and to get
Speaker 1: past that irritating problem of friction that voting stuff encounters.
Speaker 1: Although Cockroll encountered more than a little friction just you know,
Speaker 1: in the political side, as opposed to as opposed to
Speaker 1: physical friction that you would encounter in the water. I
Speaker 1: hope you are all well. Thank you so much for listening,
Speaker 1: and I will talk to you again really soon. Tech
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