'Underwater bicycle' propels swimmers forward at superhuman speed
newatlas.com
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Here’s a pedal powered smuggling submarine from the 1940s http://www.hisutton.com/Swiss-Pedal-Powered-Smuggling-Submar...
A person paddling can't sustain 6mph for very long, if they get there at all.
A guy on one of these doing the minimum speed. He doesn't look like he's casually pedaling, no?
It's probably harder to maintain 6mph than you might think.
>A guy on one of these doing the minimum speed.
With any wing, the faster you go in level flight the less drag is caused by lift. This strange fact is because moving a large amount of fluid slowly is more efficient than moving a small amount of fluid fast, and a faster wing can interact with more fluid mass per second ("m dot").
https://en.wikipedia.org/wiki/Lift-induced_drag#Calculation_...
Since skin drag increases with speed, adding these two drag curves together forms a 'valley' in the overall speed-vs-drag curve. Going slower or faster than this ideal speed will result in increased energy per mile.
The math is better explained in David MacKay's brilliant ebook, 'Sustainable Energy Without the Hot Air.'
It can take some time to get used to fins and the motions needed. Many more people have ridden a bike
If there is an article about berries and you say you love blueberries and I reply saying “I hate them”, it in the context of blueberries. It doesn’t mean I hate all berries. And I shouldn’t have to clarify that, since I’m replying to a comment about blueberries.
How else could this work?
> And everything is always in exactly one easily defined context, right? So for a comment reply we already know the full context just by looking at its immediate parent. That's how nested replies work, right?
noncoml:
> Yes..?
But somehow, also noncoml:
> You are not doing HN right if you are only reading the parent
I give up.
https://nypost.com/2023/11/15/news/taliban-seen-patrolling-k...
It’s described in the H I Sutton book, from the website above, but I think it’s out of print now
They have a .fr domain and a showroom in Cannes, France but the company is headquarted in Italy:
PARITET SRL, Via Giovanni da Cermenate 3, 22063 Cantù (CO) Italy
The whole thing does not inspire a lot of confidence. Is the product real?
https://www.nauticexpo.com/prod/seabike/product-68606-564117...
Pretty fast, but "superhuman"? For short distances Michael Phelps can swim faster :)
Super just means beyond, not way beyond. I blame Superman for this notion.
There real advantage here is that you can use leg muscle. Distance swimming is all about upper body muscles, with legs being the afterburners only really used for sprinting. This machine would invert that arrangement.
If he or someone else breaks the record with it, he's going beyond human level speed. Until then this may only have the potential to do so.
I imagine the first bikes were slower than the top runners of the time? I see potential for the idea.
Nope. He would be horrible with this device. That would be like asking a champion sprinter to compete in a wheelchair race. He would be using totally different muscles, legs rather than arms, and get schooled by most everyone with a longer history. A champion bicycle rider would do better on this contraption than any champion swimmer.
(Due to water's density, champion speed swimming is also 80% technique and body shape rather than muscle/cardio. So until the technique is developed, nobody would be "good" with this thing.)
And then an olympic pool is 50 meters long, meaning far fewer turns for a given distance. So "long course" times are generally slower than short course even at the same distance.
(Underwater is so much faster that swimming has rules about how far you can travel underwater during each length.)
https://www.boatus.com/expert-advice/expert-advice-archive/2...
At the 2020 Miami International Boat Show, Philadelphia-based Sharrow Marine introduced the culmination of a seven-year research and development project called the MX-1 Sharrow Propeller. Unlike every prop that's come before it, rather than blades, the MX-1 has loops of metal attached to the hub.
How does this change the dynamic? In a nutshell, much of a prop's inefficiency can be blamed on the blade tips, where vortices and cavitation (commonly called tip vortex cavitation, or TVC) form, creating turbulence and sapping efficiency. Simply put, the loops on a Sharrow have no tips. The net result is an efficiency gain of between 9% and 15%. But just as important, eliminating the cavitation vastly reduces vibrations and noise and makes for a smoother, quieter boat ride.
Company president Greg Sharrow tells us that the development of the MX-1 can be credited to music videos.
"I was trying to solve the problem of reducing unwanted noise from drones while filming live music productions," he says. "I've always thought it would be cool to use a drone to get cameras closer to subjects and film them from onstage, but you can't use drones for music broadcasts because they're too noisy. I knew that most of the noise comes from the blade tips and is caused, in part, by tip vortices. So, I'd have to find a way to eliminate them."
Cavitation is a destructive force and eats away at the edge & surface of the prop blades, making it VERY inefficient.
Felt a bit iffy about this claim. But looking at the research it seems cadence lowers normally when cycling under water.[0] Fun device. I wonder which pedals would be best for barefoot riding(?). Maybe those strapped ones fix riders like to use.
Secondly, I could see this being used recreationally in the ocean, but in the local pool?!?
https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1700041
> There are two main types of single-wheeled vehicles. In a unicycle, the rider sits above the wheel. These vehicles are recognizable by most people. Less well known is the monocycle, where the rider sits inside the wheel.
This seems awkward and I bet you have to use your arms just to counterbalance the twist you'd get on each 'stroke' of the leg.
So even though I think it's goofy, I bet I'd like whoever came up with this. Someone who put a ton of effort into building something they thought would be interesting despite a thousand people telling them it's goofy.
Good on them.
I run because I enjoy it, not because I’m trying to get somewhere fast. But I also bike because I enjoy it, not because I’m trying to get somewhere fast.
You seem to assume that because this thing is faster, it must automatically be less enjoyable. That’s not the case for bikes, why should it be the case here? In my opinion it sounds fun, and would probably be enjoyable.
If I were to guess at their motivations, it might be 'what could make me go faster in the water and also be enjoyable'? I'd try it out of curiosity, sure, but I'm pretty sure it wouldn't last beyond the novelty for me.
How do you draw the line at "any kind of technology"? Isn't the bike itself "technology"? How about pneumatic tires? Or computer designed tread for optimal traction? Is a bike suspension too much technology? How about electric assist that can help you up a hill but won't propel the bike without you pedaling along with it?
That's a pretty weird idea.
Skis, snowboards, or snowshoes make traveling on snow, especially downhill, much more fun.
Bicycling, rollerblading, skateboarding (basically using anything with wheels) is very commonly considered more fun than running.
Most people who swim in cold water prefer using a wet suit rather than toughing it out.
And it's pretty fun to use a boat, surfboard, or scuba gear rather than be stuck swimming without any aids.
"All the work" is useless hyperbol. There are things that simply can't be done on a road bike. There are things that can be done on a road bike without a significant loss of safety.
Sport technology can reduce the skill required for certain things, but it also tends to extend the envelope of what is possible. It is almost never correct to think of technology doing all the work but rather to think of it as an ability multiplier.
There are of course, times when it is beneficial to practice without a specific piece of equipment. Either for a challenge or/and to hone a specific sub skill.
We’re talking about manually propelled bikes here. The bike isn’t doing all the work, but it is pretty essential in reaching the speed and sustaining the pace.
Sure you can argue that if you strap a rocket to your bike then you aren’t doing any work, but that’s not the case in either of these examples, so what’s the purpose of going down that tangent?
The problem in this case is that the device is doing part of the swimming for you.
Going fast doesnt mean not enjoying it.
I could see this as an alternative to fins offered at snorkeling places. That would make a great test environment too.
That said this certainly has its place. There are lots of use cases for wanting to swim more quickly through the water, where precise control is less important and where you aren't right next to fragile life.
There are solutions that leverage a pair of catamarans and a track system, or a prop. These tend to move very slowly, much slower than a canoe or kayak. The water wheel style systems seem to move faster, but you can just get a pedal kayak and will be the fastest human powered craft on the water.
A speed comparison would have been nice. EDIT: it's already there: "This jigger, according to the manufacturers, makes you handily quicker than an equivalent swimmer with fins on."
[1] https://www.westmarine.com/mares-razor-carbon-dive-fins-41-1...
I guess the actual plan is to sell classes by taking advantage of the novelty effect.
Also depends a lot what you optimize for. For underwater swimming, especially scuba, you want to optimize for saving air, meaning minimize the total energy expenditure and keeping heart rate low (the mammalian dive reflex helps here too). In water, that means moving very slowly and with longer strokes, for the same reason container ships move slowly to conserve fuel. It looks really inefficient to pedal fast because all that water around your knees needs to be pushed back and forth for no gain.
I live near a fairly dangerous ocean in SF where I’ve gone bodyboarding with a wetsuit and fins. I’m concerned that, if caught in a current, fins are not enough to propel me out of it.
This would. The extra power and ease of propulsion could make all the difference.
Especially with a bodyboard and fins doing the right thing does not require a ton of strength and shouldn’t be stressful.
Well informed local ocean | river mouth swimmers are gemnerally aware of the currents and tend to know how far out they carry and where one can get to the side to make their way back.
That said, currents are strong, people have bad days, they can panic, water can be cold .. far colder further out than might be expected and that can weaken the body.
Surfing is a whole other ball of wax; dedicated surf spots might be well offshore and require a boat or a jet ski to even reach, if those get crunched by a slab or fail there might be a whole lot of swimming to get back to shore, assumming the surf didn't get you.
eg: The Right in Western Australia.
https://www.sfgate.com/bayarea/article/san-francisco-surfer-...
Flippers have a great deal of fine control in all axis, and this doesn't look like it does. I'm a pretty fair diver, but when you see guys who dive all the time, they look like they were born with those flippers.
And free divers? I can't imagine them giving up their fins. They take advantage of the really long and strong muscles in the legs.
The hydrofoil board with a prop and motor looks really cool.
Just not sure what the learning curve is like and kind of worried about hitting something and flying off.
I, frankly, don’t understand it. They aren’t particularly advanced devices.
I'd happily buy a well made new one for £3000 if that was what they cost, but half that price is a new good solid paddle board - so I can see why you can't get the same plus all the electronics you need for £3k.
We can hope in time the costs come down, but as a niche sport, it will be some time, if ever. Have you seen the cost (and service intervals!) of a new jet ski? All simple tech, but they don't come cheap and need a lot of looking after.
I can still dream though.
[1] https://foil.zone/ [2] https://www.youtube.com/watch?v=S9z6BP8Y42U
Since the original article is about human power, I'll also link to this foil[3] which is for pump foiling long distance. I had run across the channel well before that and thought his goal for a half hour was goofy when people were getting 90s or 2 minutes so I was quite shocked when it actually got built.
Yeah, it exists.
Engineering students have been building "underwater bicycles" for human-powered submarine competitions for decades!
Very splendid, except some dozen people managed to misuse it. Diving deeper and without small emergency bottle.
So it was banned for all eternity everywhere. Even Chinese have not rekindled this product.
Because I am fool, I tried to make my own. But gave up because breakages were indicated only by lung full of water, which tend to be fatal.
Could have been Austrian invention anyways, perhaps?
Try holding your breath and just floating, arms at your side and legs not moving. You will bob to the surface. Then quickly release your breath and snap your neck back to take a new one. Repeat. That's all it takes to not drown. You could almost do it as a quadriplegic (though I'm not 100% on "water balance" in that case).
Also, even if you are buoyant, it does not follow that being strapped to some device means you can't drown.
People who can float never believe me, but enough have now seen me in the water that I know I’m not “doing it wrong” I just don’t float.
The people who’ve seen me try it in water always say something along the lines of “huh, I thought everyone could float” we’ve done a few goes.
Most people float, I’m just not one of them.
I was a Red Cross Water Safety Instructor and lifeguard. I taught plenty of lessons to sub-10% body fat adults who had this problem. I generally have this problem too.
I can still float all day effortlessly.
I would totally try this toy out if it was at a resort and I could try it free or for a small charge. I think I wouldn't likely buy one but I would definitely enjoy trying it.
It is extremely clear to me this is a toy for expert swimmers. Anyone who has any fear at all of it should not try it. A lot of the comments read to me as people who are not good swimmers and aren't being straightforward about it and are projecting things onto the device.
But I also see no reason why you can't use this thing with a PFD. For something like a snorkeling program you could let people use it with a PFD.
A lot of people who can't swim freak out and have poor control of their breath. That's why this is a sticking point in lessons sometimes. You can tell someone to slow their breathing and hold more air in their lungs, but they are basically freaking out breathing fast and they have no control.
Nope. Not even close. If you have any other pearls than "fill your lungs" then let me know. I'll be happy to try next time I'm in the pool.
Filling your lungs is pretty easy to try and pretty much the first thing that comes to mind and almost always the first suggestion everyone gives.
I've done a lot of lap swimming, sub 30s 50m, can hold breath for ages, swim 50m underwater, comfortable scuba diving etc but that doesn't help.
The issue is not total flotation per se. It is balance. I can't push air down into my legs, so they go down. I have then lost a lot of surface tension with my body area, so I go down.
I end up vertical but with max capacity lungs I can bob near surface. But breathing out to breathe fresh air in makes me go down. Compared to someone floating happily on their back it is not relaxing.
I really wish people would give up on the "eVeRy0ne cAn f1oAt!" idea. With just my body(IE no floating aids/neoprene), nope.
What I do instead, I kick gently. Just enough to keep my feet up. That keeps the rest of me up holding surface tension. I'm pretty sure I could do this for hours if need be but never want to be in a position for survival to know.
As another commenter has said, not everyone is able to float and I have tried all “You just have to …” suggestions in this thread. I genuinely do not float.
I’ve got big heavy legs from cycling, squatting and paternal genetics, my torso is a little short for my height and I’m comfortably under 15% body fat with a BMI of 24.
I don’t float.
On average, people stop floating around 10-15% body fat, but this varies based on lung capacity and bone size.
Lung capacity is often an under appreciated factor
Inflated Lung density is about 25% relative to water, fat is 95%, organs are around 105%, and bones are about 185%
I was in swim lessons since I was like 3, on swim teams from age 8 to 18, I love the water. But I never cracked the code of floating.
I can _sort of_ float on my stomach, but this is not especially useful. And I definitely have some degree of buoyancy, I have to let out air if I want to sink to the bottom. But my default state in the water is to bob uselessly near the surface. Even with a big breath, even if I try to hold them up, my legs drag me down.
You need to be an outlier to not be able to overcome a body composition / density problem with techniques #1 and #2 above though, without observing you no one can really say if you're applying those techniques properly.
But a brick with lungs. Hold full breath. If even that doesn't work then I guess swallow air and try not to burp or fart?
Can you elaborate on that part?
You would set the cleat retention tension lower than for a bicycle. (But also this product is ridiculous, no one is actually using it.)
Design engineer: "Turns? Turns?!"
Is it really faster than flippers? Didn't seem that quick in the video.
It doesn't even have convenience going for it since you have to strap into it, so it's probably almost as much of a ball-ache to put on as fins, plus the awkward problem that it's hard to stand up.
If they can make it work without the waist strap (or have super-quick disconnect for that strap) I could see that convenience being nice, but still, I'd like proper comparison with fins.
They definitely could make it a lot more clear in the images.
Another interesting use case would be just tossing one of these into a boat that you own, or a kayak or whatever. Basically extra insurance to get you back in case your motor dies or you get swept out, similar use case as the surfboard
In the ocean this could attract some very sizable predators . . .
What is apparent when you learn to try to swim is that the largest muscles in our body are rendered hugely irrelevant. I don't have exact number, but I'd guess at least 95% of potential power output of our running-optimized evolutionary muscular-skeletal design is wasted in swimming.
Maybe Phelps and others can beat that with decades of training from an early age, body shape advantages, long feet, and superior flexibility, but I'd guess they buy just 10% more advantage in power-> speed conversion from the legs.
Other examples are how much faster you can swim with flippers. I would actually like to see good swimmers who train to use full scuba flippers vs good swimmers with this bike contraption.
This is hilariously efficient compared to that.
4mph and under $250 and I’m sold!
If it augments the human's capabilities, it's definitely super!
Something like this expands the envelope of what is, definitionally, the realm of natural human capacity… it pushes what qualifies as superhuman further away, but it doesn’t mean you’ve done something superhuman.
See: https://www.outsideonline.com/uncategorized/who-would-win-10...
so... like a normal bicycle then.