Extreme Dolfinism G2

[Kars]

Hi Kars, I've not been able to do the kind of comparison I did with the Orca and smaller blade an videos - but it is something I am working on. (changes in pool staff) Per your remarks - I think in dynamic the heel strap on a slightly loose foot pocket can make up for looseness and contribute energy storage/thrust because of the relatively low load in dynamic - just theory at this point.

Hehe new pool staff I know the challenge, building that trust, gaining the permission and space to do what we think is easy and normal.

The heel strap can help a little, but really the stiffness of the rubber and the range of free play are the main things. Many people do not know that on 'classic' monofins (basic model), there are 3 different stiffness pockets available (rubber stiffness!), who's shapes are all the same. Much of the fin's action is done by the spring behaviour of the footpockeds.

 

[Fondueset]

Hehe new pool staff I know the challenge, building that trust, gaining the permission and space to do what we think is easy and normal.

The heel strap can help a little, but really the stiffness of the rubber and the range of free play are the main things. Many people do not know that on 'classic' monofins (basic model), there are 3 different stiffness pockets available (rubber stiffness!), who's shapes are all the same. Much of the fin's action is done by the spring behaviour of the footpockeds.

Very True. Even subtle things like trimming the corners!

 

[Apneaddict]

There is no magic to be had in a monofin......

When operating on design point, hyperfins are already near the physical limits for propulsive efficiency, so we should not expect any new fin design to produce dramatic performance increases, beyond that of a good hyperfin.

......Comfort, durability, portability - these are the areas where we can expect to see large improvements from new types of hardware.

A little piece of me died when I read these statements.

 

[REVAN]

This question might be slightly unrelated, but it somewhat baffles me how after all this time hyperfins remain so uncomfortable ? There are so many other solutions such as cycling shoes (and others) that I fail to understand why these old materials and methods persist...

Hyperfins rely on flexure of the swimmer's feet as part of the fin's dynamics. Several people have tried to use cycling shoes on a monofin blade and it never works well. The examples I have seen have always taken a substantial performance hit for losing that flexure mode. The main reason for the discomfort has to do with foot pockets designed for this flexure mode. Monofin swimmers thrust from the toes and carry the loads up through the many small weak bones of the feet. So, to answer your question; they remain uncomfortable because it is part of the fundamental design concept.

Now you get someone, like Fondueset, who has toughened their feet through years of adaptation, and then combine that with a good ergonomic fit and a soft fin blade, it can be a nice fin to swim with. However, most people will never get there. The masses need something that can work for them fresh out of the box.

 

[Fondueset]

Hyperfins rely on flexure of the swimmer's feet as part of the fin's dynamics. Several people have tried to use cycling shoes on a monofin blade and it never works well. The examples I have seen have always taken a substantial performance hit for losing that flexure mode. The main reason for the discomfort has to do with foot pockets designed for this flexure mode. Monofin swimmers thrust from the toes and carry the loads up through the many small weak bones of the feet. So, to answer your question; they remain uncomfortable because it is part of the fundamental design concept.

Now you get someone, like Fondueset, who has toughened their feet through years of adaptation, and then combine that with a good ergonomic fit and a soft fin blade, it can be a nice fin to swim with. However, most people will never get there. The masses need something that can work for them fresh out of the box.

I once snapped the handle off one of my mom's cast iron pans with a crescent kick

 

[REVAN]

A little piece of me died when I read these statements.

Sorry about that.

There is always room for improvement, but those improvements will approach an asymptotic limit. I think we can all agree that nothing can be more than 100% efficient. And, in reality, I don't think any fluid propulsion systems, either man made or in nature, ever achieve more than about 85% efficiency. If we are in the mid 70s now, the realistic headroom on performance gain from making a better monofin is only about 10 to 15 percent.

 

[baiyoke]

In one perspective you are right REVAN - in another perspective things are not that fixed I think. I think however you won't disagree on this - this is my perspective at the moment:

To say we are around 70% at the moment is only when looking at the big picture - because more than anything in this sport, were efficience is everything, we also need to take into account the Who, What and Why... Because more than everything a good FIT between person and fin is important - and we might even have to take mental factors into that account too... In DYN performances the current record is set with a method of propulsion that (as far as I can see) has nothing or very little to do with the fin/foil perspectives. It's just a giant push... (I've been speculating in the possibility of making a very simple power-kick/low-drag fin).

But even in my above notion I'm guilty of being too narrow minded, only looking at the freediving competition related fin activities. Cruising 100% might come up with different adjustment (wich you have pointed out in other posts).

So in my mind, I think many people are only at a 25-50% fx... Because of personal caracteristics, physical and mental... If a different fin that fits them perfectly can bring them from 50% to 100% of their potential - the magic is back! At least for a while... To me the magic lies not in the fin alone, but in the FIT.

Now, how we get to the point where people can get a perfect fit... That's to me where people like you REVAN changes things and challenge old conceptions, show us new possibilities.

You are also restrained by production limitations... In a better world - you should have 100 different fins and setups, and a video lab for people to come and be filmed in when diving, while a computer crushes numbers and data, recommending a personalised setup. Until that day, we might get closer through your inventions. And perhaps soon a fin with more possibilities of personalized fitting can do some of the job....

I think there's still some magic left in your hat REVAN for the years to come. Getting a fin that just fits perfectly with your body and style and mental setup... that sounds magical to me

 

[neurodoc]

I think it isn't really possible to know what percentage we have achieved in finswimming or freediving. To say that all the big improvements have already been made and not much more is possible? It's just like saying that it isn't possible to drive a car faster than a mile a minute, run a mile in under 4 minutes, or break the sound barrier. All were thought by "leading minds" to be absolute limits in their day, and all have been broken and surpassed by wide margins. I do not think finswimming and freediving are any different in this regard. We will continue to improve, sometimes incrementally and sometimes dramatically as new concepts are explored and finally successfully implemented with enough trial, error and training. Some of this trial and error and incremental improvement can get in the way of business matters; I prefer to observe the improvement in all designs (DOL-fin and Lunocet as the leading examples) and see where they lead rather than criticizing their development process along the way. As a swimmer, it is an exciting time. In my other sport, cycling, governing bodies have limited/stunted product development and slowed progress in the name of dogmatic rules. It is refreshing that in freediving, two different competing designs can evolve along such separate paths.

 

[REVAN]

A new monofin with a good fit can still work a kind of magic for most people, the 90% of freedivers who are not already adapted and using a well matched hyperfin. For those 90%, it may very well feel like magic, even though it is really just physics.

Also, I'm not saying that it is impossible to improve upon the best swimmers' performances by more than 10%. I'm only saying that the solutions will come in other forms. The monofin is a part of a swimming system. Everyone already knows that you can get better performance from a hyperfin when it is paired with a good speedskin and good technique. So, don't suboptimize your thoughts into thinking the entire solution for better swimming performance resides in the monofin alone.

This chart is a good illustration. You can see here that swimming like a dolphin involves a lot more than just attaching a tail fluke to the feet of a hippo.

 

[baiyoke]

No doubt about it REVAN. There's a ton of stuff that makes the difference between a person and dolphins/Tunas....

However, what I tried to point out before was actually kind of the same, but from a different angle - that "The Fin itself" is only part of a system: Fin + body. And that system is most likely not at 70%.... And that the interaction between those two are probably only in the beginning of something... Actually I'm sure of it.

By the way: Before this thread I actually thought we were only at around 3 percent effectivenes. Where did you get the estimate of 70 % from? Is that looking solely at the foil???

 

[neurodoc]

Creative thinking, innovation, mechanical genius and occasional inspiration make a potent combination. Of course that isn't as simple as just a new fin, but the fin is the critical element of power transfer and as such makes a huge difference. My current fin works much better for me than either of my "conventional" fins including a Glide fin, in part because it seems to be a "biomechanical impedance match". It and my body get in sync much better, so I can do a better dolphin kick with it and swim more efficiently. Here's one example of the aforementioned traits/events and how they can break previously unbreakable records. His name is Graeme Obree; a movie "The Flying Scotsman" chronicles his two cycling hour records.

 

[neurodoc]

Oh, and...did you say "fluke on a hippo"? sorry, couldn't resist. You have to admit, they are pretty close to exactly that, and do swim quite well LOL.

 

[REVAN]

...what I tried to point out before was actually kind of the same, but from a different angle - that "The Fin itself" is only part of a system: Fin + body. And that system is most likely not at 70%.... And that the interaction between those two are probably only in the beginning of something... Actually I'm sure of it.

By the way: Before this thread I actually thought we were only at around 3 percent effectivenes. Where did you get the estimate of 70 % from? Is that looking solely at the foil???

Couldn't agree more. The "system" has a lot of room for improvement.

Actually the mid 70s as a percentage estimate for thrust efficiency is largely just my wild-assed-guess taking into account momentum transfers of water and some reasonable assumptions for blade efficiency. I cannot suggest that you take my word for it, but I cannot suggest a better value either.

 

[REVAN]

To tie in with neurodoc's analogy from above; only looking at the monofin for better swimming performance would be a little like the flying scotsman trying to make a breakthrough in the cycling realm by doing nothing more than reducing the energy losses of bicycle's drivetrain. It takes a more holistic look at the the entire system.

 

[cdavis]

Sometimes, in achieving one goal, you stumble onto another one. The D0l-Fin is like that. Revan was going for efficient transport. He got that one right, but there is something else. The fin is just more comfortable in the water than a traditional monofin. I don't mean feet comfort, more a sense of things are just "easier" to do, more flexible in application, easier to do a wide variety of different things, more maneuverable. I was looking for something with the advantages of a mono, but without the disadvantages. Something that was superior to bifins in an overall sense., which the traditional mono is not. The Dol-fin works for that. I think the expansion of monofins to the general diving public will be dependent on the "easier" function, not the efficiency function.

 

[Fondueset]

A few things in the above.
First - with proper technique a hyperfin is not working off a big push. Certainly it can be used this way - with a lot of knee bend - but with good technique the reality is more complex and it functions also like a foil; improving in efficiency once under way.

I have experimented with trying to swim the hyperfin more like the Dol-fin and visa versa- technique with both devices has benefitted.

I've modeled my mono fin technique on the advice of a couple of champion fin swimmers and from watching videos of Alexey Molchanova, his mom, and others. (One of the first things I was told is "NO KNEE BEND: EVER!!!")

Under way and with proper alignment the hyperfin slices through the water very much like a foil, and it is possible to swim exerting very little energy. Straining against your own drag with bent knees is replaced by an easy whole-body undulation and it feels like you are sliding through the water - almost like the fin is sliding down a hill. You try to minimize the extent to which you need always to be accelerating.

It's pretty well understood that one of the fastest way for a human being to swim, unaided, is the so-called 'dolphin-kick'. It is, however, very energetically intensive - much more so than a conventional no-fins stroke. A hyperfin/dol-fin makes this almost effortless.

No doubt everything can be improved. In terms of fins - I think the improvements will be incremental - in that Revan is correct. The limiting factor with the current tech is drag - not so much drag of the fins as drag of the human form. From here we begin to get into various wearable contrivances to reduce our drag. But then we'll hit the problem that came up with swimming competition - where the tech was unbalancing the competition and creating records that were based on it. We could find the whole field of competitive freediving starting to resemble no limits - where we essentially encase ourselves in some kind of hydrodynamic torpedo.

I personally am not down with that. It gets to be too much about the gear. Thats one of the factors in this conversation. It's got to where people talk about how cool their kit looks hanging on the wall.

One of my practices is to push off the wall - no fins - and see how far I can glide - with and without a suit. Without a suit is more instructive because I can better feel turbulence on my body, and experiment with alignments that minimize it. To me - excessive, wearable drag-reducing tech begins to take the art out of it. Much like guns can replace martial arts training. They are no-where near the same thing. One is simply technology, the other can be a kind of yoga.

 

[noa]

For competition, it will most likely and understandably go the way of technology. After all, people who compete are going for a maximum performance and always seek ways to achieve that.
If that where to remain within the realms of more drag efficient suits, why not. If it goes the direction of having to strap on devices to yourself to look like a submarine, then it will no longer have much to do with the purer concept of freediving.
As far as recreational diving goes, I personally always like to dive with the minimum suit I can bear for a given temperature. The main reason being is feel for the water. There is nothing like gliding submerged and experiencing the sensation of liquid rushing all over you.

 

[baiyoke]

A few things in the above.
First - with proper technique a hyperfin is not working off a big push. Certainly it can be used this way - with a lot of knee bend - but with good technique the reality is more complex and it functions also like a foil; improving in efficiency once under way.

I have experimented with trying to swim the hyperfin more like the Dol-fin and visa versa- technique with both devices has benefitted.

I've modeled my mono fin technique on the advice of a couple of champion fin swimmers and from watching videos of Alexey Molchanova, his mom, and others. (One of the first things I was told is "NO KNEE BEND: EVER!!!")

Under way and with proper alignment the hyperfin slices through the water very much like a foil, and it is possible to swim exerting very little energy. Straining against your own drag with bent knees is replaced by an easy whole-body undulation and it feels like you are sliding through the water - almost like the fin is sliding down a hill. You try to minimize the extent to which you need always to be accelerating.

It's pretty well understood that one of the fastest way for a human being to swim, unaided, is the so-called 'dolphin-kick'. It is, however, very energetically intensive - much more so than a conventional no-fins stroke. A hyperfin/dol-fin makes this almost effortless.

No doubt everything can be improved. In terms of fins - I think the improvements will be incremental - in that Revan is correct. The limiting factor with the current tech is drag - not so much drag of the fins as drag of the human form. From here we begin to get into various wearable contrivances to reduce our drag. But then we'll hit the problem that came up with swimming competition - where the tech was unbalancing the competition and creating records that were based on it. We could find the whole field of competitive freediving starting to resemble no limits - where we essentially encase ourselves in some kind of hydrodynamic torpedo.

I personally am not down with that. It gets to be too much about the gear. Thats one of the factors in this conversation. It's got to where people talk about how cool their kit looks hanging on the wall.

One of my practices is to push off the wall - no fins - and see how far I can glide - with and without a suit. Without a suit is more instructive because I can better feel turbulence on my body, and experiment with alignments that minimize it. To me - excessive, wearable drag-reducing tech begins to take the art out of it. Much like guns can replace martial arts training. They are no-where near the same thing. One is simply technology, the other can be a kind of yoga.

I hope it's safe to say that everyone participating in this thread knows that a hyperfin is not only working doing a big push. However, the current DYN record is set with a technique that (a little oversimplyfied) is benefitting from a kind of push-glide technique...

Again, I don't think it is a good idea to make a "gear" vs. "technique" dichotomy because this talk is everything but that. It is how well the system of gear and human works, how everything works together.

It's a different discussion when a governing body should step in and make rules for problems that might be relevant. But for the talk here and in general I'd say; full speed on the development. Let AIDA make the rules then. My guess is that there might be a "spill-over" of cheap and simple ways of making fairly big progress in fx streamlining etc. It's a question of where we/AIDA/CMAS draw the line... Not a question of either/or. Because then we should all be wearing nothing at all, since suits and fins are allready expensive.

The thing you talk about when you feel like you are flowing effortlessly through water, that's what I think can be accomplished much better and easier with new gear - something that let the body show more of its potential...

 

[cdavis]

Fondue has a good point about good technique. Most of the things I did not like about traditional monos can be over come with very good technique. Unfortunately some of us (like me) don't have the perseverance or interest to develop their technique to the required level(or don't have Slinkys in place of backbones. Fondue, you cheat).

The wonderful thing about the Dol-Fin is its ability to give the technique challenged, finning performance approaching a good mono very quickly and easily with the addition of greater flexibility and adaptability. It also provides a long long avenue for improvement. EricF once said it took him 1000 dives to really meld with his Orca. At the time, I sure hoped it would not be so in my case. But, he was right and the journey has been very interesting.

Now, can somebody just get me a Slinky?

 

[REVAN]

...As far as recreational diving goes, I personally always like to dive with the minimum suit I can bear for a given temperature. The main reason being is feel for the water. There is nothing like gliding submerged and experiencing the sensation of liquid rushing all over you.

I say AMEN to that!

However, none of us can really say what it would feel like to zip through the water with the benefits of streamlining. Not only has it never been done, but I have significant trouble even imagining how such a system would look or work. However, I think that if a system does not feel amazing in the water, then it probably would not be functional. It seems to me that those two things, function and feel, would necessarily be coupled.

So, although I totally agree with your comments about minimum gear and that feeling of water rushing over your body, I'll acknowledge that a breakthrough in new gear could easily change my mind on that. Maybe it will have even better sensations.