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Extreme Dolfinism G2

REVAN

The Right Stuff
Mar 19, 2009
808
351
118
Arizona, USA
www.smithaerospace.us
...This summer when in Malta on holiday, I happened to see that it was possible to dive with Tuna Fish ( http://www.snorkelingmalta.com/snorkeling/?snorkeling-info=tuna-park-snorkeling ) and I suddenly realized that it was an instant big wish, almost as big as diving with dolphins (I didn't go for many reasons and dolphins being mammals still makes it more interesting)....
Yes, the tuna and marlin have tails of hard bone and they are fairly rigid, but they do have a little spanwise flexibility. Between the two, I think the tuna is a far more attractive looking swimming machine. The sword allows to marlin to cheat and get it's food while not swimming as fast as the tuna.

Did you take this picture at the tuna park, Baiyoke; or is it off the internet? It is a gorgeous picture of a tuna.

It is interesting how the thickest part of the fish is half way back the length of the body. Hey Pete! I think this guy is more "Laminar" than you. I think you can tell the laminar from the non-laminar flow regions from the different color/texture of scales, front vs. back. It is very interesting.
 
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baiyoke

Well-Known Member
Nov 13, 2011
485
80
58
Denmark, Copenhagen
It is from the internet. I've seen a lot of Tuna pics lately, but when quickly googling "bluefin" in picture-setting yesterday this one caught my eye instantly. It's a Beauty...! You should put something like that on your web page.

I think however it's shot a bit from the front, other pictures show the widest area about 1/3 from the front.

I didn't attend the "diving with Tunas" for a number of reasons: 1) It wasn't part of the holiday plan 2) there are moral issues to holding them in a giant net like that and 3) it is said that the water is full of some kind of Tuna oil-like substance from the surface of the fish, and spending the holiday smelling like a tuna was not an option this time around :)

REVAN I think it's obvious why you started out with the dolphin and orca reference, but if you ever need a name for a more specialized fin like the Orca 2.0 (or version 3.0) it could be: Blue-fin ;-)
 
I disagree--I can't help but think think there are some limitations unconsciously imposed, but since you are the engineer, and your product works, I'd be kind of foolish to argue the point when I'm in over my head. :) I could go further in my opinions, and in a casual 1-on-1 conversation I might have, if the interest were there, but I think it's in very poor taste to criticize someone you don't know, in he creation of something you haven't made. Very interesting to get a glimpse at some of the thought-process which went into your creation.

P.S. Thanks for the tube-snorkel instruction video--I'm building one now!
Ichthys, I've been pondering what you mean by 'limitations unconsciously imposed'. I think one such limitation is the idea that an efficient fin must look like a dolphin or tuna tail. In the case of both the hyperfin and dol-fin, engineers analyzed HOW these tails work and based their designs on mathematical findings. The dol-fin in particular departs from romantic notions about how such propulsion should look and instead focuses on generating thrust and reducing drag based on an understanding of the laws that govern such propulsion and the materials being used. If anything this is overcoming the limitations to which you allude. Moreover, the performance of the fin supports the accuracy of understanding and execution in the design.

I don't say there isn't something better - neither does Revan say his fin is the best - and there is always something better. But your statement about unconscious bias in design is not best supported by the Dol-fin series fins - which are almost unique in their reliance of an understanding of principal - as distinct from appearances.
 
Likes: REVAN

REVAN

The Right Stuff
Mar 19, 2009
808
351
118
Arizona, USA
www.smithaerospace.us
I don't say there isn't something better - neither does Revan say his fin is the best - and there is always something better.
It is only the best I know how to make at the moment. A new product needs to have a combination of viable attributes that will hold favor in the monofin market for 2 or more years, because that is about how long it usually takes to develop a mature replacement technology. But, it seems I'm always investigating new ideas. I test dozens of ideas/concepts each year. Few of those ideas actually make it into a production monofin.
 
Likes: Chipswim

Ichthys

Well-Known Member
Aug 3, 2014
83
79
48
35
Very impressive.

Fondueset, that is certainly true that a lack of understanding or appreciation for the goal being pursued would be a limitation. What I meant was actually a little different, but I'd rather not criticize any further. Suffice to say I don't like the idea of a blade, but as it proves to be efficient I could warm up to the idea of putting one on my feet. :)

I've been wanting to ask, have you guys ever tried breaching with the DOL-Fin?
 
Very impressive.

Fondueset, that is certainly true that a lack of understanding or appreciation for the goal being pursued would be a limitation. What I meant was actually a little different, but I'd rather not criticize any further. Suffice to say I don't like the idea of a blade, but as it proves to be efficient I could warm up to the idea of putting one on my feet. :)

I've been wanting to ask, have you guys ever tried breaching with the DOL-Fin?
I think the Dol-fin is more optimized for cruise. It might be possible to breach with it, but I'd not guess that would be it's cup of tea. The only clean breaches I've ever seen were with sprint stiffness hyperfins.
 

Chipswim

Well-Known Member
May 4, 2011
481
306
103
68
Nebraska, USA
As long as the fish are swimming 30 mph and we are swimming 3 mph there is work to do and no stone should be left unturned.

So enjoy all the personalities and ideas represented in Deeper Blue!

Convinced that Revan and Ted are amongst the precious few most likely to find the next break through AND build it AND offer the product to all of us patiently watching and waiting.

Most of us continuously brainstorm what could let us swim better and faster... Effortlessly!???

There is some evidence that propellers can work really well moving things through the water....

The question becomes: How do we turn a propeller with human power while maintaining a streamlined body position?

Consider the peristaltic motor I came up with and actually built pictured below. Yes! It is compact and designed to be driven by intestinal contractions! Genius! (I thought) PSS_Dripless_Seal.JPG m1Eo7KhkXgDayV8vFMU6yog.jpg

As you can see in the photo of the completed device I then rigged it up to drive a propeller shaft! (The peristaltic motor is actually the wider part of the shaft as you can clearly see...) image012.gif

Unfortunately ¡¡ When I got it inserted it was so horribly uncomfortable that I could barely use my intestinal contractions to spin the propeller at all ¡!¡

Looks like we are back to Revan and Ted as our designers most likely to succeed !!! Rooting for them both!
 
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In the Interest of Clarity: I am not a fanboy. I don't get free fins from Ron for testing his and if I thought they were crap I'd have sent them back to him and told him. I would not have bitched about them in forums unless I thought he was being dishonest.

Nor do I think the Dol-fins are the absolute shit.

I prefer my hyperfins. But my hyperfins are a bit unusual - they are made by Alex Lichenko at Starfins - they are soft - cruise- tuned fins and they are as comfy as a pair of bedroom slippers in temperate waters - this is extremely unusual for hyperfins. It's taken me years to find a fin builder that meets my criteria.

So, in my testing of Ron's fins I am fairy careful to set aside my kinesthetic addiction to hyperfins. My criteria in testing are Cruise Efficiency, Comfort and durability. So far the three Dol-fins I've tested relative to my hyperfins go along about like this:

Efficiency:

X-20 - slightly less, Orca - very slightly less, Orca Gen2 - Probably slightly exceeds with wide blade.
An important point here is that these three models were tested with three different blades. With the wide blade on all
models I would expect improved performance.

Comfort:

All Models -Matches - Exceeds in winter when the slight compression of my hyperfins becomes a factor

Durability: No Brainer

I'll add portability - which is another win for the Dol-fins - particularly the X20.
 
Likes: PoseidonSv

REVAN

The Right Stuff
Mar 19, 2009
808
351
118
Arizona, USA
www.smithaerospace.us
In the Interest of Clarity: I am not a fanboy. I don't get free fins from Ron for testing his and if I thought they were crap I'd have sent them back to him and told him. I would not have bitched about them in forums unless I thought he was being dishonest.

Nor do I think the Dol-fins are the absolute shit.

I prefer my hyperfins. But my hyperfins are a bit unusual - they are made by Alex Lichenko at Starfins - they are soft - cruise- tuned fins and they are as comfy as a pair of bedroom slippers in temperate waters - this is extremely unusual for hyperfins. It's taken me years to find a fin builder that meets my criteria.

So, in my testing of Ron's fins I am fairy careful to set aside my kinesthetic addiction to hyperfins. My criteria in testing are Cruise Efficiency, Comfort and durability. So far the three Dol-fins I've tested relative to my hyperfins go along about like this:

Efficiency:

X-20 - slightly less, Orca - very slightly less, Orca Gen2 - Probably slightly exceeds with wide blade.
An important point here is that these three models were tested with three different blades. With the wide blade on all
models I would expect improved performance.

Comfort:

All Models -Matches - Exceeds in winter when the slight compression of my hyperfins becomes a factor

Durability: No Brainer

I'll add portability - which is another win for the Dol-fins - particularly the X20.
There is no magic to be had in a monofin. It cannot violate the laws of physics just because it looks different or cool. 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. In my opinion, achieving large improvements in performance will require more than just a new monofin. If we want to actually swim like a dolphin, we will probably have to find a way to look more like a dolphin (at least in a hydrodynamic sense).

It is great that your Starfin has such a uniquely good fit, because it provides a benchmark to strive to exceed. Most hyperfins are uncomfortable; some are extremely uncomfortable. I've never used one without getting blisters, and sometimes it only takes about 10 minutes of use to start peeling skin. From a market perspective, it is not good enough to be able to find a comfortable monofin with years of trial and error and multiple fin purchases. This has been a bane for freedivers ever since they started using hyperfins. The result has been that many freedivers simply don't use hyperfins. They never find out how much more fun can be had when dives are efficient, easy and long. This reduced scope of high performance monofin use limits growth in the sport.

Comfort and a proper fit must be made available on the first purchase, not the second or third. Comfort, durability, portability - these are the areas where we can expect to see large improvements from new types of hardware.
 
There is no magic to be had in a monofin. It cannot violate the laws of physics just because it looks different or cool. 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. In my opinion, achieving large improvements in performance will require more than just a new monofin. If we want to actually swim like a dolphin, we will probably have to find a way to look more like a dolphin (at least in a hydrodynamic sense).

It is great that your Starfin has such a uniquely good fit, because it provides a benchmark to strive to exceed. Most hyperfins are uncomfortable; some are extremely uncomfortable. I've never used one without getting blisters, and sometimes it only takes about 10 minutes of use to start peeling skin. From a market perspective, it is not good enough to be able to find a comfortable monofin with years of trial and error and multiple fin purchases. This has been a bane for freedivers ever since they started using hyperfins. The result has been that many freedivers simply don't use hyperfins. They never find out how much more fun can be had when dives are efficient, easy and long. This reduced scope of high performance monofin use limits growth in the sport.

Comfort and a proper fit must be made available on the first purchase, not the second or third. Comfort, durability, portability - these are the areas where we can expect to see large improvements from new types of hardware.
Absolutely agreed! I've had hyperfins that I had to use with silicone grease on my blisters. After 20 minutes the pain was so intense I could no longer focus on technique and, when I took the fins off, there was blood in the water.

I just wanted to clear up my position based on some communications I've received. I approach testing with a definite bias toward my personal status quo and I will never recommend anything I don't think is excellent. The Dol-fins are excellent and I highly recommend them. As I've said before - from my perspective they are definitely off probation.
 

noa

Well-Known Member
Oct 17, 2003
431
114
133
47
Crete Greece
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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...
 
Likes: Chipswim
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...
Traditional hyperfins are built for pool competition. Fins built for speed are stiff and require a tight fit to be efficient. Same is true if you are doing depth. (beyond 70m or so). In dynamic I think even if the foot pocket slips a little - it still contributes to thrust.

(I should also add that my Tropol fin is quite comfy - though not quite as so as the Starfins. It is however a very heavy fin, with a stiff blade. Still, I did my deepest dive with it and didn't even know it was there.)
 

Kars

Well-Known Member
Oct 24, 2003
3,443
564
203
40
The Netherlands
www.freeapnea.nl
Quick tip for anyone who gets blisters in their rubber foot-pockets: insert you foot in a piece of thicker plastic (old bag), slide in with a bit soap. It is true that standard rubber monofin pockets are tight, even so tight that people can only endure them for 15 minutes. The reason is that a tighter pocket has a better power to blade transfer. Monofin sprinters do not care about comfort, they prefer performance. Freedivers, who like to spend hours in the open waters and pools, need comfort.
Manufacturing rubber foot pockets is a skill. If the pocket is exact to the foot side, the rubber can be very stiff, reducing play and foot pressure.

Fondue, I like your reporting very much. It sounds like the new design may finally outperform the hyperfin in the performance department.
Is there a full review in the works Fondue?
 
Quick tip for anyone who gets blisters in their rubber foot-pockets: insert you foot in a piece of thicker plastic (old bag), slide in with a bit soap. It is true that standard rubber monofin pockets are tight, even so tight that people can only endure them for 15 minutes. The reason is that a tighter pocket has a better power to blade transfer. Monofin sprinters do not care about comfort, they prefer performance. Freedivers, who like to spend hours in the open waters and pools, need comfort.
Manufacturing rubber foot pockets is a skill. If the pocket is exact to the foot side, the rubber can be very stiff, reducing play and foot pressure.

Fondue, I like your reporting very much. It sounds like the new design may finally outperform the hyperfin in the performance department.
Is there a full review in the works Fondue?
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.
 

divebike

Active Member
Mar 29, 2014
109
25
43
46
Ichthys, I've been pondering what you mean by 'limitations unconsciously imposed'. I think one such limitation is the idea that an efficient fin must look like a dolphin or tuna tail. In the case of both the hyperfin and dol-fin, engineers analyzed HOW these tails work and based their designs on mathematical findings. The dol-fin in particular departs from romantic notions about how such propulsion should look and instead focuses on generating thrust and reducing drag based on an understanding of the laws that govern such propulsion and the materials being used. If anything this is overcoming the limitations to which you allude. Moreover, the performance of the fin supports the accuracy of understanding and execution in the design.

I don't say there isn't something better - neither does Revan say his fin is the best - and there is always something better. But your statement about unconscious bias in design is not best supported by the Dol-fin series fins - which are almost unique in their reliance of an understanding of principal - as distinct from appearances.
It's not a romantic notion of how things should look as to why I think the ultimate fin is probably more like a tuna fin, evolution weeds out such silliness, its people that come up with crap, I've read 2 different research studies that have found their fins to be an improvement on any naca foil, I don't have a link to them as I viewed them a couple of years ago. I don't think biomimicry is the be all end all , you'd be mad to look at a cheetah for example and try and devise a way to run like them, you just get on a bike. We are trying to use a fin the same as they do, by oscillating it, the main difference being the speed by which they move both the fin and themselves, which could possibly make them not the ideal fin after all, but no one has shown this to be the case, it's mere speculation.
 
Likes: Mukiker
It's not a romantic notion of how things should look as to why I think the ultimate fin is probably more like a tuna fin, evolution weeds out such silliness, its people that come up with crap, I've read 2 different research studies that have found their fins to be an improvement on any naca foil, I don't have a link to them as I viewed them a couple of years ago. I don't think biomimicry is the be all end all , you'd be mad to look at a cheetah for example and try and devise a way to run like them, you just get on a bike. We are trying to use a fin the same as they do, by oscillating it, the main difference being the speed by which they move both the fin and themselves, which could possibly make them not the ideal fin after all, but no one has shown this to be the case, it's mere speculation.
Does the ultimate human then look like a tuna?