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Extreme Dolfinism

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
cdavis said:
Also, just barely possible that somebody will figure out how to do a foil bifin, ...
Click to expand...

Have a look at Home Palmaile





[ame=http://www.youtube.com/watch?v=IUeWdxNHjzo&context=C4fa931aADvjVQa1PpcFOXw-hRZXBP2yNdwq6PgDtl9CrA_e-fuK0=]Prototype de la palme à ailes - Fin with wings - YouTube[/ame]
 
Thanks Kars, this is helpful.

Here are my initial thoughts on the practicality of including your points of interest in the review:

1. No problem.
2. No problem.
3. No problem.
4. No problem.

5. This might take longer to evaluate. If we're comparing to hyperfins and how long they last with regular use, it would take 2-3 years to properly evaluate that. Some hyperfins fall apart in minor ways after only a year or less of heavy use in the pool or ocean. Others age far better. Seems to depend on the glue and build quality.

6. I have a few beginners I will have try out the fin. I would say that this fin is easier to move than a monofin (less surface area). Issues of stability and dexterity are no different than learning a monofin. The stability of the shoes helps a great deal. But most of all, the absence of cramping or jammed feet.

7. Blade sizing is going to be difficult for me to evaluate - best to go the recommendation of the manufacturer, aka Ron.

8. Speed record: what are we really evaluating here? Does it outperform a freediving hyperfin in a sprint? How is that relevant to freediving? Also, there's a great deal of variance in comparing my best hyperfin speed record vs. my best X20 sprint. First, I've used monofins for over 12 years and hyperfins/bin fins for about 5 or so. So my sprint technique is optimized for a hyperfin. Not only that sprinting has so much to do with reducing drag and optimizing posture. I'm somewhat out of shape in terms of monofin sprints, so I don't see them as relevant. I'll do it anyway, 'cause it's fun.

On second thought, I know having a fin that is fast is always a great joy, because you can have fun with it and explore it's potential. I think we all enjoy surging ahead now and then, even if it wastes energy. And sprinting is a valuable training tool for conditioning and finding optimal technique.

I'll do my best on that one.

9. Adjustability: that will take a while as there are many configurations to try. I'm not sure how to evaluate them objectively.

10. Comparison chart. Great idea. I also like the historical thread of mono-propulsion evolution and branches on that evolutionary tree. That appeals to the swim geek in me.

The long term evaluation will have to wait until I've had the chance to use it more often and in a variety of conditions, but I'm focusing on things we can discuss and look at in the short term. Ease of use, flexibility, off the shelf performance, learning curve, subjective "feel," pool vs. open water.

Cheers,

Pete

 
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Reactions: Kars
laminar said:
Look promising, except....he's not moving! :duh
Click to expand...
Look at the video longer than just the first few seconds. They run comparative tests with normal and freediving bifins, exchanging also the swimmers (not to have the stronger swimmer always using the hydrofoil). You have to keep on mind that the prototype they test is just a quickly stitched bi-fin using a standard scuba fin as base, and adding the hydrofoils on it - the design is still quite far from any optimal geometry and glide. Still it looks it beats other bi-fins (at least in speed) easily. See more details on the website.

Of course, the efficiency won't be as good as at the single wide hydrofoil of the DOLfin, because there are bigger losses due to turbulences and bigger drag at those multiple hydrofoils, but it still looks promissing.
 
great subtopic. short version of my post:

hydrofoil-fin
rigid fin
shaped fin
oscillating fin
glide fin - i know it´s blocked, maybe someone is inspired by the argument

i agree with revan that there should be a name for the hole "hydrofoil class" because the "mono" version is just one of some other possibilities.
consequently "monofoil" seems to me not a good naming, because for the hole class, "foil" would be the logical outcome. this is so waterless and technical that it hardly means something.
ron´s fin seems to have some properties which deserve the name "fin" even more than most rubber or fiberglass things. i´d stick to this (as ron did before, when introducing DOLfin).

having the differences in design/shape in mind, "(hydro)foil-fin" and "rigid fin" is convinient, although an actually rigid one wouldn´t work...not perfect. maybe "shaped(formed?) fin"- a native speaker could tell if this makes any sense, of corse the old fins have shapes too.
Thinking of differnces in the movment of the fin: bending vs oscillating-->"oscillating fin". a name referring to the funktionality is a great idea, but you have to be an insider to get it. still i like it a lot
does anybody have an idea which is connected to the particular fin - water interaction? this would hit the mark for me. glide fin comes to my mind, every tester mentioned the low drag and it´s more gliding than pushing that produces being pushed.
 

I started getting confused with the swimmers when I watched it and then realised there are at least 3.... of which one can't be bothered to swim with the proper bi-fins and gets beaten by a mile lol
 
...monofoil, Ronofin they're all good names but honestly the original DOL-Fin was perfect choice and need no further improvements Not only it describes technology (dynamic oscillating lateral) but it also sounds like "dolphin"

The very first time I saw Dol-Fin in action we were surrounded by dozens of dolphins and this image will stay in my mind forever. To me X20 will always be "dolphin" no matter what new name You'll give it
 
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Kars said:
What do I want to know about for the review?

5) How do the shoes hold out in the sea?
Click to expand...

Kars,

You do realize it has nothing to do with the fin itself? X20 comes with Shimano bicycle shoes but there is SIDI and dozen other brands. Price range is $20 to $300, You can use any shoes You like and when sea destroys them You can install new pair. That's the beauty of modular construction of the fin, to compare try to replace footpockets in monofin...
 
Sure Nostes I understand that the shoes are not made by Ron, but I'm still curious how the particular shoe used holds out.

I've another question for Pete;

11) I believe Eric Fattah indicated that the monofoil was challenging to use at depth because of narcosis impairing the finer motor skills. Can you explore that a bit, does the monofoil indeed need fine coordination to be used? Is it forgiving for poor technique?
 
"Is it forgiving for poor technique?"

That is one I can answer, the fin is extremely forgiving of bad technique. I should know.

Connor
 
cdavis said:
"Is it forgiving for poor technique?"

That is one I can answer, the fin is extremely forgiving of bad technique. I should know.

Connor
Click to expand...

Same here, I finally found a pool to swim at and with my technique I am cruising like I had this fin for years (at least it feels like it)

About my technique - it will never be perfect. Back in 2003 I was in a car accident injuring neck and lower back. Although my neck recovered in 99% my lower back is still affected to the point that lying down on stomach I am not able to lift my butt, at least not as high as I'd like to. This move btw is the first exercise to perform in monofin swim class.

So while swimming with monofin I use core and some legs muscles skipping whole waist/butt area, that's far from perfect but my X20 seems happy.
 
When overcoming large negative buoyancy I find the Orca is not forgiving of bad technique. However with enough practice the deep ascent technique becomes habit, so I don't think narcosis is a big issue.

Keep in mind also that the negative buoyancy I get while 'fun' diving is much heavier than the negative buoyancy on a 100m+ 'max' dive. This is because the 7.5mm suit.
 
Very interesting that, at some point, the Orca gets technique sensitive, given enough negative buoyancy. The x18 has such powerful acceleration(I think of that as low end torque), not at all technique sensitive, that I would have thought it would handle extreme negative buoyancy very well.
Is there some point where the negative simply overpowers the torque, necessitating good technique? abrupt transition?, slow transition?

Connor
 
With regular monofins especially soft ones, they can 'collapse' or be overpowered, rendering them inefficient. I remember my experience with a Classic MD1 Soft fin at 40m deep with a 5mm suit and 4kg very well.

When overcoming large negative buoyancy I find the Orca is not forgiving of bad technique.
Click to expand...

Maybe the X18 is easier to control then the older Orca model? For instance adjusted to give more feedback then the Orca.
 
Kars said:
Maybe the X18 is easier to control then the older Orca model? For instance adjusted to give more feedback then the Orca.
Click to expand...

The X18 and X20 have a more robust design for the fin suspension system than what I used on the Orca. The X-20 is definitely more easy to use and does not require finer balance of the fin blade the Orca demands.

The Orca's suspension system, with its narrow fin attachment to accommodate the streamlining, needs the swimmer to keep the fin balanced. It is a higher skill level monofin to use, but with the benefits of streamlining and reduced backlash in the fin stroke to maximize energy transfer to the water. The Orca was intended to go for performance at every design choice.

The X-20 is intended to have a much more broad customer appeal, including newbies. Stability and ease of use had high importance when I was making design choices for this fin.

Ron
 
I released a video on the development of an X-15 monofin today. It is closely related to the X-20, but configured for use with scuba equipment. Please let all your bubble blowing friends know about it! :chatup

[ame=http://youtu.be/XZidkOdooeM]DOL-Fin X-15 Monofin For SCUBA Diving - YouTube[/ame]
 
Here is the first quick video of the X-20 out of Hawaii. My new camera rig seems to be working very good, and the X-20 is flawless.

Enjoy!

[ame=http://www.youtube.com/watch?v=8y3t-Xm-dJ4]Stretchy-Pants Freedive - YouTube[/ame]

PS - I'm using the size Medium fin blade.
 
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Ron

A buddy (Cdavis) is taking along his Dolfin on a freedive trip we have planned. Although he does not know it yet, I plan to "borrow" the fin quite a lot. I have a pole spear that helps to guarantee cooperation.

Can I buy *any* cycle shoes my size and just clip in? Are there recommended makes or styles?
 
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