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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.
HI Ron and others in order for this forum board to display a youtube video window one must use the long "sharing" link. "http://www.youtube.com/watch?v=NMly6qCXSdg"

[ame=http://www.youtube.com/watch?v=NMly6qCXSdg]A Backward Perspective on a DOL-Fin - YouTube[/ame]

Btw your technique seems to improve Ron, comparing the latest video with the one in the spring.

From this rearview it does look pretty good.

The only resistance, apart from my red bank account, I feel are:

- not having tested it,
- the skeletonised look.

With the latter I mean that the look of it feels mechanical and unnatural, though I'm sure it's very efficient.
The Orca cap helps a bit, but then I still miss the flowing out of tail from the toes. The tight 'waist' (connection of foil to feet) makes it look weak and unnatural. I hope these points are of any use, though I suspect it's difficult at this moment to work on the looks on a budget.

In general I think you got a winning design that will pick up popularity soon with the affordable X18 version.
 
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Kars said:
HI Ron and others in order for this forum board to display a youtube video window one must use the long "sharing" link.
Click to expand...

Thanks for the technical help Kars. I was wondering why that didn't embed in the forum like I had expected.

FYI Simos: The pool is 20m long.
 
REVAN said:
Thanks for the technical help Kars. I was wondering why that didn't embed in the forum like I had expected.

FYI Simos: The pool is 20m long.
Click to expand...

Thanks Ron - I am sure this must have been covered before but this is a looooong thread to go though; it looks like the fin should have a much lower drag coefficient compared to traditional monofins. Is this true? Do you have any comparative measurements?

I guess what I am trying to work out (hence also asking about the pool length) is how much more/less glide one can expect and overall resistance.

Also I noticed that you say in the vid that you can use the fin with small amplitude kicks (unlike traditional monofins) - this is quite interesting as presumably the streamline should break less with smaller kicks and less undulation.. Does it feel like this is the case?
 
The short amplitude kicks are what I've been calling "ankle flips" That looks like a great way to use the x18 in a cruise, sightseeing mode, or in the descent, static, stage of an FRC dive. I could get the monoflap to do the same thing, very useful, but not anywhere near as fast. With that kick, I think you could greatly speed up the FRC descent phase, until it was on par with a full lung 1 m/sec descent, with only with little more 02 burn than a static. Should work for FRC. The result is a huge % increase in bottom time.

Eric F commented somewhere that he was using the short amplitude kick for almost all his dives. I begin to see why he likes this fin so much.

Connor
 
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Ron,

Does the x18 require arms forward for balance, if you are doing a slow version of the ankle kicks? How about a stronger, higher amplitude kick?

Connor
 
Having Martin Stepanek doing a WR in CWT with your fin would be a boost too...

Has he tried it? I'm looking forward to his observations as he's a former high level monofinner.
Dave Mullins with your fin blasting out a 300m Dynamic would also be super cool, and a great advertisement.
An interview with Natalia Molchanova about the fin would also be great.
What did she say to you about your fin?
 
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Kars said:
Having Martin Stepanek doing a WR in CWT with your fin would be a boost too...

Has he tried it?
Click to expand...

This was already answered but no, he didn't try it.

But really, guys like Martin or Dave Mullins will swim loooong distance no matter what fins on their feet.

People need feedback from average Joe. Average or poor monofin swimmer too and that's what was done last month in Hawaii with good results. Maybe I should even say great results
 
Martin continued using bifins long after all records were set with mono. He said he did that because he wanted to 'penalize' himself and increase the challenge. So if that continues he would continue to use the mono even after everyone switched to DOL-Fins...

The mini-kick worked just as well with the X18, it works even without your arms extended.

When I first used the DOL-Fin I could not ascend from heavy negative ballast and I couldn't get the fin to work with my arms by my side. Turns out these were all technique problems. It took more than 1,000 dives with the fin to finally feel comfortable and efficient, but it was well worth it.
 
Simos said:
...it looks like the fin should have a much lower drag coefficient compared to traditional monofins. Is this true? Do you have any comparative measurements?
Click to expand...

The drag on the DOL-Fin is minimal and probably on par with no-fins drag. I don't have a comparative measurement for you, but the parasitic drag will be proportional to the surface area of the fin. A typical hyperfin has at least 5 times as much surface area as the DOL-Fin's hydrofoil. Also, the robust fin angle of the DOL-Fins will lower the swimmer's form drag as well.

The bottom line for you is that these fin's glide very nice. The DOL-Fin Orca is probably the best in the business. The X18 will not be far behind it and, I think, will claim a strong 2nd place to the Orca, gliding comfortably above other monofins' performances.
 
I was one of the first beta-testers of the DOL-fin classic and used it daily for a few months for my CWT practice a year ago. The learning curve was steep but after a while one will get used to its motion like i did. I don't like it myself for not "feeling" the torque of the finning and the power associated when using the muscles--when you want, which also is a psychological benefit. I switched to my bifins after using the dolfin and noted my dives to directly and immediately compare. I realized performance was better with my bifins, where after I did 65m with them-- the captain nemos. Just the other month I got the Glide Monofin.....all i can say is wow..It is a natural fit and a much less learning curve with a more instinctive finning motion that allows my body to really relax with certain knowledge if I fin with a burst I will move fast. Period. Now I'm in the 70's meters with the Glide and it feels easy without concern that I won't get the power I want when choose to apply it. I'm under contract for another year with the Dol_fin and can't sell it...but if anyone is interested I can simply transfer my beta-testing to another person to experience the DynamicOscillatingLateral-Fin because it is just here not being used.

Those that see the DOL-Fin say it is is really cool looking, however and I agree.
 
Spearo - if I'm not mistaken you'd no mono fin experience prior to the Dol-fin. If I'm right then it is not entirely accurate to attribute all of your learning curve to the Dol-fin. I may be thick - but it took me a good year to get to where I could really even make good use of instruction with a mono.

I also used basically the same version of the Dol-fin - albeit briefly - in the Bahamas. At the time I thought the design was not yet ready for free diving - but had significant potential. I noted how little effort it took to get thrust - and suggested the fin be moved further aft of the body and perhaps be given an increased surface area - as well as a better foot attachment.

These changes and others have been made to the Orca and X-18 - which would seem to be significantly different products than the one you are commenting on - which was originally developed for Scuba.

I am not privy to the nature of your agreement with Smith Aerospace - but in my own experience with Beta testing - it has always been my practice to refrain from public comment on what is by definition, an unreleased product. With the Lunocet, F.10, F.11 and Tropol mono fin I reported my findings directly to the maker and only ever did public reviews after having received release from them to say whatever I wanted.

Again - I do not know what your agreement was - but I hate to see a beta product being slammed publicly - for any reason.
 
Yeah you are right the DOL-Fin was the first mono experience and it was interesting how I was able see the differences with my bifins and now with a Glide...I'm sure the Orca and X-18 offer better performance than the classic DolFin, for sure....meanwhile...I guess got the old scuba-divers version :head
 
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I think if you have a good breath hold you may be able to pull of some very long distance dynamics with it, using it within it's range of use, both in terms of power and amplitude.

The good about the design is that it has a much faster return speed, meaning that the foil has only a very brief moment of when it's not pushing the diver forward. So I say it's design is especially good for dynamics.

I do feel tempted to ask for a test, though at this moment in time I don't have any cash to spare. Aside from that my dynamics aren't stellar either with a modest 150m. Though I now a few that do much better and would love to test it as well. My question to Ron is does he have any more questions that need answering in regard to this older design?
BTW I did already beta test for Trygons and they were very pleased with my detailed reporting. hehe, hear me some shameless self promotion! LOL

Love, Courage and Water,

Kars
 
I can say that the X-18 and Orca feel very different from the scuba DOL-Fin.
 
Little bit of talking and some underwater action by Ron. Next year we'll make better video. This time GoPro battery died just before the best dives. Plus I didn't wear any weights on my suit, struggling to keep up behind Ron underwater resulted in terribly shaky image. Well, it is what it is, hopefully it will give You idea of what can be done with it


[ame=http://www.youtube.com/watch?v=n2CyMKE5Qdc]Monofin of the future - DOL-Fin by Smith Aerospace part 1 - YouTube[/ame]
 
Very interesting video. Watching Ron's feet, I can see a lot of ankle action,even when he is bending his knees quite a bit. Astonishing that thrust is so efficient that ankles are strong enough for that.

Watch the last scene, the dolphin's tails are doing exactly the same motion as the x18 blade. Is that scene intentional?

Connor
 
The shorter version I tried was obviously very efficient. Also a bit disorienting after a normal mono - because it does not load up and release like a mono fin. It pretty much just goes - right now - and slices through the water like a knife during the glide phase.

What increased distance from the feet gives is, obviously, better leverage; i.e. more thrust with less motion. I can see how the fin would accomodate a range of kick styles and possibly be more efficient across a wider range of speeds than a typical mono.

I'd like to run one through my normal pool workout. I'd be able to tell fairly quickly how it stacked up.

Ron, you should try to get up here this spring - I think we're going to try and dive a new wreck at 120' that was just discovered this past summer on side scanning sonar.
 

Yes Connor,

Unfortunately the day we were doing this video was the only overcast day in 2 weeks but at least we had dolphins around. I like to watch the way they move so I used them as comparison to Ron's fins.
In next video You will find Ron explaining the physics, underwater drag, technology behind this propulsion as well as history of Dol-Fins, a 20 years of history!
 
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