Extreme Dolfinism

[ISeeTheStars]

Hello Revan, Erik,
Orca seems just amazing, HP looks also veeeery interesting to me. Great work Revan. I do have some questions though - for you and Erik regarding the technique. Is it really shifting the movement to ankles? Cause i think there are much smaller muscles so I would say more fatique - but maybe I am wrong also i wanted to ask if it gives the posibility to move forward with extremely small movents with the fin. That is what I use with a mono when close to bottom or in tight spaces around stones, caves etc ... And so far I never did hit anything with my mono ( fragile thing so I try to not hit anything at all). Also i dont consider maneuverability with mono so much inferior, I use both long bifins and a mono and I dont seem to be having troubles with strange maneuvers with my mono at all - in fact I feel much more in contact with the water with it... Even was able to move backwards with mono once) so ... Is the maneuverability of orca or hp at least the same as a mono or even better?
The only thing that seem to bother me is if the fin is a lot negative. My mono floats, and it helps a lot to be level ... Could there be some floaty inserts in orca premade or possibly some inflatable part to fine tune that maybe?
And one last idea - maybe its crazy, but it seems that most problems with HP for scuba is generated by it being rather wide - so - could it be made in two halves, sort of a biplane? It would be just half as wide, still i guess not so thick to be a problem too, and if the blades were detachable then in would be even easier to transport. It would look less fish like, but hey, even orca looks more weird and techy then hyperfin so I would not bother too much about more weirdness ))
Great thread by the way ....
ISeeTheStars

 

[Fondueset]

I thought about that bi-plane idea. I pictured the blades staggered and hinged so they could shift vertically relative to eachother - perhaps Revan can chime in with a bit of engineering

 

[efattah]

Work is offloaded to the ankles, away from quads, but quads and core still do work, so fatigue is actually less than with a mono.

You can move forward with tiny movements of the ankles, great when you are 'almost' sinking but not quite or when on the bottom and you need to move just a little bit.

My Orca is 850g buoyant in the water. I filled it with incompressible plastic hollow balls. This means that when descending I can relax into a total 'deadman' state and I still stay totally vertical and upside down, as the 850g of buoyancy remains constant throughout the descent-- no mono can ever maintain 850g of buoyancy at depth, since the rubber collapses.

But most of all my feet are always warm and comfortable.

 

[ISeeTheStars]

That seems really perfect solution, those balls .. Thank you man.

Btw ... Are you going to produce that wide FOV Liquivision mask we did talk a bit about some years ago? I am still waiting when it might come out)) though these days my money does go in a different direction but still ...
Sorry for a little off topic here

 

[REVAN]

...I dont consider maneuverability with mono so much inferior...

I agree. Maneuverability with a monofin is definitely different from bifins, but I have never felt hindered because of it. I think the DOL-Fins are similar to other monofins in maneuverability. One difference is the DOL-Fins tend to have more roll damping than other flexible blade monofins.

...Could there be some floaty inserts in orca premade or possibly some inflatable part to fine tune that maybe?...

I have been working on a float system for the Orca and presently have a design that I like and intend to move forward with. At present, I am still looking for the right materials to make it from. I'm looking for a supply of rigid closed-cell high density foam in 3 inch thick sheets to make the final prototype. The current prototype just uses 1 Lb/ft3 Styrofoam and will not hold up against the pressures of CWT diving. I think a 3 Lb/ft3 rigid foam is needed for this application (something that is thermal-set and crosslinked). But, the design I am working on is modular and just ties into the Orca's sub-frame without modification. So, existing units can be easily integrated with the new flotation. If anyone has any leads on an acceptable material, please let me know.

...And one last idea - maybe its crazy, but it seems that most problems with HP for scuba is generated by it being rather wide - so - could it be made in two halves, sort of a biplane? It would be just half as wide, still i guess not so thick to be a problem too, and if the blades were detachable then in would be even easier to transport...

I'm not quite sure what you mean. Can you be more descriptive? Also, the fin blades of all of the DOL-Fin products are detachable.

 

[ISeeTheStars]

Hi Revan,
Good to hear we feel the same about maneuverability and Orca is on the same level with monofins.
Also very nice that you work on float inserts - I am in love with the DOLfins for more reasons, but one is definitely your approach and attitude ... Not really too often to see.
The biplane idea is rather simple I think ... I would imagine 2 half length hydrofoils one above another with some spacing so that they provide the same amount of thrust, but are not as wide to be able to go through much more narrow spaces. Of cause that makes twice the joints and twice the wing tips etc ... But could it work like that? ( really just imagine a biplane for the configuration two wings one on top of the other, but not as wide)

 

[REVAN]

Hmm... I have not considered doing that. Multi-wing systems tend to interfere with each other hydrodynamically which would definitely make it difficult to predict the outcome; and that would make it difficult to figure out how to make it work efficiently. There wold be a lot of trial and error involved, and it may never really work the way you want it to.

Perhaps, the largest drawback would be the increased cost. It would almost be like having to manufacture two fins to get one unit.

 

[ISeeTheStars]

Yes, I also thought of the interferences, but I guess that should be possible to simulate on some Sw like Nextlimit XFlow to reduce the number of iterations needed probably. The price - that is another problem but things do tend to get more effective during the production and cheaper, so maybe even this could be solvable.
What I mean is - if there is a product that is no wider than say shoulder to shoulder, which is natural for us to estimate and know if we can fit in or not, it would take out one source of complains from those that go into wrecks and small caves etc.

 

[REVAN]

I think people tend to overestimate the width of the fin. Yes, it is wider than other fins, but not to the point where it becomes a problem. How often do you swim along a wall or vertical surface with less than 12 inches (30cm) clearance for your body? That is how close your shoulders would have to be to something for the fin tip to strike it (even less with the Orca). That is actually pretty close, and usually closer than most people would be comfortable with.

I usually find that I can just ignore the width of the fin and I have no problems with interference. The only exception is when I am trying to stir the warm surface water in my swimming pool by swimming through it and I sometimes deliberately swim as close to the wall as I can so as not to miss any of the pool's area. I have to be much closer to the wall than is comfortable to get the fin to contact the pool's wall, and even then, the fin is only rubbing a soft plastic fin tip on the pools surface, and no harm done.

 

[ISeeTheStars]

That is interesting, because from the pictures the HP looks really wide to me, but it can be also because its so slim so it appears wider than it is. Regarding comfort distance to obstacles, well I think I am used to get closer than 30, I would guess maybe like 15cm sideways (and almost scratching my belly on the stones when swiming sideways along). But ok, forget about it untill I try it and have some feeling for the real width of it. Btw have you tried swimming through the loops underwater? Oh, and if you would happen to be in Europe with your fins let me know) i would love to try it really ...

 

[noa]

someone else working on similar concepts, including double and multiple wings. interesting images, La palme ailes

 

[Spearo_the_Hero]

looks cool.

I've been testing out the DOLfin classic since last year off and on... I visualized a possible alternative..and it looks like my thought were manifested in the bottom-right picture of that website with the double-paralleled wings: La palme ailes

Some further technical information Principle Palmaile could be of interest to Ron perhaps they share the same concept.

 

[noa]

the guy from this site has apparently been working on the concept of these fins since a few years now. he patented some stuff and tried to sell the patents but that didn't happen so he put the whole project on hold since 2008.
great concepts though and fantastic drawings.

 

[REVAN]

The DOL-Fin Orca production is back underway and SN#0005 will be completed soon. Instead of the usual 30 day auction process, I'm thinking of selling SN#0005 direct to the first buyer who claims it and then closes the deal. Freedivers seem to be reluctant to bid against each other, so the auction process seemed to just waste time instead of helping to selecting the diver who needs it most. If you are interested in an Orca, check Facebook page Smith Aerospace Corp: DOL-Fin Monofins | Facebook. It will probably go up for sale within the next 3 days (By 09/11/2011).

 

[REVAN]

A very cool development has just happened today.

It looks like I will be displaying DOL-Fin monofins at the United States Apnea Association (USAA) booth at the DEMA Show in Orlando Florida (Nov. 2-5). Any freedivers planning to be at DEMA this year should stop by the USAA booth #713 near the demonstration pool and check them out.

I expect I'll also be unveiling the alpha prototype for the latest DOL-Fin project currently under development.

Ron

PS - I'm also told that Stig Åvall Severinsen will be there doing book signings for "Breatheology".

 

[cdavis]

Pardon my ignorance, but is DEMA open to the public or do I have to hook up with an exhibitor?


Connor

 

[REVAN]

Pardon my ignorance, but is DEMA open to the public or do I have to hook up with an exhibitor?

Connor

The DEMA Show is for people in the dive equipment business and not open to the public. If you are in the Orlando area and want to get in, the first things I'd try is to contact FII in Pomano Beach FL, or the USAA and see if they can help you to get in. Also, your local dive shops may be able to help as they often have representatives going to the show. Another possibility is to see if one of your former instructors can help, and if that does not work I could always meet with you outside the venue (maybe even at a hotel pool to knock out some laps).

 

[cdavis]

Thanks for the kind offer, but I'm not close enough to a purchase to warrant your time, especially during DEMA. I'll work on some more local contacts.

See you there.

Connor

 

[trux]

Connor, just contact Papa Smurf - I think he'll gladly help you to get in, as a member of the DB team. You may have to wear the DB polo, but that's probably not too bad. What will be worse is that you'll have to keep the pace with Stephan during the after-parties!

http://forums.deeperblue.com/beach-bar/92535-trip-dema-2011-want-join-db-crew.html

 

[Stephan Whelan]

Indeed - Stig will be on the DB booth doing book signings and if people need to get in I am able to get you in as a DB representative.