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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.
noa said:
sounds like there is a new version of the Orca. how has it been improved over the previous one ?
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I have started working on a new design for the Orca. It is still in the early stages of development. At this point I have modified an Orca with a few of the changes I have proposed for the new design, but it does not include everything. This is why I refer to it as an Alpha prototype. This is currently what Fondueset is using. It does not represent new hardware. In fact, it is old POP hardware; the fin Natalia used with production finishing, but then modified again for these tests. It is just a risk reduction platform to test a few of the functional changes and get direct feedback to influence the new design in positive ways to try to make a better product.

noa said:
I had asked the following in the past, but i guess there might be changes in that too, is it possible to purchase an Orca without the fairing, to be used more in an X20 manner ?
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I think the X-20 would be a better option if you want an open frame fin. However, I have the parts available to do this, and off the top of my head I cannot think of any safety reasons why it would be a no-go. If you are serious about it PM me and we'll talk.
 
I'm with Ron on the durability factor. In the event the extremely durable connectors (they look like sections of multi-ply heavy tire) started to wear, it would be clearly visible way before failure - but it looks to me like they will withstand years of heavy use.

I do not use a lot of knee bend - so that part of transitioning the the Dol-fin type design has not been much of an issue. I like the way it responds to a good core/spine undulation and I don't find it radically different from my Starfin in the respect. It covers 25 yards in about the same number of undulations for me - and they are close to the same amplitude. I experimented with smaller and larger amplitudes. Really large ones take you out of the blades efficiency envelope - small one work fine, but I like a more medium amplitude - with nice movement in my spine. Eric F. suggested using my ankles more and, in fact, you can move along pretty well with just your ankles, but the stroke I seem to have settled on doesn't involve much extra ankle movement - probably because it already has enough amplitude.

It may be there are better ways to swim with it, but it feels good to me this way and I move along quite nicely. Essentially I'm just using classic knees-straight (but not locked) monofin technique.

Coming off the bottom differs in that you don't get a huge amount of thrust from that first knee-bend kick. Instead the fin really starts working when you get lined up and start undulating. I suppose that could rattle your cage some in the beginning, but the fin goes well. I'll be testing this with a heavier weight setup as the water cools this fall, but with my 3 mil suit I have no problem. You just have to get the wave started.

The Orca I'm using is very slightly negative (close to neutral) on the surface in fresh water. It is probably buoyant in salt.

with 3 mil wetsuit bottoms on the fin is slightly buoyant at every depth I've used it. It is definitely more buoyant that my Starfins and WAY more buoyant than my Tropol - which is the fin I've taken deepest. At most I anticipate it becoming very slightly negative when the suit compresses at depth.

I'll post video as soon as I'm able to get someone to take it - or when the viz gets so good I can set a stationary cam and swim by it.
 

i'm first and foremost interested in having the attachment points close together, like on the Orca's design instead of the X20 more opened blade attachments. hence my interest in the Orca.
the other thing i would very much be interested in if at some point you develop it, is a more V shaped (vs the current straight design) leading edge blade.

could you perhaps post some pictures (or pm them to me) of an Orca without the fairing ?
thank you...
 
I meant to add - for spearos, or photographers (like me). The Dol-fin foil is much easier to work with on the bottom without stirring up clouds of debris.

Here, for the most part, the bottom is quite soft and making changes in position with a conventional mono fin can be like setting off a smoke bomb.

Also - for vertical swimming the orca wants relatively low-effort, higher frequency undulations. Using Eric's bent knee technique would yield very unsatisfactory results because much of the stroke would be wasted effort due to the angle of attack being too steep.

Moreover - and Ron may correct me on this, but I think the fin also gets more efficient with speed - so the trick is to maintain an even speed and not be constantly accelerating/decelerating.
 
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Notice how Natalia swims up in CWT, very small blade amplitude, steady pace and speed. Big undulations are not efficient, no matter what fin.

Gosh why there is no hydrofoil near me to try
 
of course that big undulations are not efficient. they just create drag and extra energy expenditure.
just look at fin swimmers, they all have small undulations. i'm very surprised that there are still experienced freedivers who believe in finning with big undulations...
 
Depends a bit upon the fin, and upon speed,and the blade angle - but this has been my finding also. I do big undulations sometimes only for the workout.

Generally you see big undulations freediving during ascent - but this is beginning to change too. (see Will Trubridge)

Still, with a hyperfin big undulations can help you accelerate (like dolphins do) and then you settle into smaller ones.

Anyway - my experience is that the Dol-fin is less tolerant of big undulations than a hyperfin.
 
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I like to explore the spinal movement during undulation in pool sessions - at least when swimming slowly, as I am here. So this first video session is with large undulations. In the sessions below I am swimming with a really bad injury to my left toe - the downstroke with my hyperfin was painful, as was the ankle stroke with the orca. My turns are generated around avoiding even the idea of stress on my toe, not technique.
It was difficult to strap the Dol-fin on with the pain - so there are no 75s with it because the straps kept coming loose. We'll try and do another shoot in a couple of weeks with more variety and distance.In the last video below I do try to show how the ankle flex works with very small undulations. Unfortunately this was quite painful so I did it only once - but I think you can still get some Idea. First two reference 75s with my Starfins, then some 25s with the Orca.

 
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Reactions: Apneaddict and Kars
Now that is really helpful, thank you. With a lot of trial and error, I worked out 3 stroke types that work with the x18m. Your vids show 2 of the three. The last is even slower, no undulation in the back at all and only minimal in the hips. Its mostly ankles.

Now I can see what I'm doing. In the "very small orca undulation: when I'm doing that, I thought it was all ankles until I looked underneath and back and could see my hips moving. Still very streamlined and efficient. I use that technique to go speeds between .9 and 1.15 m/s. You seem to get more speed out of the same stroke. Maybe its the Orca, probably better technique.
 
Reactions: Fondueset
Why is there no LOVE button Fondueset to press? - very interesting video's. I hope your toe grows back soon!
 
Reactions: Fondueset
Kudos on the review, the videos and the tenacity to press on with the videos while in physical pain!!!
 
Thanks for posting the videos, Fondueset. First and third videos appear to be about equivalent strokes, and achieving about equivalent performance.

The Starfins Hyper is averaging about 18.5 seconds and 9 strokes per length. The Orca is about 18.2 seconds and 9 strokes if you count the fin flip at the start as a stroke (the starfin used an uncounted upstroke to get going, the Orca a downstroke), 8 strokes if you don't count the starting motion. Would it be fair to call it 18.2 seconds and 8.5 fin strokes? Any way you look at it, the performance appears "equivalent" to within measurement errors.

What are your comments relating these two videos, Fondueset?

By the way, the stroke technique in the third video is similar to the technique I used for my dynamic record swim last year.
 
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To the point: Easily equivalent - no question.

For the Record: my Starfin is a 3 in the stiffness scale.
I would not want to go stiffer for dynamic.

In the slow videos I tried to start my first double-kick from about the same place in the lane.

The hyperfin gets that nice upstroke start - so I added a downstroke to give the Orca the same glide. Downstroke was inhibited on the hyperfin - but ankle work was on the Orca - so I think the handicaps work out.

I was very pleased with the Orca's performance - particularly after I saw the video.

Its interesting to me how the ankle kicks give rise to a very small whole-body undulation. Making that more intentional should really improve the energy equation.

I recently watched Alexei Molchanova's competition dynamic with Goran Golak in the next lane. Alexei has a low amp/ relatively high frequency kick-and-a-half technique that seems like it might be well suited to the Orca. The snappy half down-kick would nicely exploit the water moving already over the foil.

I was focused on doing - not evaluating - so the videos were very helpful.
I was purposely not watching my times or stroke counts - but I expected the Orca's to be higher and to see less distance-per-stroke, particularly in the slow regime.

I think the videos reveal the Orca as completely competitive with a hyperfin in the dynamic regime. What surprised me most is how well it did in the slow two-double-kick lengths. The first kick doesn't feel like much, but the second one is like an afterburner.


Connor - The Orca I'm using has a pretty wide-blade - Ron probably knows what's on your x-18.

Apneaddict - thanks. As a fellow mono fin addict I'm sure you are no stranger to agony. Before my Starfin I was putting silicone grease on open wounds.
 
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The x18's blade, not counting the wingtips is 29.5 inches, 75mm. How does that compare?
 
By the way Fondueset, I think you may find slightly better efficiency from the Orca if you space yourself more evenly between the water's surface and bottom of the pool. I think the boundary conditions posed by these two surfaces may tend to interfere with the vortex generation which produces the foil's thrust. In your videos, you were tending to swim very close to the bottom.

I don't have any concrete data, but I always feel like I loose a little performace when I get into shallow water and am pinched between the two boundaries, which makes me think they can degrade efficiency. Also, when I sprint near the surface, I can see the surface patterns in the water indicating the surface interferes with the vorticity that generates thrust (if it is captured on video because it is happening in the blind spot behind and above me). This combined with my understanding of how thrust is produced makes me believe that the best performance will happen when you minimize the influence of these boundary conditions by not getting the fin too close to either of them.

Has anyone else experienced boundary condition interference having an impact on monofin performance?
 

I'm sure that's true. I'm still working out the best-neutral depth with the suit/weight combo after a many-months hiatus from the suit.
 
If we extrapolate the 8.5 strokes per 9 strokes estimated difference between the two fins, a 200m Starfin hyper's dynamic would equate to a 212.5m Orca dynamic. On long swims, the difference adds up. In a competition, the delta is large enough that it could easily be the difference between 1st and 3rd place in dynamics.

If you think the 8 vs. 9 stroke estimate is a more accurate distance per stroke comparison, the 200m hyperfin dynamic ratios up to a 225m Orca dynamic.

Also, it is worth mentioning that my goal is for the Orca Mk-2 to outperform the original. If I am successful with that, this new product would not only outperform the best hyperfins available, but also have all the other advantages of the DOL-Fin system (i.e. - durability, portability, comfort, depth independent performance and buoyancy, warm/cold water adaptability, etc....).

To me, it sounds worthy of its own infomercial, but I'd like to know what you all think.
 

Relative to the model I'm testing we have to figure in the pain factor - the hyperfin was significantly more painful and I really had to soften my downstrokes. When I was in yesterday (sharing a lane - so no Orca) the pain had diminished to where I could put a little more into the downstroke. That experience made me revise my earlier opinion about relative handicap and think the hyper fin's performance may have been compromised a little more than the Orca's by my injury. I think you can see this in the relative vigor of the downstrokes in some of the videos. (high frequency swimming - aka ankle flexing - hurt with the Orca mainly because of the rapid and frequent changes of direction)

Testing relative to speed and stroke count could get extremely nuanced - I've done 25s with the Starfin using anywhere from eleven to one kick. I can maintain about the same moderate pace across a range of frequencies. (say between 6 and 11 - or 3 double kicks and 11)

Without a little more testing sans pain I'm comfortable saying the fins are within margin of error of each-other with the current dol-fin configuration. This leaves little doubt that improvements to the design - even a slightly wider blade - will push it over the top.
 

Hi Ron,

I'm very pleased to see some useful in pool comparisons, and I hope for more, preferable in a flat 50m pool for more consistency.
Though it's always fun to use the times and number of strokes in hypothetical calculations, I think a true confirmation would be a bunch of good monofinners doing pb's with only a short adaptation time. I think you are used to your Orca, and if you want to have an honest comparison I suggest you planning a date for a dyn pb attempt with a good fitting hyperfin in a 50m pool. Then the following day do the same with your Orca. (This does not need to be a public event). Pushing your ability with both designs will bring the strengths and weaknesses to the surface.
You see, and I assume you know, there are many more factors involved in an efficient design. Ease of use, forgivingness, manoeuvrability, ease of learning, how it matches the total set-up, how it works on specific body-types, how it works with (the many!) different monofin variants and dive tactics.


On your new design, maybe you can think of something that prevents or reminds the swimmer to keep the toes strait. I know people equate feeling pressure on the feet with speed, but pushing the toes down (like frog kick) does look very draggy and counter efficient.
Also - as I've been experimenting a little with a bicycle shoe myself - I do like the soft load up of a hyperfin because it gives me the time to rotate my hips in. How does your current design handle this moment?
 
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