Extreme Dolfinism G2

[Fondueset]

You make a very good point. The distance per stroke is not the whole story. The amplitude and effort that goes into the stroke is obviously just as important (along with drag details like speedskin vs. wetsuit, or bathingsuit).

The dilemma is that we cannot directly see the effort (i.e. - energy or work) that goes into a fin stroke. The closest observable is the velocity and acceleration profile of the fin stroke. A smooth sinusoidal velocity profile will have a more efficient distribution of vorticity throughout the stroke cycle, but a profile with sharp impulses and abrupt velocity changes will generate stronger vortices and have more energy and total thrust embedded in its motion. But, without knowing the back pressure or resistance of the fin, the work being done by the swimmer is unknown.

So, the velocity profile cannot tell us the actual total effort. It can only indicate if a particular fin is being pushed to it's thrust limits or if it's just being used normally and within its smooth and most efficient operating range.

The amplitude of the fin stroke and distance traveled per stroke are related to the fin's thrust capability and the drag of the swimmer. The amplitude and velocity profile of the fin stroke are related to the effort that is being exerted. Though it is not the whole story on it's own, that information combined with a "this is easy and comfortable feeling fin", or a "this fin is a heavier load on the feet than expected" and it can start to paint a meaningful picture of what's going on.

Without the opportunity to actually use two different fins in a careful evaluation of side-by-side performance, looking at these indicators is often about the best we can do, and with enough pieces of information quite a bit of relevant performance can sometimes be deduced. If there are persistent differences in lap times and/or differences in stroke count, differences in the velocity profile of the kick stroke and descriptions of differences in the back pressure, these indicators can often be used to uncover a performance gap between two monofins, if that gap is large enough. If the two fins are close in performance, the relatively small performance gap will probably not be resolved by this method (at least not legitimately).

Short of purchasing a Specialfins or Nemo to be able to test side by side, I thought it worth looking at the visual evidence to see what can be learned. So far, my finding has been that there is a big difference, but that's based on the videos I've been able to find which don't show the Nemo being used with a reasonably good technique, and without that, the big difference has little meaning and is probably not worth noting. There is just too much uncertainty. By the time divers get good technique, I think they often move on to swimming with a hyperfin, so there is just not a lot of video evidence on youtube to draw from that I've been able to find.

At this point I find it difficult to even swim with a Nemo - having grown accustomed to my hyperfin. I will say that, for me, it is more difficult to transition back to the Nemo than to Orca or the X-22. Having spent a couple of years using a Nemo (which I think is an excellent fin btw) I have a high order of confidence that the x-22 - and the pilot - will exceed it's performance* for a diver with good technique with both fins. - *By 'exceed it's performance' I mean energy for distance.

 

[Apneaddict]

YouTube whale Fantasia.


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[Stephan Whelan]

YouTube whale Fantasia.


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This one?

 

[REVAN]

It's a fun video to watch, but no pool metrics to use for performance predictions. This is a good example of the issue. The Nemo is a recreational monofin. Most recreational monofining is done in open water, not a pool. People doing dynamics in a standard length lap pool are usually using a higher performance monofin optimized for the task, or they are beginners just starting to learn how to monofin and the technique is crude. So, I should not compare my performance in a Pilot to their performance in a Nemo (at least not without a correction factor to compensate for the differences in monofin techniques and how that impacts the performance).

 

[Chipswim]

Who would have predicted that the most compelling technological advancement in the sport would be red fringe!?!?

 

[Kars]

Quantifying designs performances is difficult, especially when you know the results will influence believes and money.

In a way open competitions are a way so see which designs are favoured for what use. But we know the choice of materials is not only made by prooven efficiency, but often much more relying on social intelligence directed choices.
The hyperfin model is the current go-to model monofin of today. Used by record setters, and by aspiring ones. Digging into the hyperfin's highest appreciated qualities are: ease and forgiving to use, efficient, trustworthy, powerful. Downsides are: travel size, vulnerability, painful footpockets, inconsistent manufacturing, cost, weight. Ron's design addresses a good bunch of the downsides, but why aren't the top athletes seen using his design more often? Well I could think of a bunch of reasons, but the main one is that I believe in all they are pretty much content with their current fins, and see too few benefits in giving Ron's or other design's a -public - chance.
Who will pick up Ron's design and run with it? I think a number of groups: beginners with money, long timers with a love for experimentation, and possibly sprouting athletes with a itch to seek a new tool to give them a winning edge. Ron himself demonstrated that he can do national records with his design, something VERY COOL. Maybe it would be a cool promotional idea to award a diver who does a national record with a DOL-fin a special price? Or you could send a few Orca's to the bigger pool competitions for 1 extra dynamic race using the DOL-fin, awarding the winner(s) with a nice discount or a complete foil. This DOL-fin 'side competition' may help the design to earn it's acceptance as a record setting performance fin, breaching the market inertia. People need to see, touch and feel the product before they dare to commit and attach them selves to this new foil. See the Apple Macintosh store philosophy.

 

[divebike]

A good aspect of revans setup is the ability to dial in the right size fin for the riders size and power input, this is important, it's the equivalent of being in the right gear for a bicycle or a vehicle or anything else under power , where the load and power inputs vary it matters a lot. Now revan i'm sure has has dialed in the right size fin for an average sized person but there's still substantial variation between riders to warrant a close look at matching this up to the individual.There's an advantage to revans design in that I suspect it's one of the cheaper parts to interchange i.e just the foil ,an anodised extdrued aluminium section .

 

[baiyoke]

That issue has allready been addressed by Ron and he will probably explain how in detail. But in short there's a chart you can use for guidance. However the possibilities using this modular setup makes it very interesting, and I also think that big gains in performance is possible with a good MATCH of properties, i.e. lenght - width + a good deal of other parameters....

 

[REVAN]

From the beginning, I have made it a priority to maintain a very flexible architecture for my products. Not only does it allow for custom sizing of components to better fit the customer's bio-metrics and needs, but it has also allowed me to develop better products more quickly than could have been done with a rigid architecture that has more cost and time associated with trying new configurations. The current products have had a lot of evolutionary steps to refine the hardware and it's function to better optimize the products to meet customer needs. This has been a fundamental engineering strategy I have employed, that I think was a wise decision, given that the functional aspects of the products being developed were not particularly well understood at the outset of the project.

Not only has this strategy been key to the success of the engineering development of DOL-Fin products, it has resulted in an architecture whereby I can easily customize the fin blade size to whatever the customer wants. A "one size for all" strategy is not the best plan from the customer's perspective. I have standard sizes and a sizing matrix based on some general engineering estimates that make it easier for someone to decide what size to get, but if someone wants a fin that is 5 cm longer or shorter than one of the standard sizes, that is very easy for me to make. A one piece molded fin blade design would require engineering and cutting a new mold which would be a very expensive proposal. So, flexibility leads to success.

 

[cdavis]

You forgot something, Ron: the ability of the customer to come up with new modifications of his(her) fin, things you could not possibly forsee. As Peter Scott (Laminar) pointed out in his review of the x20, this is something new and potentially game changing in the free diving world. Not all of those mods work too well, but they sure keep life interesting and give you some good ideas.

 

[baiyoke]

Mod in the making coming Soon Only assembly and paintjob is missing. If it Works well I'll post more.... If it doesn't work, just forget this post

 

[REVAN]

You forgot something, Ron: the ability of the customer to come up with new modifications of his(her) fin, things you could not possibly forsee. As Peter Scott (Laminar) pointed out in his review of the x20, this is something new and potentially game changing in the free diving world. Not all of those mods work too well, but they sure keep life interesting and give you some good ideas.

That's true. In fact, the new suspension system for the fin blade was first tried by a DeeperBlue customer who was modifying his X-20 for surface swimming. After hearing about what he was doing, I realized that his modification was an attractive manufacturing simplification and his testing seemed to show that it work just fine. I optimized the other parts for their new functions and the new system is now arguably better than the old as well as being less expensive to make. This suspension system is now a standard feature of the new products, Orca2 and Pilot monofins.

Speaking of the Orca2, here is a picture of a partially completed Orca2 with gold anodized brackets. The picture doesn't do it justice. It needs better lighting to show it properly. It looks pretty amazing.

 

[REVAN]

Here is a nice picture of an X-20 sent to me from a new monofin freediver in training.

"I love your fin! I've never used another monofin, but I can tell how efficient and smooth it is, it feels great! "

 

[Kars]

Absolutely stunning photo!

 

[REVAN]

Well then, maybe you will like this one as well...

 

[REVAN]

I like this picture too even though the color and clarity is not the best. With good form, the DOL-Fin looks powerful and 'thrustworthy'!

 

[REVAN]

Hey guys, let me know what you think of this write-up (the picture is just for fun):

Whether you are a seasoned swimmer or taking your first dip in the water, you could always use a bit of help. Most guys do fine swimming on their own, but those who want a bit more power and performance can invest in a monofin.

This swimming accessory helps swimmers move through the water with little effort. The high-tech hydrofoil is crafted to mimic the fins of natural marine life, such as tuna or marlin, and DOL-Fin hydrofoils have set multiple records in the competitive sport of freediving. That being said, DOL-Fin monofins are not just for competitive athletes, recreational divers can also benefit from the power and efficiency they provide.

Smith Aerospace’s monofins fins are some of the best fins you can get. They have been developed and vetted within the rigorous environment of competitive freediving. The DOL-Fin’s patented hydrofoil designs allow for a unique combination of performance and comfort that is not attainable with any other brand or design currently available. You can zip through the water effortlessly without having to sacrifice comfort, and the unique bold look will really catch the eyes of strangers making you the envy of the beach resort.

There are a number of different models to choose from. They differ in buoyancy, performance and cost. You can choose a model based on what you will be using the fin for. The DOL-Fin Pilot2 is designed with more stability and operational flexibility to provide swimmers and divers with the ability to scuba dive, freedive, spear or just surface swim, while the DOL-Fin Orca2 is designed with positive buoyancy and streamlining to provide maximum performance for competitive freediving and those who take the time to train for high-performance freediving beyond the 20m depth range.

Despite the model you choose, all Smith Aerospace fins are crafted to be comfortable and easy to travel with. The compact hydrofoil folds to fit in a suitcase and can even detach from the support structure for even more flexibility in packing options. This makes traveling a breeze and saves money by eliminating extra luggage expenses for packing your monofin on that exotic diving vacation. One of the biggest complaints about traditional monofins is their awkward and uncomfortable fit. Many monofins will end up hurting your feet with prolonged use, and traditional monofins make you choose between effectiveness and comfort. DOL-Fin monofins differ in their design, allowing for the best of both without compromise.

Regardless of your skill level, DOL-Fin monofins are the way to go.

 

[Fondueset]

Hey guys, let me know what you think of this write-up (the picture is just for fun):

View attachment 40503

Whether you are a seasoned swimmer or taking your first dip in the water, you could always use a bit of help. Most guys do fine swimming on their own, but those who want a bit more power and performance can invest in a monofin.

This swimming accessory helps swimmers move through the water with little effort. The high-tech hydrofoil is crafted to mimic the fins of natural marine life, such as tuna or marlin, and DOL-Fin hydrofoils have set multiple records in the competitive sport of freediving. That being said, DOL-Fin monofins are not just for competitive athletes, recreational divers can also benefit from the power and efficiency they provide.

Smith Aerospace’s monofins fins are some of the best fins you can get. They have been developed and vetted within the rigorous environment of competitive freediving. The DOL-Fin’s patented hydrofoil designs allow for a unique combination of performance and comfort that is not attainable with any other brand or design currently available. You can zip through the water effortlessly without having to sacrifice comfort, and the unique bold look will really catch the eyes of strangers making you the envy of the beach resort.

There are a number of different models to choose from. They differ in buoyancy, performance and cost. You can choose a model based on what you will be using the fin for. The DOL-Fin Pilot2 is designed with more stability and operational flexibility to provide swimmers and divers with the ability to scuba dive, freedive, spear or just surface swim, while the DOL-Fin Orca2 is designed with positive buoyancy and streamlining to provide maximum performance for competitive freediving and those who take the time to train for high-performance freediving beyond the 20m depth range.

Despite the model you choose, all Smith Aerospace fins are crafted to be comfortable and easy to travel with. The compact hydrofoil folds to fit in a suitcase and can even detach from the support structure for even more flexibility in packing options. This makes traveling a breeze and saves money by eliminating extra luggage expenses for packing your monofin on that exotic diving vacation. One of the biggest complaints about traditional monofins is their awkward and uncomfortable fit. Many monofins will end up hurting your feet with prolonged use, and traditional monofins make you choose between effectiveness and comfort. DOL-Fin monofins differ in their design, allowing for the best of both without compromise.

Regardless of your skill level, DOL-Fin monofins are the way to go.

Good summary - but lacking the kind of rigor this community wants. I think it is a good advertising piece.

 

[REVAN]

Good summary - but lacking the kind of rigor this community wants. I think it is a good advertising piece.

I'm just working on some material for advertising and thought I'd run it past folks for a little feedback.

 

[Fondueset]

I'm just working on some material for advertising and thought I'd run it past folks for a little feedback.

It's pretty good!