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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.
I'll also point out that efficiency in freediving is largely about distance covered with energy expended - so 7 strokes in 25m vs 11 is huge.
 
Easy enough to do 4, 7, 11 or 15 strokes per 25 depending on how stiff the fin is and what technique you're using. Somebody really needs to bolt these fins onto a mechanical rig that roughly simulates a human kick and measure the forward thrust at various amplitudes, speeds and power inputs. Somebody with lots of cash....
 
Exactly.

Look at the Bugatti Veyron.

Original model generated 1001 bhp (746 kW; 1015 PS) and had a top speed of 408.47 km/h (253.81 mph)

The Super Sport generated 1,184 bhp (883 kW; 1200 PS) and had a top speed of 431.072 km/h (267.856 mph)

So for an 18.2% increase in power, they gained a 5.5% increase in top speed. Why? Because at those speeds, air is thick, and drag is a huge factor - in order to double the speed the force must be quadrupled (without accounting for heatloss and so forth).

In water, drag is significantly greater than in air, so it requires significant increases in power and drag coefficient to make a tiny increase in speed.

The cost however, is €1 301 980 for the base model and €1 912 500 for the Super Sport. Which is a 46.9% increase in cost! All for 5.5% more speed :)

Regards,
WMM

a man after my own heart, i keep telling people that being a rev head and a freedivier work perfectly together!
 
Ok, I just got my Classic DOL-fins off the FedEx truck...I just opened up and holy shit!! Damn things are awesome looking and so damn light! They must weigh 50% less than my fiberglass bifins.

The icing on the cake are the engravings from Smith Aerospace...nice finishing touch.

Will get with you all next month when I'm in the water and back to the water.
 
That’s great Hero. Please refer to the Owner’s Manual for instructions on mounting the fin blade. If you get it upside-down, it will not work.
 
Hello Revan,
been following the development of the fins since the begining. facinating stuff !
it's great to see some real technology finally entering the field of monofins after so many years of more or less the same designs.
besides freediving, i personally use monofins for a lot for distance surface swimming and for dynamic underwater swimming out at sea. how would these fins (i'm thinking of the HP model) work for these uses ? thanks for any input and looking forward to try out your fins one day.
delphicly,
noa
 
The DOL-Fin Classic and DOL-Fin HP are almost the same product. The difference is in the fin blade. The Classic uses a one piece hydrofoil with a rectangular plan-form, and the HP incorporates a three piece hydrofoil that has a rectangular center section and foldable raked fin tips which increase the span efficiency of the fin. The two products feel very similar in the water, but the HP’s fin is about 20% more efficient at producing thrust, so you will go a little further and/or faster for the same input. Laminar and Fondueset have both used the DOL-Fin Classic and could offer some independent perspectives on that product if they want.

These fins are simple, lightweight and maneuverable. They are also extremely comfortable to wear. The stroke resistance feels almost negligible, which results in the ability to swim with them all day long without foot fatigue. For some, this may be a drawback, because some divers like to feel the fin resistance and prefer slow labored movements in the water when freediving. I like the comfort provided by these fins, and for freediving, I think many divers will appreciate how the easy quick movements of the fin can mesh well with a kick-and-glide technique.

The low stroke resistance also provides the ability to stroke the monofin with almost no body pitching, and this combined with its ‘low gear’ cruise setting are why it works so well with scuba. However, this also makes it work well when swimming on the surface where the swimmer’s drag will increase due to surface wave formation. The minimal body pitching keeps the top of the snorkel above the waterline even when the swimmer’s arms are down at his or her side. The downward extending shape of the fin support struts help to keep the fin submerged. In contrast, the Orca fin really works best with arms extended overhead to balance the fin reactions, and especially on the surface, I notice the difference if I don’t set up a good body wave. These details don’t seem to be as important to the other DOL-Fin models, although that may just be because I'm typically not going as fast as I would be going with the Orca fin.

As much as I like the DOL-Fin HP, my concern is that anyone who gets an HP to replace a hyperfin may be disappointed with the fin. It is very different from a hyperfin style monofin in both feel and in distance per stroke. That is the primary reason why I developed the DOL-Fin Orca. Its job was to attract the hyperfin users. Given its comfort, flat body motion and ability to transition between scuba and freediving activities, it may be more appropriate to think of the DOL-Fin HP as an awesome replacement for a pair of long blade bi-fins instead of a potential replacement for a hyperfin.

Anyway, it’s about time I posted some video of the DOL-Fin HP, but all I have at the moment is some old R&D stuff from the pool. I guess I’ve just been too preoccupied with the Orca lately.
 
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For some, this may be a drawback, because some divers like to feel the fin resistance and prefer slow labored movements in the water when freediving.

Yes, such as I!

I take as much time as possible to reduce my Oxygen while freediving thus maintaining a balance of comfortable power in the initial finning on my decent until the ascent where the oxygen reserves really come into use. This is what I have become used to therefore it will be very interesting to see how the results will be with these fins. My main hope is to improve my ascent with CWT, where it is so easy going down because after only 8 slow kicks of my bi fins i'm sinking already at 20M so I don't expect these new fins to be that much of a difference (we'll see!) but I can't wait to see significant improvement on my ascent where it matters!

I'm just excited to see how different these Smith Aerospace DOLfins will act compared to my Waterway cpt. nemo fiberglass fins!

Talk to you all next month!
 
Hello Ron,
first I would like to thank you for your very informative reply. It's really refreshing to have the developer of a product put in the time and effort to share his knowledge with potential customers.
From your explanations, I still feel that in the current range, the HP would be best suited to my needs of recreational freediving (max depths of around 30m)
and long distance open water swimming.
Over the years I have used monofins for a whole range of activities, such as the ones mentioned above, as well as for bodysurfing, short island crossings, breaching attempts, dynamic sprints, openwater downwind swims etc...
I've had to tinker and modify a lot of fins to work for these applications and from what I now read your designs seem to be able to deliver what others only promised.
It would be great to also hear what Laminar and Fondueset have to say about the classic model.
When do you anticipate the HP model becoming available ?
Thanks again for you help and input.
Delphicly,
noa
Posted via Mobile Device
 
The DOL-Fin Classic and DOL-Fin HP are almost the same product. The difference is in the fin blade. The Classic uses a ...

Nice explanation of the differences between three models, thanks.

Will there be any upgrade path from the HP to Orca model? Is the blade the same?
 
My excursion with the Classic was brief - and I did not have it properly attached.
What I noticed however is that you do not get the same feedback as you do with a mono.

This is disorienting at first but I'm not saying this iits bad - it may in fact be good - because it seems thrust is generated with very little effort. My guess is that this is possible because the fin has much less drag than a mono. Also does not load and release slowly the way a monofin does - rather it cuts through the water. The tradeoff is that it has insignifant drag - so, while it does not have the same sort of loading/release as a monofin, the tradeoff is that each stroke is optimized by low drag during stroke and glide and very little loss during transition.

I would agree with Ron's assessment of the hp and classic - and am pretty geeked to give the Orca a run - I think it may be a world beater.
 
Will there be any upgrade path from the HP to Orca model? Is the blade the same?
The Orca’s blade is made from the same material stock as the other DOL-Fin models. However, I would not consider it to be something that can be upgraded to. It has many modifications for the Orca fin’s narrow suspension mounting. It would be more cost effective to sell the old fin (which should be comparatively easy because of the adjustable foot bindings) and then upgrade to the Orca fin.
 
If anyone is going to be at the DEMA Show in Las Vegas (Nov. 17-20), I will be there at the show shopping for advertising opportunities. I will not be exhibiting the DOL-Fins at the show and will not have a booth there, but I will have the fins with me. If anyone attending the show would like a DOL-Fin demo after hours, I imaging we could make use of the hotel pool for that. Also, I’m considering taking some time after the show to make a loop over to Los Angeles and possibly even down to San Diego before heading back to Tucson. So, please send me a message if you want to try to get together to do some demos in any of these locations.

Thanks,
Ron
 
I took a little time off from working on getting the shop ready for production to put together a video demonstration for the DOL-Fin HP. There seems to be growing interest in this product, but I have had relatively little information and promotional material out there for people to see.

Although I think of the DOL-Fin HP as a recreational freediving fin, it is really much more. Along with unprecedented comfort, this monofin has very capable performance and, like the DOL-Fin Classic, can work amazingly well with scuba equipment. Among monofins, the DOL-Fin HP’s diverse utility and performance capability is unparalleled.

Ron
 
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G. damn! I like that one...especially with the retractable fin edges! Would fit in my suitcase for sure!

Good video with instructions! Snorkel too...!
 
Hi Ron,
thanks a lot for that video. yeah, that fin looks like it would work for what i want which is mainly the long distance surface swimming.
when do you expect it to come out ?
thanks for your info and hope to see more of you videos.
all the best
 
I'm in Los Angeles, and would love to try the dol-fin hp and/or orca! I know a few others who would like to try it too. I just competed this past weekend in the Los Angeles Apnea competition in Culver City, hosted by Ben Weiss and Dee Dee Flores. I'm sure some of the other competitors that were there would like to try it also!
 
ok Ron, thanks a lot.
another question. have you tried different blade sizes ? how would a blade with a bigger surface area work ?
any plans to offer the fins with different blade sizes options in the future ?
 
ok Ron, thanks a lot.
another question. have you tried different blade sizes ? how would a blade with a bigger surface area work ?
any plans to offer the fins with different blade sizes options in the future ?
Yes I have used different size fin blades. More blade area will create more body pitching and higher loads on the foot interfaces as well as more thrust. The configuration I have been using for the HP uses a 37 inch center section for the foil. The default for the design will be close to this dimension but has not been decided at this time. I’m evaluating and considering lengths of 35 to 37 inches for a baseline. However, there is no reason to prevent someone from requesting a custom length. If you are a really big person, you may want to consider using a longer span fin. There are no near term plans to offer fins that are either thinner or thicker in cord length.
 
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