Extreme Dolfinism

[cdavis]

Thanks Xaid, it was truly a great experience. I'm the lucky one wearing the Dol-fin. The dolphins just went nuts for it, not sure why. I'm headed back this summer and we will get a chance to see if the reaction is the same. You can read some more detail in this thread:

http://forums.deeperblue.com/threads/bahama-dolphins-and-the-dol-fin-x18-2012.96094/

The thread references more dolphin vids, some of which include the Dol-fin.

And I don't know where Ted got the lunocet idea. Pretty sure the name never came up on the trip.

 

[Chipswim]

Very Neat! Wondered if that was you!

Different Ted I gather!

 

[cdavis]

Yeah.


That Ted specializes in spearfishing and air rifles. Hell of a guy to dive with.

 

[Xaid]

Amazing! That is definitely living the dream. The fish hash looked great too!

 

[REVAN]

Data from 2014 Lunocet thread:

View attachment 38214

Such a sexy picture.

Anyways here are some numbers for you. All swims were for 50m straight, no turns. 4 laps(reps) each to ensure replicability.
Every swim was identical. I.e identical perceived efficiency and the numbers below had almost 0 variability between them (with the exception of the luno)

Rocket fin: 8x double kick glide. 38s
X20: 9x double kick glide. 40s
LunocetClassic: 11-12x double kick glide. 50s

Sent from my iPhone using Tapatalk

By my measurements, there is about a 10% delta between the original Orca and the X-20. That would put the Orca and the Rocket fin neck-and-neck in performance. This is the 10% performance gain I've been chasing for the past year with various design concepts. I wanted that extra 10% performance available for anyone who wants top level hyperfin performance in a foil fin architecture, but the Orca was too difficult for me to make. It has been an excessively rare monofin and has only been available on a limited and selective basis.

Achieving this 10% performance gain with variations on the X-20 concept was proving difficult, and last October I decided to stop torturing myself. I already had a design that was achieving the performance goal. The smart thing to do would be to redesign the DOL-Fin Orca for production and start making more of them. I had new tools available that I had been incorporating into my development process over the course of the past year, and applying these new tools to a second generation of the Orca would be a good exercise of the technology. So, I decided to redesign the Orca for better manufacturing and make small improvements to the design where possible. In particular, I've been focusing on incorporating positive buoyancy into the design, improving the foot straps and improving the Orca's streamlining.

It has been progressing well, and I'll probably be able to start sharing pictures sometime in the near future.

 

[wjohnson100]

Yea, I got about the same performance differences between the ORCA and X-20, the X-20 taking about 1 kick-kick-glide extra over 50 meters.

 

[Triton1715]

Good Afternoon All,

I'm going to chime in here with my two-cents, but I think you'll expect change due to my limited experience. I took delivery of an (the) X-22 this past Tuesday and I finally got to get in the water with it today. What an experience!

In the interest of full disclosure, it should be noted that my view point is that of one who has never worn a monofin in my life nor am I a competitive freediver. I'm a recreational bifin diver that simply enjoys being in, and specifically under, the water for the purpose of photography, exploration, occasional spearfishing, etc. I've been using bifins since I was about 6 (about 30 years) and while I've used many variants of scuba fins over the years, I've only used 2 sets of dedicated freediving fins: plastic Sporasubs (circa 2000) and for the past 5 years or so fiberglass 20 Fathoms Edge fins. Over the past 15 months, I've found myself dolphin-kicking more and more despite wearing bifins. . .probably 80% of the time as I enjoyed breaking up the monotony of standard finning, giving different muscles a break, and for the increased speed when going all-out. This trend led me the conclusion that a monofin was in my future. My concern though was a loss of significant maneuverability coupled with the combination of uncomfortable footpockets and having to spend the time to learn a whole new swimming technique. After lots of hemming and hawing, I decided on the prototype X-22 that Ron had for sale and was being tested by Fondueset. (I should also note that CDavis has helped me a lot with this decision as his diving style is quite similar to mine and came from a bifin background into the X-20).

I've been itching to get in the water with it since it arrived 3 days ago and work has been such that I just couldn't get away. I finally got the time today and headed out to the pool. My experience was rather brief and unfortunately, I haven't had the chance to get in the water in 2 months so I am very much out of shape which only further taints my comments. Nonetheless, I brought my Edge fins with me and started doing some laps with those to get a feel for it all again and be able to have a fresh experience with which to compare the X-22 with. I was able to play with the X-22 for about 30-40 minutes before I had to go which is a very short time having never worn any sort of monofin before. Quite honestly, having my feet clamped together like that felt very unnatural and was an unexpected, but albeit minor, psychological hurdle I had to overcome. Once I got in the water, it again took me a bit of time to figure out how to "launch" myself with out banging the fin against the pool wall. This is partly due to the simple fact that our pool is deep enough that there is no place in it where one can merely stand with their head above water. You need to hold onto the wall if you don't wish to actively swim to stay afloat. Having cleared these various hurdles I was finally able to push-off and swim with the fin. I've read this forum from start to finish twice over the past 3-4 months and was aware of some issues that would arise when using this fin for new monofiners and also even experienced monofiners. However, I can say that hardly any of these issues were present to the level that I anticipated! The fin performed between pleasantly good to outright great for me right out of the gate! Since I've never worn a monofin before, I'm sure my technique is utter crap. . . in fact, I'd wager crap has a better technique than me. Yet, by the end of my meager 30-ish minute swim, the fin was pretty much matching my Edge fins in performance! Considering the many variables at play that I need to improve upon, I think that speaks volumes of praise for this fin! Sure, I have issues like any new monofiner (unequal foot-pressure being perhaps the biggest) which led to occasional and very minor side-slips or loss of strong thrust, but overall, I'm quite impressed and pleased with the way the fin performed.

I'm hesitant to write much more about it since I will need time to experiment and develop my technique, but I am quite optimistic about the future of this fin for me given my initial experience with it. . .especially considering its performance given my background (or lack thereof).

Ron, if you'll humor me, I have a question about the design of the foil attachment point. I'm curious if there was a specific reason that the foil is attached using screws through the suspension straps as opposed to being attached to an axis running perpendicular to the foil much like the elevator in the tail of an aircraft? While I completely understand this design from a manufacturing and price standpoint (simplicity, cost effectiveness, simple to replace parts which don't offer additional corrosion points, and of course one less point of friction which would otherwise degrade power transmission), I'm just curious if this idea had been experimented with to eliminate excess slop/play which results in torsion of the foil? I figure good technique eliminates this problem, but I'm just curious if it's been approached from a design standpoint to lessen the learning curve.

All in all, I'm quite excited to get it back to the pool!

 

[Chipswim]

Good for you Triton! Congratulations....What cool connections you've made. Look forward to reading your experiences!

 

[wjohnson100]

One reason the current attachment method is good is that there is never any danger of it getting corroded or clogged up by sand or muck. I have been swimming and diving with the X-20 and ORCA for several years and have never noticed any negatives from the method of attaching the foil.

Good Afternoon All,

I'm going to chime in here with my two-cents, but I think you'll expect change due to my limited experience. I took delivery of an (the) X-22 this past Tuesday and I finally got to get in the water with it today. What an experience!

In the interest of full disclosure, it should be noted that my view point is that of one who has never worn a monofin in my life nor am I a competitive freediver. I'm a recreational bifin diver that simply enjoys being in, and specifically under, the water for the purpose of photography, exploration, occasional spearfishing, etc. I've been using bifins since I was about 6 (about 30 years) and while I've used many variants of scuba fins over the years, I've only used 2 sets of dedicated freediving fins: plastic Sporasubs (circa 2000) and for the past 5 years or so fiberglass 20 Fathoms Edge fins. Over the past 15 months, I've found myself dolphin-kicking more and more despite wearing bifins. . .probably 80% of the time as I enjoyed breaking up the monotony of standard finning, giving different muscles a break, and for the increased speed when going all-out. This trend led me the conclusion that a monofin was in my future. My concern though was a loss of significant maneuverability coupled with the combination of uncomfortable footpockets and having to spend the time to learn a whole new swimming technique. After lots of hemming and hawing, I decided on the prototype X-22 that Ron had for sale and was being tested by Fondueset. (I should also note that CDavis has helped me a lot with this decision as his diving style is quite similar to mine and came from a bifin background into the X-20).

I've been itching to get in the water with it since it arrived 3 days ago and work has been such that I just couldn't get away. I finally got the time today and headed out to the pool. My experience was rather brief and unfortunately, I haven't had the chance to get in the water in 2 months so I am very much out of shape which only further taints my comments. Nonetheless, I brought my Edge fins with me and started doing some laps with those to get a feel for it all again and be able to have a fresh experience with which to compare the X-22 with. I was able to play with the X-22 for about 30-40 minutes before I had to go which is a very short time having never worn any sort of monofin before. Quite honestly, having my feet clamped together like that felt very unnatural and was an unexpected, but albeit minor, psychological hurdle I had to overcome. Once I got in the water, it again took me a bit of time to figure out how to "launch" myself with out banging the fin against the pool wall. This is partly due to the simple fact that our pool is deep enough that there is no place in it where one can merely stand with their head above water. You need to hold onto the wall if you don't wish to actively swim to stay afloat. Having cleared these various hurdles I was finally able to push-off and swim with the fin. I've read this forum from start to finish twice over the past 3-4 months and was aware of some issues that would arise when using this fin for new monofiners and also even experienced monofiners. However, I can say that hardly any of these issues were present to the level that I anticipated! The fin performed between pleasantly good to outright great for me right out of the gate! Since I've never worn a monofin before, I'm sure my technique is utter crap. . . in fact, I'd wager crap has a better technique than me. Yet, by the end of my meager 30-ish minute swim, the fin was pretty much matching my Edge fins in performance! Considering the many variables at play that I need to improve upon, I think that speaks volumes of praise for this fin! Sure, I have issues like any new monofiner (unequal foot-pressure being perhaps the biggest) which led to occasional and very minor side-slips or loss of strong thrust, but overall, I'm quite impressed and pleased with the way the fin performed.

I'm hesitant to write much more about it since I will need time to experiment and develop my technique, but I am quite optimistic about the future of this fin for me given my initial experience with it. . .especially considering its performance given my background (or lack thereof).

Ron, if you'll humor me, I have a question about the design of the foil attachment point. I'm curious if there was a specific reason that the foil is attached using screws through the suspension straps as opposed to being attached to an axis running perpendicular to the foil much like the elevator in the tail of an aircraft? While I completely understand this design from a manufacturing and price standpoint (simplicity, cost effectiveness, simple to replace parts which don't offer additional corrosion points, and of course one less point of friction which would otherwise degrade power transmission), I'm just curious if this idea had been experimented with to eliminate excess slop/play which results in torsion of the foil? I figure good technique eliminates this problem, but I'm just curious if it's been approached from a design standpoint to lessen the learning curve.

All in all, I'm quite excited to get it back to the pool!

 

[Triton1715]

One reason the current attachment method is good is that there is never any danger of it getting corroded or clogged up by sand or muck. I have been swimming and diving with the X-20 and ORCA for several years and have never noticed any negatives from the method of attaching the foil.

I was suspicious about that. The type A designer in me though is a bit of a perfectionist and seeks to eliminate play wherever it is found, but in this case I could see where the trade off would actually be decreased performance and increased production cost. Sometimes play is a good thing. I remember reading a story once about early German WWII sub engines. They were designed with such precision that unless kept immaculately lubricated, they seized up where as the US sub engines were a bit sloppier which resulted in a more dependable engine that didnt require such a rigorous maintenance schedule.

 

[REVAN]

...Ron, if you'll humor me, I have a question about the design of the foil attachment point. I'm curious if there was a specific reason that the foil is attached using screws through the suspension straps as opposed to being attached to an axis running perpendicular to the foil much like the elevator in the tail of an aircraft? While I completely understand this design from a manufacturing and price standpoint (simplicity, cost effectiveness, simple to replace parts which don't offer additional corrosion points, and of course one less point of friction which would otherwise degrade power transmission), I'm just curious if this idea had been experimented with to eliminate excess slop/play which results in torsion of the foil? I figure good technique eliminates this problem, but I'm just curious if it's been approached from a design standpoint to lessen the learning curve....

All the points you address are true, but the real reason has to do with flying the fin efficiently through the fin's stroke cycle.

The angles needed to achieve the desired fin rotations are not linear with the kicking force, and a linear single axis hinge and spring arrangement are not adequate to keep the fin flying optimally across the full spectrum of swimming uses. A non-linear mechanism is needed.

The strap system provides the desired non-linear behavior and keeps the fin blade flying efficiently, regardless of the swimming speed. Fast acceleration, fast speed, medium cruising, or tiny ankle flicks; it is important to have the foil flying efficiently over the entire swimming spectrum. The mechanism is very simple looking, but the dynamics of it are fairly complicated. The important thing is that it seems to work pretty well.

The flexing straps also eliminate issues with squeaking noises that are common with pin in socket hinges. Not only is squeaking annoying for you to hear as a swimmer, it may chase off marine life that you want to get close to when swimming in open water.

As for the lateral rigidity of the fin and foot support: The X-20 has a fairly wide mount, which provides excellent lateral fin stability. It can tolerate a very high level of unevenness without issue. The Orca and the prototype you have are more narrow at the fin mount. This mounting arrangement is more compact and looks better, but it is also more sensitive to the uneven kick pressures and other afflictions of technique common among beginners to the monofin. I think that the stability is 'good enough' and that you should quickly transition through the learning phase to where it all feels natural. You will need to let us know if that is true or not.

Once your body is trained to kick straight and evenly, the softness of lateral rigidity can actually be a nice attribute as it softens the roll damping of the fin assembly, feeling more fluid and biological.

 

[Chipswim]

Enjoyed reading that! Think I understood.

Triton1715.. Sorry my spell guesser called you Trident earlier. Kind of like it though. Goes well with your Neptune persona!

Could you put up some photos of your new fin?

 

[Triton1715]

Enjoyed reading that! Think I understood.

Triton1715.. Sorry my spell guesser called you Trident earlier. Kind of like it though. Goes well with your Neptune persona!

Could you put up some photos of your new fin?

Not a problem on my end, but I just want to clear it with Ron first. Since the fin is technically a prototype and not a production piece, I don't know if it contains any details he's not keen on releasing yet.

No worries about the misspelling. I like "Trident" too. Actually, a broken trident is my official (and registered) trademark as a jeweler. . . so it definitely fits!

 

[Triton1715]

All the points you address are true, but the real reason has to do with flying the fin efficiently through the fin's stroke cycle.

The angles needed to achieve the desired fin rotations are not linear with the kicking force, and a linear single axis hinge and spring arrangement are not adequate to keep the fin flying optimally across the full spectrum of swimming uses. A non-linear mechanism is needed.

The strap system provides the desired non-linear behavior and keeps the fin blade flying efficiently, regardless of the swimming speed. Fast acceleration, fast speed, medium cruising, or tiny ankle flicks; it is important to have the foil flying efficiently over the entire swimming spectrum. The mechanism is very simple looking, but the dynamics of it are fairly complicated. The important thing is that it seems to work pretty well.

The flexing straps also eliminate issues with squeaking noises that are common with pin in socket hinges. Not only is squeaking annoying for you to hear as a swimmer, it may chase off marine life that you want to get close to when swimming in open water.

As for the lateral rigidity of the fin and foot support: The X-20 has a fairly wide mount, which provides excellent lateral fin stability. It can tolerate a very high level of unevenness without issue. The Orca and the prototype you have are more narrow at the fin mount. This mounting arrangement is more compact and looks better, but it is also more sensitive to the uneven kick pressures and other afflictions of technique common among beginners to the monofin. I think that the stability is 'good enough' and that you should quickly transition through the learning phase to where it all feels natural. You will need to let us know if that is true or not.

Once your body is trained to kick straight and evenly, the softness of lateral rigidity can actually be a nice attribute as it softens the roll damping of the fin assembly, feeling more fluid and biological.

Thank you very much for answering my question! I had a hunch that non-linear movement was important (much like a heavily moderated movement of a bumble bee wing), but wasn't sure how to express it. That, and I have to confess that due to the compressible nature of air and incompressible nature of water, I wasn't sure which aerodynamic elements translated fully into fluid/hydrodynamics.

I had completely neglected the notion of noise though! It hadn't even crossed my mind, but I could definitely see that being a major sticking point!

Regarding the width of the foot support, I can certainly see where a wider stance would provide greater stability, but to be quite honest, I don't think it's that big of a problem. If I can go from having never worn a monofin to using the X-22 with nearly comparable performance to my bifins (over 25yds) in just 30 minutes of use. . . the stability is definitely, as you stated, "good enough".

I need to play with it more to develop a more articulated opinion about it. In the 30-40 ish minutes that I played with it, I was trying everything from going slow to going fast, arms over head and arms at side, full body undulation (or the closest approximation thereof that I can muster) vs. partial knee bends, etc. Needless to say, I didn't have much time to try any one technique over a greater period of time to develop much of an opinion beyond a vague hunch one way or another. I'm hoping to be able to get back into the pool later on this next week where I can dedicate more time to the fin and hopefully come back with more info from both a beginner's and bifiner's perspective. The one really odd thing that did happen though was that after about a mere 15 minutes, I had completely forgotten that my feet were stuck together and when I finally took the fin off, it actually felt a bit strange to have my feet free. Never expected that sensation! It definitely speaks to the comfortable and natural nature of the fin despite its more mechanical rather than organic appearance.

 

[REVAN]

...Could you put up some photos of your new fin?

The X-22 prototype Triton1715 bought from Fondueset is the same fin shown in this video:

- http://content.jwplatform.com/previews/Snp3jfQ3-C3PNGnB0

I am using the X-15 monofin with scuba, and Florida based freediver Ryan Meyers is using the X-22 prototype. The X-22 was Ryan's first experience with a monofin. This was his second time in the water with it.

 

[Chipswim]

Triton, I think you set an excellent example by asking and we all get another beautiful video in return!

The clear water, scenery, topography, and diverse sea life are very similar to the dives we experienced in Nebraska! (When I was a child....During the Jurassic Period)

Oh! It has the next generation of the buoyancy idea molded on the shoe soles CDavis was playing with! Neat!

 

[Fondueset]

Triton1715, Nice to hear your impressions. See my suggestions in that thread about heart rate for mono fin training.
I can pretty much guarantee that the x22 will blow the doors off your bifins once you get some technique (and don't underestimate how long that might take! I was more than a year in before I could even understand good instructions). Monofinners place great emphasis on keeping the knees together - I believe this is intended to get cleaner thrust off the lower legs. Possibly Ron has something to say about that. Problem is if you focus on knees together you may lose touch with knees straight - so pick one at a time

 

[Triton1715]

Triton1715, Nice to hear your impressions. See my suggestions in that thread about heart rate for mono fin training.
I can pretty much guarantee that the x22 will blow the doors off your bifins once you get some technique (and don't underestimate how long that might take! I was more than a year in before I could even understand good instructions). Monofinners place great emphasis on keeping the knees together - I believe this is intended to get cleaner thrust off the lower legs. Possibly Ron has something to say about that. Problem is if you focus on knees together you may lose touch with knees straight - so pick one at a time

Per my reply on the heart-rate thread. . .

I'm curious what your experience was with the X-22 regarding legs straight vs. slightly bent. Please correct me if I'm wrong, but I thought I remembered reading somewhere in this thread that you thought the fin favored a straighter leg approach (which would involve more body undulation. . .right?). In my brief experiment yesterday, the one thing that seemed somewhat noticeably consistent was that a mild/gentle bending of my knees brought what seemed like significantly more thrust with less effort. I'm very hesitant to write this though since I didn't have much time to really explore the fin and it could just be a repeatable phenomenon brought on by me having a repeatably bad technique. . . which seems likely The reason I ask though is two fold:

1. The above video shows the knee bend that seemed better than straight leg to me

and

2. The sensation and power was vastly different than if I were to bend my knees and kick with bifins. With bifins (maybe monos too. . I dunno), if I were to bend my knees and kick, the blade cuts straight back without resistence and I end up hardly going anywhere. However, with the X-22, it was almost akin to "jumping". It was like the water was the ground and bending my knees was like crouching before a jump. . .sort of. Obviously it's a little different than that, but it's about the best explanation I can give at the moment.

So, short version: Did straight or slightly bent work better for you? (I probably should play with it more before asking this, but just can't help myself as I'm too darn curious and won't get a chance to get back in the water until Wednesday or so!)

Thanks!

 

[Fondueset]

Per my reply on the heart-rate thread. . .

I'm curious what your experience was with the X-22 regarding legs straight vs. slightly bent. Please correct me if I'm wrong, but I thought I remembered reading somewhere in this thread that you thought the fin favored a straighter leg approach (which would involve more body undulation. . .right?). In my brief experiment yesterday, the one thing that seemed somewhat noticeably consistent was that a mild/gentle bending of my knees brought what seemed like significantly more thrust with less effort. I'm very hesitant to write this though since I didn't have much time to really explore the fin and it could just be a repeatable phenomenon brought on by me having a repeatably bad technique. . . which seems likely The reason I ask though is two fold:

1. The above video shows the knee bend that seemed better than straight leg to me

and

2. The sensation and power was vastly different than if I were to bend my knees and kick with bifins. With bifins (maybe monos too. . I dunno), if I were to bend my knees and kick, the blade cuts straight back without resistence and I end up hardly going anywhere. However, with the X-22, it was almost akin to "jumping". It was like the water was the ground and bending my knees was like crouching before a jump. . .sort of. Obviously it's a little different than that, but it's about the best explanation I can give at the moment.

So, short version: Did straight or slightly bent work better for you? (I probably should play with it more before asking this, but just can't help myself as I'm too darn curious and won't get a chance to get back in the water until Wednesday or so!)

Thanks!

You can see my preferred technique in the videos I've posted various place - 'knees straight' is a bit of a misnomer - its really more of an intention. It takes awhile, though, to get your spine moving instead of your knees. Straightish knees won't feel right to you until you get that. Maybe Ron will correct me - but a lot of knee angle is more of a 'push' than the lift/thrust which is the forte' of a foil. To date I'm an advocate of good classic mono fin technique with the dol-fin foil-based fins.

 

[REVAN]

Per my reply on the heart-rate thread. . .

I'm curious what your experience was with the X-22 regarding legs straight vs. slightly bent. Please correct me if I'm wrong, but I thought I remembered reading somewhere in this thread that you thought the fin favored a straighter leg approach (which would involve more body undulation. . .right?). In my brief experiment yesterday, the one thing that seemed somewhat noticeably consistent was that a mild/gentle bending of my knees brought what seemed like significantly more thrust with less effort. I'm very hesitant to write this though since I didn't have much time to really explore the fin and it could just be a repeatable phenomenon brought on by me having a repeatably bad technique. . . which seems likely The reason I ask though is two fold:

1. The above video shows the knee bend that seemed better than straight leg to me

and

2. The sensation and power was vastly different than if I were to bend my knees and kick with bifins. With bifins (maybe monos too. . I dunno), if I were to bend my knees and kick, the blade cuts straight back without resistence and I end up hardly going anywhere. However, with the X-22, it was almost akin to "jumping". It was like the water was the ground and bending my knees was like crouching before a jump. . .sort of. Obviously it's a little different than that, but it's about the best explanation I can give at the moment.

So, short version: Did straight or slightly bent work better for you? (I probably should play with it more before asking this, but just can't help myself as I'm too darn curious and won't get a chance to get back in the water until Wednesday or so!)

Thanks!

You will get great thrust with bending the knees. You will also get more drag. If you need to accelerate quickly to pounce on a fish you just got with a pole-spear, it is great. If you are doing dynamics, it is not so good as the drag will eventually take its toll.

A little knee bending is okay, but I find that when I have a little knee bend in my stroke is basically when I think I have none. If I think I'm bending them slightly, I am actually bending them a lot. You may have a different feel of things. Generally, it takes video analysis of your technique to figure out what is actually going on with your stroke.