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Extreme Dolfinism

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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neurodoc said:
would changing the "angle of attack" of the fin have the same effect as a softer fin? So, allowing the X-20 blade to move farther before hitting the trim tab, would simulate a softer fin?
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Revan said:
the trim plates secondary use is to match the fin's angle control to the swimmer's preference for stroke thrust and resistance. In this way, it has similar efficacy to selecting different blade stiffness in a traditional monofin.
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Neurodoc - this is exactly what I keep thinking about these days, telepathy?

My latest invention (sorry) is that I took my drill again and attacked the small plastic part which controls range of movement of the X20 suspension strap for the upstroke. I drilled new holes and moved the plastic part by 0.5 centimeters away from shoes. The consequence is that when doing upstroke, this plastic part hits the very small plastic plate which holds screws of the blade. It results in angle lock for the upstroke. Same effect as trim plates have for the downstroke.

Now when I get into position for upstroke, I can hit really hard. It feels like as if somebody gave me more power to move in the water.

If the blade was larger (I have size L), with angle lock for upstroke it would feel like as if I were standing on the ground and jumping high. Jump high is a movement perfectly supported by human body.

But obviously, with a larger blade the other stroke would be harder too so a big downstroke angle would need to rescue me. I have increased the downstroke angle already so now I just need XL blade to try and see. Next year maybe.

Ron,


In some of X18 videos it seems these magic plastic parts controlling range of suspension strap are not black but silver. Were they made of aluminium in X18 and you changed them to plastic in X20?

Nylon laminations within suspension straps provide more resistance for the upstroke than for the downstroke - it is easier to push the laminations than to pull them. I know this because I tried putting them upside down, exactly as you emphasized in user's manual that it shouldnt be done, sorry. Maximum angle for downstroke is controlled by trim plates (or mounting tab in my extremist case), but there is no maximum angle control for the upstroke (unless one changes plastic plates like I did). Why is that? Since I locked the upstroke angle, I regard a missing angle lock as a lost opportunity.

After experimenting with all parts on X20, I would say that all magic is hidden in exact size of those plastic parts limiting movement of the suspension strap (assuming suspension strap is not yet another variable, lets simplify it for now). How did you arrive at their current size? Why are they plastic?

Thanks.
 
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Kars said:
I think the smaller foil makes it easier to have a proper and efficient technique within the swimmers capacity during the whole 5km swim.
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Kars - I thought this too but a smaller blade would also minimize power consumption of the upstroke. This is unfortunate because my body can handle any amount of upstroking work.
 
trux said:
Just out of curiosity, do you know what time you need to cover that distance without fins? Just to see whether there is a problem with the use of the fin, or whether the time is proportionally corresponding to your no-fin swim.
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Hi Trux - I never swim without fins, I dont know. I remember I swam 4 km breaststroke in 2 hours when I was 14 years old, without any extra gear. When looking at my youtube video (the one where both hands are stretched all the time), I swim 50 meters in 55 seconds. For the longer trip, tracking app says my speed was usually around 2.5 - 2.7 km/h. If I were better at mathematics I could tell if these two figures align


Slapping fin is a glitch in my technique, fixable by a bit of training. I mean, my fault, not the fin's fault.

Regarding how deep is the fin, here is an underwater video (miserable quality):
[ame=http://www.youtube.com/watch?v=_rVmotHRNf0]DOL-Fin X-20: My long distance swimming style - underwater - YouTube[/ame]

The important thing to notice is that my style in the video is on its way to museum. Hands can't be stretched all the time. Actually, I came to this forum to collect ideas for different styles.

Re propulsion by hands - hands only help with breathing. Not much propulsion. Especially when without hand paddles. But I have to stroke hard with hands because due to poor technique, my legs and hips sink low, lose horizontal orientation, and generate massive drag. Stroking hand pulls the body as a sinking carcass
 
I learned from classic monofins and hyperfins that you can swim pretty fast with a soft or medium fin, but you cannot swim slow with a stiff or medium fin. This may not be much the case with a hydrofoil of which you can adjust the 'speed' sensitivity / responsiveness of the blade.

You write you have plenty of upstroke power, well then try to have a more stable position with your head and arms part. This part should be very stable and rather horizontal. From your video I see that you can use more stability, consistency, fluidness. I suggest resting your hands on a kick-board. Arms rest on your head, shoulder sunk in the body (not outstretched!) and to swim 500m with that to tune up and automate your monofin technique. Think of pushing your bud up. Keep your toes backward, roll the hips a bit in and push the bud up in combination with rolling the upper body forward.
For improving shoulder flexibility, use back crawl medium speed to sprint speed.

May I ask what your goals are swimming those 5km?
 
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Yes it is a most interesting thread. I have realized that swimming with the Nemo fin, I cannot extend my ankle enough to get the blade in line with my leg; so I'm stuck at approximately 15 degrees or a little more. This makes the glide not much of a glide unless I keep my knees bent a bit during glide, which increases resistance as well. Also, on surface swimming, if the blade is initially parallel to the surface of the water instead of at a proper angle of incidence, when I start a downward kick I pull my shoulders and head/snorkel under also. The only way to avoid this is to bend knees some, which also makes heels come out of the water more! It is really a hard abdominal workout though! but, I would go much faster and be smoother if I had a fin that would accomodate my stiffer ankles. X-20 is looking great here, as it seems to be the only adjustable monofin available. Angles are adjustable, footpockets or shoes to fit or exchange for cold season swimming, etc. This sounds much better to me than taking my best guess and ordering one that at best will work for only one scenario (ie sprint but not long distance, tight enough for deep but hurts after 30 minutes...) And I love being able to discuss these ideas with the engineer in charge!
 
Mukiker, here is a thought to consider: in my practice as a Chiropractic Neurologist, I regard strong hamstrings (back of the thigh) and weaker quadriceps (front of the thigh) as a biomechanical fault which leads to increased risk of sciatica and more knee problems. The quads are what stabilize the knees normally, so weaker is not good. If you make a big practice of swimming with upstroke and not downstroke, you are not using your quads much. Also, abdominal muscles help stabilize the downstroke, so this makes the abs strong and better, which is very good for core stability and a healthy back. Again, your upstroke-stroke style would seem to strengthen and tighten the low back and not do much for the abs-this results in a more unstable low back which is more prone to injury. This is how people usually are when they show up in my office in pain-tight low back, weak abs, tight hamstrings, weak quads. After looking at what you have posted and thinking about it, I do not think I would want to swim that way for very long as it would potentially make things worse and not better for the body. A conventional downstroke style strengthens quads and abs, which is where we all need it more to be stronger/healthier/more resistant to injury. Even the knees could suffer, as pushing the knees in upstroke when fully extended will eventually cause hyperextension injuries as you stretch those ligaments without much muscular support at that angle (legs fully straight). I hope that makes sense. I may not be an expert finswimmer but biomechanics is what I do every day. Would not want you to get hurt or wear yourself out prematurely!
 
Reactions: Kars

Hi Fondueset - regarding countering sinking body with the hand stroke - fantastic observation, congratulations. This is really the top issue. Sunken legs and hips generate so much drag that the stroking hand needs to pull with full power. Additional impact of the sunken hips is that after the hand hits the water when returning back forward, I have hard time using gravity assist as you call it.

Now to the gravity assist thing. Good that you mention that. This is how my degradation of the downstroke came about. Have a look at the underwater (poor) video above. One amazing thing about the style with hands stretched forward is the moment when the stroking hand finishes return back forward. I slap it with full power against the water. This move accelerates body turn direction deep into water. In the same second fraction I need to do a micro downstroke in order to get the fin into position so that when the body starts driving down, I am ready to kick the upstroke with as much power as the fin can provide. This leverages gravity assist to an amazing extent. Notice in the underwater video how much I accelerate in the moment when the hands enters water. A dynamic moment full of energy.

This quick micro downstroke was very resistive with default settings. It took too long to get the fin into position for the upstroke and I failed timing-wise on the gravity assist. Besides, I tried hard to make the downstroke in time which hurt in the longer run. I had to enable a quick downstroke - hence my setting changes.

Fondueset said:
A better method would be a slower downstroke - emphasizing time-under-thrust over frequency and better employing the glide aspect of the foil while minimizing effort.
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Well, my conclusion on gravity assist is a quicker downstroke, you recommend a slower downstroke. Ideally if you could provide video of random poor quality, it would help a lot. Your recommendation sounds intriguing but I can not imagine how to translate it into practical use.


Excellent. I was thinking how to address my "sinking carcass" issue. My idea is to add third kick during hand stroke. Not a full blown hard-work-kind-of-kick as is the second kick but a quick micro kick which would do what you describe - straighten the body into position with low drag and keep it ready for leveraging gravity assist.

Here is a beta version of a new style where hands spend 50% less time stretched ahead. Pool length is around 30 meters, maybe standard 25m. When swimming in the first direction, 2 kicks only. Hands work hard. In the other direction, I was trying to add the third micro kick during hand stroke. I felt this style has potential, I just need to iron out the remaining 25 other issues it has

 
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REVAN said:
- Your techniques is very relaxed, which is also very good for endurance.
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I swim around 1.5 km in the morning few times a week during summer. Guess what is my training goal for the distance? My aim is to feel relaxed as if I didn't do any swimming. Regardless of time it takes to swim it.

I remember that when I was a kid, I was fascinated watching people swim who do so without obvious effort. These people usually swim crawl / freestyle. It is as if they were not fighting against water, but as if the water was swimming with them. There was also a lady in her forties back then swimming butterfly with large bifins. People normally swim butterfly with 10 strokes and drown then. That lady kept swimming easily here and there over the 50m pool. It was interesting to watch it.

Second, compare running vs hiking. After I run 10km I am a dead man. How many kilometers do I need to hike until I reach the same level of "deadmanism"? 20km? 30km? This means that walking gets you at least 100% farther than running. If you aim for a long distance, it pays off not to run.

Third, my favorite lake is 36 km long. That's the same distance like the English channel / La Manche between UK and France. Challenge.

REVAN said:
It is all very interesting, and I have never seen anyone else use such a technique.
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You did not see it before because my former colleague who plays water polo invented it with me in a pub. I was trying to swim butterfly for a long distance, I mean more than 30 meters. I started without fins, small training fins, large bifins, front snorkel. No result. I said to him that butterfly is mediocre with regards to the need to lift the whole body out of the water in order to do handstroke and to breathe. And that crawl / freestyle is ideal in this regard because both body and head keep lying in the water all the time. He said - well, so just keep using body undulation and kick like butterfly and do hand strokes and breathing like crawl. And keep hands stretched for proper undulation.

It works great without fins too by the way, with one kick. Funny energetic swim style.


How many miles were you able to do in 20 meter hops underwater?

I hold my head high and so increase drag. A silly reason - if I put my head lower, snorkel fills with water and I can't breathe out continuously. When I do not breathe out continuously, I get headache after longer time.

REVAN said:
I suspect that as your core strength improves, you may want to increase the thrust from the down-stroke of your fin and pick up the pace of your swim. You will be less susceptible to ocean currents with a faster swimming pace.
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You wrote in X20 manual that increasing speed by one unit increases energy input by 3 units. Swimming fast is expensive. On the other hand, if I swim too slow, undulation stops working. Is 50 meters in 55 seconds too slow in your opinion? What shall be the target speed?

Thanks!
 
cdavis said:
On the surface, with the upper part of the body partly out of the water, you lose half the channeling of water that makes undulation so efficient. Net result, ankle is easier(at least for me)
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Hi Connor - thanks a lot for trying my style, it is like a birthday gift to me

I sense that your recommendation is well aligned to what Fondueset said - support body position during hand stroke with a small downstroke, not a full undulation and full kick but just something to make sure position is ok. Am I correct?

cdavis said:
Attach it to your leg and forget about it once you start moving. Works great with bifins and, as long as the line passes above the x20, it should work just as well.
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I had the board attached to swim shorts and the rope was getting stuck on X20 screws. Attaching it directly to leg may help, will try it.

Thanks!
 

Hi Simos - the areas you mention are on my list of future improvements My new beta style with one hand stretched needs to go deeper into water. Third kick is needed as mentioned above.

Ongoing undulation - again, a video would help if you can make one. Hand stroke is being done on the surface. Connor says it is not efficient for him. You say it works just fine for you. Hm? When my father taught me butterfly, he said that kicks and undulation need to go on without stops for hand stroke. I try to paste this instruction onto Michael Phelps youtube videos but I am confused... A video please!
 
Hi Mukiker.

The kick I use on the surface is not really undulation at all (I think). Quite different from what Fondueset does (I think). Most of the thrust comes from the ankles with a small amt of movement of the hips and knees to accentuate the ankle movement. There is little or no movement above the hips. Feels like completely straight leg, but isn't quite. It keeps the body sliding along the surface with minimal drag and keeps the fin in the water all the time. Nice thing about it is it seems to work just as well hands down as hands up. Since I've nearly always got something in my hands while diving, this is a nice thing.

Its not a very fast kick. 1 meter/second (50 seconds for 50 meter pool) is pretty fast for it and my ankles and lower legs get tired after a few hundred meters at that pace. Slow down to .7 m/s (2 hours for 5k)and use my arms and it is so relaxed I feel like going to sleep.

On the boogie board, put the leash on the lower leg and the board tows well behind the fin.

Connor
 

I am basically trying to do the stroke in the video below but I breathe every 3rd kick (which for longer distances will get tiring I would guess but you can experiment with how often to breathe, I find it easier to keep momentum the way I do it but probably due to my bad technique):

[ame=http://www.youtube.com/watch?v=2BwpI0glRdU&feature=youtube_gdata_player]Swimming - Butterfly - Single Arm, Extended Arm - YouTube[/ame]

Hand stroke is while submerged but arm recovery to the front is on the surface, during breathing. Obviously you only do an arm stoke when you are going to breathe, not with every kick (assuming you are breathing every 2 or 3 kicks etc). Because I have 3 kicks, I try to stay well below the surface for the kicks I don't breathe for as it's more efficient...
 
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Mukiker said:
...How many miles were you able to do in 20 meter hops underwater?...
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I am never really trying to just cover distance on a swim. I am exploring and looking for interesting things to see (marine life and/or a neat dive spot), and so I am easily distracted.

I can think of a few cases, however, where there just weren't any good distractions to be had. On one dive, I estimate I was a solid mile from the boat when I finally gave up and decided there really was not anything interesting to see at that location and pretty much headed straight back using my hop technique. Including the outbound leg, it would have been over 2 miles, but I tended to zigzag a lot on the outbound leg as I was in exploration mode and thus the timing of my dives was sporadic. I also did a couple of miles in a shallow lake once that was fairly consistent as there were few distractions to get my attention.

The distance adds up quickly. For me, 10 strokes continuous or 6 strokes KKG will cover about 20 meters. During the short breath-up, I'll cover another 5 meters on the surface before I dive again. At 25m total per cycle, I can cover about 1 km with 40 cycles of hop dives. The hops are big enough to break the distance down into easily counted increments which makes it easy to keep track of approximately how far I have gone. Since most of the swimming is done underwater, I eliminate a lot of wave drag from the surface which improves my overall efficiency. Also, if I am beating into a current, I can get close to the bottom and swim in the boundary layer to reduce my losses from the "headwind" affect (assuming I'm in shallow enough water).

Like I said, it is also great training for freediving. I had been doing this for years before I actually started "freediving" with Annabel in Hawaii, and I figure it is why I advanced so quickly. My body was already conditioned to tolerate high CO2. I just needed someone to teach me to take the time to breath-up and relax to extend my dives. Before that, it was always GO-GO-GO!
 
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Revan - my pool workout includes 30 25 yard u/w swims with <= 10 sec between. I will say it's way easier in the pool than in the bay - where I am pulling my most excellent banks board the extra-large dive flag - often against wind and wearing a 5 mil suit with weights.

With the mono fin I've found it works best when you already have speed - as opposed to constantly accelerating. If I do a surface armstroke I also generally slightly raise my rear - then bring the body straight - in this way a get thrust from the fin both from the downstroke and gravity - but the downstroke never really goes low enough for there to be much of an upstroke - or drag. It is more like using the fin and body to reduce drag and enhance glide from the arm stroke.
From what I can tell ankle flicking is more significant with the Dol-fin than with a hyperfin. I can generate significant thrust without an undulation just by bringing the fin up with my ankes - and I use this often when I am on the bottom and want to glide with minimal movement in order to avoid frightening fish. But it appears the more response foil design of the Dolfin exploits ankle movements more effectively.

I want to say also - it is possible to swim slowly with a stiff mono fin. In this case the surface of the fin is used more like a foil. I did this often with my no #1 stiffness Waterway Nemo - using a slow undulation emphasizing glide over acceleration. I liked it for getting close to fish because - since I was not flexing the blade much, it made almost no noise.

Neurodoc - your observations on the upstroke are spot on. I have a blown disk at L5S1 -(the largest rupture the neurosurgeon had ever seen - about 2 cm) I've treated it for the past 14 years or so with yoga, taiji and mono finning. One of the fascinating things about swimming with a mono fin for me is getting fluid spinal movement without letting the release points most all of us have take the brunt. I often practice with absolutely rigid legs in order to play with this - though I think a slight knee bend is more efficient. (by slight I mean almost just a tendon stretch)

With your nemo you can develop good technique - you may want to mitigate knee bend during glide with arching your low back a bit - then counter this hydrodynamically with a little forward curve in the upper back. The nemo is a fin with good potential.
 
Just wanted to say I am quite inspired by you guys to learn to up my distance - also the sea-hiker promo videos were awesome. I am useless at swimming but even then, there were a few occasions when there was interesting scenery that I just couldn't stop swimming - one that comes to mind was swimming along Amalfi coast in Italy; just kept on saying 'last cove' but then thinking 'maybe one more' lol

Just wish I had some way not having to swim back lol
 

I'm a reckless rebel. I'm not pulling a dive flag. I am as vulnerable as a manatee in the water, except that I know how important it is to watch out for boats and manatees are pretty clueless. I'll frequently do a 360 body roll to look around and see who might be heading my way, but a lot of my diving is done in places like San Carlos Mexico with relatively little boat traffic. I'm sure it is a lot different in Traver Bay mid summer.
 

Hmmm I am the same - here in Greece marker buoys don't seem to mean much to boats and jetskis unfortunately. You just need to keep looking from what I gather...

The worst is being at the bottom and hearing a speed boat or jet ski but not knowing where they are - not a bad idea to do a 360 while ascending....
 
We have to look too - legally they must remain 200ft from the flag but in the summer it is extremely dangerous - lots of rental jet skis, entitled codgers in inflatables, drunks, and people who are just not paying attention. Going without in some areas would be self-destructive.

Right now the Salmon are running - so lots of fishing boats. These are Allies on account of they present a navigational hazard to speed-boats; and fishermen, in general, have good situational awareness.

Meet my float; a Banks Board rigged for conspicuity with an oversized flag, Solas and Reflective tape. The board is extremely well designed - you can ride up on the back and lock in with your elbows to do stuff with your hands and it's got a waterproof hatch, mesh bag and very nicely done elastic strappage. Pulls easily as well as the Omer Shardana Connor used when he was here. Comes with a 3-point harness to make it a back-pack and has well-placed carry-handles on either side. I use riffe Float line - which is very low drag.

 
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Fondueset - Ever consider adding a boom and mainsheet to that dive flag? It could be dual purpose. I'm just thinking outside the box again.

I've been considering making something similar, but haven't gotten around to it yet.

About 20 years ago, I watched some dumb kids on jet skis who used a dive float as an object to make pylon turns around. Fortunately, they did not stick around long and nobody was hurt, but that is when I started to think I'm not sure I want anybody to know that I am there. I'll be stealth, like a Navy SEAL.:martial

By the way that water looks mighty inviting!!!
 
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