I was reading in WIRED magazine this week about a carbon fiber swimming fin. This was in their new, expensive and often impractical gismo section which I enjoy. Anyway there was a picture and a short blurb. The swimming fins were much longer than the "standard" fin I am familiar with. They described that the carbon blade bends as the swimmer initiates the kick and then "snaps" back into the straight giving the swimmer forward motion. It got me to thinking that it might be interesting to paddle with a blade that behaved in this fashion. Anyone seen or used such a swimming blade. Idle winter thoughts... *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
There is a very unique dive fin that I have used for years called a Force Fin. Most folks thought they were terrible or stupid since they are 1/3 the length of many fins, flexible and have absolutely no macho points (Very important consideration for many divers). You can see these fins on the Navy SEALs TV commercial as they jump out of a plane with their SCUBA gear on. They work by creating a vortex as they snap back to their original shape and one feels very little resistance to them. I am a friend of the designer and thought that the concept could be applied to a kayak paddle. I fixed two fins to a paddle shaft. There were a number of problems including the fact that the snap has to be inline with the direction of travel and the paddle was heavier than a $10 Sears paddle. I was unable to determine if there was actually a benefit and did not pursue it because of the weight issues of the special plastic required for the "blade" cya *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
There is a very unique dive fin that I have used for years called a Force Fin. Most folks thought they were terrible or stupid since they are 1/3 the length of many fins, flexible and have absolutely no macho points (Very important consideration for many divers). You can see these fins on the Navy SEALs TV commercial as they jump out of a plane with their SCUBA gear on. They work by creating a vortex as they snap back to their original shape ---------------------- Hi Bob, Would you, or anyone interested, elaborate a little bit on part about votex and thrust generated. Thanks, Chuck Sutherland *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
It is very similar to the swimming action of a tuna. The Force Fins were based on tuna studies. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Robert wrote: <SNIP>>>>>>>>>>>>The swimming fins were much longer than the "standard" fin I am familiar with. They described that the carbon blade bends as the swimmer initiates the kick and then "snaps" back into the straight giving the swimmer forward motion. It got me to thinking that it might be interesting to paddle with a blade that behaved in this fashion.<<<<<<< Isn't that pretty much how conventional swim fins work, somewhat like a fish. About 20 years ago, when considering building a kayak for Joel Rogers (a kayaking photographer), I thought of trying to build a rudder that would act like a fish tail (by making it thinner and progressively more flexible near the tip). The entire blade would be under water (on a rod) and trail straight back below the surface (so the flex puts the trust in the most advantageous direction as you push the foot pedals back and forth. I didn't think it would be terribly efficient but he would be able to stow his paddle and hold the camera at ready and both slowly propel his kayak as well as control direction solely with this rudder. His paddle blades wouldn't be waving around to scare the wildlife he might like to get closer to to photograph. To use this kind of sculling motion with a paddle (like a stern mounted oar on a rowboat) would require a whole new kind of stroke and be very inefficient. since most paddles are used perpendicular to the desired motion and swim fins are used more parallel to the desired motion I don't think that concept would work using a normal type stroke. I have found that a little flex in a paddle shaft is desirable if it snaps back quickly enough. A good paddle can be loaded up during the early less efficient (when the blade is not perpendicular to the direction desired) part of the stroke and unload when the blade is more perpendicular. Too soft a flex or too slow a snapback and the paddle just vibrates in your hand once it is withdrawn from the water and the energy put into flexing the paddle it is lost to propelling you. A pole vaulter uses his pole in a similar but much more exaggerated fashion, bending the pole while moving horizontally and having the pole release the stored energy vertically. The best paddle 9in that respect) I ever used was a wooden slalom paddle built by Azzila (or something like that) from Italy. It was owned by Werner Furrer Jr. who had picked it up in Europe during and international slalom competition there. He liked it so much right from the start that he tried to buy some more of them so he would have some back-ups in case he broke that one. Unfortunately, none of the other of the (I believe) six paddles he tried out (even though of the exact same model) had that same kind of perfect "snap" to them. Werner let me try it for a minute or two one day (luckily he also paddled left feather) and I too felt that there was some "magic" in that paddle. The paddle was well worn and didn't look like anything special but Werner told me he felt like he wasn't sure if he would be able to continue competing at the international level if he ever lost or broke that paddle. Matt Broze http://www.marinerkayaks.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> About 20 years ago, when considering building a kayak for Joel Rogers > (a kayaking photographer), I thought of trying to build a rudder that would > act like a fish tail (by making it thinner and progressively more flexible > near the tip). Funny !!! A few years ago, when DSV Seaquest was running in TV here (this future Submarine-type), I was impressed on these little fish-like-helping submarines. They moved by a fishtail. I thought, this must be a great idea in a kayaks rear end. Think on an P&H Icefloe where these massive integrated skeg is, if these would be flexible, it could act like a rudder or like a mini-motor. Hey Matt, nothing is really new, eh? I made a little note and a wrote it down. But before I could tell it someone, the next year Zoelzer in Germany came out with his new integrated rudder-system. And now it comes.... It is a compromise between a rudder, a skeg and a far-away-looking-like fishtail. Okay, no real fishtail. I´m not sure I could explain in a correct way. On his homepage must be a drawing of it. Have a look at www.zoelzer.de Think on these integrated rudder systems. But here is a peace of plastic fitted with 2 straps beside, running over the whole rudder area. If you push the pedal, the rudder flips out of its integrated box (hold inside by elastics, the plastic not the box) and function as a skeg. Push on one pedal (left or right) a little bit more and one strap will "screw" the plastic a little bit, so it behaves like a rudder and looks a little bit like a fishtail. It is quite new and I think it´s not the end of evolution of this system, but it works. But, you need bit more pedal-way and its not so silend (some user told me), and the straps are running throught the water :-( not ideal I think. But it shows whats possible, if you get the right impression of nature. bye Jochen *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> From: "Matt Broze" > Subject: RE: [Paddlewise] Flexible carbon fiber paddle > > ...About 20 years ago, when considering building a kayak for Joel Rogers > (a kayaking photographer), I thought of trying to build a rudder that would > act like a fish tail (by making it thinner and progressively more flexible > near the tip). The entire blade would be under water (on a rod) and trail > straight back below the surface (so the flex puts the trust in the most > advantageous direction as you push the foot pedals back and forth. I didn't > think it would be terribly efficient but he would be able to stow his paddle > and hold the camera at ready and both slowly propel his kayak as well as > control direction solely with this rudder. Harry Bryson did a small boat using just this system. It appeared in a profile on Harry that Wooden Boat magazine did in the last few years. -- ----------------------------------- Michael Edelman mje_at_spamcop.net http://www.foldingkayaks.org http://www.findascope.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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