Margot wrote: >It looks as if there could have been oscillation. Hobie Cat >has a video of a Mirage in a tug of war against a double at >http://www.hobiecat.com/kayaking/miragedrive.html, G'Day Margot, Thanks for that excellent link. Looks as if its the same boat described by Matt. The video's seem to provide questions for most of the explanations advanced so far. - The fins look to be the same size as the paddle blades so where does gearing come into play? - When Greg Barton and Oscar Chalupsky try to pull the flippered boat they use an unsynchronised stroke? So is speed of stroke really a workable strategy? - There is a huge amount of spray (turbulence?) at the paddle blades and no visible evidence of any around the flippered boat, better flipper efficiency perhaps? - As you say the two boats oscillate back and forth during the contest, at least when Greg is paddling by himself, so maybe the need to continuously accelerate the paddled boat is part of the problem? A puzzle is Nick Schade's observation that in a race the flipper operated boat simply doesn't perform. Is it just a question of flipper size and given a smaller unit a flippered boat would out perform the paddled boat? The advertising blurb claims these boats can reach hull speed. This might indicate that the boat in the video has smaller flippers than the one Nick saw or that the boat in the tug of war had larger flippers than the video shows? Perhaps flippers are just more efficient than paddles? I know most finned fish I try to catch are faster than my kayak. I'm also sure legs are more efficient than torsos at fairly high speed work. That leads me to yet another question - How do legs contribute when top kayakers (and even average kayakers like myself) pump them to go faster? All the best, PeterO *************************************************************************** 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/ ***************************************************************************
On Sep 6, 2004, at 5:58 AM, PeterO wrote: > That leads me to yet another question - How do legs contribute when top > kayakers (and even average kayakers like myself) pump them to go > faster? I came to paddling from sculling. In rowing, the legs are everything. The great efficiency of the sliding seat is that at least 80% of the force applied to the oars comes from the longest and strongest muscles in the body. I naturally tended to apply sculling technique to paddling with the result that my paddle stroke is driven more by my lower body than anything else. I am also most comfortable with the shallow angle that accompanies a 9 foot oar. I use a 240 cm bent shaft paddle with a relatively large blade, pushing with an almost stiff extended upper arm, twisting at the waist and driving with my leg against the foot peg. The lower arm is little more than a fulcrum or oarlock. At 62, (and every bit as arthritic as the next old man), I am able to sustain a cruising speed of near 5 knots for a distance of 20 miles with virtually no effects to my upper body. It is my legs that get sore, never my shoulders or arms. I see no reason ever to change to a Greenland paddle and suspect that if I did I would be compromising with respect to acceleration, bracing and possibly the force required for a quick turn, (aided by a sweep for example). This approach of course entirely precludes the use of a rudder, (the value of which I seriously question anyway). It is evidently very counter-intuitive since I have had little success in teaching it to others but this is probably more about my patience than the difficulty of the technique. BTW: Reading this thread one might get the impression that the contributors do all their paddling only in heavy winds and seas and only to windward. I change styles, feather angles and sometimes even paddles to adapt to different conditions and venues. For example, I feather only to windward. Since I also tend to plan my paddling ventures to avoid paddling to into the wind as much as possible, I rarely if ever have to deal with wrist problems or concern for appropriate feathered technique. Am I therefore a wimp? Cheers, Michael in Florida *************************************************************************** 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/ ***************************************************************************
Michael wrote: - >In rowing, the legs are everything. The great >efficiency of the sliding seat is that at least >80% of the force applied to the oars comes from >the longest and strongest muscles in the body. SNIP >It is my legs that get sore, G'Day Michael, Thats my experience, sore legs and upper body no problem, in fact paddling fixes up my computer caused arthritis. The thing I don't understand is how flexing those leg muscles in a kayak generates the forward movement. I know it does help through listening to what everyone says and my own experience - I just don't understand why. In a rowing boat with a sliding seat I can see that flexing the legs extends and perhaps speeds up the stroke. But in a kayak that doesn't happen. I've tried to think it out and wondered if the leg action rotates the hips slightly but that doesn't seem to be a big enough movement to explain the improved effectiveness. I also wonder if leg movement somehow makes body movement more efficient but that is very hard to analyse, if it better transmits force to the boat that seems to contravene Newton's 3rd law. It clearly works, but why? I'll bet the answer is obvious and I've just not picked it:~) All the best, PeterO *************************************************************************** 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/ ***************************************************************************
Peter wrote: >The thing I don't understand is how flexing those leg muscles in a kayak >generates the forward movement. Hi Peter, Someone who's deeper into the mechanics of things will have to give us the scientific answer, but my bet is that it's like the difference beteen pedaling a bicycle with a flexible frame and pedaling one with a stiff frame. Having been an avid cycler I tested various bikes and sure enough, less flex in the frame yielded more motion per effort expended. The bike folks say it is because it takes energy to flex the frame. So, perhaps driving with your leg supports the action other muscles. In addition, that fraction of an inch of movement is tranferred to the stroke through the joints into the long lever arms of the arms. Might not take much movement three inches from your spine to turn into a foot or two of stroke at the paddle. Just musings, not science. Cheers, Carey *************************************************************************** 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/ ***************************************************************************
Basically, it is the front of your butt and your thighs/legs that push the kayak forward. Viewing the paddler as a system which interacts with the water and the kayak: The kayaker pushes back against the water. In turn, to anchor that pushing, the kayaker pushes forward on the kayak. If somehow more stroke (e.g., rearward pushing either for a longer time or with greater force) can be achieved by pumping your legs, then there will be more total work done on the kayak, by the paddler, and therefore more energy expended moving the kayak forward. -- Dave Kruger Astoria, OR ----- Original Message ----- From: "PeterO" <rebyl_kayak_at_iprimus.com.au> > The thing I don't understand is how flexing those leg muscles in a kayak > generates the forward movement. *************************************************************************** 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/ ***************************************************************************
<<The thing I don't understand is how flexing those leg muscles in a kayak generates the forward movement. I know it does help through listening to what everyone says and my own experience - I just don't understand why.>> You are moving the boat and not the paddle this way. Joan *************************************************************************** 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/ ***************************************************************************
On Sep 6, 2004, at 5:16 PM, PeterO wrote: > Thats my experience, sore legs and upper body no problem, in fact > paddling > fixes up my computer caused arthritis. Yeah. Paddling or rowing are the only effective treatments for my low back pain, (as well as my various mental illnesses). > The thing I don't understand is how flexing those leg muscles in a > kayak > generates the forward movement. It seems self-evident to me. The leg is used in such a way as to be the cause and force of torso rotation. Here I sit in a swivel chair. My left leg is partially extended bent slightly at the knee. The ball of my foot is against the wall. Being careful not to use any other body parts I am able to make my seat, (hence my upper body), turn about 30 degrees to the right by pushing against the wall and fully extending my leg. In the boat, all that is needed is to hold my left arm out so that it pushes against the paddle loom as my body turns. I do not rely on my abdominal muscles nor on the muscles of my lower back to achieve torso rotation. Instead, my legs do it. As I do this in my chair I think that I recognize a slight lateral component to the leg movement; pushing to the left a little as well as forward? Cheers, Michael in Florida *************************************************************************** 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/ ***************************************************************************
Michael said (snip): >BTW: Reading this thread one might get the impression that the contributors do all their paddling only in heavy winds and seas and only to windward.< Really not sure how you drew that conclusion. Heavy wind and wave conditions, when encountered, do tend to test one's paddling technique, or at least raise some issues with respect to blade size, wrist stress, feathering, etc., more so than flat water. When these issues come up on a thread, paddlers naturally gravitate toward these specific environmental concerns. >I change styles, feather angles and sometimes even paddles to adapt to different conditions and venues. For example, I feather only to windward. Since I also tend to plan my paddling ventures to avoid paddling to into the wind as much as possible, I rarely if ever have to deal with wrist problems or concern for appropriate feathered technique. Am I therefore a wimp?< No, just smart. But then smart can be boring though probably easier on the wrists. I do think the list represents a good cross-section of paddlers, with the likes of race types such as Kirk, to traditionalists like Shawn, to the more sublime back-water bayou paddlers who shall remain nameless as they seek silence. That's why everyone's comments are valuable to some certain degree. I certainly got a sense of balance as I've followed the thread(s). I also see a lot of paddlers carrying two main paddles these days (both varying in purpose and design) with one or the other being employed depending on conditions. Gone are the old days of a good main paddle, with two halves of a cheap one on deck as a spare. Personally, I don't follow that philosophy, as I like my continuous-shaft paddle which I feel is stronger than a take-apart for what I use it for. I also encounter a lot more paddlers using adjustable-feather paddles, and a lot more paddlers who are aware of dihedral differences and willing to look for a paddle to match intended uses. I don't think you have a monopoly on being a wimp, if indeed avoiding aggravating arthritic contributors is considered wimpy. I've managed to avoid wrist problems, even though I have a carbon-fiber Lendal that I never use, by punctiliously avoiding too tight a grasp on the paddle shaft -- especially with the control hand. I do think the paddle-wrist interface is a fundamentally simple one (no need for dogma or much discussion) with the complexity being the spiritual connectivity between you and your paddle, as ultimately your paddle is your propulsion, your stabilizer, your turning device, your brake, your righting device, and possibly your rescue device to avoid a Jesus moment (along with your pragmatic and spiritual connectivity, respectively, with your boat of course). Your paddle may also have an aesthetic value that goes beyond the look and feel of say, a wooden GP, which is given a high regard in this category. Good torso rotation and leg involvement in the recumbent position, as you noted in the portion I snipped, is important, but can also be overstated. At least that's what I smugly tell myself as I pass all those recumbent bike guys on steep hills. :-) Anyway, I think as long as paddlers are getting out on the water and enjoying it -- either for recreational or athletic conditioning -- it really shouldn't matter what stick they are using. Doug Lloyd Victoria BC ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~ "Whatever can be said at all can be said clearly and whatever cannot be said clearly should not be said at all." Ludwig Wittgenstein ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~ *************************************************************************** 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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