Julio wrote; -> >The feather is one reason. If you try the low Greenland stroke with >a feathered paddle you are likely to ruin your wrists. >But the main reason why it is difficult (I am not saying impossible) to >do Greenland style paddling with a modern blade is that the Greenland >paddle has a symmetrical hydrofoil shape --a wing-- and modern paddles >do not. My modern blade is not feathered and I know that some builkders don't mind making unfeathered paddles. Why can't the modern blade be made with an airfoil shape? . > >Another thing that one has to watch out is that true Greenland paddles >have a short shaft, and the paddler is always partially gripping the >blade directly, there is no confusion on the position of the blade >at any time. Commercial Greenland paddles have a long shaft and the >paddle puts his/her hands in a round portion of the paddle. That can >make rolling pretty confusing, and so is bracing and paddling affected. Anyreason why a locator can't be put on modern shafts or that the shaft can't be oval? > >Racers race, Greenlanders tour or hunt. That is what the wing paddle was >designed for, racing. Atheletes would use kayaks specifically designed >for racing, and use wing paddles designed to optimize the efficiency of >motion, with the sole purpose of moving forward faster than any one. I am not sure why racing needs to be different. If you run do you not run? Do you learn inefficient running because you don't race? Ditto with skiing? Maybe the requirements are more extreme but does it make sense to try learn the skill properly no matter what you are doing? > >> And in response to Dana: >> I am confused. If the Greenland paddle slips through the water more easily >> then isn't more energy lost? If so, why does it use less energy? Seems to >> be contradiction. > >The issue is not whether or not a paddle uses more or less energy, >is how it uses it. I don't understand this. > >It might be phychological; faster and shorter strokes with less force >are probably more comfortable for the spirit of many humans. Being calm >and relaxed conserves energy, and paddling with a succession of 'umpfs -umpfs' >(pulling hard) drains mental and physical energy together. My question was why a modern blade could not duplicate the characteristics of the Greenland blade. Is that not possible or is it impossible? > >Again, modern paddles lack the symmetrical foil shape. You can try >to paddle with a model of a Greenland paddle without the foil shape >and find out that it does not take you anywhere. Why doesn't it work if it is flat? >I am under the impression that Greenland paddles work like wing paddles >but flying through the water upside down (they dig down as they enter >the water, and that force is used with the torso rotation to aid >in pushing forward) Sorry but I am dense and don't comprehend. > >The Greenland paddle flies through the water, the lift component that >is used to push the boat forward is more important than the side >component used by the drag of the blade alone. In other words you are saying that th Greenland paddle works like a wing except in a horizontal direction instead of vertically? > >A good scientific way to improve Greenland paddling would probably be >to experiment with NACA foils, and decreasing angles of attack towards >the ends, like airplane propelers. Maybe one could get to the most >efficient Greenland paddle for Greenland racing, if there ever is >that discipline. Suppose someone said that they had done this test already and discoveredf it was not valid? Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John, See below for a few specific comments of mine. On Thu, 23 Jul 1998, John Winters wrote: > Julio wrote; > > -> > >The feather is one reason. If you try the low Greenland stroke with > >a feathered paddle you are likely to ruin your wrists. > >But the main reason why it is difficult (I am not saying impossible) to > >do Greenland style paddling with a modern blade is that the Greenland > >paddle has a symmetrical hydrofoil shape --a wing-- and modern paddles > >do not. > > My modern blade is not feathered and I know that some builkders don't mind > making unfeathered paddles. Why can't the modern blade be made with an > airfoil shape? Modern blades could be made with a symmetrical airfoil shape, but apparently they are not. Modern wing paddles have assymetrical airfoils, but this shape makes bracing and rolling much more difficult. This difficulty might be a function of problems with controlling the angle of attack during the brace and roll as much as it is a function of some inherent problem with assymetrical foils. It is extremely easy to control the angle of attack with a Greenland paddle, because the paddler is ALWAYS grasping the blade itself to some degree. > . > > > >Another thing that one has to watch out is that true Greenland paddles > >have a short shaft, and the paddler is always partially gripping the > >blade directly, there is no confusion on the position of the blade > >at any time. Commercial Greenland paddles have a long shaft and the > >paddle puts his/her hands in a round portion of the paddle. That can > >make rolling pretty confusing, and so is bracing and paddling affected. > > Anyreason why a locator can't be put on modern shafts or that the shaft > can't be oval? No problem here, and this is often done. However almost all cases of this do not have enough exaggeration in the indexing to make it really effective. George G. and I both modify our modern paddle shafts with a strip of autobody moulding and tape to make the indexing much more effective. SNIP > > > >> And in response to Dana: > >> I am confused. If the Greenland paddle slips through the water more > easily > >> then isn't more energy lost? If so, why does it use less energy? Seems > to > >> be contradiction. > > > >The issue is not whether or not a paddle uses more or less energy, > >is how it uses it. > > I don't understand this. The issue here is confusing because there are really several issues involved. One is that 'efficiency' needs to be broken down into absolute power output from the paddle, versus the ratio of paddler power input over paddle power output, where the latter is my definition of paddle efficiency. The former is of interest to flatwater sprint kayakers where speed is all that matters, the latter is of interest to recreational and marathon sea kayakers where stamina and efficiency over long distances are key. This issue is further complicated by the fact that sprint kayakers and racers are paddling their boats in a different hydrodynamical (is there a better word?) regime than recreational paddlers. Racers paddle their boats in a regime where power output necessary to maintain a speed is a non-linear function of the speed itself, so every last erg of power is critical. In contrast, recreational paddlers operate in a linear regime of power vs. speed, and small differences in power output of a paddle are trivial. Therefore the differences in power output of a greenland vs a modern paddle are indeed trivial. We shouldn't waste our time arguing this. What is more important by far, is the energy expended by the paddler in producing that output (efficiency as i've defined it), and here is where I would argue that the variety and style of Greenland paddle strokes is superior to that of a modern paddle. See my previous post for more explanation of this. > > > > >It might be phychological; faster and shorter strokes with less force > >are probably more comfortable for the spirit of many humans. Being calm > >and relaxed conserves energy, and paddling with a succession of > 'umpfs -umpfs' > >(pulling hard) drains mental and physical energy together. > > My question was why a modern blade could not duplicate the characteristics > of the Greenland blade. Is that not possible or is it impossible? > > I really doubt that the problem is psychological, although it may indeed have a relatively minor effect. > >Again, modern paddles lack the symmetrical foil shape. You can try > >to paddle with a model of a Greenland paddle without the foil shape > >and find out that it does not take you anywhere. > > Why doesn't it work if it is flat? Technically speaking, even a flat plane is an airfoil, as is a cylinder or sphere. However the angle of attack window which does not produce turbulence is much much smaller for a flat plane than for a foil shaped paddle. A greenland paddle makes it much easier to maintain laminar flow and therefore maximum lift during the entire stroke. I don't know how easy this is with a flat blade, or whether it is practically possible. > > >I am under the impression that Greenland paddles work like wing paddles > >but flying through the water upside down (they dig down as they enter > >the water, and that force is used with the torso rotation to aid > >in pushing forward) > > Sorry but I am dense and don't comprehend. I don't comprehend either. My understanding is that a greenland paddle works identically as a modern wing paddle, however because of the symettry, it is possible to generate lift while the paddle is digging down and also while lifting up by slightly altering the angle of attack. > > > >The Greenland paddle flies through the water, the lift component that > >is used to push the boat forward is more important than the side > >component used by the drag of the blade alone. > > In other words you are saying that th Greenland paddle works like a wing > except in a horizontal direction instead of vertically? The greenland paddle is a wing, period. However some of the strokes used have a different form than modern racing wing technique, and therefore the lift and drag vectors may be different. > > > > >A good scientific way to improve Greenland paddling would probably be > >to experiment with NACA foils, and decreasing angles of attack towards > >the ends, like airplane propelers. Maybe one could get to the most > >efficient Greenland paddle for Greenland racing, if there ever is > >that discipline. Actually, I would be interested in how a greenland paddle would work in a marathon kayak race. Well, That is all for me today. Cheers, Kevin > > Suppose someone said that they had done this test already and discoveredf > it was not valid? > > Cheers, > John Winters > Redwing Designs > Specialists in Human Powered Watercraft > http://home.ican.net/~735769/ > > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
John wrote: > > I am not sure why racing needs to be different. If you run do you not run? > Do you learn inefficient running because you don't race? Ditto with skiing? > Maybe the requirements are more extreme but does it make sense to try learn > the skill properly no matter what you are doing? Racing is different because races normally take place in ideal and controlled conditions. Racing boats are not designed to roll and move around rocks and waves, neither racing paddles. Racing gear is designed to maximize the efficiency of the human body motion to move forward in ideal conditions. If the conditions were variable, race results could not be compared against each other, and one wave would determine who is first and second in a race regardless of the quality of the athelete. > In other words you are saying that th Greenland paddle works like a wing > except in a horizontal direction instead of vertically? The lift of the wing has a vertical and a horizontal component. The vertical component is upward in wing paddles, and downward in Greenland paddles, unless they are use for sculling or bracing. Since the lift is not perfectly vertical, up and down, the objective is to take advantage of the horizontal component of the lift. > > > >A good scientific way to improve Greenland paddling would probably be > >to experiment with NACA foils, and decreasing angles of attack towards > >the ends, like airplane propelers. Maybe one could get to the most > >efficient Greenland paddle for Greenland racing, if there ever is > >that discipline. > > Suppose someone said that they had done this test already and discoveredf > it was not valid? Then I would be happy to know that I do not have to do that test myself. Has it really happened? Could you give me a pointer to the tests so I can find out what, and how, they were testing. Could explain why the test, or the idea of the NACA profiles was not valid. - Julio *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Thu, Jul 23, 1998 at 02:18:41PM -0700, Julio MacWilliams wrote: > Racing is different because races normally take place in ideal and > controlled conditions. Racing boats are not designed to roll and move around > rocks and waves, neither racing paddles. Racing gear is designed to > maximize the efficiency of the human body motion to move forward in > ideal conditions. What? Race boats, at least slalom racing boats, *are* designed for precisely that purpose. Same for the paddles; and the designs of both represent attempts to maximize speed and maneuverability simultaneously. Which means compromises have to be made: slalom boats aren't as fast as downriver/wildwater boats in a straight line, but they turn far easier (flat-spins or pivots). Similar comments can be made about creek racing boats, where the important design criteria are shifted somewhat toward the safety issues involved. And so on onto flatwater/sprint racing boats, marathon boats, and so on. ---Rsk Rich Kulawiec rsk_at_gsp.org *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Thu, 23 Jul 1998, Rich Kulawiec wrote: > On Thu, Jul 23, 1998 at 02:18:41PM -0700, Julio MacWilliams wrote: > > Racing is different because races normally take place in ideal and > > controlled conditions. Racing boats are not designed to roll and move around > > rocks and waves, neither racing paddles. Racing gear is designed to > > maximize the efficiency of the human body motion to move forward in > > ideal conditions. > > What? Race boats, at least slalom racing boats, *are* designed for > precisely that purpose. Same for the paddles; and the designs of both > represent attempts to maximize speed and maneuverability simultaneously. > Rich! Open your mind a little bit, for crying out loud. Julio is obviously talking about flatwater sprint kayak "race boats", not slalom boats. Do not assume that all "race boats" are slalom boats. remember, this is a SEA KAYAK list, although there are plenty of whitewater friendly people on this list. I am starting to wonder if you are not trying to deliberately antagonize people with your whitewater single-mindedness. > Which means compromises have to be made: slalom boats aren't as fast > as downriver/wildwater boats in a straight line, but they turn far > easier (flat-spins or pivots). Similar comments can be made about > creek racing boats, where the important design criteria are shifted > somewhat toward the safety issues involved. And so on onto flatwater/sprint > racing boats, marathon boats, and so on. > > ---Rsk > Rich Kulawiec > rsk_at_gsp.org > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Fri, Jul 24, 1998 at 08:38:11AM -0700, K. Whilden wrote: > > Rich! Open your mind a little bit, for crying out loud. Julio is obviously > talking about flatwater sprint kayak "race boats", not slalom boats. My mind *is* open. Julio DID NOT specify what kind of boats he meant: he could have meant sprint kayaks, downriver racing boats, open-ocean racing boats, slalom boats, are anything else. By not specifying it, however, he made a blanket statement covering all race boats, and that statement is incorrect...which is why I made the comment that I did. > Do not assume that all "race boats" are slalom boats. I made no such assumption. (Why would I? It would make no sense.) > remember, this is a SEA KAYAK list Oh? Please give the precise location where that's specified. I just retrieved the current copy of the list information (by sending the command "info paddlewise" to majordomo_at_lists.intelenet.net) and I do not see it mentioned there. ---Rsk Rich Kulawiec rsk_at_gsp.org *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Julio wrote; > >Racing is different because races normally take place in ideal and >controlled conditions. Racing boats are not designed to roll and move around >rocks and waves, neither racing paddles. Racing gear is designed to >maximize the efficiency of the human body motion to move forward in >ideal conditions. If the conditions were variable, race results could >not be compared against each other, and one wave would determine who >is first and second in a race regardless of the quality of the athelete. I question whether racing is only for ideal conditions. There are a number of open water races Dan certainly whitewater racing includes plenty of rocks, manoeuvring etc. The Caveman put out a video of racing across the Molokai Channel. Would you call those ideal conditions? I am not yet convinced that ones opinion on these things constitutes proof of anything. Basically Julio's opinion could be sound but someone else with as good as or better credentials could have (and do have) opposing opinions. I guess I must be from Missouri. One should have to prove a thing not just state it is so unless it is prefaced with a disclaimer that it is purely opinion in which case one can take or leave it. Not so? > >> In other words you are saying that the Greenland paddle works like a wing >> except in a horizontal direction instead of vertically? > >The lift of the wing has a vertical and a horizontal component. >The vertical component is upward in wing paddles, and downward in >Greenland paddles, unless they are use for sculling or bracing. How do you know this? If the lift is downward how does it pull the boat forward? Maybe using Cartesian co-ordinates would clarify what you are saying. > >> Suppose someone said that they had done this test already and discovered >> it was not valid? > >Then I would be happy to know that I do not have to do that test myself. >Has it really happened? Could you give me a pointer to the tests so >I can find out what, and how, they were testing. Could explain >why the test, or the idea of the NACA profiles was not valid. I was just asking what your response would be not suggesting that such a test had been done (it may have been) . The reason I ask is that a lot of the Greenland paddle stuff has the appearance (to me anyway) of a lot of subjective opinion masquerading as fact. What I am seeking are quantifiable facts. If there are none it is not a sin but at least one knows what kind of credibility to attach to the opinions. This, of course is not to say that you would respond that way since I suspect that you would prefer facts as well. In the meantime Fluid Dynamic Drag by Hoerner and Theory of Wing Sections by Abbott and Doenhoef might be a good place to start. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Fri, 24 Jul 1998, John Winters wrote: > Julio wrote; SNIP > > > >The lift of the wing has a vertical and a horizontal component. > >The vertical component is upward in wing paddles, and downward in > >Greenland paddles, unless they are use for sculling or bracing. > > How do you know this? If the lift is downward how > does it pull the boat forward? Maybe using Cartesian co-ordinates would > clarify what you are saying. Julio did use cartesian coordinates! He said the vertical component of lift is in the downward direction. This would necessarily imply that the horizontal component of the lift (i.e. the one that does the work) is in the horizontal direction... at least on this planet. > I was just asking what your response would be not suggesting that such a > test had been done (it may have been) . The reason I ask is that a lot of > the Greenland paddle > stuff has the appearance (to me anyway) of a lot of subjective opinion > masquerading as fact. What I am seeking are quantifiable facts. If there > are none it is not a sin but at least one knows what kind of credibility to > attach to the opinions. Oh is it facts that you seek? In whose opinion are facts actually facts? Yours? Maybe we should add a disclaimer to the bottom of the Paddlewise trailer which says that all facts are provisional until approved by Mr J. Winters. :) That last bit definitely touches a sore spot for me. There are very few quantitative data in kayaking, except in the simplest possible situations, and when there are quatifiable data, there is not much of a peer review process so one must be cautious of calling anything "fact". But even without little gauges and dials measuring things, it is quite possible for someone to give a purely subjective opinion which closely approximates physical truth. Indeed, I think that kayaking is such a complex combination of static and dynamic processes, that quantitative modeling is rather pointless. A red flag goes up for me whenever I see too much importance placed on so-called quantitative facts. I think too little importance is placed on trial and error in kayak and paddle design. Eskimos spent generation after generation of trial and error in kayak and paddle design, and for them it was more than a hobby, it was their livelihood. As far as I know, no current designer can accurately predict all handling characteristics of a kayak with computer programs alone. Current designers spend plenty of time testing their boats on the water too. Not too many quantifiable facts there... Having said that, I am currently in the market for a nice kayak design program that will make a model of boat from cross sections, and then calculate static righting moments from varying degrees of heel or pitch. Is there any freeware of this sort? Knowing when to apply a computer is as important as know how to apply one. Cheers, Kevin > > This, of course is not to say that you would respond that way since I > suspect that you would prefer facts as well. > > In the meantime Fluid Dynamic Drag by Hoerner and Theory of Wing Sections > by Abbott and Doenhoef might be a good place to start. > > Cheers, > John Winters > Redwing Designs > Specialists in Human Powered Watercraft > http://home.ican.net/~735769/ > > > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
At 07:07 AM 7/23/98 -0400, John Winters wrote: > >I am not sure why racing needs to be different. If you run do you not run? >Do you learn inefficient running because you don't race? Ditto with skiing? >Maybe the requirements are more extreme but does it make sense to try learn >the skill properly no matter what you are doing? > > When you run, you use a different technique if you are a sprinter or a marathon runner--or somewhere in the middle. When you race road bikes or mountain bikes, or tour on either, you use a different technique. In both cases the appropriate technology is important (spikes make piss poor road shoes). Which paddle is appropriate technology? Which stroke style is the right one for me piddling around the marsh? I dunno. I don't care. Neither does the "average three rides a week, 60 miles tops" cyclist, or "fitness" runner. Comfort, both psychological and physical, is the main concern. We want the exercise, but we want to use something we are comfortable using. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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