Thank you for your responses and I apologise to John Winters for bringing up a subject that has "gone around and around". I have just discovered this paddle and am very enthusiastic about what it offers. If it is all a bit mundane, excuse me for I know not until told. I think this paddle offers more than just " possible improvement in rolling ability." For exposed ocean paddling - shore exploration - there is the important category of support. To be in close to shore in rough water with incoming and rebound making conditions jumpy, this paddle is rock solid. Not relying on the water surface but down under where a simple scull is like a hand on the dock. Being able to skull 360 almost as slowly you want is a real treat. Yes, some rolls are very easy but the support is a very important area of ones paddling abilities that will keep you from having to roll. I gave my paddle to a friend who is a very good paddler. He tried some of the rolls and support strokes and the first thing he said was "it's too easy". A possible hint why women take to it. I live on Vancouver Island. We have the whole range of sea conditions here, so a good repertoire with your paddle is a good idea. I have been using this paddle for a couple of months now. It is true, one must give it some time. I think it was Chuck Holst who called it a 'variable length paddle'. Very apt. I took a clinic with Derek Hutchinson a few years back and was introduced to extended paddle use. I now see where Derek got this from and the altered hand position. My second question about bouyancy and possible throw weight/swing weigh was more a confused intuitive thing. It still may be! I will try again. But does the fact the blade in the water is supporting its' own weight shift the center of this throw weight/swing weight to the inboard hand. The hand position for the Greenland paddle is about shoulder width. This hand is near the centre of the boat during a good portion of the stroke.There must be some force change between holding a lever and then pushing on it. When pushing you no longer have to actively hold it up. I am obviously not a physicist. All this may be looking for something that isn't really there because I am trying to answer a subjective observation. That being - the weight increase with this new paddle didn't seem to bother me as much I thought it should. Here's to clouds in my brain Terry *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Gordon wrote; >Thank you for your responses and I apologise to John Winters for bringing >up a subject that has "gone around and around". I have just discovered this >paddle and am very enthusiastic about what it offers. If it is all a bit >mundane, excuse me for I know not until told. No apology needed. As you will note some opinions have changed since the last time this went around. That is why we go round and round. One of the nice things is that one can change one's opinion went confronted with new evidence. Not being bound to a particular opinion is a blessing. So far I have seen no reason why a Greenland style paddle is better than a modern style of paddle. Everything that the Green land paddle users claim they can do I have done or seen done by someone using a modern style of paddle. That does not mean that everyone should rush out an trash their paddles. Check out Nick's discussion of "Purity" etc. If a person likes something that is fine. However, if he/she manufactures specious arguments to support their preference they only kid themselves and others. It seems to me that a personal preference is a personal preference and not the same thing as, for example, Bruce's discussion of the physical phenomenon. Let me cite an example. Much is made of the East Greenland sliding stroke as if it has something to do with the paddle. Surprise! I use it regularly with my super lightweight Lightning paddle. I also scull with my paddle. I paddle a variety of areas and experience a wide range of conditions with my modern paddle. It also takes time to learn to use it properly. I say all this not to make fun of anyone but to point out that the magic in the Greenland paddle may be in the mind (a good place for magic). The question is, are there physical reasons why the Greenland (or any paddle) is better? If so, what are they? It is my experience that they do roll better but then, I don't capsize. :-) Other than that, what are the advantages and what can you do with them that you can't do with a lighter, shorter, more efficient modern paddle? Just asking folks? 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 Tue, 21 Jul 1998, John Winters wrote: > If so, what are they? It is my experience that they do roll better but > then, I don't capsize. :-) Other than that, what are the advantages and > what can you do with them that you can't do with a lighter, shorter, more > efficient modern paddle? I can only do one handed, (with help of the paddle as bouyancy) rolls with the greenland. None of my other paddles have sufficient bouyancy. I also haven't done well doing a sculling roll with anything but the greenland. I suppose you meant skills for those of you who don't capsize.... For longer distance paddles I find I tire differently using the Greenland than using one of my modern paddles (wing, ultralight lightening, or bow). I tend to wear out the muscles in my shoulders and hands using a larger bladed paddle. With the Greenland I run out of energy before any particular muscle starts to give in. A few weeks ago I tried an aleut paddle, it too was different (very little blade flutter), sometime I'll have to make one to add to my paddle choices. The paddle blades on the Aleut paddle have a center ridge and are concave on both sides of the ridge. Anyone on the use an Aleut paddle? If so any comments? kirk *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
In a message dated 98-07-21 08:12:43 EDT, 735769_at_ican.net writes: << ...what are the advantages and what can you do with [Greenland paddles] that you can't do with a lighter, shorter, more efficient modern paddle? >> One advantage for me is that I can cruise all day with a Greenland paddle and not feel too awfully beat up, where my Lendal Archipelago will trash my arms and shoulders after a long paddle. Maybe that's my technique or stroke or something --- and I'm not a fanatic about Greenlands. Maybe they're more just forgiving of a lousy stroke. Bottom line for me --- they work. Joq *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Joq wrote; << ...what are the advantages and what can you do with [Greenland paddles] that you can't do with a lighter, shorter, more efficient modern paddle? >> >One advantage for me is that I can cruise all day with a Greenland paddle and >not feel too awfully beat up, where my Lendal Archipelago will trash my arms >and shoulders after a long paddle. Maybe that's my technique or stroke or >something --- and I'm not a fanatic about Greenlands. Maybe they're more just >forgiving of a lousy stroke. Bottom line for me --- they work. > I can do the same thing with my paddle. I think if I knew why a paddle "worked" for me then I would be able to find a paddle that may "work" even better. Not a big deal to you young strong men and women but a big deal to old farts like me who really do need more efficient boats and paddles just to keep up. Without them we may as well paddle solo and then we get chewed out for taking such big risks. Kirk wrote; >I can only do one handed, (with help of the paddle as buoyancy) rolls with the greenland. None of my other paddles have sufficient bouyancy. I also haven't done well doing a sculling roll with anything but the greenland. Have you tried it with a higher volume modern paddle? Say one with an airfoil shape as opposed to the flat blades most have? Maybe you should keep building Euro style blades until you get one that really fits. :-) >I suppose you meant skills for those of you who don't capsize.... >For longer distance paddles I find I tire differently using the Greenland >than using one of my modern paddles (wing, ultralight lightening, or bow). >I tend to wear out the muscles in my shoulders and hands using a larger >bladed paddle. With the Greenland I run out of energy before any particular >muscle starts to give in. Nahh. Why not include those who capsize a lot too? I find I tire faster with the Greenland style. Why? Maybe because my blade (Modern) is the right size, my paddle is lighter, my shaft is the right flexibility, and who knows what? That, of course, is the question. Why? If we knew why the Greenland paddle was so good then Hank and his minions could make a modern paddle that was better. Or then, are we saying that there is nothing and can be nothing better? Gordon wrote about art and science. Why are the two separate? Is asking why a thing is as it is an affront to art? Will not art stand up to questioning? Maybe art is and science tries to explain why it is. Is that bad? Julio wrote; >Greenland paddling is just a style of paddling. The paddle is different, >as well the strokes, and the things that people do with them. There is >as much reason to say that one style is better than another as there is >to say that wering a green shirt is better than wearing a blue one. But why? Why can't you do the same style of paddling with a modern blade? Why is the one better than the other? >The Greenland style paddle moves in smaller circles than the modern one. >A wing paddle is most effective when held vertical to the water, and >that blade goes from that high position to below the water level on >the other side. A Greenland paddle just jets a few inches over the water >before it dives again, that is why it takes less work. You will have to explain this to me. If the lower style is more efficient (less work) why do racers paddle differently? Seems to me they would want to do less work. There are those who paddle very upright and find it more relaxing than the low style. How is this explained. I have heard here that people just have to give the Greenland paddle a chance. Isn't the opposite true? Dana wrote; >I have been using a Greenland paddle for quite a few years and each time it >amusing to me on the merits given to it by people just discovering it. Yes >it takes less energy to use,cause your stroke is shorter and you pace is 1 >1/2 to twice as fast. The overall sq. inch surface of each blade is close >to most modern paddles. Instead of a stroke from your ankles to your hips, >it is from about your knees to your hips.Some thing long and skinny passes >through water easier than some thing short and fat (that comment resembles >no one in particular). But with all the hype you would think its a modern >miracle but in fact it is a ancient miracle. 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. It seems to me that if the Greenland paddle slips through the water more it must have a lower drag coefficient than the modern style of blade. If so, why can't the modern style be made smaller yet so it will have the same net drag but will have a smaller blade and be lighter than the Greenland style? Another puzzle. The Greenland stroke is wide (well away from the side of the boat) as such does it not tend to cause more turning and thus waste energy that would be spent on propulsion forward? Just asking. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>Dana wrote; > >>I have been using a Greenland paddle for quite a few years and each time >it >>amusing to me on the merits given to it by people just discovering it. Yes >>it takes less energy to use,cause your stroke is shorter and you pace is 1 >>1/2 to twice as fast. The overall sq. inch surface of each blade is close >>to most modern paddles. Instead of a stroke from your ankles to your hips, >>it is from about your knees to your hips.Some thing long and skinny passes >>through water easier than some thing short and fat (that comment resembles >>no one in particular). But with all the hype you would think its a modern >>miracle but in fact it is a ancient miracle. > >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. It seems to me that if the Greenland paddle slips >through the water more it must have a lower drag coefficient than the >modern style of blade. If so, why can't the modern style be made smaller >yet so it will have the same net drag but will have a smaller blade and be >lighter than the Greenland style? Another puzzle. The Greenland stroke is >wide (well away from the side of the boat) as such does it not tend to >cause more turning and thus waste energy that would be spent on propulsion >forward? > >Just asking. > > Some things just can't be proved so you have to have faith. With out it , well lets just say who cares. Next subject Dana *************************************************************************** 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 asks some good questions; here are my answers: John Winters wrote: > ... If the lower style is more efficient > (less work) why do racers paddle differently? Seems to me they would want > to do less work. There are those who paddle very upright and find it more > relaxing than the low style. How is this explained? The higher angle stroke, when done properly, *is* more efficient, and the difference in efficiency becomes important at race speeds (or when sprinting, for example to catch a wave). However the difference in efficiency is very small at the speeds at which most kayakers cruise. Moreover, the high-angle stroke is somewhat more difficult to master, and if done improperly (or with an improperly sized paddle) there is a significant reduction in efficiency gain. With sufficiently poor technique (or with a sufficient error in paddle sizing) the "gain" may be negative, and the Greenland paddle may actually result in less work. John also asks: > > 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? It doesn't use less energy, it uses more energy, but the difference is trivial. Proponents of Greenland paddles point out that the effect of the slippage is to mimic the effects of using a "lower gear" in cycing, reducing stress. I say "mimics" because it is not quite the same--there is no slippage when using a lower gear on a bicycle. A more efficient way of reducing the "gear" of your paddle is to use a shorter shaft (but with a modern blade), in combination with a more vertical stroke. But again, the difference in efficiency is trivial for most folks. > It seems to me that if the Greenland paddle slips > through the water more it must have a lower drag coefficient than the > modern style of blade. If so, why can't the modern style be made smaller > yet so it will have the same net drag but will have a smaller blade and be > lighter than the Greenland style? It could, but the cost of customizing the grip size, etc., for each individual paddler would be prohibitive. A very substantial advantage of the Greenland paddle is that it is possible to make and modify such a paddle at very low cost. One can get a paddle that is highly customized. The cost of producing "one-off" modern paddles is much higher. I'm sure that there are many folks who have a great time making and customizing their Greenland paddles. In the end they have something that works quite well, even if there is some (trivial) loss in efficiency. Moreover, there may be some gain in ease of rolling (as you acknowledge). So you end up with a low-cost, highly customized paddle that is fun to make, easy to use, nearly as efficient as a modern paddle, and facilitates rolling. What is it again that you don't understand? > Another puzzle. The Greenland stroke is > wide (well away from the side of the boat) as such does it not tend to > cause more turning and thus waste energy that would be spent on propulsion > forward? Absolutely. Although once again it is easy to overstate the importance of this at low speeds. (Disclaimer: I use a short, ultralight graphite paddle, and prefer a vertical stroke.) Dan Hagen Bellingham, Washington *************************************************************************** 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 in response to Julio ; > > But why? Why can't you do the same style of paddling with a modern blade? > Why is the one better than the other? 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. 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. > > >The Greenland style paddle moves in smaller circles than the modern one. > >A wing paddle is most effective when held vertical to the water, and > >that blade goes from that high position to below the water level on > >the other side. A Greenland paddle just jets a few inches over the water > >before it dives again, that is why it takes less work. > > You will have to explain this to me. If the lower style is more efficient > (less work) why do racers paddle differently? Seems to me they would want > to do less work. There are those who paddle very upright and find it more > relaxing than the low style. How is this explained. I have heard here that > people just have to give the Greenland paddle a chance. Isn't the opposite > true? 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. If you want to race use race equipment, if you want to paddle in the Greenland style use Greenland paddles and kayaks. Hybrid possibilites are not ruled out, anyone does what he/she likes. > 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. 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. > It seems to me that if the Greenland paddle slips > through the water more it must have a lower drag coefficient than the > modern style of blade. If so, why can't the modern style be made smaller > yet so it will have the same net drag but will have a smaller blade and be > lighter than the Greenland style? 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. 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) > Another puzzle. The Greenland stroke is > wide (well away from the side of the boat) as such does it not tend to > cause more turning and thus waste energy that would be spent on propulsion > forward? 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. You can try to paddle with a 2x4 piece of lumber, which effectively is a Greeland paddle that does not have the foil shape yet. That experiment should convince you of that the key to Greenland paddling is the foil shape. 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. - Julio (having a lot of fun with this discussion :-) ) *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>> Another puzzle. The Greenland stroke is >> wide (well away from the side of the boat) as such does it not tend to >> cause more turning and thus waste energy that would be spent on propulsion >> forward? > >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. > >You can try to paddle with a 2x4 piece of lumber, which effectively is >a Greeland paddle that does not have the foil shape yet. That experiment >should convince you of that the key to Greenland paddling is the foil shape. > >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. > >- Julio (having a lot of fun with this discussion :-) ) > OK yall have worn me down, I just can't paddle with a paddle that the blades are crooked, so I paddle with unfeathered paddles buuuuuttt the wind was a bear so I went to but a little dipper but at $180 I freaked and yanked a 2x4 out of the back of my pickemup truck pulled out my 8" pocket knife ( I left the small one at home) and wittled me a paddle. Because the 2x4 is 3 1/2 x 1 1/2 I could not make a blade bigger than that with out some glue and all I had in da truck was 16 penny nails. I don't know if them greenlanders had 2x4's up there but we do down here and they make good paddles. They help with shoulder problems, wrist problems, back problems, money problems and coordination problems. So what do yall's paddle do for you? Dana *************************************************************************** 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 11:59 AM -0700 7/22/98, Julio MacWilliams wrote: > >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. > >You can try to paddle with a 2x4 piece of lumber, which effectively is >a Greeland paddle that does not have the foil shape yet. That experiment >should convince you of that the key to Greenland paddling is the foil shape. > >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. > This concept has been brought up before. The idea that the greenland paddle uses lift to propel the boat just makes no physical sense. The paddle just does not move far enough laterally through the water to provide significant lift. It, like most paddles is being used primarily as a parachute, not a wing. Try paddling by only moving your hands up and down - no forward-backwards motion, no body rotation. In other words do your best imitation of a airplane propeller. You will be able to move yourself, but not as effectively as if you just pull. The greenland paddle is an efficient wing in long sweeps where the blade is slicing through the water. While paddling this is just the up-and-down component of the motion, which given, the low hand possition is intentionally small. Little motion = little lift => not much power. The wing paddle is much better at this. The paddle is pushed deep and then swung out to the side. There still is not a huge amount of lift provided, but enough to improve it's overall efficiency. Nick Schade Guillemot Kayaks c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222 (603) 744-6872 Schade_at_guillemot-kayaks.com http://www.guillemot-kayaks.com/ >>>>"It's not just Art, It's a Craft!"<<<< *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Nick, It sounds like you have never used a greenland paddle properly, so let me answer a few things. ___________________ / Kevin Whilden \ |Dept. of Geosciences \___ |University of Washington \ |kwhilden_at_u.washington.edu| \________________________/ On Thu, 23 Jul 1998, Nick Schade wrote: > At 11:59 AM -0700 7/22/98, Julio MacWilliams wrote: > > > >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. SNIP > > This concept has been brought up before. The idea that the greenland paddle > uses lift to propel the boat just makes no physical sense. The paddle just > does not move far enough laterally through the water to provide significant > lift. It, like most paddles is being used primarily as a parachute, not a > wing. > This is simply not true. I have a degree in physics as well, and it makes perfect physical sense to me. The greenland paddle in its three main varieties of strokes has a high lateral component of velocity at the ends of the paddle. With the proper angle of attack and with a well constructed foil shape, there is laminar flow across the paddle, and lift is generated in the opposite direction of which the paddle is being pulled. Learning how to make the lateral velocity of the paddle fast enough to generate lift takes a fair bit of practice -- I can do it reliably in two of the three kinds of strokes. Come to Seattle and I'll show you. Greenland paddles generate lift. > Try paddling by only moving your hands up and down - no forward-backwards > motion, no body rotation. In other words do your best imitation of a > airplane propeller. You will be able to move yourself, but not as > effectively as if you just pull. This is not the same physical scenario as a wing paddle. Now if you swung your arms sideways out and in from the boat, with the hands cupped, then it would be the same. Kind of a dumb concept however, because your arms will never generate as much power as a paddle. > > The greenland paddle is an efficient wing in long sweeps where the blade is > slicing through the water. While paddling this is just the up-and-down > component of the motion, which given, the low hand possition is > intentionally small. Little motion = little lift => not much power. The paddle is indeed held low, however the hands are also held quite close together, so relatively little vertical hand motion is needed to make the ends of the paddle travel quite fast laterally. My paddle generates lift as I slice it downwards, and then again as I slice it upwards. This is in the high cadence "cruising" stroke that I defined in a previous post. > > The wing paddle is much better at this. The paddle is pushed deep and then > swung out to the side. There still is not a huge amount of lift provided, > but enough to improve it's overall efficiency. > There is enough lift generated to make the paddle leave the water technically farther ahead of the point that it was planted. There have been video studies that proven this, I have heard from racing friends. Greenland paddles can be used in the modern style of wing paddles... I call it the "racing" stroke. I use it to accelerate to catch waves. It's fun to talk physics regarding paddles. Cheers, Kevin > > > > Nick Schade > Guillemot Kayaks > c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222 > (603) 744-6872 > > Schade_at_guillemot-kayaks.com > http://www.guillemot-kayaks.com/ > > >>>>"It's not just Art, It's a Craft!"<<<< > > > *************************************************************************** > 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/ ***************************************************************************
Yes, there is lift. However, Nick is saying that the lift contribution to forward motion is very small, which seems to be a valid claim. The effects of the lift are dramatic when doing rolls, braces, and sculls, but even though one can feel the lift also when paddling forward, that lift is much smaller than when doing rolls. There has to be something else going on that makes the Greenland stroke so powerful, as it is hard to believe that such a thin stick would move you forward at all. Maybe the combination of foil shape and narraw blade creates a fast eddy around the paddle that provides the mass*velociy factor necessary to provide a good momment of inertia to the kayak (m*v = M*v') Whatever it is, the Greenland paddle works incredibly well, but the real reason why remains a mystery. If there is ever some serious scientific study aimed at improving or refining Greenland paddles, then we might know. - Julio K in response to Nick wrote: > > This concept has been brought up before. The idea that the greenland paddle > > uses lift to propel the boat just makes no physical sense. The paddle just > > does not move far enough laterally through the water to provide significant > > lift. It, like most paddles is being used primarily as a parachute, not a > > wing. > > > > This is simply not true. I have a degree in physics as well, and it makes > perfect physical sense to me. The greenland paddle in its three main > varieties of strokes has a high lateral component of velocity at the ends > of the paddle. With the proper angle of attack and with a well constructed > foil shape, there is laminar flow across the paddle, and lift is generated > in the opposite direction of which the paddle is being pulled. Learning > how to make the lateral velocity of the paddle fast enough to generate > lift takes a fair bit of practice -- I can do it reliably in two of the > three kinds of strokes. Come to Seattle and I'll show you. Greenland > paddles generate lift. > > *************************************************************************** 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 and Nick, I do not understand why the lift generated by Greenland paddles must necessarily be small. My fluid dynamics is pretty weak, but if someone wants to give me the calculations of the lift force vs. the drag force, I would be very appreciative. I tend to think of the so-called "lift" force as this... -- Consider pulling the greenland paddle straight back, with no lateral motion whatsoever, and therefore no lift force will be generated. There is a very noticeable slippage through the water. -- Now consider paddlingg with proper technique and plenty of lateral motion. The paddle feels like it is planted in cement. -- The difference in power between the two scenarios is very remarkable indeed, and the difference in physics is that the latter has laminar flow across a foil while the former does not. -- I interpret this difference as the lift force. I call it lift because whatever force causes the "cement" effect, it appears to be derived from the laminar flow of water across the foil shape of the paddle, and in general, laminar flow across a foil always produces lift. I guess as a scientist-type, lift seems the most plausible explanation, and I will not change my theory until I see proper quantitative evidence otherwise, or until a more plausible theory appears. Now also let me say that my book on swimming technique gives me a lead on a possible alternative theory, and I might investigate a little bit, although my initial appraisal says that it probably applies to a different physical mechanism than the one currently in question. I hope that we can paddle together sometime. Cheers, Kevin /--------------------------------------------\ /---------------------------\ |Something there is that doesn't love a wall | Kevin Whilden | |That sends the frozen-ground-swell under it | kwhilden_at_u.washington.edu | |And spills the upper boulders in the sun | Dept. of Geologic Science | |And makes gaps that even two can pass abreast| University of Washington | | -- Robert Frost |(206)543-1975(w) 632-5140(h)| \--------------------------------------------/ \---------------------------/ On Thu, 23 Jul 1998, Julio MacWilliams wrote: > Yes, there is lift. However, Nick is saying that the lift contribution > to forward motion is very small, which seems to be a valid claim. > > The effects of the lift are dramatic when doing rolls, braces, and sculls, > but even though one can feel the lift also when paddling forward, > that lift is much smaller than when doing rolls. > > There has to be something else going on that makes the Greenland > stroke so powerful, as it is hard to believe that such a thin stick > would move you forward at all. > > Maybe the combination of foil shape and narraw blade creates a fast > eddy around the paddle that provides the mass*velociy factor necessary > to provide a good momment of inertia to the kayak (m*v = M*v') > > Whatever it is, the Greenland paddle works incredibly well, but > the real reason why remains a mystery. > > If there is ever some serious scientific study aimed at improving or > refining Greenland paddles, then we might know. > > - Julio > > K in response to Nick wrote: > > > > This concept has been brought up before. The idea that the greenland paddle > > > uses lift to propel the boat just makes no physical sense. The paddle just > > > does not move far enough laterally through the water to provide significant > > > lift. It, like most paddles is being used primarily as a parachute, not a > > > wing. > > > > > > > This is simply not true. I have a degree in physics as well, and it makes > > perfect physical sense to me. The greenland paddle in its three main > > varieties of strokes has a high lateral component of velocity at the ends > > of the paddle. With the proper angle of attack and with a well constructed > > foil shape, there is laminar flow across the paddle, and lift is generated > > in the opposite direction of which the paddle is being pulled. Learning > > how to make the lateral velocity of the paddle fast enough to generate > > lift takes a fair bit of practice -- I can do it reliably in two of the > > three kinds of strokes. Come to Seattle and I'll show you. Greenland > > paddles generate lift. > > > > > > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
My thought why the greenland paddle works so well is: kayaks are easy boats to propel. Once you get them moving, you don't need a powerful grip in the water to keep them going. Since the energy wasted is a function of v^2, if you don't have to push the water very hard, you don't waste a lot of energy. I would not want to move an oil barge with any kind of paddle. Kayaks are good boats, thats why the paddle works so well. At 4:17 PM -0700 7/23/98, Julio MacWilliams wrote: >Yes, there is lift. However, Nick is saying that the lift contribution >to forward motion is very small, which seems to be a valid claim. > >The effects of the lift are dramatic when doing rolls, braces, and sculls, >but even though one can feel the lift also when paddling forward, >that lift is much smaller than when doing rolls. > >There has to be something else going on that makes the Greenland >stroke so powerful, as it is hard to believe that such a thin stick >would move you forward at all. > >Maybe the combination of foil shape and narraw blade creates a fast >eddy around the paddle that provides the mass*velociy factor necessary >to provide a good momment of inertia to the kayak (m*v = M*v') > >Whatever it is, the Greenland paddle works incredibly well, but >the real reason why remains a mystery. > >If there is ever some serious scientific study aimed at improving or >refining Greenland paddles, then we might know. > >- Julio > >K in response to Nick wrote: > >> > This concept has been brought up before. The idea that the greenland >>paddle >> > uses lift to propel the boat just makes no physical sense. The paddle just >> > does not move far enough laterally through the water to provide >>significant >> > lift. It, like most paddles is being used primarily as a parachute, not a >> > wing. >> > >> >> This is simply not true. I have a degree in physics as well, and it makes >> perfect physical sense to me. The greenland paddle in its three main >> varieties of strokes has a high lateral component of velocity at the ends >> of the paddle. With the proper angle of attack and with a well constructed >> foil shape, there is laminar flow across the paddle, and lift is generated >> in the opposite direction of which the paddle is being pulled. Learning >> how to make the lateral velocity of the paddle fast enough to generate >> lift takes a fair bit of practice -- I can do it reliably in two of the >> three kinds of strokes. Come to Seattle and I'll show you. Greenland >> paddles generate lift. >> >> Nick Schade Guillemot Kayaks c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222 (603) 744-6872 Schade_at_guillemot-kayaks.com http://www.guillemot-kayaks.com/ >>>>"It's not just Art, It's a Craft!"<<<< *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Dan wrote; First, Dan, thanks for responding to my questions without getting your shorts in a knot. Some Greenland paddle users have not been so helpful. (SNIP) >The higher angle stroke, when done properly, *is* more efficient, and >the difference in efficiency becomes important at race speeds (or when >sprinting, for example to catch a wave). However the difference in >efficiency is very small at the speeds at which most kayakers cruise. >Moreover, the high-angle stroke is somewhat more difficult to master, >and if done improperly (or with an improperly sized paddle) there is a >significant reduction in efficiency gain. With sufficiently poor >technique (or with a sufficient error in paddle sizing) the "gain" may >be negative, and the Greenland paddle may actually result in less >work. Good point but isn't the same true for the Greenland paddle? Seems to me (and the comments about building many Greenland paddles until you get it right bear it out) that sizing the paddle is important. Also it seems that it is very important to do the Greenland stroke correctly if one accepts what people have said here about learning how to do it properly. I recall people even suggesting a video so you could see how it should be done. >John also asks: >> >> 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? > >It doesn't use less energy, it uses more energy, but the difference is >trivial. Proponents of Greenland paddles point out that the effect of >the slippage is to mimic the effects of using a "lower gear" in cycing, >reducing stress. I say "mimics" because it is not quite the same--there >is no slippage when using a lower gear on a bicycle. A more efficient >way of reducing the "gear" of your paddle is to use a shorter shaft (but >with a modern blade), in combination with a more vertical stroke. But >again, the difference in efficiency is trivial for most folks. Good point again. But how does this explain the belief that the Greenland paddle has some kind of superiority? If what Dan says is true, it really isn't better at all. It is just different and maybe not so good (from an efficiency standpoint). That isn't the message I have been getting so maybe I am reading the posts wrong? >> It seems to me that if the Greenland paddle slips >> through the water more it must have a lower drag coefficient than the >> modern style of blade. If so, why can't the modern style be made smaller >> yet so it will have the same net drag but will have a smaller blade and be >> lighter than the Greenland style? > >It could, but the cost of customising the grip size, etc., for each >individual paddler would be prohibitive. A very substantial advantage >of the Greenland paddle is that it is possible to make and modify such a >paddle at very low cost. One can get a paddle that is highly >customized. The cost of producing "one-off" modern paddles is much >higher. I'm sure that there are many folks who have a great time making >and customizing their Greenland paddles. In the end they have something >that works quite well, even if there is some (trivial) loss in >efficiency. Moreover, there may be some gain in ease of rolling (as you >acknowledge). So you end up with a low-cost, highly customized paddle >that is fun to make, easy to use, nearly as efficient as a modern >paddle, and facilitates rolling. What is it again that you don't >understand? I am not sure I see this. Yes, making custom one-off paddles is probably prohibitively expensive but making one off wood paddles is pretty much the same in cost regardless of type isn't it? Aside from needing some masking tape and glue the cost of materials is pretty much the same for making both types of paddle isn't it? In fact, if one uses the Culpeper method of making a paddle too large and then cutting it down to size may even be less expensive in the long run. I guess I don't what makes the Greenland paddle better. Is it just because it is easier to make at home? Is that what people have been saying here? > >> Another puzzle. The Greenland stroke is >> wide (well away from the side of the boat) as such does it not tend to >> cause more turning and thus waste energy that would be spent on propulsion >> forward? > >Absolutely. Although once again it is easy to overstate the importance >of this at low speeds. Good point but then why do the users of Greenland paddles claim such efficiency and ease of paddling if it really isn't easier and even if it was easier it can't be noticed or isn't important? Dan seems to point out at least two ways in which the Greenland paddle is less efficient. I will take his word for it that the difference is small for the time being but that doesn't explain why the one group of paddlers feels that the opposite is true and dramatically so. Is it all in the mind? 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/ ***************************************************************************
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