On 07/17/98 14:22:24 you wrote: I've enjoyed the discussion on Greenland paddles and have toyed with the idea of building one myself - but after I build my second wood kayak - one must have their priorities after all ;-) I'd like to address the question about throw-weight or paddle inertia. Its an important question and a potential energy sapper. Physics states that an object moving thru the space will continue in a straight line until a force acts on that object. One of the replies to this question suggested that since the paddle is moving more or less in a circular or elliptical manner without stops, that this "throw-weight" is not important. This is not accurate, paddle inertia is very important. If you tie a string to an object and swing that object around your hand, the centripetal (center-seeking) force provided by your hand to the string (to keep the object from flying out straight is given by Force=(mass)X(velocity squared)/(radius squared). This equation tells us the faster we swing the paddle, the force necessary to hold the paddle will increase rapidly, such as doubling the stroke speed will increase the force required to keep the paddle in its path by a factor of 4. I had an opportunity to test this the otherday. I was out paddling when I met this young couple who were neighbors of mine. The wife had a difficult time keeping up (nice kayak but no upper body strength). I offered to switch paddles with her, which she did, and for the next two hours, I paddled with her beautiful Sawyer paddle and she used my beat-up chipped Eddyline Swift paddle (bought used for $135). The wood paddle felt heavier to me but I really noticed the difference when it was in motion - felt more cumbersome. When she handed it back to me, she took her wood paddle and said, "wow, that's heavier". I had the same reaction, my paddle seemed like a feather after using the Sawyer. Some good things about the wood paddle, it was noticeably warmer than my fiberglass shafted paddle and the varnished finish seemed stickier and much easier to grip than my paddle (can you varnish over fiberglass?) Now, before I get flamed, the greenland paddle is shorter with smaller blades than the Sawyer paddle I had and would obviously be easier to paddle into wind - I can't speak to advantages or disadvantages of Greenland paddle, never used one but I'd like to try one someday. Also, I'm not against wood, I use my Pygmy plywood kayak all the time now because its 11 lbs lighter than my fiberglass Easyrider Eskimo 17', easier to maintain and easier to get on and off my van. Good paddling and may all jetskis run out of gas Phil Baumgaertner Bremerton, WA > >This is a question about Greenland paddles. Maybe Chuck Holst and John >Winter might have something to say. > >Now the questions. By the way the weight doesn't really bother me but >prompted this. >1 Throw wieght-what is it and how is it helpful or a hindrance? > >I'm tired of all this ultralight carbon or flatulium filled with hydrogen >core this and that. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Phil wrote; (Large snip) Let's hear from Bruce on this. I am not convinced that Phil hasn't confused the effect of a heavy paddle on the work he does to support it with the effect of the heavy paddle on the force required to develop power. In other words, what is the effect of weight on developing power as opposed to weight you have to support. I mentioned that heavy paddles were more work but was not convinced they were less efficient in developing power. This may seem like splitting hairs but I don't think so since it goes to the heart of how weight is distributed on the paddle. Suppose we have tow paddles of equal weight but one has most of its weight in the blades and the other has most of its weight in the center of the shaft. Which will be easier to paddle with? Certianly when we wiggle the paddles back and forth the heavier bladed paddle with take more effort since we have to stop and start its motion. Is that the case for the more circular motion of the paddle blade? Certainly the "feel" Phil felt was real but was the feel really of increased paddling effort i.e the increased effort to keep teh blades moving or was it from the added effort to hold the paddle. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/Cheers, *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Paddlewisers: Phil Baumgaertner (pbaum_at_ix.netcom.com) wrote: >I'd like to address the question about throw-weight or paddle inertia. Its >an important question and a potential energy sapper. Physics states that an >object moving thru the space will continue in a straight line until a force >acts on that object. One of the replies to this question suggested that >since the paddle is moving more or less in a circular or elliptical manner >without stops, that this "throw-weight" is not important. This is not >accurate, paddle inertia is very important. It sure is, in my opinion, also, but maybe for different reasons than some have thought about. The paddle seems to be moving in circles (elipses, whatever), but the forces the paddler applies are mostly forward and back, like the piston in a car's engine. I think the start and stop force for overcoming inertia is much greater than most people believe. Momentum *may* get the blades up and down to some extent to start the next stroke (though not much in my opinion), but you do have to exert force to keep the paddle moving and accelerate the blade. The bottom blade actually does essentially stop in the water - the boat moves on past it (hopefully or you are going nowhere fast!) - and the upper blade travels faster to make up for it. Yup, start, stop, start, stop..... The center of the shaft travels the same speed as the boat. If the bottom blade stops, the upper blade has to be traveling at an average of twice the speed of the boat to get ahead for the next stroke. You are accelerating the upper blade of the paddle from a dead stop to twice as fast as the boat (or more for a short period of time). And if you paddle unfeathered, think of the wind resistance! Phil's back onstage: >If you tie a string to an object and swing that object around your hand, the >centripetal (center-seeking) force provided by your hand to the string (to >keep the object from flying out straight is given by Force=(mass)X(velocity >squared)/(radius squared). This equation tells us the faster we swing the >paddle, the force necessary to hold the paddle will increase rapidly, such >as doubling the stroke speed will increase the force required to keep the >paddle in its path by a factor of 4. Yup, acceleration is expensive in energy costs. But, does this matter as much as you think? The paddle shaft has a counterweight at the other end, the string does not. One paddle blade cannot go flying off on the tangent into orbit because of the shaft and the blade on the other end. Drill a hole through the center of the shaft, insert an axle, mount the axle in bearings and give the paddle a spin. It will go in circles until air resistance stops it (meaning pretty soon). Forces keeping the blades together balance so no energy expended in that regard. People don't paddle like this when in a boat, just when standing on the ground. >Some good things about the wood paddle, it was noticeably warmer than my >fiberglass shafted paddle and the varnished finish seemed stickier and much >easier to grip than my paddle (can you varnish over fiberglass?) Yes the cedar strip and stitch and glue canoe/kayak makers do it all the time (several coats, even). John W and others - input on the above physics, please. Thanks, Hank Hays Lightning Paddles *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
We've been through a similar argument before. One of the problems, that John alluded to, is that muscular work can not be calculated like physical work. If you put a weight on a shelf, it can just sit there without the shelf continually doing work on the weight. If you support a weight with a muscle that is not fully extended (i.e. limp) then the muscle must continuously do work, physiological work, to keep itself contracted against the pull of the weight. An analogy might be a leaky tire: it won't stay up unless you keep pumping air into it. If you could support the paddle in some rigid device (think of a double paddle wheel with only one paddle/blade on each side, with one blade up when the other was down), and then move the pair of wheels by turning a crank, the weight of the blades would be unimportant. The weight would be borne by the paddlewheel bearings, whether the wheel were turning or not. But when the wheel is turning, the bearings also need to hold it against vibration because the wheel hasn't enough balance. It needs at least two blades on each side to not vibrate. Because the real paddle is moving in a cone, not a circle, it too will cause reaction against its supports, depending on the weight distribution. (It can't move in a circle, because you're using one blade on each side of the boat.) Thus contrary to John's opinion (and contrary to mine the last time he and I discussed this sort of thing), the weight distribution of the paddle (moment of inertia) is important in the amount of (physiological) work one does, supporting the paddle against its inclination to turn in a disc instead of a cone. In a sense it is the added effort to hold the paddle, but it is the added effort to hold the paddle against this twisting, which depends on the radius of gyration (a measure of the weight distribution) as well as the weight. Hank Hays wrote: [snip] >The bottom blade actually does essentially stop in the water - the boat moves on past it (hopefully or you are going nowhere fast!) - and the upper blade travels faster to make up for it. Yup, start, stop, start, stop..... The center of the shaft travels the same speed as the boat. If the bottom blade stops, the upper blade has to be traveling at an average of twice the speed of the boat to get ahead for the next stroke. You are accelerating the upper blade of the paddle from a dead stop to twice as fast as the boat (or more for a short period of time). And if you paddle unfeathered, think of the wind resistance! [end quote from Hank] The same argument will tell you that a bicycle wheel is also stopping and starting continuously. You need to be working in a coordinate system that is moving with the (mean motion of the) boat. Wind resistance is important, but in the present argument is something of a red herring. But this does indicate the reason for feathered paddles, which we inherit from the flatwater racers. They race only in essentially calm conditions, so if they're going at seven knots, the upper blade of the paddle is feeling a breeze of fourteen knots. Hank again: >Yup, acceleration is expensive in energy costs. But, does this matter as much as you think? The paddle shaft has a counterweight at the other end, the string does not. One paddle blade cannot go flying off on the tangent into orbit because of the shaft and the blade on the other end. Drill a hole through the center of the shaft, insert an axle, mount the axle in bearings and give the paddle a spin. It will go in circles until air resistance stops it (meaning pretty soon). Forces keeping the blades together balance so no energy expended in that regard. People don't paddle like this when in a boat, just when standing on the ground. [end quote from Hank] Thank you, Hank. This illustrates my main argument nicely. If we go back to my paddlewheel analogy, drill the hole obliquely through the centre of the shaft, and see how hard it is to support the bearings. Bruce Winterbon bwinterb_at_intranet.ca http://intranet.ca:80/~bwinterb All states have laws to protect the rich from the poor. Few attempt the more difficult task of protecting the poor from the rich. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Bruce wrote; (Large snips) >Thus contrary to John's opinion (and contrary to mine the last time he and I >discussed this sort of thing), the weight distribution of the paddle (moment >of inertia) is important in the amount of (physiological) work one does, >supporting the paddle against its inclination to turn in a disc instead of a >cone. See how useful it is to have Bruce around. Now this raises a question. Typically wood Greenland style paddles are heavier in the ends (blades) than modern lightweight paddles. Nevertheless, users claim they require less effort to achieve the same result as work than the low aspect ratio modern paddles. What is the explanation for this? 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/ ***************************************************************************
At 06:55 AM 7/21/98 -0400, John Winters wrote: >Bruce wrote; > >(Large snips) > > > >>Thus contrary to John's opinion (and contrary to mine the last time he and >I >>discussed this sort of thing), the weight distribution of the paddle >(moment >>of inertia) is important in the amount of (physiological) work one does, >>supporting the paddle against its inclination to turn in a disc instead of >a >>cone. > > >See how useful it is to have Bruce around. > >Now this raises a question. Typically wood Greenland style paddles are >heavier in the ends (blades) than modern lightweight paddles. Nevertheless, >users claim they require less effort to achieve the same result as work >than the low aspect ratio modern paddles. > >What is the explanation for this? > >Cheers, >John Winters >Redwing Designs >Specialists in Human Powered Watercraft >http://home.ican.net/~735769/ > > >What is the explanation for this? "Karma" is the answer plus the fact that the paddle is held lower for the stroke. With a lower height you don't notice the weight as much. 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 8:40 AM -0400 7/21/98, dldecker_at_mediaone.net wrote: >>What is the explanation for this? > >"Karma" is the answer plus the fact that the paddle is held lower for the >stroke. With a lower height you don't notice the weight as much. > >Dana When I'm just cruising along, I hold my modern blade with my hands right at the coaming, how much lower can you go? I think the height you need to hold your paddle is more a function of the boat than the blade. 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/ ***************************************************************************
At 01:56 PM 7/21/98 -0400, Nick Schade wrote: >At 8:40 AM -0400 7/21/98, dldecker_at_mediaone.net wrote: > >>>What is the explanation for this? >> >>"Karma" is the answer plus the fact that the paddle is held lower for the >>stroke. With a lower height you don't notice the weight as much. >> >>Dana > >When I'm just cruising along, I hold my modern blade with my hands right at >the coaming, how much lower can you go? I think the height you need to hold >your paddle is more a function of the boat than the blade. > > > >Nick Schade >Guillemot Kayaks >c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222 >(603) 744-6872 This is true Nick, you can't go below the coaming with your paddle stroke. It seems a lot of people like to air out their arm pits when they paddle, at least around here. The low coaming kayak is easier with the greenland type paddle than a higher coaming. I will try to paddle below the coaming and let you know if I succeed 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 Winters wrote: (snip) 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. 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. Some people like me have discovered a new universe in Greenland paddling and that is what we like to do. Others live in the world of wing paddles and race kayaks, and do that. There are also the worlds of folding kayaks, sit on top canoes, etc. What I see as a current serious problem is the fact that one can only get ACA certification by showing proper strokes with a modern style paddle. After I get my certification I will be free to teach Greenland style paddling. But in the meam time it sucks that I have to polish my modern paddle strokes just to pass the exam. (in another message John wrote) > heavier in the ends (blades) than modern lightweight paddles. Nevertheless, > users claim they require less effort to achieve the same result as work > than the low aspect ratio modern paddles. > > What is the explanation for this? 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. - 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/ ***************************************************************************
At 01:39 PM 7/21/98 -0700, Julio MacWilliams wrote: >John Winters wrote: > (snip) > 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. > >Greenland paddling is just a style of paddling. >- Julio 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. 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 6:30 PM -0400 7/21/98, dldecker_at_mediaone.net 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. No, it is just a paddle. To paraphrase Freud: "Some times a paddle is just a paddle." 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/ ***************************************************************************
At 04:38 PM 7/22/98 -0400, Nick Schade wrote: >At 6:30 PM -0400 7/21/98, dldecker_at_mediaone.net 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. > >No, it is just a paddle. To paraphrase Freud: "Some times a paddle is just >a paddle." > > > >Nick Schade >Guillemot Kayaks >c/o Newfound Woodworks, 67 Danforth Brook Rd, Bristol, NH 03222 >(603) 744-6872 Gee whiz its just a paddle are you sure?? I don't agree with Freud on a lot of other things either 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/ ***************************************************************************
>Gee whiz its just a paddle are you sure?? I don't agree with Freud on a lot >of other things either Yea, other than the comment I paraphrased, Freud was an idiot. He makes good saw blades tho. 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/ ***************************************************************************
>At 04:38 PM 7/22/98 -0400, Nick Schade wrote: >>To paraphrase Freud: "Some times a paddle is just >>a paddle." ...and sometimes a gator whacker. But a duck can be too. Not as efficient as a greenland paddle though. Y'all gotta come down here 'fore it all burns up. Wynne Americus, GA USA *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
>From Dana, <snip> >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. how many sq. inches of surface area does your Greenland Paddle have? and who knows what is available for small bladed modern paddles? Current Designs offers the Sabella at 84 sq in. http://www.cdkayak.com/paddles.htm what are the alternatives. bye bye bliven *************************************************************************** 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 07:05 PM 7/21/98 -0400, Larry Bliven wrote: >>From Dana, > ><snip> >>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. > >how many sq. inches of surface area does your Greenland Paddle have? > >and > >who knows what is available for small bladed modern paddles? > >Current Designs offers the Sabella at 84 sq in. >http://www.cdkayak.com/paddles.htm > >what are the alternatives. > >bye bye bliven > > My greenland blade is 78 sq inches. and my spare is 84 sq inches per blade. 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 1:39 PM -0700 7/21/98, Julio MacWilliams wrote: >John Winters wrote: > (snip) > 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. > >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. > WHAT DO YOU HAVE AGAINST BLUE? Blue has got been subjugated for too long. People say "I'm feeling blue" as if it is a Bad thing. "Blue bloods" are considered snobs. And, worst, when babies are born blue, extraordinary efforts are made to change there color. Blue has a long and proud tradition. Heck, the sky is blue. Now, those people that wear aqua, they are heretics. Not content with blue, they want to add some green. 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 wrote; >WHAT DO YOU HAVE AGAINST BLUE? Blue has got been subjugated for too long. >People say "I'm feeling blue" as if it is a Bad thing. "Blue bloods" are >considered snobs. And, worst, when babies are born blue, extraordinary >efforts are made to change there color. Blue has a long and proud >tradition. Heck, the sky is blue. > Let's hear it for blue. "She wore blue velvet" (Bobby Vinton?) Raise your voices for the bluebird of happiness, blues and Billie Holliday, and blueberries. What's wrong with blue chip stocks, blue cheese, blue collar workers, didn't the Blue Jays win it all a couple of times, and where else would you rather be than Blue Bayou? Blue laws, blue stockings and bluenoses are anathema? Lets' fly the blue peter for the Blue Ridge Mountains and all bow down to Blue Tezcatlipoca. Three cheers for true blue. I hate red. 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/ ***************************************************************************
I'd like to return to the argument about imbalance and the cost of reaction against it. Recall Hank's suggested thought-experiment of drilling through the centre of a paddle shaft and putting an axle in there. Then we can easily spin the paddle on that axis. But if the hole is drilled obliquely, at such an angle that the axle is horizontal and each blade dips into the water on its own side of the boat, it's hard to hold that axle steady, and the faster the paddle is turning, the harder it is. Normally (except when we're trying to roll?;-) the paddle blade barely dips below the surface, so if our hands are held low, the blade is well out from the boat, and for an "efficient" vertical stroke our hands ar held higher. The higher our hands are, and the faster the stroke, the more physiological work we are doing to support the paddle against both gravity and its own angular momentum. This is in a sense work at zero efficiency, because it's only the part of the work that we do to support the paddle, the part that would not be work if we rigged up some sort of mechanism to hold the paddle. Thus we do less work by lowering the hands (gravity: independent of speed), or by making the stroke more vertical (reaction against turning: increases rapidly with speed). For any cadence, then there is a paddling angle, the point we choose between a vertical and a horizontal stroke, for which the amount of physiogical work in holding the paddle is a minimum. If I'm touring along the edge of a marsh looking at dragonflies, my least-work stroke will be nearly horizontal. Passing a less-interesting bit of shore, my stroke rises a bit, and when I notice the thunderclouds overhead, it becomes nearly vertical. A lot of work has shown that animals (including people) automatically change gaits, as their speed varies, to minimize physiological work, measured as oxygen consumption. As the treadmill speeds up, we break from walk to run. But we know that animals can be taught to hold a specific gait even when it costs more -- race walkers and trotting horses are examples. Paddling is not an inborn activity; we need to consciously learn it. Some of us learn to do it in a specific way, and others "listen" to our bodies more, and automatically vary our "gaits". There have been comments that could be summarized as "Shut up and paddle". But when we paddle, sometimes we let our minds go blank, sometimes we enjoy our surroundings, and sometimes try to improve our technique. Trying to analyze what we are doing, and how it could be done better, whatever we choose "better" to mean, is a legitimate part of paddling, provided it does not become obsessive. And, as has been pointed out, if it is obsessive when we're off the water, so what? What better coiuld we be doing? Besides, as we age we must substitute better technique for waning strength, or, perish the thought, slow down. Bruce Bruce Winterbon bwinterb_at_intranet.ca http://intranet.ca:80/~bwinterb All states have laws to protect the rich from the poor. Few attempt the more difficult task of protecting the poor from the rich. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
This archive was generated by hypermail 2.4.0 : Thu Aug 21 2025 - 16:32:50 PDT