On Friday, June 6, 2003, at 11:34 PM, Michael Edelman wrote: > Nick Shade wrote: - > >> Moving water indicates kinetic energy in the >> water that could have been kinetic energy for >> the kayak. > > Not necessarily. Water moving in the opposite direction of the > movement of the kayak indicates that energy was transferred to the > kayak. We had a lot of discussion some time ago about votex shedding > off the blade and how that contributes to the lift generated by the > paddle. And so on. Yes, absolutely. Any water motion is energy that in a 100% efficient system would have been kayak motion. In real life water motion is inevitable consequence of applying propulsive force against a fluid, but that does not mean it is not lost energy. Vortex shedding may add to lift, but the vortex is still lost energy. This not to say that a paddle that creates a vortex is not more efficient than one that somehow avoids making the vortex, but lost energy is lost energy regardless of the form it takes. 100% efficiency is only possible when pushing against an absolutely stiff object of infinite mass, for our purposes the solid ground of the earth is a reasonable approximation. Poling your kayak would be as close to 100% efficient as is possible. Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 USA Ph/Fx: (860) 659-8847 http://www.guillemot-kayaks.com/ *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sat Jun 07 2003 - 16:56:36 PDT
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