Nick wrote: > Changing the size of the blade does not change the gear ratio. The > "gear ratio" is only related to the length of the paddle. Changing the > size of the blade changes the speed at which it moves through the > water, in other words it changes its efficiency. This is more analogous > to having a bicycle chain skip or jump on the gears or having the gear > rotate slightly relative to the peddle. Changing the blade size does > effect the perceived gear ratio because for a given cadence it will > take less force, and for a given force it will require a higher cadence. Didn't we thrash this to death last year? ;-) There's a conceptual confusion between the notions of biomechanical efficiency (translating muscle power into propulsion), paddle "efficiency" (translating swept are into propulsion) and mechanical advantage (paddle as lever). I think I noted back then that the "efficiency" of coupling the paddle to the water does *not* equate to efficiency in converting muscle power to propulsion (biomechanical efficiency). Two different things. A small blade doesn't move as much water with each stroke as does a large blade, but at the same time, it doesn't require as much energy input to move through the water. So yes, enlarging the blade has the same end result as does lengthening the paddle: It increases *both* the energy in and propulsion out for a given swept area, even though it accomplishes it in a different way. And both are indeed similar to changing gears on the bike. Shrink the blade or shorten the arm, and you increase the rate to get the same propulsive force over time. And that brings us to biomechanical efficiency. By experimenting with the tradeoff between blade size/paddle length and rate, you can find the optimum combination for you to transfer maximum power *over time*. -- mike ------------------------- Michael Edelman medelman_at_ameritech.net http://www.foldingkayaks.org http://www.findascope.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 Fri Jun 06 2003 - 14:18:55 PDT
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