Brian wrote; - >Would anyone know the effect of adding weight to a kayak on the energy >required to paddle it. That is, if I double the weight do I double the >work I do? Is the effect proportional or something very different? There is no simple way to answer this accurately because as you increase displacement various form parameters change too. Wetted surface increase, prismatic coefficient may increase or decrease, length and beam ill increase an so on. But if we assumed the unlikely case that everything remained constant here is an example of what might happen. These are resistance figures for a 13.7' waterline kayak at 215 and 430 pounds. The speeds begin at 2 knots and increase in half knot increments up to six knots For 215 pound kayak 0.760, 1.139, 1.591, 2.252, 3.265, 4.841, 7.435, 10.525 ,13.869 For 430 pound kayak 0.789, 1.184, 1.657, 2.440, 3.784, 5.569, 9.453, 13.703, 18.427 There isn't much difference at low speeds where wavemaking is small but once wavemaking becomes important things happen pretty quickly. At 4.0 knots there is about 15% difference. Keep in mind that, because I haven't included any of the other changes this would be higher in real life. 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/ ***************************************************************************Received on Fri Apr 03 1998 - 05:04:24 PST
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