Jerry wrote; (SNIP of performance prediction of boats of differing displacements ) > >The example you cite is for a very large increase in weight. What if the >weight delta were smaller and you made the assumption that the drag >difference was zero? Then the inertia would be the only effect. Would it be >better to have slightly more weight and be slowed less? Especially in >choppy conditions. > >Another question. If the weight delta were smaller, would the knee of the >curve of increased drag occur at a higher speed? If so the effect of >increased weight might be less than expected at touring speed. The drag will not be zero since for smaller displacement increases the form factors won't change nor will the shape of the drag curve change so long as form factors remain constant although wetted surface will increase. Whether the increase in drag is small enough to be unimportant depends upon the sensitivity of the paddler. If one is concerned about resistance in waves then there are more important factors like the moment of inertia, the vertical prismatic coefficient, the boat length relative to waves (and consequently the period of encounter) and (possibly) the stroke cadence. If there is a benefit to adding weight just for weight's sake it is stability. That is why I invented Genuine Canadian Ballast Rocks (TM). You will note that no where in our advertising do we claim that Genuine Canadian Ballast Rocks (TM) improve performance, make you look younger, improve your sex life, nor will your friends be more attractive and your children better behaved or your laundry come out whiter than ever before. All that will happen is that your boat will be more stable.If you use our Genuine Canadian Radioactive Ballast Rocks (TM) mined from abandoned uranium mines in northern Canada you may become sterile but that is the only known side effect and that may or may not be a good thing. Claims that users of Genuine Canadian Radioactive Ballast Rocks (TM) can detect kidney stones through the sides of skin boats and that they cure prostate cancer are unsubstantiated. 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 Sun Apr 05 1998 - 07:11:17 PDT
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