Time to get out the GPS and clock one I guess. No idea how fast they are, but they fairly fly around the marina here. I know this is heresy on this list, but theoretical hull speeds do not always work... Scott Found a new beach. Its in the garage. What, thats not a sand dune, its dads car? *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Scott wrote; >Time to get out the GPS and clock one I guess. No idea how fast they are, but >they fairly fly around the marina here. I know this is heresy on this list, >but theoretical hull speeds do not always work... Actually not heresy at all but just plain fact. Hull speed is not a limit to speed. It is a term coined by William Froude for the speed at which the transverse wave system produced by the boat coincided with the effective waterline length of the boat. For ships and boats of high displacement/length ratios this is a practical limit to speed as enormous amounts of power are required for greater speeds. Even so, high displacement ships etc. can and do exceed hull speed. For light displacement boats or ships displacement speeds are easily exceeded because wavemaking resistance is so small. Sea kayaks, rowing shells, etc. regularly exceed hull speed while in a displacement mode. Sprint boats race at speeds 50% higher than hull speed and my old worn out body can produce speeds 20% higher than hull speed when testing kayaks. Some warship models are tested at speed length ratios of 4.0 or almost three times hull speed. The term "hull speed" is unfortunate and I am sure if Froude could have foreseen how it would be misused he would have thought of something different. My suggestion would be Coincident Speed since that does not imply any limitation. 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/ ***************************************************************************
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