Matt wrote; >Okay, here is what I know about that. I was at the towing tank the day >before observing the tests and trying to talk the testers to run a rudder >down test (and also to try an old scratched up Boat which I had vs. a brand >new one with a shiny bottom which they had already tested). (Large SNIP) Sounds interesting. I can see why the results puzzled the tank people. If you can get it Horner's "Fluid Dynamics" might supply the information needed. I copied some parts of the book but not the ones needed for this. Maybe someone with an affliation with a university can get a copy. The presence of cavitation on rudders and skegs interests me most. I have read cavitation defined as "the process of formation of the vapour phase of a liquid when it is subjected to reduced pressure at constant ambient temperature" . I interpret this as meaning that, since water cannot support tension the flow breaks down with the formation of bubbles and cavities (I.E. it vaporizes) . It seems like one needs pretty low pressures to do this. If cavitation does exist then that may well explain the higher drag since the creation of such low pressures might involve a lot of energy. Cheers, John Winters Redwing Designs Web site address, 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.paddlewise.net/ ***************************************************************************Received on Tue Oct 05 1999 - 03:39:17 PDT
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