Doug wrote: > > Speaking of prestige and writing in the same breath, if anyone on the list has > access to the latest Wavelength Magazine issue, Doug Simpson has a great little > piece about the brief history of his company, Feathercraft (available on-line, > but requires a PDF download unfortunately - until next month). He talks about > how his company made up mock kayaks with see-through materials in order to study > the flow of water over the skin and so help design boats (how about that Mr > Winters?). Always nice to hear about people using more than intuition to design boats. Did he mention how he "visualized" the flow? Some methods work quite well and some don't. For example, using tufts of wool taped to the bottom gives deceptive results particularly where the boundary layer gets thick enough to 'bury" most of the tuft. Also the wool seems to adhere to some surfaces better than others. In 1972 I used windows in the bottom of a Star boat to study the effects of different wetting agents and waxes. This was how I learned that some waxes cause bubbles to adhere to the bottom which increased the surface roughness (BUMMER). I injected dye in front of the window in two locations and compared the speed that the dyes crossed the windows. LUX liquid detergent gave the best results. Please don't go smearing LUX on your boat. Aside from the pollution it washes off quite quickly. Probably the most useful information (for a folding boat) would have to do with flow over the chines. I have found that deep forward chines seem to increase resistance slightly (less than the repeatable accuracy of the tank or program) so unless one deals with odd shapes it looks like one can put the chines almost anywhere without doing too much harm. The Nordic Folkboat people used to argue the merits of lapstrake versus carvel construction since boats built with both constructions raced together. Each side vehemently argued for his preferred construction. I think that, in the end, they had to agree that sails and sailors made more difference except in light air when the added wetted surface of the lapstrake boats made them less competitive. Cheers, John Winters Web site address http://home.ican.net/~735769 *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Fri Oct 20 2000 - 05:08:18 PDT
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