> >-----Original Message----- >From: Matt Broze <mkayaks_at_oz.net> >To: John Winters <735769_at_ican.net> >Date: May 29, 1999 5:17 PM >Subject: Re: [Paddlewise] Pro's and Con's of the "Swede Form" > > >(SNIP) > >>> >>I'm still having trouble seeing this.There still must be an altered >pressure >>distribution underwater (but without creating any waves) and there is no >>"wave" drag then. One of the reasons submarines can be so fast. If the >waves >>created alter that pressure distribution in some other way and cause drag >>(as you seem to have said) that would seem to indicate that the waves >>(altered pressure distribution) was causing the drag. > I think I see where you are going on this. Seems like the bow wave would alter the pressures aft but the bow wave results from the pressures forward so I guess yo might say the pressures are teh first cause of wavemaking and then the wave produced affects the pressures aft so I see your point. A fascinating point is that even submerged submarines have wave making drag when operating near the surface and also when operating at the interface of start of water at different temperatures. >> >> >(SNIP) > >> >>Okay, at some point for speed to get higher the boat must climb higher >(and >>also out of that even deeper hole it sank into (due to Bernoulli). As it >>climbs higher the bow wave is reduced because there is less draft pushing >>through the water. This reduces the part of the total drag that is due to >>wave creation. So while technically one may not be climbing over the bow >>crest it still looks to me that we had to climb out of the wave trough as >>well as the hole in the water that was just due to the boats displacement. >>This acceleration vertically requires energy (which my waterskier jumping >>off the pier didn't have to do) so there is additional energy expended >>climbing--beyond the considerable energy needed to maintain the elevation >>against the pull of gravity once you get up there. >>Anybody have any problems with that explaination? > I like it. 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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