> From: Nick Schade > Subject: Re: [Paddlewise] surfing and hard chines > > At 5:05 PM -0500 1/17/02, Michael Daly wrote: > > > ... > >Basically, to plane, you need to hit a speed/length ration of 1.5 or greater. > >The speed/length ratio is the speed divided by the square root of the length. > >This is familiar, as hull speed is defined as a speed/length ratio of 1.34. > >So you have to go at least 12% above hull speed to plane (ICF racers in > >kayaks excede this without planing - not a planing hull). > > > ... > I think as a practical matter this is probably true. But as a thought > experiment get a short little WW kayak surfing on a wave and up there > planing along nicely. Now start building a lightweight extension on > to the bow. Light enough that it doesn't effect the trim or > displacement. At what point does the fact that the boat is longer > make it so it stops planing? ... > > ... > I like the definition where the boat lifts up and drag is reduced. I.e., the hull is generating a large amount of hydrodynamic lift. How about, "when a boat displaces significantly less water than its actual weight". Of course, then we need to figure out what "significantly" means.... -- mike ----------------------------------- Michael Edelman mje_at_spamcop.net http://www.foldingkayaks.org http://www.findascope.com *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Fri Jan 18 2002 - 12:15:47 PST
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