Matt Broze wrote: > [Lots of good information about hull speed and wave-making.] ... > Holding a heavy > boat up against gravity means that a lot of energy is being used to do so ... While I commend you on a good description of hull speed and the transition between displacement and planing regimes, I do have a quibble with the above sentence. It takes energy to initially lift the boat against gravity when it starts to plane, but no further work is done against gravity once the boat is at a constant level while planing. In the same way energy is required to lift your boat up onto some sawhorses, but the sawhorses do not expend any energy while holding the boat up at a constant height. The energy required to move a planing boat goes into wave formation, surface friction, air resistance, and some losses to turbulence at the propellor (or paddle) to water interface. Adding up all of these will give the total energy with no additional amount needed to hold the boat up against gravity. *************************************************************************** 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 Wed Dec 11 2002 - 06:59:41 PST
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