Nick wrote about planing: >>>>>I like the definition where the boat lifts up and drag is reduced. If a long boat can do this a low speed or a short boat can do this with an external power source, so be it. Of course since I am not the arbiter of the English language I guess it is not my call.<<<<<< I like the lifts up part (which is Savitsky's definition) but drag is not reduced when planning. Only its rate of increase with increasing speed is reduced. Or am I misusing the term drag to mean all the energy required to over come all the "drag" forces including gravity and you are referring to only frictional drag? I think someone said earlier that a boat gets more efficient when it is planing. That is not true (unless we are defining "efficient" differently too). A displacement boat of the same weight will go from point A to point B a whole lot more efficiently than one that is planing. The planing boat is using a whole lot more energy to constantly hold itself up against gravity than it ever can get back by reducing its wetted surface when it is planing). In other words, the planing boat will get there quicker but its gas tank will be emptier when it arrives. It seems to me that surfing meets Savitsky's (raising the CG) definition of planing. The CG is higher than it would have been were it not for the motion of the object. Why quibble about the power source driving the object? Matt Broze http://www.marinerkayaks.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/ ***************************************************************************
[Paddlewise] Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-paddlewise_at_paddlewise.net Precedence: list X-Listname: Paddlewise Mailing List X-Subscription-Info: paddlewise-request_at_paddlewise.net >Nick wrote about planing: >>>>>>I like the definition where the boat lifts up and drag is reduced. If >a long boat can do this a low speed or a short boat can do this with >an external power source, so be it. Of course since I am not the >arbiter of the English language I guess it is not my call.<<<<<< > >I like the lifts up part (which is Savitsky's definition) but drag is not >reduced when planning. Only its rate of increase with increasing speed is >reduced. Or am I misusing the term drag to mean all the energy required to >over come all the "drag" forces including gravity and you are referring to >only frictional drag? > OK, I'll accept that, at least as a practical matter. I do think the drag can reduced theoretically, but don't know that it happens in actuality. Seems to me the when I've waterskied that the tug on the rope went down between the time when my body is out of the water, but the ski is still deep, and the time when I am up and really going along. Both situations strike me as "planing" but the latter seems to have much less drag. Couldn't the same happen is a kayak, on surf? Nick -- Nick Schade Guillemot Kayaks 824 Thompson St Glastonbury, CT 06033 (860) 659-8847 *************************************************************************** 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/ ***************************************************************************
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