On Sun 02 Dec 2001, Scot Hume wrote: > I'm trying to understand why rocker makes a boat turn > easier. My current idea is that if a boat drafts 6 > inches all the way along, a sweep stroke or other > force such as a wave has 6 inches to work against at > the end of the boat. However, if there is rocker, the > power of the sweep stroke is pushing against only a > couple of inches and it takes less force to move the > bow on a pivot point back near the paddler. Is this > correct? You are correct. Visualize using a 3ft pry bar and then you try prying with a 6ft pry bar. The resistance created by the water has similar leverage out from the center of rotation. Force of rotation is called a moment of rotation and is defined as F x d where F is the force (in this case the force of resistance provided by the water) and d is the distance out from the center of rotation. Hey, I gots no books here, so I may have just butchered that, but I think it gives some perspective on how force works, and where the water has more leverage. And another thing to consider is the shape that the water has to flow across during the rotation. Is the bottom squarish like some boats or more smooth and eliptical like others? This design factor could also help to allow the water to flow easily across the hull during sharp turns. -- Mike McNally mmcnally3_at_prodigy.net *************************************************************************** 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 Mon Dec 03 2001 - 08:46:47 PST
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