"al.m" <al.m_at_3web.net> wrote: >> What I can't figure out, is how much weight I'm lifting at the stern, when the bow is already on the bar. Should be a little less then full 58 lbs, but more than half-weight, >> You're correct -- but it depends heavily on the angle. If you do a vector analysis of the forces, you will find out that if the kayak is perpendicular to the ground as you pick upthe stern (an unreasonable case), then you are lifting all of its weight. If the kayak is horizontal to the ground, then you are lifting with a force equal to 50% of its weight (also not the case at the ground, but the case when you are ready to slide the stern onto the rack). In between those angles (90 degrees and 0 degeees), the force decreases from 100% to 50%. If you start with the kayak at about a 30 degree angle, then the lifting force is pretty close to 60-70% of the kayak's weight. A better deal than lifting the whole thing, but not half of the whole kayak's weight To check this, put a spring scale in the system and measure the lifting force when the stern is on the ground, and watch the force needed to keep the kayak in equilibrium as you move on up. -- Dave Kruger Astoria, OR *************************************************************************** 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 Sat Mar 08 2003 - 14:54:36 PST
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