Dan wrote; (SNIP) >All of this certainly makes sense (at least to my feeble mind). Doesn't >this also imply that hulls with a single hard chine may have an >advantage in such circumstances, since they tend to be more resistant to >"side-slipping", thereby reducing leeway? Off the cuff I would think, yes. However, (ain't there always a "however"?), it would depend upon chine height, chine depth at the ends, flare of sides, and maybe a lot of ETC's. If I use my program for controllability I can get the same lateral resistance in both round bilge and hard chine configurations. Of course, stability, resistance ETC. vary so you have to decide what characteristics you want to hold constant. For example, a wide shallow hard chine boat might not have as much lateral resistance as a narrow deep round bilge boat. But at that point you have to ask if the comparison makes sense. In one of my curious modes I created a generic boat with hard chines. I then created a similar boat with a round bilge but same beam, length displacement etc. The round bilge boat had one square foot less wetted surface than the hard chine boat so one could easily add more lateral plane area to achieve more lateral resistance while maintaining similar resistance to forward motion. Then I increased the draft of the round bilge boat until it had the same wetted surface as the hard chine boat (length etc. remaining equal) and was able to increase the lateral plane by 0.35 sq.. ft. No telling how this deep boat would handle but it serves to show how complex things can get. >Has anyone tested the >resistance of different hull designs to slide-slipping? Not me. At least not in a way that I would publish as gospel. Nevertheless, one might apply data from sailboats and see what happens. >It would seem as >though this may an important factor in "real-world" performance. As >someone who paddles frequently in the wind, I do not spend much time >traveling in the direction my boat is pointed. And yet the standard >resistance formulas measure (or seek to measure) the resistance of a >boat that is traveling straight ahead. It would be useful to know more >about these other factors. Absolutely. I have read some information on added resistance due to leeway but nothing I felt I could apply to canoes or sea kayaks with any reliability. I have tried measuring leeway with poor success because I cannot separate paddling influences from wind and boat influences. Some of the most informative stuff I have read and heard comes from windsurfers who use different skegs for different conditions. (would sea kayakers would balk at buying a selection of skegs at about $100.00 a pop). Cheers, John Winters Redwing Designs Web site address, http://home.ican.net/~735769 *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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