Purely arbitrary. 3-5 miles would probably work. -- Dennis C. Touche' 35-1 #83 Mandeville, LA
On Fri, Apr 5, 2024 at 4:33 PM Matthew Wolford via CnC-List < cnc-list@cnc-list.com> wrote: > Thanks, Dennis. How did you arrive at 10 miles. Sent from my iPhone > > > On Apr 5, 2024, at 5:31 PM, Dennis C. via CnC-List < > cnc-list@cnc-list.com> wrote: > > > > > > Personally, I think sailing to polars can be challenging. I prefer to > use VMG. VMG rules for windward/leeward race courses! Bear with me on > this. > > > > First, a couple of definitions used by Touche's Nexus instrument system. > > > > Velocity - speed and course > > VMG - velocity made good wind based. The velocity directly upwind or > downwind. > > WCV - waypoint closure velocity. The velocity made closing on the set > waypoint > > > > Okay, if your instrument calculates VMG (wind based), simply steer the > boat to maximize VMG. Done! > > > > If your instruments do not calculate VMG (wind based), here's how to get > your GPS to closely approximate it. First, many GPS systems show VMG which > is actually WCV when a waypoint is set. If you set the upwind (or > downwind) mark as the waypoint, WCV will incur more error as you approach > the layline. Visualize it. As you approach the layline, your WCV will > decrease to zero as you near 90 degrees to your course to the mark. (If > you overstand, WCV will turn negative as you've sailed past your mark.) > > > > So, set a waypoint 10 miles directly upwind or downwind of the race > mark. Now your GPS WCV will closely approximate VMG (wind based). Steer > to maximize WCV and your course(s) to the mark will be optimized. > > >
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