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Old 04-20-2012
keforion keforion is offline
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Re: Polar Diagrams

Most interesting.

Polar Diagrams used to be published with every sailboat review in the old issues of Yachting, Rudder and the like. You do not see them anymore. I wonder why. Perhaps the fact that they START at 52 degrees from the true wind angle is a clue.

As a point of reference, my IOD, designed in 1938, and horribly slow, inefficient, and otherwise unsuitable by modern standards, sailed at an average of 39 degrees to the true wind as measured by the course over the ground between known landmarks on the shore of a relatively narrow channel (The Alameda Estuary, Oakland California.) This was before gps, so some experimental error is in there but this is an average of about a dozen runs up the same channel, roughly six legs, dead to windward usually, and it is taken from courses plotted on a chart, by reference to shore marks at each tack. And we were not pinching or trying to prove point. I only did the measurements after the fact when a question like this came up. We were just sailing.

I suppose if I were the NA of a thing that couldn't go much closer to the wind than 50, or even 45 degrees, I would not want the curves published either.
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