Explanation of Polar charts..
Hi.. I copied this from a prior posting by Mike Pilolla.. Polars show how your specific boat, given specific variables like sails used, displacment, keel type depth, etc., should perform at specific points of sail at specific wind speeds and direction, both true and apparent. I hope I'm not too confusing with the answer. The best way to see how it might be relevent to your own sailing is when you start to plan a course or passage and want to find the fastest way to get from point of origin to point of arrival. A direct line, or plumb line isn't always the quickest way because of winds, current, sea state, boat performance. Have you noticed if your boat sails faster on one tack than the other? If it does, it may have to do with any number of things like rudder drag in the water caused by any number of things. Also, even though you may have an idea your boat is quicker on a beam reach than close hauled, it would be great to know how much quicker it should be based on all the variables. Then, with the polars for your boat and a given set of conditions you may find that sailing due south to pick up a new wind direction will get you to your destination a day earlier or a few critical hours earlier, say going into Bermuda in the late afternoon rather than getting there at night. If you sail at 9 kts on a reach and only make 5.5 kts beating into the same wind speed, it might be much faster to go around. Sorry for the long winded explanation but it was difficult for me to understand why I would even care about the Polars for my boat until someone explained how I would use them in something other than racing situations. Hope this is helpful. Mike Pilolla s/v Carolina
