Joel
Your plotter will give you VMG relative to a pre selected way point. Probably useable if that point is DDW or is it linked to your wind indicator? The numbers from the polars are VMG relative to true wind direction.the Raymarine ST 60 instrument pack will give that info on the fly, VMG (wind) for any wind angle. With this VMG's downwind are negative numbers while VMG's upwind are positive.makes it real easy to find the optimum angle on a beat but it does require that you pay careful attention to the compass so that you don't sail away from your race mark on a header, for example, because going fast in the wrong direction can lead to an undesired finish position. Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS _____ From: cnc-list-boun...@cnc-list.com [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Joel Aronson Sent: September 20, 2012 11:10 AM To: cnc-list@cnc-list.com Subject: Re: Stus-List final spinnaker questions You guys are the best! Yes my plotter can tell me VMG, but it seems to indicate that there is a pretty wind range where angle does not matter, at least with the jib, so the reference points are also a big help. If its blowing around 10 I may just use the .75 oz chute. Both are original but "low mileage". If its a reaching leg, I'll use the asymm and avoid the drama of using the pole. Joel On Thu, Sep 20, 2012 at 9:27 AM, dwight veinot <dwightvei...@hfx.eastlink.ca> wrote: Joel According to the polar diagrams I have for a 35 MKII the optimum VMG on the run in 10 kts true wind is at an angle of 148 degrees, at 12 kts it is at 162 degrees, at 16 kts it is at 173 degrees and at 20 kts it is 174 degrees. This agrees with Dennis's reply but gives you some numbers. These numbers are based on a 153% jib but the optimum angles might be quite similar with the spinnaker. For the 35 MKII the VMG at 20 kts and 174 degrees is 7.65, at 16 kts and 173 degrees it is 6.90, at 12 kts and 162 degrees it is 5.82 and at 10 kts and148 degrees it is 5.08. These wind levels are all true wind. I expect numbers for the 35 MKIII might be quite similar. If the kite is newer and not picked I would say you could probably use the 1/2 oz up to 12 kts true, maybe higher, as long as you sail at 162 degrees or above to 180 ...the 1/2 oz probably may not last long if you try to reach closer at 12 kts true wind. The size and cut of the spinnaker are just as important as the cloth weight but I assume a 1/2 oz or light air kite is 180% and tri radial cut. My lightest kite was a 180%, 3/4 oz so I am just making an educated guess about the 1/2 oz sail. Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS -----Original Message----- From: cnc-list-boun...@cnc-list.com [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Joel Aronson Sent: September 20, 2012 8:55 AM To: cnc-list@cnc-list.com Subject: Stus-List final spinnaker questions 2 questions: What is the maximum wind speed for a 1/2 oz chute? What is the ideal apparent wind angle on a downwind leg to get to the leeward mark on a 35/3? 140 degrees 150 degrees 160 degrees? Assuming about a 10 knot wind and calm seas. Joel 35/3 The Office Annapolis Sent from my iPad _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2441/5277 - Release Date: 09/19/12 _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com -- Joel 301 541 8551 _____ No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2441/5281 - Release Date: 09/20/12
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