good posts ,- <br> <br>-On min.crew weight , several have suggested 350 ,-and a few have stated that they would be excluded from the 20 class at this 350 min. requirement weighing in at around 300 themselves , Alan Marc and others. <br> <br> I am 6,4 -225LB - and have felt at a disadvantage sailing smaller cats unless it was blowing 15 to 20 , many larger sailors feel this way , <br>--actually gained 20 LBs one year to be able to add 50 LB of dead weights in place of a crew racing H-18s which was allowed within H-class rules.--a-fun year of racing ,but no one to talk stategy with or spot marks or countdown the start and spot the rival teams boats on the course, - <br> <br>- -We should encourage as many as possible into the 20 class , If a 350 min crew weight is desired, then lets allow 50 in dead weights ,and allow weigh in wearing ,harness ,life jacket , and dry suit. -approx 8 to 10 LB s <br> Equal weight is the goal ,-not to exclude 20 racing sailors . <br> <br> This 350 min. would eliminate the need for spin size variables as Mike noted. <br> <br>-Sail areas -main , -The reason 18s are standardizing is to simplify measurement , and allow mfg. control .,this also creates more of a one design type class. <br> I don.t believe we can expect all new 20 designs to match the Inter , this would establish a very limited set of total design variables that would have to corespond ,plus eliminating all other existing 20 cat and 20 F designs . <br> If we allow variation , we have to define the extent of that variation ,--The ISAF or Texel provides a means or standard way of measurement ,but not a class definition or exact sail configuration within a size limitation. - <br>- <br>-As we see in the A-Class developement of main sail area , numerous variations in sail outline of where and how this 150 sq ft of sail area is configured. <br>-Effects =remember reading about an Aclass worlds racing championship where particular Italian A cats who typically raced in light wind conditions and had optimized their sail to light air ,-moving sail area up higher proportionally , -a larger sq top and added roach area, won and placed well the first day of the championships in light winds . <br> The second day came in with much higher winds in the 12 to 15 range and the expected favorites won, while the light air designs dropped to the middle of the pack from then on . <br> <br>-Even within the same sail area there can be variations and performance differences , this is difference in allowing some types of limited developement as opposed to one design racing , and what we are attempting to define as a 20 class now. <br> Again the 18s in N A eliminated this , partially for this reason , but we have different existing conditions. <br> <br>-One scenario a potential F-20 designer may go through . <br>They may target a windspeed and design a 20 to that av windspeed, Barry noted his average in all regattas was 8 mph ,-light- <br> The designer would optimize hulls with a low P C . shape and sections , typically dividing the hull in 10 equal areas along its length and drawing sections for each station.- <br> P C is prismatic coeffient which is a measurement in section of the most volume as a total constant solid , in comparison with the actual hull volume . <br> A low p c number has lower wetted surface , optimal to reduce frictional drag and better light air performance , A lower P C number is achieved by a hull shape with finer ends -{bow and stern } and more rocker -{more curve in for and aft lines of hull } . <br> This design consistant with proper volume calc , for total crew and boat weights ,may also seek to minimize board and rudder areas . <br> These features combined with all the other eliments of proper design and the aforementioned higher area sailplan optimized for light air would have much better performance in those ideal wind conditions. <br> <br>-Posted this so all understand more clearly the developement aspects even of this more limited type of class structure. <br> <br> To me it was not a large jump to propose more of a developement type class in weight to sail area trade offs , <br> with the proposed goal of including all existing 20 ft designs as they were listed and included previously , realizing refinment was required, but stating the existing conditions of current designs , which again we wished to include as a class rules goal and starting point. <br> my appologies to those I was rude to in not explaining this goal more clearly , Realizing most do not have a basic understanding of cat design , though I am an amature . <br> <br> -If we can finalize these basics believe we can proceed with e mail in minor detail of rules , then set up a similar web site and get better contact with the other Formula groups to coordinate more events . <br> <br> Carl <br> <br>-<br><br>
