The first question most current owners will ask is "What does this mean for me?". How about starting the discussion with a simple table that outlines the differences between existing designs... something similar to the table http://teamteets.dhs.org/mystere/43specs.html including all current 20 footers. Anyone have something like that?
<br><br><br>Mike Teets
<br>Dublin, Ohio
<br>I20 #246
<br>M4.3 #59

Hi Mike
<br> thanks for posting ,-this should be fun , but also a tremendous education , and alot of work -research -communication -and promotion will be needed for this to be successful ,-maybe why I,m for a more open inclusive less complex rule formation and 20 Class
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<br>-All mfg's publish boat specs. with their advertisement , I will find some basics and post them , as we get basics established we will rely on top sailors sail makers ,designers etc with experience in various boats to provide recommendations on upgrading existing catamarans to the max.rating,-or equivelent grandfathered in to existing F-20 rating ,whichever direction the group desides,--at present everything is open for discussion I presume .-There can be a seperate article written and published on each , hopefully with volunteers or a particular sailmaker with explaination and photos of various modifications to the particular cat along with spin setups ,-self tacking jib set up etc.
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<br>-Existing F-20 s presently manufactured that come to mind are the Fox -I-20 {non conforming in the U S } and new Storm -plus others -existing cats that may be modified to become compeditive are N-6-0 P-19 H-20 Mystere 20 ,-we can run through the list in the ratings columns -
<br> There are also a few lightweight existing 20s --the CFR 20 and Marstom 20 .-I,m not sure if these lighter cats would rate into the 20 ft catagory using a Design Formula approach to the class ,-it would depend entirely on what the group desides would be a max.rating allowed ,-and then what trade offs would be required as in porportional reduced sail area from existing to equal a rating number within the proposed formula .
<br> I also understand that boats will and are being built in antisipation of this class .
<br> The interesting aspect is that some boats within the rule will have an advantage in particular sets of wind and sea conditions ,just as they do now in open racing,
<br>-All the N-6/0 Sailors have been through modifications and the boat exists in 4 or 5 different configurations from it's original, sure there will be some valueable input there on boat modification.
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<br>-Believe your right ,-we should list all 20 ft cats and specs .
<br> We all need to be familiar with existing F-20 rules -
<br> and become familiar with ISAF and Texel ratings and formulas .
<br>-Hopefully many others will post and add valuable input and information ,-I did send Bill Roberts gen specs on several 20s a few months ago for a spread sheet he was working on ,-his knowledge and readily available design formula information he regularly posts always is greatly appreciated.-
<br> Again hopefully many knowledgable catsailors will post and help walk us through the processes and give expert advice and direction to make this the excellent and exciting racing class I believe this will become .
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<br>-All the best
<br> Carl<br><br>

Here is the data from your posts Carl.
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<br>http://teamteets.dhs.org/F20/F20%20compare.htm
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<br>So the question will be, what has to change on each to make any proposed formula rule.<br><br>Mike Teets
<br>Dublin, Ohio
<br>I20 #246
<br>M4.3 #59

thanks Mike -
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<br> Wanted to add this excellent discussion from the open forum for future reference -on WEIGHT -BEAM -effects on design and ratings .
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<br>-The Tornado class has stayed competitive over the years because it is an excellent design. Excellence in design does not age. It was not designed on someone's kitchen table or scratched out in the sand at the end of a stick on a California beach.
<br>Another way the Tornado class has stayed competitive over the years is through weight reduction. Back in the late 1960s and early 1970s, I was sailing a Flying Dutchman. Frequently I went down to the Miami Yatch Club for all class regattas. I was amazed at the speed of the Tornados. They would go really fast but they frequently broke down. I have seen inside these original boats and they were built with fiberglass mat totally, no core and no cloth. These boats weighed 450 to 475 pounds. I have seen these boats weighed on the scales at the MYC. The class minimum weight was 375 pounds. These boats were soft and rubbery and squeeked and squaked in a chop as they twisted and flexed going to windward.
<br>During the past 30 years several improvements have been given to the Tornado class by various builders. Marstrom has probably made the greatest contribution to the Tornado class. His boats are strong and stiff and don't flex in a chop and easily make class minimum weight. This untalked about weight reduction that occurred in the Tornado class has done much to keep this boat competitive over the years.
<br>The other very obvious design feature that makes the Tornado faster than others is the 10ft beam. This is 15% wider than 8.5ft beam boats which converts to 15% more sail thrust. Since thrust equals drag at steady state speed and drag is a function of velocity squared, the 10ft beam becomes a square root of 1.15 speed advantage or 7% faster than 8.5ft boats when the greater righting moment is used. The Tornado Sport PN is presently 59.4 and going down. If I increase 59.4 by 7% I get 63.7 and I just jumped right in the middle of a whole bunch of 8.5ft wide boats. And remember that 59.4 PN is on its way down.
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<br>The easiest way to make a cat going faster is to reduce its weight. A better shaped hull and a faster mainsail can give you only a few 1/10s of knot advantage. Make yr 16' boat 10 kg lighter, and after one hour, for a given speed of 10 knots, it will have to "move" 37 m3 less of water. How many hundreds yards of advantage do you think is all this "volume" worth?
<br>: If it is not true, according to you which is the "secret" of A class cats?
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<br>: My answer:
<br>: 1) If you want to race equally, buy a one-design cat! Someone wrote a few months ago on this Forum: put Mitch Booth on any boat and he will win anyway. If you want to race equally with him or any other better sailor than you, you have to choose an "handicapping" system based on personal
<br>: performance (more wins, more high rating)
<br>: 2) WEIGHT!!!
<br>: 3) Box rules are more advanced because allow lighter boats to race
<br>: 4) Smaller but better built.
<br>: 5)I push the F16HP because it has not an unreasonable minimum weight and allows light boat to race. The BIM 16 with spi weights 95 kg ready to sail. If the Formula 16HP allowed only 130-140 kg boats like the NACRA BLAST, I would not push it.
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Be carefull with beam width. A wider platform will only START to gain advantage when the smalelr beamed boat crew is double trapped. (15-20 knots wind !) At windstrengths below that extar width won't help at all. If US is mainly light air than width is of secondary importance to teh US F20 class.
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<br>Wouter
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Believe a basic box of 20 Length and 8.5 Beam but allowing variables when less along with sail area and weight.-again all based in ISAF / Texel rating .
<br> Eventually a F-22 or Open rated Formula will accomodate higher rated cats .
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<br>-reposting an excellent Formula regatta senario by Kirt and the Pn # info for future reference.--The F 20 class needs to work with everyone and encourage freedom of information concerning all aspects of the various existing rating systems.
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<br>-Thanks for clarifying the point here. I was NOT trying to promote NOT taking finishing times by the committee I WAS trying to make the point that the RACERS themselves really don't have to worry about taking time to "know" if they beat another boat in their "formula". We definitely DO want times recorded to demonstrate potential of the different boats, generate reliable PN's for open racing and to be able to "fine tune" things if necessary.
<br>By the way, I would assume USSA is willing to provide PN's for specific Formulas? Could you please tell me what, exactly, would be needed to have a provisional Portsmouth number assigned for a Formula?
<br>Thank you!
<br>Didn't mean to upset you, sorry :-(
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<br>Kirt
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<br>: PLEASE DO NOT PROMOTE not taking times of formula boats at regattas. For formula ratings to be valid, we must have a good database to support the ratings. This will allow the boats to sail in open class events (when required) with good ratings. Thanks.
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<br>: Darline
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<br>: : There is NO need for "handicapping" within each Formula as all boats rate the same (race "heads up") so only ONE PN number need be assigned, all boats within a given formula start together and finishes need only be taken in order.
<br>: : So at a "Formula Regatta" for instance (if such a thing ever occurred) there would be only a specified number of starts-
<br>: : For instance: 1) F16 HP (uni and sloops), 2) F 18 [and under Texel and some other handicapping systems which rate these two equal you COULD even combine these two starts - and finishes], 3) "A" class, 4) iF20, 5) Tornado, 6) Everything else if desired-
<br>: : These five classes can accomodate most catamaran racers if desired since you have a "small" sloop and uni w/ spi, high tech larger uni (no spi), larger sloop w/ spi, large sloop w/ spi, and high tech large sloop w/ spi and Olympic status.
<br>: : As many manufacturers, sailmakers, etc. as you want as long as they conform to the "box rules" of the formulas and ALL International Classes too!
<br>: : Kirt Simmons
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