Thanks Mike -
<br> also thanks for the offer to help organize a distance race in MI again , -it will have a FORMULA class .
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<br>-Good news for the comptip guys ,
<br>-Have heard that all F-18s are going through extensive improvements and are on their 3rd or 4th versions in the factories attempts to make them the top boat ,--Nacra has refined their 18 hull shapes , and the Tiger keeps updating ,-I saw my first one in the 98 Worrell 1000 ,-it is a very nice looking cat. -
<br> It is amazing what equal competition will do for the quality and performance of boats .
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<br>-Believe if we look ahead and specify lighterweight boats being allowed to race equally, in several years time we will similarly have a number of excellent higherspeed lightweight designs in the 20 class ,-just as a group did for the 18s in 1993 when Formula was started in Europe.
<br>-Eventually the 18s will have to also update to the lighterweight design technology and building techniques.
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<br>-Saved this post from a noted catamaran designer on weight - this may be a good place to add it to the discussion with a few comments after .
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<br>-The parameter that will bring this discussion on crew weight to focus is "overturning moment to righting moment ratio". The overturning moment corrilates with sail area times the height of the center of effort above the center of bouyancy of the burdened hull. The total righting moment is the sum of the boat righting moment (boat weight X boat width/2) plus the crew's righting moment plus the skipper's righting moment. This ratio tells the tale as to the optimum weight for the boat. Boats designed with a larger number (ratio)favor larger people and boats designed with a smaller number (ratio) favor smaller. Boats designed with a larger number tend to become overpowered sooner (less wind) and boats with a smaller number are more controlable in stronger winds and will excell in stronger winds.
<br>Designers have gradually increased this ratio in an effort to build faster boats at low cost than the competition via higher sail area to weight ratio. This doesn't work if you can't hold the boat down, does it? Remember the recent Olympic catamaran selection trials? The old boat 10ft wide with 237sqft of sail area beat all the new designs with more sail area including spinnakers but only 8.5ft wide. If you don't go up in righting moment as you go up in sail area, then you can't drive the sails to their capability and the boat moves out of the competitive weight range for normal weight people and it won't perform well in strong winds. How do you go up in righting moment? Make the boat wider! My first beach cat was 12 feet wide with 275sqft of sail area and it dominated the 20ft beach cat class for many years. It is as simple as this: To increase performance, the sail area to weight ratio must increase. Solution add sail area. Answer WRONG! Add sail area and width in a coordinated fashion to achieve higher sail area to weight ratio and hold overturning moment to righting moment ratio. The only other way to increase sail area to weight ratio is to reduce weight. With this approach manufacturing cost takes off like a rocket and the light weight boat is very fragile. What I'm talking about here is building two hulls for the weight of one. The low cost way to acheive higher sail area to weight ratio is to add sail area and width in a coordinated fashion. What's happening with the 'new boats' they are powered up with more sail area and no improvement in righting moment and the big people are favored.
<br>Good Sailing,
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<br>-These are always great posts , greatly appreciated by many of us ,
<br> We do now have several examples of lightweight cats available at reasonable cost , would be the only minor point of different opinion.
<br> The only way to equalize this described advantage if a total boat weight and crew weight rule were to be implimented as Steve would advocate would be to add adjustable or telescoping racks or wings to the hulls ,-Like the H-21 -17 OR Mystere has available . This would allow lighter crews a proportionally longer lever arm option equalizing weight at the point out from the center of effort on the sail plan with a measurement from the leeward hull .
<br> If someone can design a lightweight inexpensive c f rack we can all add to the 20s I.m all for the equal boat and crew rule .
<br>maybe 10 lbs each -
<br> If not then we need to state that all crews are responcible for maintaining their own ideal crew weight at min 325 .
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<br>-The other option used of carrying weights and various jib and spin sizes for crew weight that particular race weekend seems overly complex , inflexable and adds burden to sailors and measurers , also never liked the idea of carrying added weights though have in years past , and really does not equal the playing field as accurately as racks would achieve .
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<br>-Carl
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