The assumption prior to the next text is that US F-18 is EU F-18.
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<br>It looks like the Nacra 5.5 is a very good platform to modify towards the F18-rule.
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<br>Texel measurements give:
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<br>Length overall-----weight----Main area----main luff----jib area -----jib luff
<br>---5,49---------------176--------16,26--------8,44-------5,58------5,74
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<br>The raid version (I don't know if US has that one) has a jib of 4,53 and a jib luff of 5,54
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<br>The measurements of F-18 are
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<br>5,52 mtr. 173 kg 17,00 sq. mtr. 8,47 mtr. 4,15 sq.mtr. 5,50 mtr.
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<br>However most F-18's measure in with main area 16,75 sq.mtr. that is the result of the fact that F-18 class measures the whole mast (and boom ?) and includes that in the total area instead of just the effective mast area and mainarea like Texel does. Or simpler put F-18 uses ISAF measurement methode and that is slighly different from Texel. 173 kg' is the weight of the plaform without the genaker gear.
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<br>Now many sailors (nearly all in EU) remove the flap under the N5.5 sail in order to get a slower rating. Many believe that this area doesn't really help in performance but does help in getting a faster rating. So in the US you'll still have to the area of this flap.
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<br>Now as you acan see the measurements of N5.5 are quite close and often on the right side of those of the F-18. Only real violation is the jib size, so you might need to get a new F18 jib if the US F-18 doesn't grandfather in your jib. You probabbly want a new jib anyway in order to sheet it of the forebeam and clean up the trampoline.
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<br>Ofcourse you need to add a genaker too.
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<br>Main point here is that platform, mast and mainsail are full comliant. Jib is not.
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<br>Good luck
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<br>Wouter<br><br>