Guy,
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<br>A note of caution, even though ISAF is heavily based on the Texel system the two systems are not perfectly equal. ISAF uses the original set of 7 complex equations while Texel has been simplied by a regression methode which produce one interpolation formula that arrive at similar relative results but is easier to handle and explain. Typically ISAF produces ratings that are 2 points lower than Texel but in a relative sense they produce very similar results. So the Hobie miracle 1,02 in ISAF equal to about 104 in Texel.
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<br>ISAF also rates genaker somewhat differently and handles, is expanded to incude aspect ratio of boards and corrects for carbon masts and uni rig sails.
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<br>I have both Excel calculators and have the transcription of the ISAF internal workings is either of you is interested.
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<br>Wouter<br><br>