Mark,
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<br>As you may know, I like numbers and calculations. Your comment confirmed something I was suspecting about the I-20. Its rig is to high and big for a 2,5 mtr. wide platform in the stronger winds when going upwind.
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<br>Is your experience that you can keep up with I-20 upwind in stronger winds the result of many of such instances ?
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<br>And what are your experiences about light air (not medium) performance of the I-20 ? My calculations estimate the wetted surface of the I-18 to be 93 % of the wetted surface of the I-20. Their rated mainsail ratio = 14,73/15,98 = 92 %, their rated jib ratio = 3,89/4,63 = 84 %, genaker ratio = 21/25 = 84 %
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<br>sailpower upwind est = (92% *3 + 84% *1) / 4 = 90 %
<br>sailpower downwind est. = (92%*1 + 84%*3)/4 = 86 %
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<br>Given that today boats take longer to go upwind than downwind at about the minimal ratio 1,5 :1 will give the ratio of the I20 time to I18 time around a race course.
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<br>0,6 * sq.rt (90%/93%) + 0,4 * sq.rt. (86%/93%) =
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<br>0,6 * 0,967 + 0,4 * 0,962 = 0,965 or make the I-20 only 100% - 96,5 % = 3,5 % faster than the I-18 in light air and not the 6 % it gets from the Texel rating or even de USA D-PN.
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<br>Does your expieriences support Texel or these estimates ?
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<br>Wouter
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<br>And it is really sunny here in the netherlands isn't it ? =) I'll be at the NK hobie this weekend I hope the weather improves.<br><br>