This is really an accurate and honest description of how shape details influence performances, and about one of the biggest curiosities of mine!
I am reasoning on Ian's contribution not comparing S100 to iS94/96, but rather thinking about performances differences between older narrow boards such as RRD 281 and 278, and more modern "wider" shapes as my S95. Now I understand (hope so at least). On the S95 with 7.0 I use a 34 SL2 fin, while on my older boards with 6.9 it was much smaller 31 (Tectonics Spitfire design) or 32 (elliptical Deb) from RRD. I used to have a 33 too (Spitfire design) and it felt BIG and slowing down the board, even in marginal conditions! And in fact it was, as early planing was achieved by efficiency rather than power; sharp rails and small fin, rather than big sail and enough fin to push against. And it finally explains how the bigger feeling S95, with thick rails and wider beam and tail, feels much easier in high winds.
Only, I must observe one thing; and this relates to another thread about changes. It seems to me that in the end the wind range has been shifted, rather than just expanded. Older boards, once up and planing, were incredibly fast even in light winds, while my S95 is a dog when not fully powered. In higher winds, S95 range is after all similar to that of my older boards; by sure it feels much easier, but the RRDs felt more efficient and... do I dare to say... OK, better no.
So in the end (and not considering the extremely hard to sail, and rewarding, RRD281): both RRD278 (84 lts, 55 wide, 32.5 tail) and S95(100/94/96?) (around 95 lts, 58.5 wide, 38 and up tails) share about the same optimal sail range, 6.0 to 7.0; once planing, older boards were competitively fast against bigger stuff (I'd say faster) while for modern boards planing is not enough, they need full power (in marginal 7.0 winds, say 12-15 knots, I can plane my S95 but whoever on bigger slalom stuff is passing me, while I used to kill everybody on my older boards; things change once in the 15-18 and up range); modern wider boards can carry bigger sails and fins, but this does not seem to expand much the "top performance" envelope in light winds, just enhances accelleration and upwind a bit (and slows down top speed...); and modern boards can go out in overpowered conditions better than old ones; but nevertheless, outside of their optimal range, I don't see modern boards any competitive against "right sized" stuff. So what is achieved in the end? I'd say just the ability to face an extremely wide range of conditions; but competitive performances are achieved in the usual much smaller optimal wind range.
Just my sailing impressions, and some reasoning about ian's great post.
Last edited by geo; 26th October 2007 at 04:42 PM.