Originally Posted by jogi1111
Take the iS122. Take a rider with 70 kg and he would have no problem to sail a 11.0 on that board at light wind (I can !)
I respectfully disagree. The iSonic 122W75 paired with a Select RS7 55 cm fin and a Code Red 11m2 sail is a total pig when sailing upwind: zero upwind pointing ability. By comparison, HS105 is vastly superior (a few degree less than a dedicated FW) followed by iSonic133W85. Rail shape, scoop-rocker line, deep concave with a center spine, overall hull lenght, mast-track and footstraps inserts positioning more on the back of HS105 are apparently important contributors to such a large difference. Planing as of 7 knots is no problems with any of the 3 hulls with my 65 kg, however.
Upper wind range is as follows: HS105 (5.4 sail+ 26 cm fin) 25 knots > iSonic122W75 (6.6 sail + 32 cm fin) 20 knots > iSonic 133W85 (8.2 sail + 40 cm fin) 15+ knots. Wider and thicker boards just become less and less controlable in higher wind and chop, especially with too large a fin for me. Very small fins do not work on super wide flat-bottomed iSonic whereas they do work as a charm on the HS105 for my light weight.
As for a heavy weight 105 kg pal, he's on a FW + Code Red 11m2 sail in such light wind. Forget using small HS105 or iSonic 122/133: he just sink them all which is plenty inefficient in low wind range. Just to show that 40 kg body weight difference means a lot: to be on par with medium 12-18 knots wind, he's on a Carve 162 + 52 cm fin + 9.5 m2 sail combo while I'm on Kombat 86 + 30 cm fin + 6.9 m2 sail combo.