With your light weight and gear combo, I see no "diminishing returns" except trim. For a heavy weight rider, this is another story of course.
I suspect some sail trim misadjustments with your Code Red 10.0 m2 is the main culprit if you experience no difference in early planing WRT your Code Red 8.3 m2. I have tried a Code Red R2 11m2 sail on iSonic 133 + Select RS7 55 cm fin combo and I can start and sustain the planing as of 7 knots of constant wind without any problem. Active pumping is required to achieve that low range : if I wait sitting in my harness, it's not gonna work that early for sure.
Sail trimm I'm using (183 cm x 65-68 kg) is typically the following :
1) 7-10 knots wind : 572 cm luff (i.e., - 3 cm as compared to the recommended 575 cm setting); boom lenght 261 cm (i.e., - 4 cm as compared to the recommended 265 cm setting). Board starts to plane as of 7 knots board speed as determined by GPS measurement and can reach a typical speed of 15 knots upwind and 20 knots downwind.
2) 8-12 knots wind : 573 cm luff (-2 cm); boom lenght 263cm (- 2 cm).
3) 9-13/14 knots wind: 574 cm luff (-1 cm); boom lenght 265 cm( - 0 cm). Typical Vmax are in the order of 24/25 knots downwind. Note that with such a high wind setting, it's not possible to start the planing as of 7 knots of wind for me. The sail is clearly not powerfull enough.
I would suggest you start experimenting different sail trim with your Code Red 10.0m2 sail to find out the sweet spot for light wind planing. Key is you've got to trimm it with plenty of power and grunt because there is a lot of difference between a 10 knots breeze and a 7 knots puff in your sail : the power of a sail increases/decreases with the square of windspeed velocity : that means there is a 2 fold less sail power between 10 and 7 knots of wind...! To compensate for such a loss of power, you've got to trimm your sail with full power : deep draft and a tighter leech by easing both downhaul and outhaul a bit.
The other aspect of your trouble is the planing technique per se with such a short board lenght, but I surmise you know how to dial up your board in that matter, do you ? Where is located the mastfoot position in the mast-track ? Front and back footstraps settings ? Which mast are you using with your Code Red 10.0 m2 sail: a Severne Red Line or Enigma 530 cm IMCS 32 mast I guess ?
Cheers & ride on !
Last edited by Jean-Marc; 16th October 2010 at 02:45 AM.