For 2011 we saw Starboard and some others lowering the mastfoot towards the waterline. Most extreme example at this moment is the Starboard iSonic. After a couple of months sailing the iSonic 107 its time to evaluate...
Upgrades 107 vs 111
Upgrades: very deep deck concave, harder rails/more square rails under backfoot, slightly more V (overall).
First the extra V and harder rails. The board has a little extra freedom over lenght axle also less drag at the tail thanks to this extra bit of V. The harder rails are easy noticed, and thicker tail, clearly the board can be used now with some more tailpressure.
The Very Deep Deck Concave, first times sailing on the iS107 board the improvement was not really clear. Lateron I tested the iSonic 107 in 30kn gusts (and even more a bit later), NOW it was finally clear. In highwind for (each) iSonic the board has been improved (and this probably doesn't come from xtra V& harder rails). The board has become more neutral trimmed in overpowered conditions, nose doesn't go upward as easy in the gusts. Especially when making a lot of airtime in choppy conditions it helps, and makes windsurfing fast easier
Also I have this feeling the very deep deck concave prevents rolling over the lenght axle a bit, because afterwards looking to the board shape I was amazed not to notice the extra V on (only the good things that come with more V= speed)
Conclusion Very Deep Deck Concave
- Board becomes more stable in the air in highwind flows
- Rolling over lenght axle reduces a little bit