Jake
You are right, the top of the board is thick, but this thick part does not reach the bottom of the slot. The board is loose at the bottom of the slot and this allows it to TWIST. The board does not actually gybe but twist upwind.
I am trying to demonstrate this with the boat on its side in the boat test that was mentioned earlier in this thread;
www.nacraeurope.com/download.php?fileid=10When the board is raised so that the thick bit is above the deck, it just floats evenly in the trunk and so does not 'gybe' for downwind.
Paul GBR7
