RobKoci said:Hmmm. Then where does lift come from?
pugwash said:My pet theory - When you windsurf upwind you lean the mast into the wind a portion of the drive created from the sail is forwards at some angle off the bow. A smaller but very interesting portion of the drive is upwards - lifting the board upwards through the mast step and through your footstraps - so the more you "windward heel" the more upwards lift you create, the less weight is on the water and the faster you go.
The one thing that I use as an indication that I have the foils working right with windward, upwind heel is that the tiller is about 1" to 1 1/2" to lee of the boat's centreline with NO HELM PRESSURE. No helm pressure is really important. I can let the tiller go and the boat still tracks staight with the rudder in that position. It's kinda cool cause is shivers a little like you would imagine the fin of a fish but sticks to that general position. Is it possible (this question is directed at the engineers) that the tiller is acting like the flap at the back of a airplane wing relative to the board? Because that is certainly the position it takes. If that was the case, then the board and rudder would be creating a shape similar to the shape of the sail (concave on the windward side).
Does this make any sense?
Yiannis said:The boats centreline is not pointing to the direction you are going but slightly to windward. This means that your centreboard is pointing to windward. So water is "hitting" your centreboard from the leeward side (more presure) while it creates a point of lower pressure on the windward side. This pushes your centreboard and consequently the boat to windward.