On spot, but the quoted sentence may be misunderstood. The boards are not supposed to create unlimited "lift to the upwind mark", only the necessary to keep forces in balance. The boat automatically adjusts the leeway angle (angle of attack) so the underwater lateral lift component is kept equal to the aerodynamic lateral lift component (sails).

I would also like to add some important details, however obvious for some of you:

1) Some designers prefer to separate vertical and horizontal foils in order to optimize each specialized foil independently (example: Rave and Trifoiler).

-Vertical boards are optimized to generate lift with minimum angle of attack and drag.
- Horizontal boards are optimized to generate a definite lift to keep the boat at the desired attitude (lift = part of the boat weight) or foilborne (lift = total boat weight)with minimum drag, regardles the angle of attack.

2) Other designers prefer canted boards/Bruce foils because they make it easier to self-stabilize the boat. Their lift is in the general direction of the sails' center of lift, so the boat almost wouldn't heel when foilborne. Take a look at Hydroptére.

3) If we disregard weight, complexity, price and other practical aspects, the best performance should be with a pair of vertical asymetric foils for lateral lift, plus a pair of canted/banana foils or horizontal foils (not sure which one) for horizontal lift.

4) It is not for performance reasons that ORMA 60 tris use curved/banana boards instead of straight boards: it is for practical reasons. My 27 ft tri has straight canted boards and the most difficult task on board is to insert and remove them from the amas. I can't imagine doing that on a singlehanded 60ft tri.

- It is a lot easier to handle a large curved board than a large straight board. Ian Farrier was probably the first to notice this and designed the F27 prototype with curved foils. The straight foils hit the dock when up, so you can't dock unless you take them out or live them in the water.
-The advantage of canted/banana boards vis-a-vis horizontal foils is the ability to reduce their span (raise partially or totally).
- It is a lot easier to raise a curved board than a canted straight board. A curved foil can be "hoisted" from the shroud or mast, but how do you pull a long and heavy straight board to the outside of a float?



Photo taken after the first sea trial: the board doubles as a backrest for the crew after the first attempts to pull it out failed. The applause is sarcastic.

Regards,