Back to way at the top of the threads someone mentioned the H16 and it's asymetric hulls. The H16, P16, H14, P18.... boardless boats were designed with asymetric hulls to produce lift w/o boards (notice that flat side is out and curved side is in...air/water foil. Ok... the biggest problem with the asymetric "lifting" hulls of these boats is the aspect ratio. Since the hulls are very long vs. their draft, they are low aspect, producing less lift for a given speed at the expense of more drag. Now, lets look at the I-20/18. Their boards are high aspect. With a hight aspect foil, the lift to drag ratio if increased significantly (more lift--less drag). What Jake was trying to say earlier, but used different words( I think) is that if you look at something like a jumbo jet/cargo plane their wings have more draft/curve in them to produce more lift at a lower speed w/more drag and limited top speed. While if you look at a higher performance aircraft... I like to use the voyager as an example (ya know the little white plane that flew around the world) it had very very high aspect wings (foils to us) wich created a high lift to drag ratio... ok... they did that for efficiency. While a jet fighter which flys at higher speeds also has a less drafty/flatter wing because it has more air flowing accross it and can produce the lift it needs with less draft at higher speeds with less drag... (yeah...drag like reading this post.......Zzzzzzzzz)
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<br>What does all this boaring crap mean to us? If we had high aspect asymetric daggers we could use a smaller board and get the same lift as a larger symetric board with less drag(increased board efficency with lower wetted surface). HOWEVER!!! since in some conditions (ligh air) we need more lift we would need more board or a board with more draft, which gives more drag. Sooooo do you optimise the board for a wind/hull speed range? Guess so....what do you do then when your boat is sailing outside the design range? There in lies the problem. Designing a board that is asysmetric and produces the optimum lift at all times is IMPOSSIBLE. As hull speed varies, lift varries...drag varries... what is best at one point is not at all others. The one thought though is... if you build a board with enought lift at slow speed then you can just pull it up at higher speeds to reduce drag/heeling forces. Well even this isn't great, at higher speed you need a less drafty board (board... like me writing this post....and you if your reading it). So nothing will ever be 100% optimal, however their is an A class boat out there with Asymetric boards... don't remember which one though.
<br>So... I think yeah.. if you want to remember to tack your boards all the time, but go faster... asymetric, but if you wanna K.I.S.S. (keep it simple stupid) then go high aspect sysmetric. I'm not gonna try to calculate the difference in drag vs. lift vs. too much weight on my right cheek vs. my left. I'll leave that up to someone else... bet you can't guess who!
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<br>Well I've rambled for WAY too long....
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<br>Will<br><br>