With all the talk about curved and RLB (ridiculously long boards), someone mentioned the same lift/lateral resistance could be achieved by moving the daggars forward.

Would anyone care to elaborate? If this theorum is true, would it make sense to just have shorter/straight boards further forward?

Ask Bill Roberts about this and the wild sucess of the 21 that sailed around Fl for a while I believe.

It's more complicated than fore/aft. The boards/rudders work in conjunction to provide the necessary lift (lateral resistance) to make the boat go forward.

At low hull speeds, the amount of lift created per area of foil is less than at speed (related as the square of the velocity, just like drag). Therefore at lower speeds, you need more board to provide the necessary lift to "stop" lateral slippage.

The only thing that moving boards forward or aft does (with conventional straight foils) is change the relative center of lift of the foils in relationship to CE/CL of the sails. You don't create additional lift, you only move it. i.e. if you move them further forward, you will load the rudders more and change the helm.

With regards to length, typically the designers are going for efficiency. The aspect ratio of the board is directly related to their efficiency. Longer boards are more efficient, but don't produce as much lift at low speeds and have a MUCH narrower grove. Short board provide more lift at low speed, however are less efficient, but have a wider grove.

One other factor is "tripping". Longer boards will fly a hull faster than shorter boards b/c of their increased lever against the hulls.

It's all a trade off for one performance gain against another. Build something that is theoretically more efficient, but won't ever hit it's range and it's likely to be slower than a less efficient platform that will be able to reach it's operational range.

gotcha.. Figured as much. Build a high-performance boat with a narrow groove to keep the racers happy, but at risk of dissuading the general weekend warrior types who rarely find the groove...?

But then it won't tack W.A.P. (worth a poop).

I don't think they think about it directly like that, but I think that is the root of the process. A word comes to mind and that's "sailability". If the boat "sails well", it's design is probably pretty good and you'll feel it feel good more often. I sail on a boat with a super narrow grove and you can tell when you're not there. It is super fast, but you have to be on your toes at all times or you're not getting close to hitting your number.

All I knew to feel when I started sailing was whether or not a hull was flying. I would have had as much fun on a spin-less F18 as my Nacra 5.2 and not known any difference. Now, finding a spin-less F18....

Found one, taking the spin off costs extra though.