but compared to current F16 the idea seems to be to move the front beam and daggerboard way back, allowing an higher aspect main
You can't not have a higher aspect sail on a F16 as the boats already have, unless you are prepared to remove sail area. That is because the max sail area, max luff length and max mast height are all limited under the F16 class rules.
So if you want a 15.0 sq. mtr F16 sail (and you do when racing in light to medium winds) then the aspect ratio will always be equal or small then 8.1^2/15 = 4.375
Wouter
Wouter. Utter rubbish, Of course you can have a higher aspect sail on an F16 than are currently built. I think myself (and including all those with GP mainsails) and Hans propbably have the highest aspect minsails at present. Mine is (I think) about 970mm. The A class guys are mucking around with heads around 1100mm. Bigger head in the sail means less sail area DOWN LOW; thus foot length reduces and thus the aspect ratio increases.
Biggest you could go is a head and foot of approx 1.85 and a 8.1 luff, as you say 4.374. BUT no-one has got close to this yet and there are loads of reasons why they would not get that far, possible? maybe, desirable? Prob not.
I also have an F16 design in my head that would look VERY much like the most recent A classes, perhaps even more extreame as the F16 rules allow T foils, you do not NEED volume up front, you can use T fouls to provide the "anti-pitch" when needed.
If I ever get the money to commission a build, the hulls will look like thin rowing 8's (but not as long) very fine bow entry and either thin or planing sterns.
