Sam Evans wrote this bit : "The ARC 17 weighs 11.8% less and has a 12.6% larger main, a 14.1% larger jib, a 28.3% larger spin, (20.6% larger sail area overall) than an F18."

Wow. Sounds like a really powerful boat.
But then Bill says it`s a beginner`s boat, NOT built for performance ? Take a Hobie Tiger, reduce the weight by 11.8%, and increase the sail area by 20.6%, and you have a really tame beginner`s boat.
Ok, I get it, aimed at the American market, where either they have no wind, or the sailors are REAL heavy.
My guess is it gets really interesting with the kite up in around 15 knots, looking at the sail area comparison made by Sam. I`d love to see one, but in a nice 25 knot Cape South Easter. I hope the underside of the trampoline is made from UV-protected material, `cos it`s gonna see a lot of sunshine !
Please Bill, be honest about the intended design - It`s meant to be fast & hairy, don`t try flog it off to beginners. Some of them might be fooled by your marketing campaign, buy one & be scared off of cat-sailing for life.
Tell us it`s faster than a Tornado, a F18 or whatever you like, just don`t tell us it`s for two teenage girls who are just getting out of Optimists.
I`m sure it`s a great boat, just seems a pity that it was designed to purposefully fit nicely between both Formula classes, that way it doesn`t have to compete with either. It`s interesting that some folks will buy into the "in-betweener" rather than something that can be raced against boats of very similar designs.
I`m also confused by the fact that it was designed for use as unirig, double-handed, spinnaker or non-spinnaker use, yet this discussion thread is highlighting how critical the CLR position is for each use. Does this mean that the CLR is along the entire length of the hull, as the Dart 18 was meant to be ? If so, my comment on the Dart 18 is that it`s really crew-position sensitive, as well as mast-rake sensitive, and is sailed with a lot of aft rake by the faster guys. It has a deep-v shaped hull along the full length to provide lateral resistance, yet still goes sideways almost as fast as it goes forward, and can`t handle a spinnaker, and also steers like a pig (my nickname for my Dart was in fact "pig". I did love her though.)
I hope you`ve managed to overcome all these obstacles in designing symmetric hulled boardless hulls - in my experience these boats aways have very heavy steering tendencies. Like I said, I`d really love to see one, sounds like a good fast boat suitable for scaring the living daylights out of beginners with.

Cheers
Steve