I have conducted a preliminary weight estimate based on a mosquito arrangement. This is where a displacement of 260-270kg has come from.(If you are pushing 180kg total soaking wet crew weight or above, you should probably consider an F18 or bigger!) I would share the weight estimate but it is too hard atm. If someone could do a weight estimate for a Blade or Taipan F16, that would be good. Don't forget that we have a rigged minimum weight to meet already, so that simplifies the weight estimate process drastically, it is the structure that can get fine tuned to bring the weight down below this, then add a bit of lead.

I agree with leaving the hull shape to later, it is really influenced by everything else, including crew weight. With a range of displacements from 180kg 1-up to 270kg 2-up, it makes it very difficult to design for all conditions. Just look at the extreme end of 1-up mode, Gary on Altered. It would not perform with 160kg of crew weight onboard, but is very good in a 1-up configuration.

As far as prismatic coefficients go, we would need data for other successful beach cat designs to have an idea of this. I don't believe that data exists in the public domain. If people have this data it could be very beneficial.

I'm looking into a new method of sharing and contributing to this Open Source F16. Bear with me, my skillz at web administration are newberish at best.