Folks,
The fact you can teach 7-12 year olds on a 12 ft cat is fact because I've done it for several years at my old sailing club.
I even made sails for each of the 6 12 footers that we had. 80sq ft of sail area and cost me around $200 per sail to make including the cost of batterns.
So that was just basic material cost at wholesale prices.
It was while back now.

All the maths will do is put you in the ballpark or in this case conveniently out of the ballpark.

Interesting to note the 12 ft cats never pitch polled although my youngest at times did drive the crap out of them downwind when the breeze was up and with the spray coming off the front of the boat I was always waiting for him to stick it in. He claimed he knew what he was doing and had everything under control but from the standpoint of an anxious parent.........
The main draw back was the time it took to rig the boats and they were not pleasant on the eye and heavier than I'd like to move around.
You have to put this in context in as much as we had a bunch of Hobie Hawks at the club. (very small dinghy for young kids like the optimist dinghy.) That was our training boat until we got the cats. After the cats arrived we couldn't get the kids to use the Hobie Hawks. The Hawks were near new shiny and very colorful sails. Still they would fight over the old cats.

This whole experience is what prompted me to come up with the idea of a 12ft cat with a free standing rig because in order for me to go sailing I had to rig 3 boats. My own and one for each of my two sons.

So while lying on the beach one day looking out at my kids in the surf I was trying to come with terms of the enjoyment of sailing,the hassel of rigging their boats, what attracted them to the sport and what discouraged other parents after their initial enthusiasm at the sailing school.
Over a 2 week period I did some sketches to design a neat and asthetically pleasing way of mounting the rig.

Sinse then Wouter has developed the concept more in line of a boat for older children and himself.
This is quite different from what I originally started out to do and I will not be persuaded that I can not design a very good boat for 7-12 yr olds that meets all of the goals I'd set for the design.
For me this is about bringing cat sailing to young children,
between the ages of 7 and 12. It can be done, it has been done but in order for it to spread it needs to be done better.

Please feel free to disagree with me as we are all entitled to a point of view. I have just expressed mine and will let anyone who wants to crap on to do it unhindered. I have no interest in all this arguing.
Life is just too short.

BTW:-
I hope what Wouter is working on works out for him and anyone else in need of such a craft. Afterall this is about getting people on the water.

Regards,
Phill