Wouter, not that I’m asking you to design it, but would it be possible to build an 11 foot cat that would meet the objectives Mary laid out – or is 11 feet just too short? If it was possible, the F11 could address the younger kids at a low cost & lower performance, and the F12 would address the teenage market - which I believe is important.
Everything is possible, but the F11 would only be slower, not cheaper.
That is a concept that is not understood by several in this discussion. A rudder setup for a F12'10" is just as expensive as a rudder setup for a F10. Same goes for the ply used and the sail and the blocks used etc. Cutting the mast down from 6 mtr. to 4.5 meter will not save much money if it saves anything at all. You still have to buy standard lengths of tubing. If a F11 platform still needs 5 sheets of ply, same as the F12'10". The only difference is that at after the building is done you are left with more waste.
You guys are thinking far to much along irrational lines. Price is not always proportional with size, most often the prices changes with jumps like when an additional sheet of ply is needed or when the mast is longer then can be shipped using normal procedures. Going smaller therefor does not often make a product cheaper if the orginal setup was already making use of the cheaper setup.
The only real draw back of F11 is that you are both reducing overall weight (bouyancy) and hull length (pitch leverage) meaning that the sail area you can carry will reduce more then the length of the boat. And if you don't do that then the craft will be noticeably more difficult to handle or control in any breeze. Neither of which is very attractive in giving a well behaved craft to young children. And chances are that you'll spend just as much money.
So summarizing : same money investment, much less performance and worse control behaviour if you are not careful.
Wouter
