I see one small problem.
The only boat that fits is the N20. Would you race an older design (Nacra 6.0, mystere 6.0 etc)even up with an N20? You set the rules so the N20 is the scratch boat. Open up the beam width to 10' so all the 20s can play. But then you will no longer be the scratch boat.
I also find it interesting that the name was changed to OPEN when it eliminates the recent boats in the higher performance range. If you are going to create another F18 class that is two feet longer, you should leave it as F20. There is already an open class. If indeed you are trying to set a more open class at least set the width to the Nacra F20 Carbon. I am sure Nacra did a lot of research and found the 10'6" beam to be the best choice for a 20' boat.
