Simon
I don't think the Inter 18 was produced to be a F18 boat. The Inter 18 has a carbon mast and snuffer system that would have to be changed to race in the F18 class. For a while the Inter 18 was allowed to race with the carbon mast but not anymore. If you are going to buy an Inter 18 you will have to change the mast and snuffer system to race F 18 now. That cost might make the Inter not such a great deal.