Moths is a no brainer dude. Gone from 30 at the Worlds a decade back and the same people each time, to possibly 80+ in Weymouth next week. To get a new Prowler is a 12 month waiting list, and Bladerider is prob 4 to 6 months. And the other manufacturers are similar. But the moths went from being possible footnote in history to one of the most popular things happening in sailing.

A-Cats on the other hand had one of their most successful worlds outside of Europe with 98 boats.

But the old skiff moths can be retrofitted with foils rather easily.

For the A, rebuilding a centreboard case (and possibly moving to another part of the hull) is a different story. Does the boat have the structure to take loads in an area not previously designed for it? And development of boards would start in earnest.