gee what a surprise beach cats still go around 25 knots. this endlessly asked question has come around again.
the slalom guys at kanaha have a contest where they pass around a gps and they went around 30knots on a good day. there is no doubt in my mind that they are faster than an F18. it doesn't make sense that a spi. would be a speed sail. they were created to power up a boat in under powered conditions. at some point they must become drag. from my experience, less is more in high winds...bearing in mind that speed sailors do use very large sails, but they do keep the drag low.