Simon, I must read trough my collection of old "Multihulls" magazines to back up this, but I think the boats racing in "Thomas Crown" was Formula 40's (or Prosail 40's).

The tri in Waterworld was actually two identical boats, one rigged with the strange rotating rig and the other one with the traditional rig. In both cases, the full crew was sailing the boat from below deck!
Both boats was ordered brand new from France, and assembled in Hawaii before they was made to look 200 years old. The design was very hot and fast when delivered.

I remember "Multihulls" ran articles about both movies. Still have the issues in the bookshelf, but finding both would take some time..