Thank you! Yes, the Fast Cat has a different shape cowl and the hull is a bit shorter than the earlier hull and slightly different bottom design (shallower tunnel depth and width I think) as well, don't know if there was much of a performance difference though. All of the Prather tunnels were designed to use a turn fin though. This one is actually a fairly new build, put it together a couple years ago, still have a NIB Lap Cat 1 and the full array (31", 40" and 46") of the Deep Vee's in the build que. I don't race but really like the old Prather stuff....