I had an Aqualon cover custom made 12 years ago for my Supra Comp and it is still in great shape. Cost was $500 back then. Aqualon is waterproof so there is a vent. I travel with it on and have had zero problems with boat finish. It pulls down very tight with a line running around the base and then 7 lines connecting underneath the boat and 2 on the platform. I am having it modified to go around a Roswell tower today (about $125). The guy who is doing the mods for the tower said he makes boat covers out of Aqualon today. Very durable stuff. If I get another boat, the first thing I would do is get another Aqualon cover made.