A friend of mine kept his Catalina 22 in a slip on Percy Priest Lake in Middle Tennessee. This lake is plenty warm. He used to scrub the hull once or twice a year with mask, snorkel, and scrubrush. He said the algae came right off without the benefit of antifouling paint. Steve Tyree, P-15 #2098 "Amy Anne" In a message dated 12/23/2003 3:09:33 PM Central Standard Time, david_hill@idg.com writes: Hi Mike -- I have M17 Hull #619. I kept it on a mooring in Lake Winnipesaukee, NH, for two and a half months this past summer. I put on my mask and snorkel and scrubbed the bottom three times in the course of the summer and it came out clean as a whistle in the fall. Winnipesaukee is a large northern lake, but the surface gets reasonably warm in the summer. I doubt you need any special coating on your boat.