I made a few mistakes with our Islander. First, I actually added up the price of everything I bought (I keep a log book), plus club dues and slip fees for a year. I believe that was the second year we owned the boat. Then I compounded that mistake by dividing the total by the number of times we went sailing that summer. As I recall it worked out to just under $1,000 per boat ride. I never did that again and never shared it with the admiral.
I justify this whole deal by including the social side of boat ownership. Hanging out at the place, telling stories and drinking a few beers with friends.