About the best 2 years of my life ...
I spent two winters on a 30 foot sailboat in Southeast Alaska. I loved it, plan on doing it again. The inside hull was insulated with one inch closed cell and then covered with rug material. You could lay up against this in a T-shirt and it felt warm. This insulation was already in when I bought it. Being in a harbor with commercial fisherman insured a great water supply as well as fresh fish almost on a daily basis. Heat from the smallest sized diesel heater keep it plenty warm. With a little snow on the deck that acted as insulation, I usually had to open the hatch to keep from over heating. Since the heat was dry, no moisture collected except when I occasional boiled water cooking. I had no problem having a ‘dirty heater’ that required cleaning. We had winds gusting to 100 mph once in a while in our floating harbor. Like MattGardner said above, it was great. Being in salt water, it didn’t require extra circulation. Could hear the whales singing occasionally through the hull.