GO, thanks for the mention of the Origo as a heater. Having it in the cockpit would have helped my coldest sail ever this spring. When I got back in the car and warmed up, I recall thinking that if I had a tarp over my lap, heater under, and my head and torso out.what a warm way to sail on a cold day! Have to be careful not to have something burst into flame or course. Anyway, thanks for the possibility of a cockpit heater. John, I too would love to see photos of your M15 installation, or just a description with some detail. Where have you put the Charlie Noble? Thanks for the info. And for the reminder about a solar vent. David Message: 4 Date: Wed, 10 Jun 2009 09:09:33 -0500 From: "John R. Butler" <theoldcat@cox.net> To: Boats Montgomery <montgomery_boats@mailman.xmission.com> Subject: M_Boats: cabin heaters Message-ID: <0B18314C-49D6-4728-A00D-8965457BD79A@cox.net> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed I have had successful cabin heaters on a Cape Dory Typhoon, a Cape Cod Catboat, and now my M15. I always had a good Charlie Noble for each, and I believe that using an external combustion air source is counterproductive to one of the benefits of cabin heat: Any vented, internal combustion heater lowers the relative humidity in the cabin by raising the cabin temperature. I used natural oak charcoal for fuel on the first two, and Sterno "canned heat" on my current heater which had to be built smaller for the smaller cabin size. Solar powered cabin ventilation provide more than enough combustion air. John R. Butler theoldcat@cox.net First M15 was "Joy", '83 #264 Now sail "Rejoyce!", '86 #361