Had to put the project on hold for a few days to help my sister install in new well pump at her cabin way up in the north end of the Idaho panhandle. Of course the day we picked to bury the water and power lines it rained about half an inch!
I would love to have a simple bulkhead heater like a Dickinson Newport but though it is a 42 footer (Cataliina) there is no place to put one without being seriously in the way unless I do some major interior reconfiguration. If it was not the 3-cabin version it could be done. Then there is the issue with the boss wanting hot water...
Found a new Espar M-II 12 kw unit on eBay and it is on order. It puts out 1.2 to 12.0 kw (4000 to 40,000 BTU/hr) depending on the load. It will have enough output to heat the whole boat. There is already a "red dot" type heater in the main saloon built up from a fan I had left over from a control systems project and an auto heater core from my local radiator shop. Will build up one more for the main saloon, one for each of the 3 cabins and one in the forward head. I will try to remember to take some photos of the project as it gets installed.