Been there !! Done that!! Christmas boat parade is pretty big here on Long Island and we participated in it once. My 1st advice to you is to get a slip with shore power to view the parade from your boat and plug in a heater and stay right there and you get to view the entire parade as it passes.We enjoyed this way much better than participating and way safer and way less of a potential headache.Potential issue is going to be fogging of your windshield and plastic windows/sidecurtains. The more you have conversation , the foggier your interior will be. NOW to answer your initial question I will tell you what we did that worked out pretty good.Very important to get boat heated up completely hours prior to leaving the dock.We put an electric heater in our aft cabin (lowest and coldest part of the boat) and let it run for approx 5 hours.Entire boat was toasty warm .We let the cabin warm for 3 hours and then opened the cabin door and let the heat overflow into the cockpit with all canvas zipped closed.We used a Mr.Heater propane when we unplugged and left the dock.We placed it in the aft cabin and only used it during idle speed which for us was the entire time so this worked quite well.Bring a spare propane or two for sure.The Mr.Heater was plenty warm on the low setting.I think some of the newer MrHeaters come with a built in fan which is a good idea for circulating the hot air. clearly you must use common sense as to where to situate the heater and constantly take turns taking a look at it. After a while we moved the heater to the center of the cabin floor so we could view it from the cockpit with little to no extra effort.as I previously stated ,this worked out quite well with plenty of heat as long as you keep everything zipped closed, HOWEVER it is waaaaay easier and we found much more enjoyable to just get a good slip and plug in to shore power and watch the parade go by. Charlie
