The Mr. Heater portables are not a good option for the boat. They are made to be run indoors and are designed to burn up most of the gas and fumes. As such the design is not windproof. Any small amount of wind across the heater will blow it out. I tried using one last year and had to return it for that reason.

Next I got one the propane tower heaters and that worked pretty well. Without any type of enclosure all that heat goes straight up and out the boat. That heater was then recalled due to issues of it catching fire!!!!! Mine never did but a heater that catches fire is the last thing you want on the boat. I see that they are selling them again so that flaw must have been fixed.

This year I went with a propane catalytic heater that you attach to the 20lb propane tankes. That thing can really throw some heat and it is directed out the side instead of straight up. I had a tempory enclosure setup on 3 sides of the boat and it was burning us up in there on high. Even with my enclosure the wind would whip through every once and awhile and mess with the flame but it never went out like the Buddy heaters.