Hi Bernie, I am re-doing my 62' safari, these are some of the things I thought about for heat though I haven't yet installed my heater:
there are several different heaters on that site.
I am going to install a tiny 1' square woodstove - images here:
I thought for a while about this vis-a-vis safety... I want to be able to work in cold weather with solar power (my airstream will be a live-in studio) and boaters seem to have more options for heating a similar kind of space - these heaters seem to be widely used and I figure my installation will be safer than a boat... if I have a fire, the windows offer a way out. On a boat? I think I would worry more about an escape route.