When I used to teach sailing many years ago, the season generally began in March—a month that could be bitterly cold in Britain’s wonderful climate. So it wasn’t surprising that when supper was cooking the crew were cheered up a little by the additional warmth.
The only propane-powered heater option at that time was the truly nasty catalytic heater that also vented the products of combustion directly into the cabin. As burning one gallon of propane produces around 0.8 gallons of water, these sources of heat inevitably turned the cabin into a dripping crypt streaming rivers of condensation, with the added threat of death from carbon monoxide poisoning. So you ended up opening the hatches to stay alive and, in doing so, let the cold right back in—ahh, the good old days!
Happily they don’t make those things anymore and new, safer propane heaters are on the market: