First, you need a ventilated stove if you are talking heating
a boat with ambient temps much below 50 degrees. If the heater isn't ventilated the water vapor in your breath and the by product of combustion condense on the interior
of the boat. I spent one winter in Norfolk, VA heating
with a couple of electric
heaters. The condensation
was so bad that I thought I had massive deck leaks
. Every surface was wet and water would pool in low areas. Everything in the boat was clammy and unpleasant. Was the most unpleasant 3 months of my life. Fortunately, the winters are short in Southern VA or I probably would have given up on cruising outside the tropics.
Any bulkhead mounted heater should be mounted as low as possible, preferably on the cabin sole
. Heat rises and the higher the heater, the more a fan will be needed to distribute the warmth. Had one boat with the stove mounted about 4' off the sole. Without a fan, my head
would be sweating while my feet froze. In any case, a fan will probably be needed to distribute the heat. The higher the stove is mounted, the more powerful and amp hungry the fan will need to be. Also, the longer the flu, within reason, the better it will draw and the more trouble free heat it will put out.
Propane is the simplest way to go and probably the cheapest. The problem is keeping the beast fed. If you have smallish bottles and/or want to hang out away from a marina and a car, refilling the tanks
gets to be a pain. My new boat came with a propane catalitic heater. It goes through a 1lb bottle in a few hours on high setting which is necessary when temps drop below 50 degrees. Too expensive to use with the small bottles.
Diesel is great for long term use in all conditions. They will heat a even in arctic conditions. Highest heat output and most boats carry a lot of fuel. Diesel heaters are expensive to install, however. A separate filter is reccomended, they either require a day tank or a fuel pump
, and running the 3" flu is often a challenge. The cost of flu pipes, pump, etc can come close to the cost of the heater, itself. There can be backdraft problems though think that is mostly caused by too short flu run. If your boat is going to live in cooler areas, a diesel cook stove is a good source of heat and cooking
Wood stoves work well. The problem is dealing with the ash and storage of fuel. Big advantage is the fuel is free if you're coastal cruising. Plenty of dead wood available in the more remote
areas. For daily liveaboard
use, dealing with finding fuel around a marina and clean up of ash is a chore.
If you want true liveaboard
comfort, the forced hot air or hydronic heaters are the way to go. They can be thermostatically controlled for consistant heat output. It is a dry heat and can be distriubuted to all areas of the boat. The heater can be tucked in some out of the way place that would be otherwise dead space. The big problem is they are expensive. The ducting is relatively large, do take up a significant amount of space and a problem to run that could be a concern especially on smaller boats.
Alcohol to me is a non starter. Fuel is high in cost and low in heat density. Unvented, they put out a lot water vapor.