i'd use diesel.. Wallas is awesome!
I sail Ceil (31' Trimaran from the 60's.) I pulled the propane out because it was over 30 years old. I replaced with a Wallas diesel stove that also works as a forced air heater in the cabin. This stove rocks! It is mounted in the counter top (mine is as I have a tri so don't need a wobbly stove) but you can install it on gimbls I suppose... there is only a 1 1/2 inch exhaust tube that in my installation vents out the side of the hull just under deck level. There is NO diesel smell and this unit is completely automatic. It is controlled by an on/off switch and a temp knob. When the top is open it acts as a cooker - the stove top is temered glass and large enough for a 2qt and a 10" skillet to coexist. The stove becomes a forced air heater when the top is closed (like a laptop computer sort of). You should at least check it out - it also vents all the combustion produced water out with the exhaust gas so the boat ends up 'drying' out inside instead of getting wet like with propane or alcohol.