Onboard boat lamps and lanterns are designed to provide controllable light and be smoke free and odorless when fueled properly. The key to obtaining desired results is a well-designed oil lamp or lantern, a clean, properly-sized fiberglass wick and a clean-burning odorless paraffin lamp oil. Simple stuff.
I am sure you have operated your lamp or lantern when your boat is closed up for several hours and noticed an accumulation of fumes that are at best annoying and at worst dangerous. The less-polluting particulate released by a fuel provides safer air to breathe.
A soot-free chimney provides clear evidence of a clean-burning fuel. Keep in mind wick control is essential for efficient use of fuel and better control of light and smoke.
People have recommended mineral oil. I tried it and could not get the wick in my lamp to even wick up to a point to light. I tried priming the wick with the mineral oil hoping the wick would draw the mineral oil up for use. I lit it and had a small flame until the prime burned out. Mineral oil was expensive, did not work and ruined the wick. $6.00 to replace the wick.
I have used kerosene mixed with diesel fuel in an emergency and found it to be very smoky and it stinks. Believe me, it had to be an emergency to use that stuff. Took 2 hours to clean up the sooty mess.
I have also used Tiki torch fuel in a pinch. It even says on the bottle exterior use only but it was all I had; smokey, smelly and burned out very, very quickly. The chimney was black with soot in 30 minutes even with a small flame. That stuff is not suitable as a fuel for lanterns or lamps just because of the soot on the chimney and the burn rate.
The use of quality paraffin lamp oil intended for oil lamps and lanterns will provide a relatively smoke-free flame with little or no odor. Paraffin oil has been the best choice for many years.
There is no economy in using a cheap fuel substitute for a quality paraffin fuel. In my experience, the Firefly CLEAN Lamp Oil is the best value for the money. Either fuel will provide long wick life, cleaner burning (clean, soot-free chimney) a brighter flame and long burn times.
“May your winds always be favorable”
Capt. Phil Tyson