Wood should be dry and hard. Soft and semi-rotted wood, bark, or compositions boards produce little heat and will rapidly clog up the boiler tubes and stack. A stack blower may be used if the engine is rather larger than usual or if the boat is a bit too heavy for the engine and boiler combination. A good fire with good wood does not require a blower. Leaking propane forms in puddles in all of the low spots in the boat ready to be ignited at the slightest provocation, causing extremely serious damage.
Propane also requires lots of additional air for complete and efficient combustion.
Rapid use of propane will frequently cause the bottles to freeze, slowing the system. Oil combines many of the attributes of the first two alternatives. It tends to be a bit noisy, and requires some sensible attention, as the standard safety devices that one is familiar with on household oil burners are absent. These oil burners rely solely on the awareness of the operator for safe operation. It boasts unequaled simplicity of design, construction and maintenance.