Portable heaters come in many different types and sizes. One can find alcohol, solid fuel, propane, electric, diesel, forced air, and forced water as the more common sources of portable space heaters. Each of these different types has their own benefits and issues. The ABYC (American Boat Yacht Council) considers space heaters as unattended appliances and therefore must meet certain special requirements for marine use.
As a general rule, electric heaters are considered safer than the fuel burning type. Whether you have propane, alcohol, diesel, kerosene, or a solid fuel heater, all of these give off carbon monoxide and deplete the oxygen in the area. Liquid fueled space heaters put out lots of heat but must be used only with plenty of ventilation and then only occasionally due to the risk of carbon monoxide poisoning. Never take these heaters into confined spaces; the result can be deadly. It is also important to remember that propane is heavier than air and does not dissipate rapidly. If you smell propane, promptly ventilate the area and do not turn on any spark producing device such as an electrical appliance or switch.
Electric space heaters should not be used around moist or damp areas as contact with water could result in an electrical shock to the user. A portable electric heater suitable for use on your boat is built specifically for marine use. It has a casing made of stainless steel or aluminum and it will last longer in the moist and humid conditions found around a boat. Marine heaters often have additional safety features designed with boats in mind. Some models are designed with stay-cool housings reducing the risk of fire from nearby combustible materials. Others have tip-over protection that will shut-off the heater should a wake or other sudden motion knock it over. Look for portable heaters that have a thermostat control, multispeed fan, and a stable base. Plug your portable heater directly into an outlet that can handle the wattage, and ensure the plug fits tightly and make sure that it has a three-prong safety plug. Never plug it into an extension cord or power strip or into the same outlet as other heavy-duty appliances.
Consider how you plan to use the portable space heater. Supplemental heat in colder spaces, emergency heat, or will it be your primary source of heat onboard. Safety features that shut off the unit should include overheating, low oxygen levels, tip-over, and touch. Portable heaters are not a good choice for preventing freeze damage in the engine room, use an engine room heater designed for this purpose.
Claim data from one insurance company indicates that the leading cause of winter vessel fires is from unattended portable electric space heaters that have stressed the vessels AC electrical system. Placement of the unit is also important, especially in smaller spaces. As a general guideline the heat portions should be no closer than 36 inches from flammable materials, not be placed on combustible surfaces such as carpets, and don’t have flammable liquids in the space the heater is being used.
Captain Pat Carson