Keeping Your Boat Warm

Most recreational boats are not equipped with heaters or furnaces.  After all, boating is mostly a warm weather activity,  Heaters of any kind would not be useful or effective on an open boat.  However, sometimes things can get chilly in the cabin overnight or even when out on the water.

First way to keep the cabin warm is to reduce heat loss.  Keep all the hatches and portholes closed as much as possible.  On many small boats, the inside "wall"of the cabin is the inside of the hull so there is little protection against the cold temperature of the water outside.  Placing foam insulation pads against the hull can help reduce heat loss.

Cooking stoves can add a little cabin heat, while your are cooking.  However, NEVER use a cooking stove directly for space heating!  They are not designed for that purpose and they required adequate ventilation to prevent suffocation.  Catalytic heaters similar to tent heaters can sometimes be used, but although they don't emit toxic fumes like a cooking stove, they do consume oxygen so you still need adequate ventilation.  If you have 120 volt power available from shore power or from an onboard generator or battery bank you can use an electric heater.

Body heat will provide a surprising amount of added warmth in the small space of many boat cabins.  The human body puts out about as much heat as a 100 watt incandescent bulb.  If the hull and cabin are adequately insulated this heat will be preserved and will accumulate, often enough to keep it quite comfortable.  The amount of heat people can produce can be surprising.  I once had to open the doors and windows of my house in Utah during a family visit when it was about 17F outside because heat from 20 or so people inside made it too warm, without any other heat on in the house!

Of course, if you happen to have a yacht or cabin cruiser that is equipped with a heater or furnace, be sure to take advantage of it!  You will still want to minimize heat loss and always be sure the heater or furnace is in good operating condition and is properly vented the outside.

Stay warm on the water!