About this time of year, sailors in the temperate zones are looking for inexpensive ways to warm the cabin. We’ve done several reports on LPG systems like the Dickinson heater, but you don’t have to install an expensive built-in heating system just to get you down to SoCal or south of the Mason-Dixon line. However, when opting for one of the less-expensive options, you do have to use common sense.
Our report from nearly two decades ago comparing the various heating options “Boat Heating Options,” dug into the thermal limitations of the various fuels as well as details of various permanent and portable heating options. Although the products themselves have evolved since that report (though not significantly) and prices have gone up (very significantly, in some cases), the report still offers a good overview of the options, ranging from simple to complex.
The most simple option is also one of the oldest, inverting a clay-pot over an oven burner will serve as a good source of radiant heat in a pinch. But bringing BTUs to the sleeping cabin often sends sailors looking for more portable solutions. Keep in mind that the portable cabin heaters – whether they are electric or fuel-burning – can be dangerous. Even the simple clay-pot option, because it involves an open flame, has its risks (more on that below).
Many readers have shared their cabin-heaters close-call stories with us. Fuel-burning heaters require oxygen, so going to sleep in a closed cabin with an ignited fuel-burning heater (or stove) invites asphyxiation. Other stories have to do with articles of clothing, like a parka, or a sleeping bag falling off a bunk onto the top of a heater and catching fire.
Most electric heaters have an automatic overload heat shutoff device, an important safety feature. An automatic shutoff device that engages if the heater tips over is a good feature, too. Some PS readers say they prefer oil-circulating heaters, rather than ones that use an integrated fan, which if it fails can lead to circuit overload, and potentially, an electrical fire if the thermal fuse does not work as designed.
If you purchase a heater with an automatic overheat shutoff, test it out to make absolutely certain that it works. Drop a big, old towel on it and see if it shuts down without catching fire, making smoke or acrid fumes. Do this outside, in case it doesn’t work. Keep the receipt.
A few years ago, one PS reader told us he had trouble with a portable heater from West Marine because heat apparently distorted the fan blades, which contacted the cover, stalled the motor, and tripped the heat overload shutoff.
Our most recent experience with a portable heater was the alcohol-powered HeatMate, which is still working fine aboard contributor Frank Laniers Union 36. The HeatMate has an advertised output of 5,200 BTUs. The thermostat is a horizontal damper that slides over the throat of the fuel canister, limiting the size of flame.
The HeatMate can even convert into a stove by simply removing the heater lid and flame spreader. We placed a quart of water in a standard teapot on the HeatMate, and we had water hot enough to make a cup of coffee in roughly 11 minutes, with a rolling boil achieved in just less than 17 minutes.
With any open-flame heating system (including the clay pot/stove-top option), it is important that the boat is properly ventilated, to avoid carbon monoxide poisoning. Along with the potential fatal risks of carbon monoxide poisoning that is associated with any open-flame heater, most alcohol heaters also have a risk of spilling, since they are designed for camping, not for boating. For this reason, many insurers may prohibit their use on your boat.
Back in 2005, we tested portable heaters for a report comparing a range of portable heating options. One conclusion (not surprising) was that although the 12-volt heaters like the 3000C Back Seat Heat Plus work, they quickly will run down a battery if you are not connected to shore-power. In a follow-up test we looked at the popular Mr. Buddy propane heaters, which, for safety reasons, are not recommended for boats. We also did a review of a well-made, wood-burning stove from Navigator Stoves.
If you have no plan to push quickly southward, then you will likely start thinking about insulation, as well. We’ve featured some do-it-yourself insulation projects in our previous issues. Sometimes, improving insulation is as simple as installing a new liner. If you’re liner is sagging and useless, here’s a helpful step-by-step article on installing a new liner on a sailboat.
If you’re serious about beefing up insulation, according to past PS contributor and author Steve Dashew, Armaflex is a desirable material for this project. One couple recently documented their insulation project for Ocean Navigator. I also found this YouTube video of Armaflex being glued into a bare hull.
Many other sources offer what is probably the best solution for a cold cabin-follow the sun!
PS will be looking at a range of more sophisticated heating systems in the future. If you have some systems we should look at, or experiences to share, let us know in the comments fields below or by writing me at firstname.lastname@example.org.
The most effective way to keep warm at sea on cold nights is a warm body beside you. Next best is a fleecy sweatsuit as pyjamas and a wool blanket.
I once did a delivery in late January from San Francisco to Ventura on a Yorktown. I wore a snowmobile suit with a survival suit over it. It was so cold out there that no one else could say on deck for more than 1/2 an hour. I was actually too hot and had to open the survival suit for some cool ventilation. I did the entire night watch as the only one on deck. The key here is that I was prepared for the very cold weather. If ice had formed, I would have been just fine.
I sail on the East End of Long Island and Long Island Sound, and love sailing during the shoulder seasons. During the winter, I like to keep the boat in the water because there is always something to fix or upgrade, and it is far easier to work on the boat when I dont have to climb up a ladder to with tools. I am able to do this because some years back, I added a diesel heater, a Dickenson “Lofoton” floor mounted stove with a cast iron top, and I have never regretted that upgrade. In the shoulder seasons, when I get chilled on deck, I go below into a toasty cabin, and the cast iron top lets me heat water for coffee, or a mug of soup. At night, if we decide to sleep on board, I dial it down a bit and wake up to pleasantly warm cabin…and a warm cast iron stove top so that I can quickly make a pot of coffee! If you have the room for it, it is a great addition. BTW, my boat is an 1985 Endeavour 35
Mr. Buddy makes an indoor safe heater, model MH18B. I’d like to see your opinions on it in some future update.
When sailing my older boat (San Juan 28) in northern British Columbia years ago even the Canadians were complaining about the weather. In addition to using the clay pot over the stove burner I had collected some large palm size rocks which I heated over the stove and placed in the shallow dry bilge (a trick I learned from an old Star Trek episode). Both took the edge off the cold and dampness overnight.
I have a Dickenson Newport diesel fired unit. It provides plenty of heat, has a virtually unlimited fuel supply from the ship’s fuel tank, and has a nice ‘fireplace’ ambiance with a view of the flames through the glass door. I’ve had it for 28 years and use it often. My concern has always been the risk of carbon monoxide poisoning when left on overnight, which I have never done. I would like to know the opinions on the CO issue.
We used a Mr. Heater on our 2003 Catalina 350 at the end of the season in New England (end of Sep, early Oct). However, we never used it when we were asleep, moving, or during a rolly anchorage/mooring. We keep the canisters in a homemade propane “locker” under the cockpit table (4″ PVC pipe with cap on one end and screw cap on the other. Holes drilled in the bottom to let any leaks drain). Our boat has an open transom in the cockpit, so any fumes should drain off the cabin sole. Propane canisters NEVER spend the night below deck. We turn the heater off, remove the propane back to the propane locker and ensure the heater is cool/secured before going to sleep.
Not the “ideal” solution but one that warms up the salon on a chilly night or cold morning. So far, no great problem with condensation (always an issue with propane). And the Admiral enjoys getting up to a warm cabin. We’d love to have a Webasto diesel heater, but the cost isn’t in the sailing budget.