Heat

[Dale Tanski]

It's beginning to be that time of the season again.... the heating season.  One of the luxuries that I added to the boat by necessity turned out to be a great addition overall.  The refit of Maruska took about a full year and because she was over 350 miles away, I made a trip every other weekend for a total of 31 trips to make that happen.  This only got her to the stage where I would trust her to get my family from the Chesapeake to Buffalo NY under her own power and on her own keel safely.  This meant I spent half of the weekends of their winter in Maryland, and to my surprise it gets very cold down there.  I would arrive at the boat somewhere around 2:00am on Saturday morning and I often saw temperatures in the low teens.  By the afternoon it would get to the mid 40's and the ice would leave the marina, but at night it got very cold once again. 

Like most marinas they had a rule about boats plugged in unattended on the hard.  My solution was to purchase a Espar diesel fired forced air heater that I temporarily installed in a set of companionway boards that I dropped into place when I arrived at the boat.  When I left they and the heater simply stowed below when I headed home.  I used a 5 gallon can filled with diesel placed on deck which I simply dropped the fuel feed hose into.  One 12 volt dc power connection and the Espar fired up in mere seconds.  Once that was running I plugged the boat into shore power and supplemented the heating system with a small 120 vac quartz electric heater that I kept in the V-berth.  I would scurry into my 30 below nummy mag and chatter myself to sleep.  By morning the boat would be in the 60's and arriving back from an early breakfast the boat felt quite cozy.

Throughout the weekend it was T-shirt warm no matter how cold or how windy.  The electric heater in the V-berth never restarted once the boat was up to temperature.  A boat out of the water is far more susceptible to the cold than one in the water as the surrounding water never gets below 32 in fresh and 28 in salt water.  In my case the entire boat saw whatever the outside temperature  and wind chill was.  I refilled my diesel can just before I left for home every week. On average it only used approximately 1-1/2 gallon over the typical 36 hour period that I stayed there.  A lot of that fuel went to bringing the entire boat up to temperature from where ever it started.  The Espar is now permanently installed and is a wonderful addition especially late into the fall.  I try to keep the boat in at least until November as I love sleeping aboard during those stormy autumn evenings when there is a distinct chill in the air and the boat is a rocking and rolling. There is just something about having heat aboard, especially arriving to a toasty warm boat. 

I will only speak to nonsolid heat sources as to me a wood or coal fire aboard a boat that has a fifty gallon diesel tank just doesn't make sense and I worry about safety.  There are two distinct ways to go, diesel fired or electric.  Diesel of course allows the heat to continue once you shove off.  With an electric  shore power system, once you unplug it's over. 

   Electric – You can run small portable resistance electric heaters inside the boat.  The two basic types are a heating coil with fins and a small circulating fan or a coil surrounded by an oil reservoir.  In the oil filled unit, the coil heats the oil and the oil heats a finned container that heats the space. The advantage of the oil is similar to that of a cast iron radiator, mass.  Once it gets warm it stays warm, and provides a more even level of heat.  The disadvantage is its larger size and additional weight.  The other style of suitable resistance electric heaters just heat a coil surrounded by aluminum fins and then utilize a small fan to disperse the heat into the space.  They produce heat almost instantly and when they shut off the heat stops almost instantly.  This on/off heat mode most often is noticeable and may not feel as comfortable.  If you need heat now this is the way to go but your boat is bigger and colder than you might think. 

If you are in a climate where you may desire AC, invest in a heat pump unit that heats and cools.  This type of unit extracts heat out of the water surrounding your boat and transfers it into the boat.  In the summer it takes heat out of your boat and transfers it out into the water.  Heat pumps are double duty and work wonderfully but once the cord is gone, unless you have a genset running nothing comes out of the box until its plugged back in.  The amount of heat a heat pump unit can produce is limited by the temperature of the source water.  If you are in an area where the water temperature approaches the solid form, this is probably not the way to go.  Anything below 45 degree source temperature and the efficiency plummets.  Heat pump style units cannot be operated on the hard unless you devise a way to get water to and from the unit during operation.

   Diesel – There are two major manufactures of Diesel fired heaters typically used in boats, Espar and Webasto.  All in all they are very similar under the cover and both are considered very reliable.  Both are used extensively in over the road trucks to heat the sleeper units and still meet the no idle laws.  Their secondary markets are the RV and marine worlds.  Each makes a forced air unit and each make a water heating unit (hydronic) similar to a home style boiler.  All of the units no matter who makes them are very reliable, clean to operate and put out tremendous amounts of heat for their physical size. The biggest issue for reliable safe operation is proper installation.  They can be installed by a handy do-it-yourselfer but if in doubt don't.  One of the installation concerns is the length and routing of the exhaust pipe.  Typical exhaust of the unit is out the transom, and the closer you can get to the exhaust point the better as there are restrictions on distance.  On the forced air unit this often makes it difficult to run ductwork to the forward section of the boat as there are always obstructions and the ducts are in the 3 to 4" diameter range.  I set mine up to just dump the heat as low to the floor as I could get, and it blows toward the V-berth area.  That being said if you close the V-berth door or the head door there is not heat getting to those areas.  Adding ductwork will help that issue but running it on a 36 foot boat is a bitch.

The hydronic style unit simply heats water.  A small circulator pump moves that hot water through small diameter plastic tubes anywhere you need it or can get it to.  One tube supplies the hot and the other returns the cooler water back to the heater for reheat.  Small water to air coils are installed where heat is required and equipped with circulation fans. A "room" thermostat controls the fan when heat is needed. This method allows multiple zones throughout the boat with each controlled as necessary.  Larger boats incorporate base board style fin tube heaters in addition to the forced air heater boxes. Often these are located in the engine room space and utility areas to keep those areas from freezing.  If I were to live aboard, I would install a hydronic (hot water) multi zoned system.

I hope all of this helped and has not only started you thinking about extending your season with the addition of heat and enhancing your experience aboard the boat. If you need help selecting and sizing a unit for you boat, let us know.

Dale Tanski
Obersheimer Sailor Supply
Buffalo, New York
(716) 877-8221

[S/V Deo Volente]

Heat in the cabin for those of us in cooler climes is beyond pleasant! I had a 26 foot boat with a wood burning  fireplace, it needed a fan to distribute the heat, and was wonderfully cheery. I do miss it, but there was not a good place for one in the pilothouse. Shortly after buying the Pearson I put in a "bus" heater that does a nice job when the engine is running. It needs a pump to get good water flow. I added an early Webasto forced air heater that had stopped working for the previous owner. I was able to repair it and agree with everything Dale has said. I would have preferred a hydronic heater but the price was right.
With diesel "furnaces" the heavy electrical draw is at startup when the glow plug heats up so the fewer cycles needed to maintain heat is best. Newer models tout blower control or multiple btu models. In my case I would like a multiple btu unit that would heat up with a larger flame and then maintain with a lower output without cycling. There is nothing like coming in from the cold and wet to a warm dry cabin. I love sailing in short sleeves in the pilothouse when others are bundled up and wearing foulies.

[Dale Tanski]

Yes indeed, the newer models of diesel heaters (last 10 years) have automatic, multiple steps in their heat output. The one I have the Espar D4, has 4 levels of heat output, 3400, 6800, 10200 and 13650 Btus per hour.  The brochure says it consumes anywhere from .03 to .13 gallons per hour of diesel depending on the heat output.  Amp draw ranges from .6 to 3.3. 

They work by sensing the return air temperature and adjust the heat output all by themselves up or down.  The older units that were known to be problematic and often soothed up, basically just went on or off.  This hot / cold operation method was not so go.  Today the units basically runs all of the time and automatically adjusts how much heat it outputs to maintain the wall thermostats setting.  This constant run method constantly circulates air minimizing cold spots and that start up draft.  They are remarkably quiet as well. 

Dale