Friday, January 30, 2009

But Isn’t It Cold in the Winter?

Living on a boat was a natural choice for me. I like to say that if I designed in houses I’d probably live in one. Since I design boats, I suppose I’d feel a bit disconnected living ashore. I know the problems I face daily on my Alberg 35 are not identical to those my clients might encounter on larger commercial boats, but there are important analogies. Climate control is one challenge I have had to resolve both at home and ‘for hire.’

The most common inquiry I get during the colder months from land dwellers is, “But isn’t it cold in the winter?” My answers vary but “depends on where I set the thermostat,” is my favorite. It’s not quite that simple, but then it’s not too much harder. Since the variables of heat requirement are numerous, I’ll confine my discussion here to some general means of bringing heat on board. In sixteen years I’ve run a winding course from simple and tedious to relatively complex and convenient ways of keeping warm when the mercury drops.

Charis’ very first ‘boat warming’ gift was an aged but well made solid fuel stove. It was a Dickenson Newport, probably at least ten years old then. I learned that while any heater can warm the toes, something in the flicker and glow of a wood fire warms the heart too. I was never disillusioned in the thought that this would be my only heat source through a New England winter, but I soon realized I could never be really comfortable wintering aboard without it. For early and late season cruising it was at least adequate, subject to the foibles of getting a proper draft through a range of wind conditions. Installing a woodstove low is always best since draft strength is proportional to stack height. At the same time, internal stack pipe will radiate heat into the cabin. But how low is always a function of the arrangement the stove is joining and therefore always a compromise. I add a small section of stack pipe above deck in the winter, but draft continues to be a problem with certain wind directions.

In the Tobago Cays several years ago I found a new application for the woodstove. Trash disposal is a problem there. To extend our visit I burned much of our refuse. It was this use that ultimately brought about the death of the old woodstove. The firebox sides had grown thin from years of use and finally burned through with a particularly hot batch or trash. I ordered an identical (or so I thought) replacement when I returned to New England. As it turns out, the replacement had little in common with the original. Most distressing were the thin metal gauge, large gaps between parts and razor sharp sheet metal edges. With some modification and more moderate use expectations a truce has been reached, but one day I will apply the lessons learned toward a custom stove.

I bought Charis with the knowledge that her shore power system needed to be replaced. Working in the industry gave me access to the knowledge and materials to do this properly. Somehow I made it through that first two cold winters with one 30 amp shore power service providing electric heat, hot water, and all other house services. There was much juggling of appliances though, and I knew I needed something better for the long haul. In the boat I chose ceramic element heaters for their compact size and safety features. These are inexpensive enough to discard at the first indication of trouble and still form the backbone of my dockside heating system.

During these first winters I learned all I could from dock neighbors about their heating systems. Some used forced hot air diesel units such as Espar and Webasto Heaters originally designed for busses. Hydronics units from the same manufacturers offered an enticing host of side options such as engine preheating, water heating, and even simple bilge and locker heating. But one thing became clear to me in this research. These units were expensive, power thirsty, and relatively complex. Considerable space for equipment and ducting was required. All had a reputation for expensive low voltage failure. Ignition was typically achieved with glow plugs which try to compensate for low voltage with higher amperage, potentially overloading wiring harnesses. With relatively low battery capacity, these would be strictly dockside solutions for Charis.

My compromise solution therefore became more of the same. A second 30 Amp shore power service was installed with one thermostatically controlled outlet each for the forward and main cabins. Ceramic heaters are switched on and off by these outlets according to their settings. The resulting ‘two zone’ effect is a side benefit. In severe cold, there is adequate capacity in the main shore power system to allow a third heater to be run full time. Sixty Amps of shore current has proven adequate to maintain comfortable cabin temperature. It helps that the Alberg 35 has a relatively low volume cabin and I’ve added internal insulation where possible. There was an added advantage of being able to leave the only bulky parts of the system (the ceramic heaters) behind when I sailed south.

Over the years a noticeable shift in attitudes about off season dockage has taken place in my home waters. Where once was the concept that a low price for off season dockage was better than open slips, it is now common to maintain high off rates while slips go unoccupied. It started with a shorter length for ‘off season.’ I coped with this by remaining longer at a member owned club which was my summer base. Then they caught the disease and quadrupled their off season rate one year. To remain in my home waters and live aboard year round, I had to find ways to remain off the dock for more of the calendar year. With appropriate trepidation I tried propane camping heaters. None were appropriate for unattended use and a cold boat in the morning seemed unavoidable. For a while I thought about replacing the woodstove with a diesel or kerosene unit heater. From local fishermen I learned of a reliable burner type called a ‘drip pot burner,’ found in many Scandinavian marine unit heaters. It was not necessary to pressurize the fuel to this burner in order to burn it cleanly. Since pressure in the fuel system could tend to magnify the danger of any leaks, and since that pressure would need power or attention to be maintained, the advantages of a gravity burner were clear. The fact remained, however, that a unit heater was still dependent on draft and therefore stack length. More importantly, I wasn’t ready to give up the glow of my woodstove.

A brief exchange of ‘favorite gear’ comments with a passing cruiser put me on the trail of a company called Wallas® in my quest for a heating solution. Among the products Wallas® manufactures is a forced hot air marine furnace which utilizes a burner similar in concept to the drip pot type. A small resistive element is used for ignition. Combustion and cabin air are separate throughout the process and are provided by small fans. Exhaust is vented through the center of a double walled flex pipe, while combustion air is brought in and preheated in the outer passage of the same pipe. The outside of the pipe gets warm, but never hot.

The more I investigated this unit for my installation, the more advantages surfaced. The Wallas® uses less 12 Volt power to ignite and run than any other forced hot air heater I found. Less than 10 Amps of current starts the combustion process. Two to three amps are adequate to power the fuel delivery pump, control circuit and fans thereafter. This was within my energy budget even with limited battery storage capacity. Low ambient noise made installation in a hanging locker between the forward and main cabins possible. As this is part of the head, both it and the locker would benefit from residual heat around the unit. Ducting was simple given the central location. Direct wiring to the battery with an inline fuse is recommended. This was advantageous as the run from the battery was shorter than from the main breaker panel. The exhaust fitting was installed through the cabin trunk side, far above the waterline. A separate fuel tank in the bottom of the locker is convenient for the ability to vary the heater’s fuel diet in spite of the more frequent need for refilling. As a final perk, the control head for the Wallas® is installed on the bulkhead at the head of my forward cabin bunk. Reaching out from under the covers to switch on the heater certainly beats getting up to light the woodstove.

No machinery installation is ever perfect, and some of the limitations of this system were clear initially while others have surfaced along the way. Wallas® has a very small market share in the U.S. As a unit specifically designed for marine use, this is hardly their fault. Most weekenders store their boats before the frost falls. But with increasing crowds and demand in the high season come larger number of off season sailors. Hopefully this will improve the presence of Wallas’s® line of products. Currently they are distributed and serviced in the U.S. only by ScanMarine of Seattle, WA.( phone: 206-285-3675) Perhaps ‘only’ is an unfair label since Karl has been professional, fair and knowledgeable, even if a week away by ground shipment. The trade off is in having a unit that is more user serviceable than most along with good parts availability, albeit with service more distant if serious attention is required.

All of the available forced hot air units I considered have a cycle life between major rebuilds of between 2500 and 3000 hours run time. A quick look at the math will show that this would make them unsuitable as the full time primary heat source for a liveaboard boat unless annual overhaul were accepted. Specifically, the small fan motors and some minor internal burner components in the Wallas® create this limitation. That both of these replacements appear in the ‘user serviceable’ category somewhat alleviates the long distance service issue. Since there is not presently a system with the long duty cycle life of a land based furnace and the energy efficiency of the Wallas®, maintenance is the cost of the compromise. For my own purpose of extending my ‘unplugged’ season, this simply meant not discarding the shore power electric heating system.

I’d venture there are as many different ways to heat a floating home as a land based one. One thing I’ve learned from all of this has been that there’s always more to learn. Building codes and a larger consumer market make options for heating a house fairly easy to research. This is probably why land dwellers get together and talk about the weather while we floating folk talk about what to do about it. It seems the best way to spread ideas afloat is still the good old fashioned ‘word of mouth’ method. But then that’s a good part of the fun of it I guess. So if you see Charis in some cozy backwater, please come over and tell me about your favorite bit of outfit. Who knows, maybe we can solve some of each others vexing liveaboard problems over a cold sundowner or hot chocolate, depending on the season.

Christopher Melo is an independent naval architect, marine engineer and licensed captain based in South Dartmouth, MA. His professional focus is on commercial, passenger, and educational vessels. Charis, a 1966 Pearson Alberg 35 has been his home since 1990 and magic carpet between the Caribbean and New England.


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  2. I'm also have an Alberg 35 (Auriga Hull#54)and live in the Northeast. I've been comtemplating living aboard on the hook next winter and I'm considering scrapping my LPG system and going the diesel route for cooking/heating. I've heard that when cruising the tropics (which I plan to do) that a diesel cooker can make the cabin unbearably hot. Any opinion on this?

  3. I was told the same about a black hull. I think good ventilation and a steady breeze has more impact on comfort than cooking fuel or hull color. Aft cabin boats, for example, had more to complain about since getting a breeze aft of the cockpit isn't easy.

    I also have a diesel seaswing stove on board when I cruise as a backup to the LPG system. It's not any hotter to use, but maybe a bit more work due to the priming and pressurizing needs.

    I've not done a northeast winter on the hook yet. It would get expensive to do this with the Wallas as it would run the hours up quickly and probably need a fairly expensive rebuild after one winter. I'd probably lean toward a Refleks or similar radiant heat fishing boat type stove for this as they are simpler and cheaper to service.

    Please keep me posted on wintering on the hook as it sounds like a great adventure.


  4. Also Brob, you might try e-mailing Kevin Boothby at the Ruth Avery link on the left. I think Kevin cooks with diesel and has done so on his circumnavigation and several Caribbean cruises.