Marine Russian Stove

During the decade or so we have spent living aboard, we went through a succession of methods to keep the cabin warm during the cold months. On our first journey south, we cast off from Boston in mid-October, the day before the marina would have kicked us out because we hadn’t signed a contract for winter dockage. We progressed south rather more slowly than we had expected, and made it as far as Charleston in early December. There we decided to overwinter, and proceeded further south three months later. When we first set off, all we had on board was an electric space heater, plus a propane heater powered by 1 lb. camp stove canisters. We went through a large pile of these. The electric space heater only worked when we were tied up at the dock and plugged in to shore power. While under way, we tried to keep warm by burning propane. But propane generates a lot of moisture as it burns, causing the entire cabin—the clothing, the bedding, everything—to become dank, robbing the body of heat, while the moisture in the air condensed on the underside of the cabin top, causing it to literally rain inside the cabin. (There are few things more disagreeable than an intermittent cold drip on your head as you are trying to sleep.) When we got to Baltimore, we tied up at a marina to which I had previously arranged to have shipped a propane-fired Cozy Cabin Heater. It was designed to be plumbed to a 20 lb. propane tank, and included a flue, thus solving the moisture problem. I installed it using the materials on hand and life got significantly better. Once in Charleston, where we overwintered, we used this heater along with the electric space heater, and the cabin stayed comfortable.

Eventually we got back to Boston, by which point the Cozy Cabin Heater died, as had the company that made it, and hunting down replacement parts for it turned out to be a nightmare. This is not at all unusual: most of the equipment manufactured for the recreational marine market is shoddy, overpriced and falls apart rather quickly. At that point, as part of a thorough refit, I replaced it with a Tiny Tot charcoal stove, made by a tiny company somewhere in Michigan. The heat it delivered was intense and very dry, and kept the cabin toasty all by itself on even the coldest nights with no condensation problems. But we had to get up every 2-3 hours to add 5-6 charcoal briquettes. Solid fuel stoves were forbidden at the marina where we stayed, but nobody noticed. Also as part of that refit I insulated the entire cabin with two layers of radiant barrier, ½ inches of Pink Panther foam insulation, another layer of radiant barrier and a layer of fancy 1/16-inch varnished cherry plywood with oak trim. This made a huge difference: there were no more condensation problems and the cabin felt warmer than one would have guessed by looking at the thermometer. The one remaining problem was the cabin sole: there was no way to insulate the bilge and it was still cold. In spite of putting down rugs everywhere possible, it was difficult to keep our feet warm.

We were about to set off sailing again when we became pregnant and had to “upgrade” to a larger boat. The reason “upgrade” is in quotes is because we sold a very good boat—Hogfish, the eminently serviceable, versatile and fun 32-foot sharpie custom-built by Chris Morejohn—and bought an unwieldy, boring maintenance nightmare that is the typical commercially built yacht—a 36.5-foot Pearson. Its only real selling point is that Pearson made a mistake and made the fiberglass of the hull ridiculously thick, thus making it fairly indestructible. Over the five years that I owned that Pearson I came to genuinely detest it. Rest assured that I will never buy another commercially built production boat again, having learned firsthand all the different ways in which they are crap. As far as I am concerned, it’s either going to be a Quidnon—or a nice homestead. But if all goes as we expect, I’ll have one of each.

The Pearson came with a very strange piece of equipment: a Newport evaporative diesel heater. It used a little electric pump to squirt diesel oil into a bowl, and it was your job to get it burning. This involved tossing in some tissue paper soaked in diesel, lighting it on fire, and using a little electric fan to vent the fumes and fan the flames until the bowl of oil heated up enough to start evaporating and burning on its own. When everything was working as it should, it produced a pretty-looking warm glow, much like a fireplace. The rest of the time it produced prodigious amounts of soot and made the cabin stink of diesel oil. And the once in a while—invariably on a cold and stormy night—it would blow out, and coat the walls of the cabin, and everything inside it, with a fine film of smelly, oily soot. We used that heater for one winter, then gave up on it and let it sit, unloved and unused. As far as the rest of the boat, we did get some use out of it. I moved it south one summer, single-handing all the way down the coast, then had my family fly down, and there it stayed, at the dock, until we sold it. I didn’t enjoy sailing it; it sailed like a pig, with a strange corkscrew motion and a jarring “stomping on the breaks” effect at every other wave as the Pearson buried its fat snout in it. Well, that’s what you get with a hull that’s shaped like an endive. Its best feature by far was the heads: it had a full-size shower stall. Its second-best feature was the galley—once I tore out and rebuilt half the cabinetry.

Another problem with an endive-shaped hull (and most production cruising sailboats are, unfortunately, shaped like that) is that is almost impossible to insulate. On Hogfish, the sides were made of flat plywood sheets, curved in a single direction, and this was easy to insulate by adding flat slabs of foam. This is also going to be the case with Quidnon. Also, on Hogfish the sides were accessible, while the Pearson the cabin was a mess of fiberglass forms, one wedged into another before the deck got screwed on. (Yes, the deck was screwed on, not bolted on, using sheet metal screws bedded in epoxy; the wonders of commercial boatbuilding never cease to amaze!) Clearly, the designer had spent zero minutes thinking about how this hull could ever be insulated. Thus, the Pearson stayed uninsulated, and the cabin felt cold no matter how many electric space heaters we had going. We used a thick rug in the salon and electric blankets under all the mattresses, and that helped. We also taped bubble wrap under all of the hatches and insulated the companionway hatch as best we could.

As an aside, the economics of unique, versatile, custom-built boats like Hogfish, and like Quidnon is going to be, and sloppy production boats like the Pearson are very different. When I put up Hogfish for sale it sold almost immediately, and I doubled my money on it. If I hadn’t accepted the first offer (which I did because the buyer matched my asking price) there would certainly have been a bidding war. The Pearson stayed on the market for six months and eventually sold for a miserably small amount of money, because there is a glut of very similar boats sitting on the market forever, unused and unloved. The closing date for the sale fell on my birthday, which I took to be a sign that Neptune had taken pity on me. This contrast hints at what the situation will probably be like with Quidnons, once there is some number of Quidnons floating about. There are likely to be bidding wars for any of them that come on the market, be they bare hulls or be they finished boats with all of the equipment and amenities installed.

Getting back to the question of how to heat the cabin, our plans for Quidnon is to make it very comfortable and cheap to heat. Last week, Chris Raine asked a profound question: “Will this houseboat also have a Русская печь?” This question, I thought, requires an equally profound response, so here it is. What follows is an excerpt from my book Shrinking the Technosphere.

The design of the Russian stove is several centuries old and seems to have emerged soon after the spread of firebrick, which is a formulation high in silica that is less susceptible to spalling when heated repeatedly. It is a massive masonry structure with its own foundation. At its center is a vault with an arched ceiling and a flat floor, often high enough for someone to squat inside. Fire is set inside the vault, far inside the stove. At the front of the stove is a flue, which includes a dogleg with a gate that is used for hanging meat and sh for smoking. Right back of the flue is a threshold that protrudes down from the top of the vault, holding hot combustion gases inside the innermost part of the vault, resulting in better heat transfer. The top of the vault is filled with solid fill and covered over with a layer of brick, forming a platform, and a straw-filled mattress, which is often big enough to serve as a bed for an entire family of five. Between October and May, when the stove is red twice a day, the temperature of the platform stays at a constant, comfortable 25–27ºC (76–80ºF). During the hot part of the summer, when the stove is not red because cooking is done at an outdoor hearth, the stove provides a cool place to sleep.

The outer wall of the stove has several niches. They improve heat conduction from the stove to the air in the room and are also used to dry clothes, herbs, mushrooms and berries, to keep food warm and to provide a place for the samovar, which boils water for tea. The firebox of the samovar, typically stoked using pine cones, exhausts into the flue of the stove. Under the stove is a space that is used to store firewood and can be a warm place for animals to sleep. The stove can also be used as a sauna—by sitting cross-legged inside the vault when it is relatively cool.

The Russian stove includes an entire dedicated set of utensils that are specific to it, each perfected over the centuries to have the largest possible set of functions. Food is cooked in clay pots and in cast iron skillets that lack a handle. The pots are placed inside the stove using stove forks, which come in three sizes and grab pots by the neck, while the bread and the skillets are moved about using a flat-bladed wooden spade, similar to the paddles used to handle pizza.

For the sake of comparison, let’s consider what you’d have to shop for if you didn’t happen to have a Russian stove. To heat the house, you’d need to buy a furnace and either install an oil tank or hook the house up to a gas main. Then you’d need to construct a way to distribute the heat, through either forced air or baseboard heating, and this involves installing lots of either ducts or pipes. You could also install a modern, energy-efficient wood stove, but then the bedrooms would be cold, so you’d probably run out and buy some electric space heaters and, to keep the beds warm, some electric blankets. To cook food, you’d need to buy a cooking stove with an oven, either gas or electric, a toaster and a microwave oven. You’d need a separate smoker for smoking fish and meat, plus some drying racks for drying things. Or you could just get rid of all this expensive, short-lived junk and render yourself naturelike by building yourself a Russian stove and using it in place of all of the above.

From Shrinking the Technosphere, p. 139-40

So, how does one adapt the Russian Stove concept to a boat? Obviously, placing a massive masonry structure on board is out of the question. But after giving the question some thought I found ways to provide for most of the rest of its uses, including all of the following, using a relatively lightweight structure made of sheet metal:

• Keeping the cabin warm and providing warm, dry places to sleep and sit
• Heating water for showering, bathing and washing and to keep water ballast tanks from freezing
• Cooking
• Making steam for sauna
• Generating electricity
• Drying things

There will be two identical stoves—one in the galley, one in the heads/sauna—that will burn wood, charcoal or propane (since some doing like having to stoke a stove, and some marinas forbid the use of solid fuel). To burn propane, the ash box is replaced with a propane burner; the firebox can then be repurposed as an oven and used for baking or broiling. But when cruising or overwintering along wooded shores propane may be hard to come by while firewood is likely to be plentiful and either cheap or free for the taking, and so the option to burn wood is very useful.

Above the firebox is a stack of three heat exchanger compartments. Flue gas from the firebox can be sent through any of them using diverter valves. Right above the firebox is the water heat exchanger; next is the air heat exchanger; and at the top is the hot plate used as a cooking surface. The flue gas is then discharged into an 10-foot smokestack that penetrates the deck and rises above it, to produce plenty of draft. The sides and the back of the stove are double-walled, with a layer of rock wool between the walls for insulation.

The back wall, which is in contact with the hot flue gas, is especially well insulated, with a layer of aluminum flashing sandwiched between two layers of rock wool to provide a radiant barrier. A patch of the back wall is left uninsulated; there, a thermoelectric generator module is attached directly to the steel plate that is contact with the hot flue gas. The cold side of the thermoelectric generator is cooled by circulating ballast water through a water jacket. The two thermoelectric generators will provide a total of 100W of DC current—50W on each stove—and also keep the ballast tanks from freezing.
In the heads the hot plate surface has a pile of sauna stones attached to it using a stainless steel mesh. Having a sauna on a smallish sailboat may seem like an extravagance, but the Finns, the Russians and many others would disagree. I am sure that anyone overwintering on a Quidnon would value having a sauna on board.

Since most people prefer to cook with propane rather than fire up the stove for that purpose, in the galley the hot plate will usually have a propane cooktop placed over it. Above it is an exhaust hood vented to the outside; in the relatively small space of the cabin, it is essential that cooking smells not be allowed to permeate the cabin.

Space heating is via warm air. A circulator fan takes a mixture of outside and inside air and pushes it through the air heat exchanger. The output is injected into a network of ducts and plenums under the cabin sole which distributes the heat evenly throughout the cabin.

The plenums can be adjusted for optimum heat distribution and to suit the preferences of the occupants of each cabin and berth. Some of the warm air is sent under all of the berths, to keep the bedding warm and dry. In addition, warm air can be sent into the cockpit lazarettes and the cockpit well, to keep the cockpit warm and to provide warm places to sit while sailing. To keep the heat in, the cockpit can be enclosed using sliding window panels along the sides and a transparent vinyl curtain across its aft end.

The water heat exchanger is used to heat up water in the hot water tank used for bathing, washing and showering. The hot water tank is fitted with an alarm: when the water temperature rises above 80ºC, an alarm sounds, informing the stoker that it is time to turn the diverter valve on the water heat exchanger to off and to turn off the hot water circulator pump.

There are several good reasons why there are two stoves instead of just one:

• When overwintering on a Quidnon in the far north, hauled out on ice or on shore, and temperatures drop below -20ºC, both stoves would need to be fired in order to to keep the cabin toasty.
• During the warm and hot months in the temperate latitudes, and in the tepid ones, people still want hot water to be available, but lighting the stove in the galley would make it uncomfortable to be in, but the stove in the heads can be used instead.
• Having a large wood-heated cooking surface is very useful when preparing large quantities of food—whether to feed large groups or to process and lay up supplies for the winter—but the one in the heads is occupied by a pile of sauna stones.
• Having a pile of hot sauna stones to throw water on is the excellent, traditional way to generate steam for a sauna.

Above deck, one more flue gas diverter and heat exchanger can be installed to supply heat to a hot box that can be used to dry various things: mushrooms, salted fish, herbs, fruits and berries, clothing and footwear, etc. The hot boxes—one for each stove—can be made in one of two ways: as an easily assembled temporary installation, or as a permanent fixture attached to the bulwarks. In either case, the hot boxes provide additional warm places to sit while out on deck.

Two things need to happen in order to make the Marine Russian Stove a reality. First, with your help, I hope to sanity-check the concept and see if I made any mistakes or omissions. Second, if the concept is sound, comes the step of doing the math and producing the mechanical drawings, and if any of you are knowledgeable about stoves and heating system design and have the interest, I would welcome your input.