Playing it Safe with LPG Heat

A propane fireplace is within reach of the handy sailor.

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Dickinson P9000

Photos by Drew Frye

Unlike many sailors, Practical Sailor contributor Drew Fryes version of sailing occurs in any weather where the water isnt frozen. So when his family purchased a used PDQ 32 catamaran six years ago, one of the first items on the To-Buy list was a cabin heater.

For ease of installation, efficiency, clean heat, and size, Frye chose the Dickinson Marine P9000 Propane Fireplace (retail price about $800). Rated at 4,500 British Thermal Units, it seemed more than adequate for the type of short trips Frye and his family envisioned.

The fireplace is suggested for monohulls up to 32 feet, and estimated fuel consumption is between five (low fire) and seven hours (high fire) per pound of propane. Because the P9000 is a self-contained heater, there is no ductwork or a thermostat to install. After six years of sailing with the Dickinson, Frye reported that he is generally pleased with the choice. He offered the following comments on the P9000s installation and performance.

Safety First

Installing a wall-mounted heater is well within the capabilities of the diligent do-it-yourselfer, but it does require attention to detail for a safe, standards-compliant installation. The American Boat and Yacht Councils (ABYC) Standards and Technical Reports for Small Craft offers explicit guidance on LPG systems like the Dickinson.

An LPG heater is an unattended appliance in the eyes of the ABYC, so it must meet certain special requirements, as described in Section A-26 of its standards. One often overlooked requirement is that the heater must have a room-sealed combustion system, a combustion system in which incoming air, the combustion chamber, and the outgoing products of combustion are sealed from the boat interior. This helps reduce the risk of potentially fatal carbon monoxide poisoning. Unfortunately, many LPG heaters do not meet this standard; one such example is the popular Cozy Cabin heater, which has a prominent warning regarding its use in unventilated areas.

The online version of this article has links to other important safety guidelines.

Other details to consider:

The right location isnt always obvious. Frye and his family sailed all summer with a cardboard mock-up taped to the bulkhead in the chosen location to be sure it was the best spot for the heater.

A proper propane locker houses the regulator and shut-off solenoid, and provides overboard drainage for any gas leakage. Although its less desirable, cylinders can be mounted abovedecks, so long as the gas-flow path is overboard and not into the cockpit or any locker.

A cut-off solenoid connected to cabin gas sensors and a control panel is required. Fryes catamaran has a sensor in each hull, near the appliances; these must be as low as is practical.

A separate gas line is required for each appliance, with connections only in the propane locker and at the appliance. The test boat has four lines for four appliances (refrigerator, stove, water heater, Dickinson P9000). These lines are supplied in pre-made lengths with the fittings attached.

The gas line must be well secured to reduce motion and run through a vapor-tight fitting from the propane locker into the cabin. Pre-assembled with 3/8-inch flare fittings on each end, the vapor-tight fitting is a standard item that can be ordered through marine retailers or Dickinson.

A 12-volt electric supply, preferably via a dedicated breaker, is required for the units fan. The Dickinson will run without it, but the heat output is considerably less and not well distributed.

The required side clearances for the Dickinson are only about two inches, because the fan circulates cold air around the firebox, keeping it cool. Additionally, the combustion air is drawn through the deck and around the flue via a double-wall pipe (measured at 175 degrees), so it requires no additional insulation where it passes through the deck. Other cabin heaters may require greater spacing and flue guards.

Because of the weight and vibration of the heater, through-bolts are preferred for mounting.

Any heater will produce exhaust hot enough (measured at 329 degrees, but most heater stacks are hotter) to damage running rigging. This will require a line guard to keep running rigging from snagging (and possibly burning) on the chimney.

Check all gas connections for leaks with diluted dishwashing liquid and a brush. Periodically test the system for leaks by shutting off the tank and all appliances; pressure should maintain for at least two hours. Test the propane leak sensors by exposing them to propane; you can do this by using a cigarette lighter without the flame lit. A good fume detector will have a relay that automatically shuts off the fuel supply at the tank solenoid.

Although the Dickinson switches off automatically if there is no flame and is sealed from the cabin, a carbon monoxide monitor is a good idea on any boat that uses fuel for cabin heat.

Installation

The most stressful part of installing the P9000 is boring a 3-inch hole through the cabin roof. Before starting, confirm that there are no wires concealed by the liner. Even after careful measurement, confirm the location by drilling a centering hole through both sides before proceeding with the hole saw.

Coring around the hole should be removed and sealed with epoxy, a process described in most marine repair books like Don Caseys This Old Boat (available in Practical Sailors online bookstore). The cabin liner will also need to be cut; running the drill in reverse and using very gentle pressure worked for us. Scissors or a sharp knife will also work. The Dickinson unit comes with an interior trim ring, and the deck cap is a required accessory.

Make certain the stack runs according to the instructions with no low spots. The supplied gaskets and fasteners worked fine. An assortment of rubber grommets from Home Depot protected the electric and gas pass-throughs near the heater in our installation.

The most difficult installation step for Frye was drilling the hole into the propane locker and fitting the new gas line; access was though a salon locker and required advanced boat yoga. The rest of the work was accessible, requiring only planning and diligence.

Total labor was about five hours. Buying hoses and other installation parts ran about $150.

Insulation

Installing a heater without making other simple heat-efficiency measures onboard is plain wasteful and pointless. We recommend replacing insect screens with plastic glazing (see article this issue) when the temperatures drop. Sew rolled-up towels into sausages for blocking draughts around companionway sliders. Use rug runners and throw rugs to help warm bare floors. Cover the companionway on the outside with a large beach towel secured at the top. Eliminating even the smallest draughts and cold spots makes a huge difference.

Conclusion

After six years, the P9000 delivers the rated heat capacity (see accompanying article on sizing a heater) with minimal fuss. To light it, you simply open the units glass door, depress and hold the fuel knob until the gas lights, and keep the knob depressed while the flame stabilizes. Release the knob, close and secure the door, and adjust the flame.

The sealed double pipe flue excludes moisture. The air stays healthy and dry (relative humidity generally hovers around 55 percent), and the flicker of the flame is pleasant on a cold night. Typically, Frye gets five to seven days of use from a 10-pound propane tank in frosty weather; this includes fuel used for cooking.

Frye had a few minor complaints about the P9000. Heat capacity is no more than a typical space heater, and distribution through the boat is limited. He located the heater so that a cabin fan blows down on the flue and across the heater, increasing efficiency by cooling the flue and spreading the heat; this also should be a part of your installation plan.

The aluminum fan in earlier heater models was a bit noisy, but Dickinson now supplies a quieter plastic fan. Frye retrofitted his stove with the new fan, and was pleased with its sound level.

The flame can blows out in beam gusts over 25 knots; fortunately, the flame sensor cuts off the gas supply within seconds. Gusts from the bow are not a problem, and this can be eliminated by an improved line deflector design. Even so, Frye does not run the heater while asleep-opting instead for lots of blankets.

All in all, the Dickinson P9000 heater has proven to be an efficient, dependable, and relatively easy to install heater for 32-foot catamaran test boat. The P12000 should be suitable for monohulls to 36 feet and catamarans to 34 feet. Sizing depends on expected weather and installed insulation. Long-term liveaboards should consider a diesel-forced air heater, which is more cost effective and provides more-even heat distribution.

Fail Safes are at the Heart of LPG Heat
Darrell Nicholson, editor of Practical Sailor, grew up boating on Miami’s Biscayne Bay on everything from prams to Morgan ketches. Two years out of Emory University, after a brief stint as a sportswriter, he set out from Miami aboard a 60-year-old wooden William Atkin ketch named Tosca. For 10 years, he and writer-photographer Theresa Gibbons explored the Caribbean, crossed the Pacific, and cruised Southeast Asia aboard Tosca, working along the way as journalists and documenting their adventures for various travel and sailing publications, including Cruising World, Sail, Sailing, Cruising Helmsman, and Sailing World. Upon his return to land life, Darrell became the associate editor, then senior editor at Cruising World magazine, where he worked for five years. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.

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