Last year, my friend Eddy, who lives aboard purchased his “dream boat,” a pre-owned Meridian 391 in Hilton Head, SC, and brought it up to Annapolis in November. She is a beauty that was well cared for by her original owner. The trip north was enjoyable and uneventful, except for the swiftly declining temperatures outside the enclosed fly bridge.
Based on his many years as a liveaboard, he knew that as soon as the water temperature dropped into the 40s (F) the reverse cycle A/C–heater would be of little use. Basically, these systems can raise the temperature only about 20 degrees higher than the water temperature, and time was getting short. His experience provides valuable insight and a solid foundation for exploring what a boat owner should consider if or when making a decision to install a hydronic diesel heat system to make your boat a true “four-season vessel.”
I reported on the installation of an onboard electric heater in the November 2014 issue of PropTalk. However, a hydronic diesel heater system is a much more complex project; it offers the added benefit of providing heat while underway or on the hook, without shore power or a generator, and from an alternative fuel source. Eddy started his research by visiting the websites of Webasto (webasto-marine.com) and Espar (espar.com), both German companies, the best and largest in the transportation business. The companies offer several diesel boat heaters with the important factor being the number of British Thermal Units (BTU) produced for the cubic space to be heated. Some of the heaters are specifically designed for the harder, daily use required by liveaboards.
The Webasto website is particularly good in calculating the boat size, type (sail/power/open), number/size of portholes, boating region, sailing seasons, and more to come up with the recommended size/type of heater. Espar’s website provides a simple chart based on boat size to calculate the proper size heater.
The diesel heating systems he researched produce up to 41,000 BTUs with a fuel burn ranging from 0.04 to 0.40 per hour. For average heating requirements, his system should burn one gallon of diesel for five hours of heat at full load and more likely eight to ten hours per gallon. With diesel fuel averaging $2.50/gallon this comes to $11.80/day in the coldest weather and $5 in normal weather/operation. Not inexpensive; however when compared to his electricity bill of $700 for one winter month, it starts to make a lot of sense.
For a project of this complexity, research is the most important first step. Determining the required BTUs to comfortably heat your boat and its distribution is paramount to a successful project. It also will serve to enhance your comprehension of the contractor’s proposal inclusive of the system size and design, work hours required, operation of the system, and finally the cost. You will be more comfortable asking questions about the project when you have two estimates. Simply put, a knowledgeable boat owner can make for a better customer and a more satisfied owner in the end. My friend is the kind of mechanical/engineering guy who would love to sink his teeth into this project and do it himself, but he did not have the time and he wanted it ASAP, so he called a local company with diesel heater experience. A quick check of the internet (and PropTalk) produces several companies on the Bay that install diesel heating systems. My suggestion is to ask any company for references, specifically from their customers with comparable boats and a similar heating installation.
In this case, the owner shared his research with the company and asked for a project cost estimate which totaled approximately $10,000. The breakdown was $7500 for the boiler, controller, and distribution system, and, $2500 for labor. Wanting to move quickly and have the project completed, he wrote a check for $7500 and gave the green light to start in December 2013. Aside from the diesel boiler, the hydronic diesel heat system also requires radiators, vents, and control systems to better manage and direct the heat in zones throughout the boat. It accomplishes this by sending hot water/coolant from the boiler through a three-quarter-inch hose to the radiators in a closed-loop system. A simple diesel heating system only has a thermostat, with a boiler and fan in the engine room, and pushes the heated air through four- to five-inch hoses through the boat.
Neither Webasto nor Espar manufacture the additional equipment for the hydronic diesel system for boats. Eddy found a third-party radiator manufacturer called Sure Marine Services in Seattle (suremarine.com) to provide this additional equipment. The importance of the look and efficiency of the radiators will be key to your long-term happiness with the system in the cabin, so pay special attention when purchasing this critical component of your heating system. This leads us to the number of zones or areas you will want to heat in your boat, which determines the number of radiators necessary. The owner wanted three, separately controlled zones with one radiator and three vents to heat the forward two cabins and head; one radiator and vent for the main cabin; and one in the engine room (to replace his electric BoatSafe heater (theboatsafe.com). The radiators cost approximately $250-$500 each.
The location of the two cabin radiators took serious study and thoughtful review. The secret is to find a space the radiator box will fit and not require costly remodeling work, while also placing the heat where most efficient and effective. Potential locations that have ample space to accommodate the radiator are bench seats, couches, cabinets, counters, or beds. Another consideration in deciding on location is the importance of the storage space lost with the installation (see picture of radiator under galley sink). As for vents, locating them close to the cabin sole in a central area is an obvious starting point. The owner and contractor discussed the engine room radiator because some boats don’t require one due to their limited size and sufficient heat produced by the boiler and exhaust hose. The owner’s boat has a large engine room, and he did not believe it would have sufficient heat during a Polar Vortex, so he requested to have another radiator installed. In addition, warm diesel engines are a lot easier to start than cold ones when you want to go for a winter cruise.
If you have a specific place in mind for hose or radiator installation, be very precise with the contractor so they don’t place it where it blocks access to storage space. Mounting the radiator, valves, or hoses in the front or middle of a compartment can make the remainder of it unusable. This also applies to the decision of whether or not to install ball-valves for each vent. This could result in additional lost space if the owner doesn’t plan to use them. However, the ball-valves do allow for the system to be drained near the site of a problem, versus draining the entire system. Sounds obvious, but it would be prudent to have the contractor “place not secure” the system until the owner approves. This can reduce serious and expensive misunderstandings or surprises later.
The contractor placed two ball valves at the diesel boiler to turn off water and to drain the system. The owner said it will be very user friendly and should be easy to operate and maintain. In hindsight, he said that if he had installed solenoids in the system, the heat loss between zones could have been reduced. Due to scheduling issues, parts delivery, contractor priorities, and reworking some of the system to meet the owner’s desires, the work did take longer than expected, which is common for complex boat projects. System design changes increased labor costs by $4000. There are several lessons to be gained from this project. First, ask for a firm price and a completion date, and get estimates from two companies. Second, pay 50 percent up front, but leave enough on the table that it will be worth it for the contractor to complete the project quickly. Third, make sure you and your contractor fully understand how the system will be designed and perform. A hydronic diesel heat system is not a quick install. Fuel, air, and ducting requirements make it a complex project. A warm and toasty boat should be ready when temperatures start to fall and Jack Frost comes knocking on the cabin door this winter.
About the Author: Captain Paul “Bo” Bollinger contributes to PropTalk when he is not cruising Chesapeake Bay or working on own his boat.