As you’ll remember from my previous post, we’ve made some changes recently to our location and our style of living. No longer at the dock with unlimited power, we’ve had to get creative and upgrade our systems to support everyday life without shore power. I’m ecstatic to report that the solar panels have continued to impress, leaving us more than enough power for daily activities and charging our batteries for the endless rainy days.
Even with an abundance (relatively speaking) of power, there are still some things we just can’t do. One of them is to heat water with an electric water heater. Before I get into the nitty gritty of our situation, I’ll give you a spoiler: we have found a way to make hot water with little electricity or fuel. It is incredible. We now have electricity, refrigeration, and hot showers. This must be what yachting is like!
So how did we get here? Many boats carry a water heater that can operate on either electricity or from engine heat. We have that style of water heater, and so, in theory, we could use our engine to heat our water, but we chose not to for a few reasons.
The first reason is that we just don’t want to run the engine every day. It’s noisy, heats up the boat, and causes unnecessary wear. Since most days are spent at the mooring, or at anchor, running the engine would be solely for the purpose of heating water, and thus the engine would run under no load. Diesel engines are made to do work, and without a substantial load you can slowly cause damage due to a buildup of carbon.
Additionally, our engine is quite old. We have worked through a variety of issues over the last few years, and one of the major themes was overheating. Since the water heater would tap into the engine’s cooling system, we have decided, for now, that we do not want to add any new variables into the engine temperature equation.
So if we aren’t heating water with electricity, and we refuse to run the engine, how do we make hot water? That’s where our brand new on demand water heater comes into play. But this is not the kind of instant hot water you’re imagining. Rather than use propane or electricity, it utilizes already available hot coolant from our heater.
Propane water heaters are cheap and readily available, making them hard to resist. There are no currently produced models, however, that are approved for marine use. Since they don’t meet nationally recognized standards for marine equipment, that means they likely won’t be covered by insurance. It sure would stink to have your home blow up and then have insurance reject your claim due to a noncompliant device.
If you have been following us for a while, you will remember that we did a substantial furnace installation before our first winter aboard. Similar to those ashore, our furnace heats coolant in a boiler, which is distributed throughout the boat to radiators. The heater comes up to temperature relatively fast, usually within approximately 20 minutes, sipping both fuel and electricity.
Once again working with Sure Marine Service out of Seattle, we ordered an Everhot instant water heater, designed to work with exactly the kind of system we have installed. Once the boiler is up to temperature, the coolant circulating throughout the boat will also pass through the Everhot water heater, heating our potable water to 170 degrees Fahrenheit in a single pass. To avoid warming the boat during the summer, we can simply shut off each of the various zones at a manifold in the engine room, leaving the hot coolant isolated to circulating in only the engine room to heat our water.
The installation was easy and results were immediate. The water is hot and provides up to 6 gallons per minute at full temperature. Yet, as you may have keenly noticed, this only works when the furnace is running. During the summer we don’t want to keep the furnace running full-time; that would waste both fuel and electricity. So after a bit of pondering, sketching, and chin-scratching, I decided to put the new water heater in series before the old water heater. Since the old water heater can hold 11 gallons of water and keep it warm for several hours or more, this would allow us to make hot water rapidly in the morning, and then store it for the day.
It sounds great, but ultimately I had one more hurdle to overcome. To fill that tank with hot water I would have to displace 11 gallons of cold water previously sitting in the tank every time I make hot water. With only 200 gallons of water storage aboard, we can’t afford to simply run the hot water until all of the cold water in the tank has been displaced. That would amount to 11 gallons of wasted water per day! To alleviate this, I added a recirculating loop with a remote solenoid valve that allows me to circulate hot water through the water heater tank and back to our storage tank until the water is up to temperature. This way we never waste any water by running the tap and waiting for hot water.
If I’ve lost you in all of my plumbing induced excitement, I apologize. You have to understand that this project is a welcome improvement for our life off the grid and on the move. Slowly but surely we are turning this boat into a fine vessel. Enough progress on the systems has been made that we are even beginning to talk about cosmetic improvements! Each item off the to-do list is an accomplishment, and it feels particularly so when the item involves problem-solving, independent of the readily available solutions.