Maintaining Your Propane System
A little attention can go a long way toward keeping your crew safe and your onboard gas appliances working like they should.
Most modern cruising boats are equipped with propane as their primary cooking fuel, and northern sailors often use it for heating as well. It’s perhaps one of the best fuels for these purposes, as it’s readily available and burns cleanly. Despite its convenience, however, propane does carry some hazards, and although not very common, propane explosions and fires can be devastating on a boat.
Considering the danger if a fault were to develop, I’m often struck by how little effort sailors seemingly put into maintaining their propane systems. The problem isn’t lack of concern on the part of boat owners; rather, it’s a lack of knowledge about how exactly to maintain the systems and where to look for problems. With this in mind, understanding the propane system and how to keep it functioning properly is important for any boat owner carrying propane on board.
Understanding a bit about propane will help you understand why systems are designed the way they are and how to avoid problems. Propane is a hydrocarbon gas that becomes a liquid when under pressure. When the pressure is released, the liquid becomes a gas once again. This makes the storage and transportation of propane relatively easy. Propane, which is heavier than air, settles into a bilge just like gasoline fumes do. If you’ve ever watched the vapors from dry ice flow over the sides of a container, you have a pretty good idea of how leaking propane flows. Of course, like gasoline, these fumes can be very explosive.
Most systems are relatively simple in design, consisting of a propane locker, a propane tank or tanks, a gauge, a regulator, a solenoid valve, and the supply line, which is fashioned from either propane-rated hose or copper tube. Let’s look at each component, then at how they all work together.
A propane locker is designed to prevent any leaking propane from entering the boat’s interior. The U.S. Coast Guard requires lockers to be vapor tight to the inside of the boat and have a top-opening lid with a gasket and latch. Lockers must have a drain at the bottom that vents to the outside of the boat above the waterline. This drain must be a downhill run with no loops to trap water. Hoses and wires that exit the locker need to be sealed vapor tight. The propane locker tends to be the weak point in any installation—often, they aren’t properly designed or built. Don’t assume that the locker is correct just because the builder installed it. Lockers mounted on the deck or on the rail need to meet the same requirements as well.
The first thing that goes into the lockers is the propane tanks. Tanks come in all shapes and sizes, but the most common sizes found on cruising boats are 10- and 20-pound tanks and, very often, one or two of the small, 1-pound camp-stove bottles for a grill. All propane tanks must be stowed in the propane locker—even the smaller camp-stove bottles.
Connected to the tank is the regulator and the pressure gauge. The gauge is on the high-pressure or tank side of the regulator and is used to detect leaks. Contrary to what some people think, the gauge won’t indicate how much fuel remains in the tank. The regulator reduces the high tank pressure to a lower, working pressure for your appliances. The regulator and fittings must remain in the propane locker with no connections extending outside the locker.
Downstream from the regulator is the solenoid valve, an electric valve that’s remotely operated from a switch near the appliance. The solenoid valve is normally closed, and it opens only when power is supplied. This is your primary safety device and should be left in an off position unless you’re using your stove or heater. Although not required, there should be a red light located near the switch to indicate when the power is on and the valve open. It makes sense to locate the solenoid switch separately from other switches and indicator lights so that it can readily be sighted if left on accidentally.
Connected to the solenoid is the supply line to feed the appliances. If you have more than one appliance, say, for instance, a stove and heater, then each unit should have its own supply line originating within the propane locker. The supply line can be either rubber hose with permanently attached end fittings or copper tubing with flare fittings. The supply line must be a continuous run from the propane locker to the appliance. The only place an inline connection is allowed is when using copper tube with a gimbaled stove. In that case, a section of flexible hose needs to be used to connect the copper tube to the stove.