Refrigeration on a smaller sailboat

 By Jack Brennan
Shanachie, 1974 Bristol 30
Tierra Verde, Fl.

One of the best improvements you can make to a smaller cruising sailboat is to add refrigeration.

Think of it — a cold drink always within reach, no searching for block ice, no pumping out dicey water from the icebox, the ability to keep meat, butter, milk and other perishables indefinitely as you go from harbor to harbor.

The two obstacles to effective refrigeration are the poorly insulated iceboxes on most older sailboats and the limited availability of electricity to run the refrigeration.

fridge

The portable 12-volt fridge sits tightly in the head of the port quarter berth.

If you spend $1,000 or more — sometimes, much more — adding permanent refrigeration to your existing icebox, you may find that you’re using 80 amps or more a day on a sailing trip unless you install thick insulation on the inside and fiberglass it over.

There’s also the space problem that plagues every small sailboat. On my Bristol 30, three sides of the icebox are somewhat accessible for installing the refrigeration unit. One side leads to the footwell for a settee, another leads into the engine compartment and the third leads to the battery compartment, none of which is really suitable.

After poking around on the Internet, I came across what turned out to be a great solution for me — a portable, 12/110-volt refrigerator that stores as much as a good-sized cooler, uses 30-40 amps a day on 12 volts and can chill drinks for a daysail in the time it takes to prepare the boat at the dock and motor out to sea.

Better yet, these units are less than half the cost of an installed unit, even though they use the same type of refrigeration unit, which is powerful enough to freeze food and make ice if you so desire.

Note that I’m not talking about thermoelectric coolers, which are less expensive and can reduce the temperature about 40 degrees maximum from the outside air. That’s not nearly good enough for me because I sail in western Florida, where the temperature is 90 to 95 degrees for a large part of the year.

I also don’t recommend converting a dorm or RV fridge that runs on 110 volts for use on a boat. There are lots of reasons not to do this, most importantly for safety, because you could electrocute yourself or start a fire. They simply are not built for use on a boat.

The refrigerators I’m talking about are most commonly manufactured by Waeco/Dometic (the same products under different brand names) and Engel. The Engels are top end and sell for twice as much as the Waeco/Dometics.

The big advantage over permanently installed refrigerators is that these units are well-insulated and don’t use nearly as much electricity.

I bought a 40-quart Dometic on the Internet three years ago for a little more than $500. They sell for a few dollars more these days. A similarly sized Engel goes in the neighborhood of $1,000 on the web.

On my Bristol 30, a model with a double-settee cabin and port-side quarter berth, the logical place to locate the refrigerator was in the cabin at the head of the quarter berth, which is used for storage.

fridgeinside

There are two sections to the interior of the refrigerator. The compartment at right is the perfect space for small items such as butter or the filled plastic bag inside a box of wine.

It sits under the electrical panels and is easily accessible from the galley. It’s also easy to reach in from the cockpit and grab a drink.

Other possible locations include a cockpit locker, which would make the cabin a little less crowded but also make it more difficult to get into the refrigerator. (Not necessarily a bad thing because lots of openings use more amps.)

To complete the installation, you have to perform two tasks.

The first is electrical. The 12-volt plug is the cigarette-lighter type with an eight-amp fuse inside. At first, I installed a compatible outlet nearby and ran wires to one of my electrical panels, where I commandeered a spare switch with an eight-amp fuse to protect the circuit additionally and give me an easy way to turn the refrigerator on and off.

After two years or so, I noticed the plug was heating up, a cause for concern even though it was not breaking the fuse. So I replaced the plug and outlet with quick-connect fittings that are available in every hardware or marine store.

With a second set of quick-connect fittings and another plug, I would be able to remove the refrigerator from the boat and use it in my SUV while making a long-distance trip.

The second task is to strap down the refrigerator so it doesn’t go flying through the cabin during rough weather. My Dometic unit has handles on either end. It was a simple matter to use battery straps to secure them to the wooden base of the quarter berth.

I have used the refrigerator on multiple trips of a week or longer with a house bank of two Group 24 deep-cycle batteries isolated from a separate Group 24 starting battery. If I watched my electrical consumption, I could go two days at anchor without using the diesel to recharge.

I have beefed up my electrical system for reasons unrelated to refrigeration — two golf-cart batteries and a Sterling alternator-to-battery charger — so I don’t expect the Dometic to be any cause for concern in the future.