Portable Freezer and Icebox Management

[Polar Opposite]

We just completed a long trip from Connecticut to the Gulf Coast of Florida that included offshore and ICW legs, with a broad mix of sailing, motoring, anchoring and marina periods. Our boat, a 1984 Contest 32 CS ketch, was only equipped with a factory-installed icebox, and like many cruisers, we struggled with choosing a strategy that minimized cost and complexity while providing cold food storage and ice, but minimized battery loading.
What worked for us: A Dometic CF-35 portable refrigerator-freezer, adjusted to its lowest achievable temperature (0 degreees F). We used it almost exclusively to make ice for the icebox. We made ice using empty 2L coke bottles, with one bottle freezing in the Dometic, and a second bottle cooling the icebox. We swapped them daily. The electrical load of the Dometic was minimal, especially since the lid was only opened once a day. The icebox stayed reasonably cool, even in July temperatures, and there was always ice-cold water in the Coke bottle for drinking. The bottles contained the melting water, so the icebox remained dry and didn't lose heat through the melt-off running down the drain. And there was extra room available in the Dometic for small amounts of frozen food. Just remember to burp a little water out of the Coke bottles before freezing them so they don't split open. I realize this approach is simplistic and maybe not very profound...but after living with it for a couple of thousand miles, I'm still happy with how it worked out.

[boatsail]

I have thought of doing the same thing. Glad to hear it worked. Thanks for sharing

[Island Time O25]

Is that portable freezer 12v or 110v?

[nigel1]

Looks like they are dual voltage
Dometic CF-35 CoolFreeze Portable Refrigerator / Freezer

[Island Time O25]

Originally Posted by nigel1

Looks like they are dual voltage
Dometic CF-35 CoolFreeze Portable Refrigerator / Freezer

Great! Now all that's needed is to find a used one for a fraction of the new price.

[Panope]

I do same thing as Polar Opposite.

Works great. Simple.

Steve

[a64pilot]

As a kid working, we used 1 gl milk jugs, same principle though

[Polar Opposite]

As mentioned, they are dual voltage, but to keep things simple, we only used the 12v cord, even when we were on shorepower in a marina. It was one less cord to manage, and one less thing to remember to do when we cast off lines.
We had zero luck finding one used. I think the people that have them really love them and rarely part with them. I had one problem on a previous boat where a drip of saltwater fried the digital circuit board. Dometic was unable to source a replacement board, but I eventually found one through an Australian company.
I think this model is too small for gallon milk jugs, but the quart-sized ones with screw-on caps would be great, and probably tougher than Coke bottles. Good idea!

[Peter1949]

Polar opp
Would the domestic ice maker@ $200 been a better choice?
Amp draw look minimal
Would be nice if you could see one at a supplier
Pete

[PuttingDoctor]

Take a look at the EdgeStar line for dual voltage freezer / refrigerator for less. I'm leaning toward the 63 quart model mounted below my Nav desk. https://www.ebay.com/itm/121912091994

[Polar Opposite]

Originally Posted by Peter1949

Polar opp
Would the domestic ice maker@ $200 been a better choice?
Pete

I don't think so. If we're talking about the same product, I owned one of those for at-home use, and they only make a pound of ice or so at a time. Then they have to be emptied and refilled. The advertising is somewhat deceptive, because they imply that the units make a certain amount of ice per day. I suppose they do, but only if they are emptied and refilled regularly. Also, I don't think they would take the rocking and rolling very well, and the one I owned only lasted a few months before breaking. As for amp draw, the portable freezer was only pulling about 30 amp-hours a day.

[Peter1949]

Polar pop
Thanks for info on the ice maker
Where do you place your dometic freezer when sailing?
Thanks again about the ice maker
Pete

[Polar Opposite]

Originally Posted by Peter1949

Where do you place your dometic freezer when sailing?
Pete

Good question. My choices were limited to the v-berth and the salon floor because those are the only locations with 12v outlets I used the v-berth, but in the future I will fabricate some built-in storage to keep the unit secure and out of the way. Small amounts of condensation form on the outside of the unit under conditions of high humidity, so that should also be considered when selecting a location.

[a64pilot]

Whatever it is worth, what you are doing is less efficient than using an Engle or other fridge / freezer directly.
I understand why you do it, cause you get to use all that space in the icebox, but by making ice to cool an icebox, you are using more electrons than if you cooled the icebox directly, or used a stand alone fridge.

[Polar Opposite]

Originally Posted by a64pilot

Whatever it is worth, what you are doing is less efficient than using an Engle or other fridge / freezer directly.
I understand why you do it, cause you get to use all that space in the icebox, but by making ice to cool an icebox, you are using more electrons than if you cooled the icebox directly, or used a stand alone fridge.

I completely agree. Nothing here gets us around the Laws of Thermodynamics. I should have discussed some other factors that were in play:
- The icebox on a Contest 32 is quite small, making installation of a conversion refrigeration system problematic.
-The small icebox size does, however, lend itself well to cooling with frozen Coke bottles. A larger box or poorly insulated one may not stay cold enough.
-Aesthetics: Although my boat is 30+ years old, the factory interior is quite nice. It makes me think twice about doing any hacks necessary to install fixed systems.
-I already had a portable freezer. If I was starting from scratch, I may have come to a different solution.
-Volume: Just like you said. This method gave us the volume of the portable freezer plus the volume of the icebox, while only powering one compressor.
There's no doubt that the ideal solution from an energy draw perspective would be the system you describe. Our method sacrifices an acceptable amount of current draw to gain the advantages of simplicity, portability, and ease of installation. Plus, you can keep the portable freezer if you ever sell the boat!