Spray Foam Access

[J Kleber]

I'm a new owner of a 2004 -'Moondance' and working out a few issues, notably the performance of the refrigerator/freezer. I'm in Lake Michigan and the summer water temp gets into the 70's late in the season. I've got the original compressor setup, and the doors and seals were previously replaced. During the summer, I can get the freezer and refrig compartments into the 40's and can get ice in the evaporator box. Coincidentally, late in the season, the water is colder and the internal temps drop- and the freezer actually gets into the 20's.

I noted everyone's solution from drilling holes, and adding panels, etc, and none of these interest me, as they require a lot more work and possibly losing internal space.

I'm considering drilling larger holes (3/4") from the outside- specifically take the drawers out and gain access to the cavity from the right side-, and would shoot 'Great Foam' using an extended tube into the recesses. What I don't know is what's behind the box, and any potential issues I might encounter? Ideally, it would be good to have an assembly or shop drawing and photos showing what's behind the walls of the icebox.
Thoughts?

[Captain Kirk]

hello and welcome new owner

We bought Sand Dollar about 7 years ago. The freezer really couldn't keep up with our needs on our 10 to 12 week summer cruises. Like you, I reviewed all of the postings here regarding different ways to 1) get the temp down in the freezer and fridge, 2) reduce the amp/hr. costs.

We found that our type of cruising doesn't require the amount of volume in both the freezer and the fridge.

I drilled and filled the entire package - fridge, freezer, doors, lids etc, from the inside. Drilled the bottoms and all the sides of the " tub". It took lots of Hi density spray foam. This was tested for a whole season with some good improvements.
The condenser/compressor was getting flakey so i bought a new one, same as the original one and had it professionally installed, this improved things also.

The best improvement I made was to the line the freezer with 2" of HD rigid foam board and the fridge with 1.5 " of the same foam board. This gave us a big gain. And we reduced the overall volume by about 15% ... this is a plus.

The last 2 seasons of cruising with this system was the test for us. I have temp sensors in the freezer evaporator box, lower part of the freezer area, and one in the top of the fridge. We are able to maintain an average -11 deg C, (this varies through the day, between -16 and -9 C) in the evaporator, and around + 6 C in the top shelf of fridge where we keep condiments and other less critical items. Drinks in the lower part of the fridge are kept icy at + 3 deg C.

The power for all this comes from the new 480 watt solar panel array. We never need to plug into shore power and if needed, we get any additional A/Hrs when we motor in and out of anchorages. We don't need to run the engine at anchor and we don't have a Honda gas generator.

One other point -make certain that the copper line from the Cond/comp to the Evap is not frosting up. That indicates the need to adjust the R134 charge.

FYI - 3 deg F = -16 deg C Also 40 deg F = + 4.5 deg C

Cheers

[KenKrawford]

John, Capt. Kirk has given you some great info and advice. I'll add some additional thoughts. First and foremost, if you go the spray foam route be aware that there are 2 types of DIY spray foam. You don't want the "big gap filler" type. It is very powerful when it expands it can severely distort and damage your box liner. The "straw" nozzles on those products are only 1/4" - 3/8" in diameter. If you drill 3/4" holes you'll find that most of the product will ooze out. I also think that the hull side of the freezer box is most important when it come to insulation. With sun striking that side of the hull, you've got a fairly small area between the freezer compartment and the ambient outside.

[Captain Kirk]

As Ken mentioned the starboard side in the hot sun will definitely tax the system.

To reduce this I made certain to spray into that side all the way to the bottom of the freezer. At the top of the box liner there is small gap to the hull, maybe about 1/4" - 3/8th; but the liner curve doesn't match the curve of the hull so the lower you go with the holes, more foam is needed as the gap widens significantly. Also when we're cruising and decide to go dockside I always try to get the starboard side of the boat in a north or east orientation to avoid having the hot afternoon sun directly on the freezer.

Good advise to not use a 3/4" hole size, it might make it difficult to get enough foam in. I used small plastic inserts to fill the 1/4 " holes after the expanding foam hardened.

You could do your project in phases to see how far you need to go to get to your desired result. My target was to keep ice cream hard for at least 2-3 days. ( and also to have ice cold beer in the bottom of the fridge.) A Yeti or similar ice chest in the cockpit is also a good addition.

[Olivia Mae]

Foaming from the inside is pretty easy. Use the minimally expanding door and window foam and seal the holes with epoxy or 5100. Note: the first pic below is the finished job.

[KenKrawford]

Great idea taping the liner before injecting foam. The last pic shows why ! Also wear disposable gloves. The foam is nasty and difficult to get off unprotected skin.
If you go this route, be very careful when moving the evaporator. There is copper tubing hiding under the black foam insulation and can be kinked if you're not careful.