Our Malo 41 is a good, well-made Swedish boat, but the Swedes don't have to worry much about serious refrigerator insulation. That makes for problems in the tropics.

Other Malo owners have been able to glue on foam to the underside of the box and then drill strategic holes from the outside and pour in two-part foam to expand into the spaces around the box. This stuff starts out runny so it's necessary to seal escape routes as much as possible. A small hole can yield a grapefruit of foam on the other side. Small batches are in order so pressure doesn't build.

I had a consultation session with Mark McBride at Miller and Miller Boatyard here in Seattle. I would describe him as the best kind of geek when it comes to refrigeration. He's certainly one of the best in our area. He even does experiments on refrigeration at home. One time he took some of the two-part foam home to test in a bucket of water for water penetration. He was happy that the water stayed out. But then he has seen boats with waterlogged foam insulation. One of his sources noted that water VAPOR can penetrate the foam and condense near the box. Dang! Ideally, one would surround all the foam with a vapor barrier. That's not really possible when the foam is going into inaccessible places. The other downside is that the dewpoint tends to move out to the wooden partitions and bulkheads that surround the refrigerator. Moisture and wood spell TROUBLE. Oh well... just another boat tradeoff.

The final question to McBride was a list of options. It came down to tear it all out and start over for the perfect solution. We all knew that was a non-starter. The only other option wa use foam board where there's access, two-part foam for most of it, and more expensive and probably less effective spray-in foam for the rest. (We had already ruled out shrinking the box by putting insulation on the inside. It is a small fridge to begin with. This Isotherm unit has a small freezer compartment that can make a little ice and fit a small hunk of frozen food.)

Now I'm looking for a right-angle drill to borrow for making exploratory holes followed by larger ones to pour foam through. The iPhone video camera will be very handy for peering through those holes.

This is a job I've been putting off for months. Ugh.