I'm looking for suggestions on how to improve the insulation in our aft (and only) freezer.
We have had condensation from the freezer running into the deck locker just to stbd of the freezer for some time. When we pulled the freezer out (not too bad of a job) I see that Amel used a liquid foam method where they built a form around the freezer (upside down) and injected foam to form the walls. Then they put a bottom on the wall forms and injected foam thru a 4" diameter hole to form the bottom. The thickness was: 3" bottom; 2" stbd side; 2.5" port; 1.5" fwd;
The insulation was soaked at the joint between the "walls" and the "bottom" foam applications due to cracking/shrinkage/poor jointing, because air could penetrate through the voids and get to the cold surface and condense. The foam was also deeply cracked in several places, again causing condensation. It was so wet in these areas when you pressed on the foam, water would flow out. I can't imagine why Amel didn't use a closed cell foam. I would say this is not one of Amels finest moments (OK, I'M READY FOR THE FLAMING ARROWS). The saturated insulation was frozen where it was close to the box, and the wet unfrozen insulation must have been nearly worthless (I estimate this area to be 50%). It must have been in this condition shortly after construction, but if you're not living aboard the insulation has a chance to dry out between uses.
The wood panels forming the stbd and fwd sides are not removable without cutting through fiberglass tabbing and disconnecting the refrigerant lines, which seems to me major surgery I'm not eager to take on afloat.
I've removed the wet insulation on the bottom, and the sides up to the wood panels (took about two hours). Above that level there wasn't much saturated foam (I think it was wicking upward into the "wall" from the "bottom" joint). I'll let it dry on the main cabin table for a week. I'm thinking of replacing this with 3 inches of closed cell EPS foam insulation board. There is room on the back for an additional 2" of EPS (Amel put a 2" batt of insualtion there taped to the galley cabinets). Then painting all the insulation I can reach with a paint intended to cut off vapor transmission to the foam. This EPS has an R value of 2.9 per inch of thickness, so 3" is 8.7 which has to be better than the sauturated insulation. On the back with the additional 1.5" board it will be an R of 13.
The insulation has to be glued to the freezer box (polyurethane construction glue?), and since the box has rounded corners there will be voids. I'm thinking of leaving gaps between the "walls" and "bottom" insulation joints and filling them with one of the spray can crack filling foams to try to make it as vapor tight as possible. I thought about a plastic vapor barrier but I can't access behind the wood panels on the fwd and stbd sides.
Any thoughts or suggestions on this method?