Hello, we have hull
53 built in 1977/78. When the PO decided to refrigerate the box he decided to insulate it. He went with the theory that there was no insulation installed.I was his gofer guy. He methodically drilled 1/4 inch holes in the the walls about 2 inches apart which was 4 in a two inch square.Very tedious work. He then injected expandable foam through these holes until over flow. When dry he cut off the excess inside the box with an exact type knife. This was in 2004 and then he was off to the Bahamas
. Did it work?? I can tell you that the evap plate was turned into a freezer
and yes it works, we have that vessel and still use the same equipment
that was installed back then. The conversion kit is a Norcold and no issues have developed.