Would like to improve insulation on icebox in Capri 26 1991. Spending severals 3 days or more in a row during summer, how to know what degree of insulation is left in icebox without taking it all apart. I do not want to re-build the whole icebox since it was built as one piece with the sink and burners . Insulating from the inside would loose to much space. Is spray foam any good for this utility or not ? Has anyone ever dismantled his icebox to see what it's in there if any ? As far as I know, Capri 26 were designed to be daysailor boat . Any suggestion ?