A steady diet of bananas, beets and bean sprouts takes its toll. To preserve cheese without refrigeration, I cut it into bite-sized cubes, place the pieces in a Mason jar and cover them with olive oil, garlic cloves and peppercorns. The oil, minus seasonings, also works for butter - it keeps for months. Farm-fresh eggs will last weeks if coated lightly in Vaseline and turned regularly. Some things just need moderate cooling.
Fresh fish keeps a day and a half if kept in the coolness of the bilge.
Just don't forget it's there, as I did once. That's when I use the ultimate trick for fridge-free living. It works best in crowded anchorages. First, you keep your ears tuned for the boats that are running their motors for an hour every morning and evening. That's a dead giveaway that they have a fridge and need to charge the boat's batteries.