I have a 1988 Carver Montego that has mildew forming underneath the mattress in the foward cabin. There are no leaks, it appears to be condensation on the fiberglass form for the bed. Does anyone have an idea about this?
check you're humidity levels.. they make various devices for controlling humidity and condensation for boats.. bleach kills the mold.. im in a very dry area so don't have much humidity.. a lot of condensation..
I guess this should be obvious, but here in FL where some folks consider this a high humidity area, I've had no problems with mold or mildew by leaving my air conditioner on in the humidity mode all the time.
I have seen these course foam liners that lay under the mattress. The idea is to let air flow under it. I've never had the problem and not sure off the top of my head where to find it. The boats I work on swear by this real course foam. Not a clue where to start but someone on this forum can point you correctly soon.
Clean mattress and foundation with bleach - really good. Then put a permeable mattress support (many types out there) underneath. Works for me.