In hindsight i should have uncovered my 7.9 this spring while we still had COVID closures, but i didn't. As a result of the excess moisture the entire boat on the inside was entirely covered in mold. the boat's interior and headliner are lined with indoor/outdoor carpet. This was a big job.
Ventilate and wear a mask for what i'm going to tell you...
I bought a new tank sprayer (like the ones used for weed control in yards and filled it with undiluted vinegar first and literally hosed down the entire boat. From what i read the acid in the vinegar kills off the spores and prevents the mold from spreading.
Step 2 was to take the same sprayer and dilute a 4:1 water bleach mixture (make sure you take out any upholstery to do this part). Did the same, sprayed down the entire boat, but avoided places i was concerned the bleach might do damage. It's remarkable how the bleach just makes the black vanish at this point.
The final step was purchasing one of those Bissell hand steam cleaners for cleaning furniture and cleaning all the carpet surfaces.
Needless to say, for a 40 year old boat it looks almost new. I'm pretty religious with a de-hu in the summer, but so far over a month in not a single spore has returned and the typical musty boat smell it used to have is completely gone.