DSK said:
All that does is equalize the humidity inside & outside the boat.


Dave wrote:
If I'm not mistaken it's not just the humidity, but a combination of heat
and humidity that creates a real problem.

Well, you're mistaken

Seriously, in one way you're right *if* the ambient air circulating is
cooler than the mildew likes. If you are in a warm humid place, like the
South, then the ambient air will support mildew blooms very nicely. If
it were only a matter of heat, well, heat kills mildew & spores... it
just has to get hot enough.

... Providing some circulation should
reduce the time the boat is like a steam bath because the sun is beating
down and warming it while cooler air can't get in.

If that cooler air is bringing in more moisture, how is that going to
help? The problem is not the simple fact that it gets hot (but not hot
enough to kill mildew & spores, just hot enough to germinate them), but
rahter that you have a thermal cycle... the boat cools off at night but
humid air is trapped inside, where it condenses on various surfaces.
Then more air of ambient humidity is drawn in, it gets heated up by the
sun, then cooled and condenses again... the boat is basically a thermal
condenser cylcing around the temp & humidity range that mildew thrives
in. The problem is best attacked from both angles.

BTW my congratulations on a boating related post. You did great for a
first-timer

Fresh Breezes- Doug King