Are you shrink wrapping or using a tarp?

Well, it doesn't matter I guess. I wash the boat, open all the
cabinets, make sure the drains are clear, put vents front and rear at
the top of either the tarp or shrink wrap and just leave it at that.


I use a standard tarp during the usage months - last year put it in
garage over winter with a breathable cover - elasticated edge, like a
large shower cap.
Just thought it worth looking at dehumidifiers, I saw an add some time
ago (maybe Overtons) that had a complete bubble cover (like the ones
for cars) and this had a dehumidifier under it.

Boat is a closed bow outboard powered runabout.