Although the boat I race on uses a full cover... keeps the deck quite clean. But he has problems with mold that have required him to use a huge dehumidifier.

My little Nicovent seems to do a great job, the boat interior generally smells fresh... if it is otherwise, I look for a problem. (left some water standing in the head months back and that made a musty odor, that was fixed by flushing the head dry.)

I think I would prefer some smaller covers... so this may change my approach with this canvas guy.

I have a bid for about $1K for something that would basically cover the entire cabin top down to some side rub rails.