Winterizing sailboat

by Wendy
(Vancouver, BC Canada)

We have a 45ft cc hunter sailboat, and will be leaving it for an extended period this winter. It will be moored in fresh water in Vancouver. Last year we used 2 drizair fans, crystals, and

a heater for below freezing temp. All of the soft goods were bagged, doors on all cabinets and lockers open, bed mattresses propped up. We had mildew in all of the caninets and lockers. i would like to avoid the same problem this year...marina electricity is very expensive.
We have 4 hella turbo 12v fans mounted and I wonder if these would be better than other 110 fans. We want to consider power consumption, heat and air movement carefully.
Any thoughts on the best way to go?