Carver Boat Cover Adjustable Support Pole w/Boat Vent II 
Boat Cover Adjustable Support Pole with Boat Vent II
Replace a conventional support pole with one that provides an air vent to reduce moisture, heat and mildew under the cover. Includes an adjustable (22″ to 70″) anodized aluminum pole, boat vent and simple installation instructions.
These lightweight telescoping poles are designed to support your cover so that water does not pool.