I purchased a cover from Intensity sails,
www.intensity sails.com, and was very happy with the price, quality and service. They charge about $240. plus shipping which varies on your location, they ship from the manufacturer in California. The cover fits around the rub rail without the mast or boom crutch in place and has tie down straps to secure it. I keep the boat on a trailer with the mast on a support bar mounted on the trailer tongue and resting on the outboard bracket at the stern. To keep water from collecting in the cover at the stern, I fabricated a support bow from a length of fiberglass flat stock purchased at West Marine. The boat is now clean and dry and the deck is protected from constant UV exposure.
Good luck,
Kevin