Boat Cover Question

My boat cover is 5 - 6 years old now and still in pretty good shape but,I would like to make it more water repellent than it currently is. Does anyone out there have a product they would recommend that I can spray on to improve its water repellency?

Thanks

303 high tech fabric gaurd, or aqua block, Can get it from most parts & service departments.

Camp Dry.

Double D.