Glue or Not?

I am using 1/8 ply to skin the 1/2 in. sides. Besides brads, do I need to glue? Liquid Nails? Gorilla Glue? How do I prevent water from getting between the skin and the sides. A bead of Silicone seal near the edge of the skin? I will be usiing spar varnish to finish the sides and painting the top with oil base enamel.
Mary in Central California
Mary in Central California
