I purchased a 1972 Mako 19 on April 4th. It came with a 20" shaft Johnson 140, a soft deck, 2 broken stringers, and a wet transom. I removed the deck and transom over several days, and took out probably a thousand pounds of wet foam.
The transom is my first big project. My plan was to build a template out of lauan, raise it from 20" to 25", and enclose more of the opening. My lamination schedule is going to be a layer of heavy mat on the outer transom skin, to seal the 43 holes in it, a layer of 1708 up against the inside of the transom core for strength. The core is two pieces of 3/4 Okume marine plywood. The resin I am using is vinylester from US Composites.
Core test fit
Core and 1708 in place with a pair of strongbacks and bolts as a clamp.
Last night I placed fillets around the core, in preparation for laying a glass inner skin.
Today I filled all the screw and bolt holes in the transom, redid some of the fillets from yesterday that turned out bad, and I laid a layer of chopped strand mat over the fillets. I don't think it was required, but I'm hoping it will help with preventing the air bubbles tomorrow when I lay my inner skin.