Re: Plywood transom replacement...
If it is exposed, like the one in the picture, I would go with epoxy. You can use resin alone to bond the sheets together. But I recommend some light cloth and resin to cover the outside. It will make it more water tight and last much longer. I also recommend you paint it with a good marine paint. It will have UV light inhibitors in it to prevent the epoxy breaking down in the sun light. It will cost a little more time and work but if you do it right, it will be there for a long..long time.