Boat transom project

[BearLakeFishGuy]

Since you did not use marine-grade plywood (where there are no voids between the laminations), you really need to seal those edges. I would use a filler and make sure there are NO voids where water could enter the edges. I did my transom like this about 15 years ago and its still going strong on my old boat that I sold to a friend. I did my research and the marine plywood was difficult to find and I had to have it ordered in, but it was worth every penny. I then laminated two, 3/4" sheets together with the 5200 marine sealant. I used stainless screws/bolts to reattach the aluminum "skin" and did not have to have anything welded. The real trick was to seal the ends completely to exclude any water/moisture. You're doing a good job. Did I mention, make sure to seal those edges!