Hold that question. I might be able to answer that in the near future. I'm planning on replacing my transom core with Coosa Board. I can already tell you one downside is cost. Reatil for 1 sheet of Bluewater 26 3/4" x 4' x 8' is around 180 bucks. (1 inch thick is about $210) Times that by 2 (of the 3/4") if your looking for the original thickness of the V20 transom. Needless to say if your looking to go thicker it gets more expensive.