hi i have 84 offshore 24' that i am in process of replacing transom seal on. my ? is, there is some kind of chalk that is all cracked covering the layers of plywood not sure what to do. i have removed all the chalk or sealer that was cracked and need to know what to replace it with. my thought was merine-tex or fiberglass mat resin? the plywood looks feels good to my was a little wet but drying out now. any sugestions would be great. thank you!