Just a thought I fixed an area of cored deck 1' X 2' on an old 17' CC with Get Rot. Drilled holes from the topside through the wood but stopped before drilling through the bottom. Left it open for a week. Kept a shop vac on the boat and several times a day sucked out what I could. Then used the Get Rot. After it curred I beveled the holes and filled with Marine Tex. It did take more Get Rot that I anticapated but its a strond deck now. The water entered via holes drilled for a seat. I drilled them out removed wood from between the layers of glass, filled with Marine Tex, and reapplied the harware.