O'day decks are cored with balsa. However, under the mast it would be cored with something more substantial, generally plywood. I have the same issue on my 192, but with the molded raised area under the mast bracket, I'm not sure what it would be. I know a guy on another forum that had a fair amount of cabin top coring to repair on a 222. I asked him what was under his mast step, and he said it was some kind of black stuff. He said "You'll just have to get into it and see." I also asked Rudy, and he just doesn't remember. So, given that I see depression at the corners of the raised "plinth" where it joins the cabin top, I imagine I'm going to have to remove a fair amount of top to see what's going on. I'm planning to try and peel back the carpeted cabin liner gently, so that it can be re-used to hide repairs, and go at it from underneath. Of course, repairing from the deck would be easier, what with gravity aiding rather than dripping all over, that leads to a world of gelcoat matching, and unmatched non-skid pattern, etc. I'm figuring when I get under there, I'll probably wind up laying up with many layers of woven, maybe some mat. Maybe I'll find that there is a block of ply under the plinth... In any case, under the step where the compression post attaches, the is a dimple upwards, so it's not like I can just fill in all the space with a plug of hardwood and glass over it, without cutting, shortening, and re-welding the compression post, which I'm not about to do. Kinda hoping for better weather, or at least more consistently warmer weather to untarp and get into it. I've been burned by snow in March before...
