Deck composition and "sponginess": attn Arnie

Posted By: Greg CM26 Seattle CLM005771173
Date: 1/27/08 2:11p.m.

Report: outside forum guidelines

Hi Arnie, That thread was wandering all over the place, and I think this topic deserves its own. First of all, to the best of my knowledge, the CM26/FD did not come with a "V-berth hatch." If your boat has one, most probably a P.O. put it there. And that's probably the beginning of your spongy problem. Yes, indeed, there is a plywood sandwich there (see photo). My P.O. put in a non-opening "light" in the focsle ceiling (not a bad idea), but didn't put trim in the hole, so I have a nice cross-sectional view of my deck. As you can see in the photo, there is a lamination stack in the 3/16" to 1/4" thick neighborhood that constitutes the outer surface of the deck. Under that is a 3/8" plywood layer, then a thin layer forming the underside surface. I believe most people instinctly understand that lumber in general tends to act like a sponge when wet. Of course, after a given piece of wood has been saturated for a while, its mechanical properties (i.e., "strength") go bye-bye. That's very likely what you're dealing with. Keep in mind that, just like a real sponge, the soaked wood can wick the moisture a considerable distance from where it first infiltrated. There have been several discussions on the topic of rebuilding the poptop (see archives). Same problem, somehow water got in there. I suspect you've got the same thing going on with your transom. I have no experience resecting a Clipper transom, but I'm pretty sure there is wood in there, too, and a rather substantial piece, I suspect. I recall reading a description of the transom rebuilding process, too: again, check the archives. Sorry for the bad news, but I trust you now have a clearer idea of what you're dealing with. Greg