We have quite a few areas of wet core -- mostly around the mast, on the foredeck, below the portlights, and worst of all at the chainplates. I drilled two core samples the other day:
cores by
Wyoming offgrid, on Flickr
The right-hand core is from just in front of the seahood. It was dry and well-attached to both skins. Moisture content under 6%. The left-hand core is from near the aft port-side chainplate. It was weakly attached to the skins, wet to the touch, and spiked the meter at over 30% MC. Foam+inner skin weighed 18g four days ago; it is down to 9g & 10% MC this evening.
What is interesting (to me) is the degree of structural integrity it still has. Most of the wet balsa I tore out of our San Juan had the consistency (and compressive strength) of porridge. This foam is still very rigid, apparently retaining its compressive strength. While you'd
like for it to be glued to the FRP, truth is its only critical function is keeping the inner and outer skins 1" apart from each other. So our plan is to strip the inner liner from part of the side decks, open the main cabin and foredeck liner where appropriate, and just let it air dry for six months. Several places on the foredeck will be getting solid cores, anyhow. That's the only spot of actual bubbled decks we've found, despite lots of freeze/thaw cycles.