Final note on Albin deck cores. I've since learned the core material is Divinycell, a high-density PVC foam. Still made and available in Europe and North America. The plug I removed was 1.77 cubic inches of foam. The foam weighed 14g wet (30+% MC)at removal; in less than five days in a warm house, it has stabilized at 4g and 6-% MC. Upshot is, if you expose the core & keep the ambient RH low, your foam will go back to factory-dry in jig time.
Despite undergoing many freeze-thaw cycles in the upper Midwest, the foam is structurally very sound & resistant to compression. So wet decks on Albin boats are less of a deal-killer than they might be on other marques. Cheers.