First Rot Sighting

Tonight, in the process of removing the cable thru-hulls near the mast step, I uncovered the first rot. The fittings were thru-bolted in 4 places each and the only bedding material used was a very flexible sealant. The balsa was a lovely shade of dark grey, and offered almost no resistance to my screw driver. This is the first section of deck core that I have opened up. I have a feeling that the whole deck is like this.