J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment concerns with older j30

I would guess that percentage saturation refers to the relative weight of the saturated wood. Balsa can hold several times its own weight in water.

A cored boat can maintain its structural strength even with wet core. However, once a core is wet, it will eventually rot. Once that process starts, the skins will delaminate and, ultimately, there will be a void between the two skins when the wood fibers break down. It's at that point that it becomes a significant structural issue.

Here's a photo of me squeezing rotten, saturated balsa core from a Pearson Triton - note the water that's squeezing out. In this case, the saturated deck section failed and, when someone jumped from the dock to the boat, it caused a six inch crack in the deck.