Linseed oil

Prior to covering, the old dry wood is coated with warm linseed oil. This keeps the hull from soaking up water in use. The exterior is covered with canvas, but water inside the hull can easily run through the gaps between planks and get between the canvas and the hull.

This also gives you an idea the tone the wood will have when it's varnished. The lighter wood is cedar from Menards in Wichita. The darker wood is either original planking or cedar from Home Depot in Washington. From the inside the lighter wood won't be as noticeable because it's under the decks.