When Tom finishes, there will be twelve planks on this boat, or in actuality, 24 half planks. The planking material isn't long enough to span the entire length of the boat so two half planks are joined somewhere near the middle of the boat. The joint that connects the two planks is called a scarf. Scarfing is the process of beveling each plank so they can be overlapped and epoxied without creating any additional thickness to the plank. Tom uses an 8:1 scarf on these planks. This means that for every one increment of plank thickness, the bevel will be eight increments wide. For this boat, the planking stock is about 1/4" thick so the bevel needs to be 2" wide. The bevel will start at the full thickness of the plank and will end at the end of the plank in a feather edge. One plank will be beveled on its topside and the other on its bottom and when the bevels are slid together, they will equal the thickness of the plank. The 8:1 scarf provides a large surface area for gluing and makes for a very strong joint. Once the epoxy has cured, the scarf joint will be stronger than the rest of the plank. Aside from aesthetics and strength, another benefit of this type of joint is that it allows the plank to continue its fair curve and not develop a flat spot that other joint types, such as a butt joint, would.
Row, row, row your boat...life is but a dream.
