The keel of the boat is 17ft, 3 inches long, measured from tip to tip. The max length of a plywood strip is 8ft long - I needed to join several strips together to make a full length keel. For the joint, I decided to use a Scarf Joint rather than a Butt Joint. The first step is creating the scarf. Scarf joints need to be long: the length of the scarf needs to be about 8 to 12 times the thickness of the material. I stacked the keel pieces up, spacing them every 2 inches.