Scarf joints are used to join 8-foot long plywood sheets together to make longer sheets so you can cut panels as if from one piece of plywood. The plywood scarf joints when properly done, typically 8:1 angle, will be as strong as the plywood and flex the same as continuous wood.

Joints between panels on S&G kayaks are usually not mitered to make a tight fitting joint that would be tedious to make with the changing angle along the length of the panels. The mating edges are usually rounded so the two mating panels touch at tangent points rather than teetering on mating corners. Epoxy fillets and epoxied glass cloth and/or glass tape reinforce the panel-to-panel joints.

I suggest you read The New Kayak Shop before making any S&G kayak.

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