After installing the battens on the hull and the transom,  the next step is to add internal strips, as shown, which are installed to fair up the battens between the frames.   The battens that need to be joined can be joined on these fairing strips.   Installing these fairing strips is a job for two people.   One person to nail through the batten into and through the fairing strip, and another person inside the hull structure with a “dolly”,  or heavy metal weight against which the nail can be driven.   This procedure will cause the nail to bend over and clinch up tight.   Clinching is a common boat building practice and one that you would use frequently if you were building a wooden boat.   The “dolly” should be a solid piece of steel, of a size that will fit comfortably in the hand.   The ideal shape is a piece of solid round steel say 2 ½” diameter by 6” long [60mm x 150mm].   The dolly is used end on.   When the battens are joined between frames on the plywood fairing strip, they will be held firm and fair.   If there any small irregularities they can be lightly sanded at a later time.

   Use adequate plywood strips, at least one or two between each frame and no more than 1’-6” [500mm] apart, so if frames are more than 3’-0” [1 metre] apart, use two strips between each frame.   Clinch nail to every batten.   Best cut the strips into 4” [100mm] widths and use ¼” [10mm] to ½” [12mm] thickness of plywood.