Shaper's Square - is a layout tool that speeds up the process of marking out points for building surfboards. No need to divide whole width numbers in half, just mark where indicated. Includes fin marking matrix that is easy to use. Features a ruler at each end for measuring and marking. This shaping square is made from durable 1/16" polycarbonate that is nearly unbreakable and thick enough to not be floppy.
To use fin marking tool, set the bottom measurement the desired distance away from the rail, for a standard thruster, that is about 1.25" make sure the vertical lines are parallel to the stringer and mark at 0", move up to the corresponding fin base measurement (most standard fins are about 4.5") and mark the tow over, usually 1/4" for a standard thruster. Move over to the other side and repeat.