SPIRAL™ ... creates the 3-dimensional sail "mold"

Spiral initially defines the sails’ three-dimensional shape as a ‘molded’ surface without any wind pressure or load applied. Precise control over all aspects of a sail’s shape allows a broad range of mainsails, genoas, jibs and asymmetric spinnakers to be designed. Every dimensional aspect of the sail can be adjusted both in horizontal and vertical axes.
Left : Comparison of roach profiles. Right: Gausian curvatures (shape analysis) for a TP52.© North Sails
Design inputs for a STP 65 jib.© North Sails