Vortex generators for sails

Claim 1

A blank to be folded into a vortex generator for attachment to the surface of the sail of a sailboat comprising a strip consisting of a substrate of said material, being foldable into four panels including first and second central panels adjacent each other, a first foot panel adjacent the first central panel, and a second foot panel adjacent the second central panel, a layer of pressure sensitive adhesive on one surface of the central panels and the foot panels, wherein the first and second central panels are adapted to be joined together by the pressure sensitive adhesive along their one surface to form a central member of the vortex generator, the foot panels are adapted to be joined to the surface of the sail by the pressure sensitive adhesive along their one surface, with the central member of the vortex generator projecting into the flow of air along the surface of the sail to which the vortex generator is attached wherein: the blank is a rectangular element divided into the two central panels and the two foot panels and includes a release liner over the pressure sensitive adhesive on the one surface of the central panels and the foot panels, a first line of weakness defined in the liner between the first foot panel and the first central panel, and a second line of weakness defined in the liner between the second foot panel and the second central panel, wherein the liner is separable along the lines of weakness into a first section under the first foot panel, a second section under the first and second central panels and a third section under the second foot panel.