The wishbone is a particular Espar which makes it possible to tighten a sail with the manner of a Bôme. Its design in double clotheshanger, on both sides of the veil, the fact of resembling a poultry bone, the Breast-bone from where its name of origin anglo-saxone ( wishbone , the bone of the wishes). It connects the mast to an intermediate point its height at the point of listening of the veil.

From the light sailing ships of Polynesia, this gréement was initially used in light veil at the 19th century and allowed to leave free the curve of the veil and thus to give him a contour of beautiful quality. It was also used to increase the surface of certain sails in particular in the tops (as in the PEN-Duick III). It became emblematic boards with veil of which it constitutes the basic concept. It makes it possible, in this case, to direct the sail with the hand completely, in all the directions.