A couple of German inventors (obviously sailors) have applied for a U.S. Patent on a sail membrane impregnated with nanomaterials that results in a surface structure especially suited for sailing with wind astern, which can thus be used for the making of spinnakers and gennakers.
According to its German inventors in U.S. Patent Application 20100000456, Uwe Stein and Heiner Schillings manufactured a “sail membrane of woven synthetic fiber fabric which is provided with microroughness in the form of intersecting groove families or sets arranged so as to achieve a density of 5 to 25 grooves/mm and deposited on or integrated into the fabric structure. The sail is characterized by hydrophobization achieved by means of perfluoropolyalkylene and a nanoparticle coating.”
The sail membrane is impregnated with a nanoparticle layer aimed at improving the membrane’s water repellency. Its water absorptiveness can be significantly reduced in this way and the sail remains dry even when in use.
The sail is covered with a continuous coating of a water-repellent agent–as well as a coating intended to reduce the permeability to wind which can be dispensed entirely over the sail so that altogether a considerable reduction in weight of both a dry sail and of a sail in use at a given time is achieved.
The term “sail membrane” means any woven fabric made of synthetic fibers suited for and/or employed in sailmaking. Such sail membranes are, in particular, intended for the making of sails used (also) when sailing with astern wind. “The fabrics may be manufactured from fibers of a single type such as, for example, polyamide fibers, polyolefin fibers and polyester fibers but may as well comprise mixed systems. Said fabrics may be coated in a manner known per se with a view to reducing or eliminating their permeability to air and, as a rule, are hydrophobized. To bring down their permeability to air the fabrics may also be rolled and/or treated thermally, for example by fusing a fiber with a low melting point of a mixed fabric consisting of various synthetic fibers.”