Advanced high efficiency mainsail

Abstract

A sail comprising a rotating flexible mast sleeve wrap surrounding the mast and attached to a sail track for controlling the movement of the sail. The sleeve assembly is slotted to allow for partial rotation of the sleeve wrap, the sail track and the sail, so that the sleeve wrap, the sail track and the sail rotate to form an aerodynamic shape on the lee side of the rotating flexible mast reducing aerodynamic losses.

1 . A sail attached indirectly to a fixed mast, the sail comprising:
 a rotating flexible mast sleeve wrap surrounding the mast and attached to a sail track for controlling the movement of the sail, wherein the sleeve assembly is slotted to allow for partial rotation of the sleeve wrap, the sail track and the sail, so that the sleeve wrap, the sail track and the sail can rotate to form an aerodynamic shape on the lee side of the rotating flexible mast reducing aerodynamic losses.   
     
     
         2 . A sailing boat with a mast and boom, wherein the majority of the open space between the boom and deck or coach house has a skirt extending horizontally from the mast to more than half-way to the mainsail end or clew, wherein the skirt reduces the majority of the otherwise loss of efficiency and drive under a traditional boom. 
     
     
         3 . The sailing boat of  claim 2 , wherein the skirt wraps around the base of the mast so that there are two skirts behind the mast. 
     
     
         4 . The sailing boat of  claim 2 , wherein the skirt allows for vertical movement of the boom end. 
     
     
         5 . The sail of  claim 1 , wherein the mast sleeve wrap and sail track assembly house a vertical furling tube assembly for vertically furling the sail. 
     
     
         6 . The sail of  claim 1 , wherein a tack of the sail is not fixed but allows for the partial rotation of the sail tack area, so that sleeve wrap, sail track and sail tack rotate to form an aerodynamic shape on the lee side of mast at the foot of the sail, reducing aerodynamic losses at the foot of the sail. 
     
     
         7 . The sail of  claim 1 , wherein the fixed mast has non-circular cross section, having a substantially semicircular-shaped rear radius and a front radius smaller than the rear radius. 
     
     
         8 . The sail of  claim 1 , wherein a root of a spreader has a horizontal central point which is forward of the front to back center of the mast section to allow for maximum rotation of a rotating sail track or vertical furling system. 
     
     
         9 . A sailing boat of  claim 2  where a skirt is furled by at least one vertical furling tube behind the mast and predominantly below the boom.