Chambered structure for wing sail

Abstract

A so-called “wing” sail for a sailing vessel, having an airfoil section performing substantially in the manner of an ideal airfoil on either tack is described. A two-sided inner sail structure having resiliently deformable battens slidably engaging a track, fixed to the mast of the sailing device and extending rearwardly, the mast being rotatable about its vertical axis in either direction relative to vertical planes along the longitudinal axes of the sailing device and the boom. Translation of the two main surfaces of the wing sail as well as the surfaces at the clew corner while maintaining proper tension in the surfaces, is accomplished by opposed inflatable air bladders. An aerodynamic seal is provided along the trailing edge of the wing sail. A horizontal control bar is attached to the mast to control the pivotal movement of the mast. The outer sail members wrap, around the mast and are fastened to the mast by a zipper. Air bladders establish and maintain the desired airfoil shape, while allowing the batten members to flex when the wind moves from one side of the sail to the other.

What is claimed is:  
     
         1 . A sail for use between a rotatable mast and a conventional boom, comprising: 
 a first and a second flexible planar members, attachable substantially spaced parallel to each other between the mast and the boom each in the substantial manner of a sail, facing surfaces of the two planar members defining between them a space;    a plurality of elongate substantially rigid batten members located roughly spaced parallel to each other in the space between the two planar members, each batten member slidably mounted at a one end to the mast at spaced apart locations along the mast and each batten member extending roughly parallel to the boom to the reach of the planar members;    a first inflatable gas bladder in a space between the plurality of batten members and a first flexible planar member;    a second inflatable gas bladder in a space between the plurality of batten members and a first flexible planar member; and    means for selectively inflating the first, or the second, gas bladder so that, consequent the selective inflation of both gas bladders, outward-facing surfaces of the two planar members assume the contours of the surfaces of an airfoil.    
     
     
         2 . The sail according to  claim 1  wherein each batten member is slidably engaged to a sail track vertically mounted on the mast.  
     
     
         3 . The sail according to  claim 1  comprising a fully battened inner sail.  
     
     
         4 . The sail according to  claim 1  wherein each bladder is secured by bladder retainer flaps welded to the bladder and attached to the inner sail.  
     
     
         5 . The sail according to  claim 1  wherein the first and second flexible planar members form an outer sail shell.  
     
     
         6 . The sail according to  claim 1  wherein the outer sail shell luff edges wrap around the mast, which mast acts as a pivot point of the sail.  
     
     
         7 . The sail according to  claim 1 , wherein said luff edges are removably united by a zipper means.  
     
     
         8 . The sail according to  claim 1  comprising a plurality of loose outer shell retainer straps, each retainer strap attached at one end to the luff of the fully battened inner sail and at the other end to the luff aspect of the outer sail just reach to the mast.  
     
     
         9 . The sail according to  claim 1  wherein inner and outer sail shells are secured to each other at the reach of said sail.  
     
     
         10 . The sail according to  claim 1  wherein gas within the bladders is regulated by a three-way transfer equalizing valve.  
     
     
         11 . The sail according to  claim 1  comprising means to purge gas from the conjoined bladders.  
     
     
         12 . The sail according to  claim 1  further comprising a gas distribution transfer pump.  
     
     
         13 . The sail according to  claim 1  wherein the front of the mast facing windward and the inflated leeward bladder opposed by the deflated windward bladder together operate to form a wing-like airfoil, smoothly concave windward and smoothly convex leeward, thereby providing substantial lift and minimal drag.