Removable sunshade for sailboats
BACKGROUND OF THE INVENTION 
     This invention is a sunshade that is affixed to the backstay of a sailboat and can be easily attached and detached. 
     Existing sunshades for sailboats consist of either semi-permanent attachments utilizing stainless-steel tubing or similar materials, or simple sheets hung from the boom. Both of these have their drawbacks. The former are usually made-to-order to fit a particular boat, and cannot be removed on occasions when there is little sunlight. The latter are suspended from the boom, which is used to maintain tension on the sail, and thus cannot be used while actually sailing. 
     SUMMARY OF THE INVENTION 
     This invention was conceived to eliminate these drawbacks, while serving to block strong, direct sunlight while under sail and/or at anchor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a plan view of the sunshade. This shows the sunshade as it would appear when laid flat, not as it appears in actual use. 
     FIG. 2 is a side view of the sunshade as it would appear in use on a sailboat. 
     FIG. 3 is one-quarter view of the sunshade as it would appear in actual use. 
     FIG. 4 is a three-quarter view of the sunshade as it would appear in actual use. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, the sunshade consists of two sheets (2), each in the form of an isosceles triangle, which have been laid out with their long sides together to form a diamond shape. Bisecting this diamond (perpendicular to the long sides of the sheets) are 2 flat spars (1) which are fixed in place, sandwiching the sheets. The sheets are not joined along the long edges, thus creating an opening (6) for the backstay (explained below). 
     The spar combination (1) is the point at which this invention is connected to the boat, by way of an attachment line (4). Multiple holes in the spar (5) are provided to facilitate attachment to any type of boat by allowing adjustable fore-aft positioning (at least three holes). Grommets (3) are positioned at both corners of each sheet, permitting the sunshade to be secured to the boat. 
     This invention is intended to be used as a sunshade for use solely with sailboats. Most sailboats have a backstay, which is used to support the mast. They also require a boom to unfurl the main sail. Thus, the obstacles posed by the complex nature of the rigging on sailboats make it difficult to erect a sunshade. 
     However, as shown in FIG. 2, this invention was designed to accommodate the backstay and boom of any sailboat. 
     To set up the sunshade as shown in FIG. 2, the spar combination (1) is suspended from the backstay of the sailboat to form the upper part of the sunshade. Then the grommets (3) at the lower comer of each sheet are tied to their respective sides of the boat, affixing the sunshade. 
     More specifically, the set up of this invention would involve tying the attachment line (4) to the foremost of the top-mount holes (5), tying the attachment line (4) to an appropriate point on the backstay, and then running the remainder of the attachment line (4) back to another of the top-mount holes (5&#39;) and tying it there so that the attachment line (4) forms a triangular shape. If, at this point, the boom and the spar combination (1) overlap each other, the attachment line&#39;s (4) rear mounting (5&#39;) should be re-attached at a more forward hole (5&#34;), to ensure that the boom and the upper part of the sunshade do not much. The provision of multiple mounting points on the spar makes it possible to easily attach the sunshade to any type of sailboat, and adjust its positioning to maintain proper distance between the boom and the sunshade. 
     Next the openings (6) are positioned around the backstay, and the grommets (3) at the lower comers are pulled taut and tied in place against either side of the pulpit, the lifeline, or another appropriate part of the boat. 
     FIGS. 3 and 4 show the attachment line (4) tied to the backstay and the grommets (3) tied to the lifeline or other position on the boat. Tying the sunshade in multiple locations helps keep it stable in strong winds. Furthermore, when attached, the sunshade forms a pair of inverted triangles with bases above and tips below, allowing the operator a clear field of view, for greater safety. Finally, since the sunshade does not overlap the tip of the boom, which is needed to keep the sail taut, the sunshade can be used under sail without difficulty. 
     Other noteworthy advantages of this invention are that it can be easily erected when the sunshine is strong, and easily taken down when not needed, and since it is made mostly out of fabric, it can be rolled up and stored compactly onboard.