Abstract:
A boat hull patch anchor adapted to be placed on the inside surface of a boat hull over and overlapping a hole in the hull. The hole in the boat hull may be tapered prior to bonding. A repair compound is applied from the outside surface of the boat hull. A method for the repair of a boat hull including tapering the profile of a hole in a boat hull, applying the patch anchor from the inside of the hull, and applying repair compound from the outside of the hull so as to fill the hole and anchor the patch.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention is generally related to the repair of boat hulls and similar items, and more specifically to a boat hull patch anchor and a method for its use. 
     2. Description of Related Art 
     Boat hull repair is often facilitated by the placement of a temporary backing plate inside of the hull covering a hole in the hull. The temporary backing plate acts as a form over which to create a patch. The plate acts to give support to the repair compound so that a hole can be traversed. After the repair, the backing plate is removed. Often the backing plate must be hammered or chiseled off the back of the repaired area due to adhesion to the patching compound. Wood has often been used as such a backing plate. In addition to being unsightly and bulky, wood must be removed to prevent it from becoming mildewed and rotten. 
     What is called for is a method and means for patching a boat hull without the need for removing a backing plate. What is also called for is a material that can be used as a backing plate for hull repair that can be formed to the various contours of a boat hull. 
     SUMMARY 
     A boat hull patch anchor adapted to be placed on the inside surface of a boat hull over and overlapping a hole in the hull. The hole in the boat hull may be tapered prior to bonding to help prevent the patch from being pushed through from the outside. A repair compound is applied from the outside surface of the boat hull and the repair compound is anchored to the hull in part by the bonding of the anchor to the repair compound. A method for the repair of a boat hull including tapering the profile of a hole in a boat hull, applying the patch anchor from the inside of the hull, and applying repair compound from the outside of the hull so as to fill the hole and anchor the patch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a boat hull patch anchor according to one embodiment of the present invention. 
         FIG. 2  is a perspective view of a boat hull patch anchor according to one embodiment of the present invention. 
         FIG. 3  is a cutaway view of a boat hull patch anchor according to one embodiment of the present invention. 
         FIG. 4  is a cutaway view of a boat hull patch system according to one embodiment of the present invention. 
         FIGS. 5A–E  are illustrations of a boat hull hole and its repair according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a top view of a boat hull patch anchor  150  according to one embodiment of the present invention. A plate  101  has a plurality of through holes  103  that extend from its top side to its bottom side. In some embodiments, the plate  101  is a deformable, relatively thin plate. In some embodiments, the plate is made of a material such as a PVC plastic, kevlar, or aluminum. An example of such a PVC plastic material is Sintra®, by Alcan Composites of St. Louis, Mo. The plate  101  is made of a suitable material that can bend out of plane slightly with relative ease while maintaining rigidity. In some embodiments, the plate  101  is made of a material that can be significantly deformed with the application of heat, such as with a heat gun or a hair dryer. In some embodiments, the plate  101  retains its deformed shape after cooling. In some embodiments, the plate  101  is 1 mm, 2 mm, or 6 mm thick. 
     The plate  101  has a plurality of through holes  103  that extend from the top side of plate  101  to the bottom side of plate  101 . In some embodiments, the plurality of through holes  103  are comprised of circular holes  104 . In some embodiments, the circular holes  104  are approximately one quarter of an inch in diameter. In some embodiments, the holes are in the range of ⅛ th  to ½of an inch in diameter. In some embodiments, the through holes are squares, rectangles, or other shapes. Although the boat hull patch anchor  150  is shown with a particular number of holes, this is an illustrative representation. 
     The boat hull patch anchor  150  may be of a variety of sizes and shapes. The boat hull patch anchor  150  may be manufactured in large sheets or rolls, and later sized for a particular application. In some embodiments, the boat hull patch anchor  150  may be manufactured in bulk sizes of 4 feet by 8 feet with a 3 mm plate  101  thickness. In some embodiments, the boat hull patch anchor  150  may be manufactured in bulk sizes of 4 feet by 1 feet, and 4 feet by 2 feet. 
       FIG. 2  illustrates a perspective view of a boat hull patch anchor  100  according to some embodiments of the present invention. A plate  101  has a plurality of through holes  103  through from its top surface to its bottom surface. A fabric layer  102  is adhered to the bottom surface of the plate  101 . In some embodiments, the fabric layer  102  is made of a blend of 30% rayon and 70% nylon. In some embodiments, the fabric layer  102  is made of a Pellon 30 product. In some embodiments, the fabric layer  102  is made of kevlar. In some embodiments, the fabric layer  102  is made from a fabric that does not fray and is easy to cut and work with during the manufacturing of the boat hull patch anchor  100 . The fabric layer  102  prevents the patching compound used with the boat hull patch anchor  150  from flowing all the way through the plurality of through holes  103  when repairing a boat hull. The fabric layer  102  allows the patching compound used with the boat hull patch anchor to be absorbed, enhancing the bond strength of the boat hull patch anchor  150  to the patch. 
     In some embodiments, a curable adhesive is used to adhere the fabric layer  102  to the plate  101 . In some embodiments, the adhesive is an adhesive such as 3M Hi-Strength 90 multi-purpose adhesive, by the 3M Corporation of St. Paul, Minn. The fabric layer covers substantially all of the bottom surface of the plate  101 , as well as covering across the bottoms of the holes  103 . The fabric layer  102  provides a somewhat porous fabric bottom  108  to the holes  103 . 
       FIG. 3  illustrates a cross-sectional side view of a boat hull patch anchor  200  according to some embodiments of the present invention. A plate  201  has a first surface  208  and a second surface  207 . The plate is made of PVC plastic in some embodiments. A fabric layer  202  is adhered to the first surface  208  of the plate  201 . In some embodiments, a thin layer of adhesive  206  adheres the fabric layer  202  to the plate  201 . The fabric layer creates a barrier  204  at the bottom of holes  205  in the plate  201 . In some embodiments, the holes are regularly spaced circular holes. In some embodiments, the holes are 0.25 inches in diameter on a regular 0.5 inch spacing. The back surface  209  of the fabric layer  202  creates the back of the boat hull patch anchor in some embodiments. 
       FIG. 4  is a cross-sectional side view of a boat hull patch system  300  utilizing a boat hull patch anchor  304  according to some embodiments of the present invention. The boat hull  301  has an outer surface  309  and an inner surface  310 . The outer surface  309  of the boat hull  301  is the surface which resides at least partially in the water while the boat is in use. The boat hull  301  is typically made of fiberglass, graphite epoxy, or other materials. 
     The hole  302  has its edges tapered in some embodiments. In some embodiments, the hole  302  has its edges tapered at a 45 degree angle. The boat hull patch anchor  304  provides a backing plate and anchor for the patching compound  303 . The boat hull patch anchor  304  is joined to the inner surface  310  of the boat hull  301  with an adhesive  306  in some embodiments. The patch  303  is formed of a patching compound which has flowed through holes  308  in the boat hull patch anchor  304 . Some holes  307 , which are not open to the hole  302 , do not have patching compound in them in some embodiments. The patching compound has permeated the fabric layer  305  enhancing the adherence of the boat hull patch anchor  304  to the patch  303 . 
       FIGS. 5A–E  illustrate the method steps of repairing a boat hull according to some embodiments of the present invention. As shown in  FIG. 5A , the outside surface  501  of boat hull is seen. A hole  503  with a hole contour  504  extends from the outer surface  501  of the boat hull through to the inner surface  502  of the boat hull. In some embodiments of the present invention, as seen in  FIG. 5B , the hole contour  504  has been altered to facilitate repair. The hole contour  504  is tapered outwards from the inner surface  502  of the hull to the outer surface  501  of the hull. The diameter of the hole  503  is increased due to the tapering. The hole  503  may be tapered to a variety of angles, including in the range of 30–60 degrees. The tapering may be done using a file, a saw, or with other means. In some embodiments, the tapering is done with a portable grinder with a 40 or 60 grit disc. 
     In some embodiments of the present invention, as seen in  FIG. 5C , serrations  505  are cut into the hole contour  504 . The serrations  505  may be cut into the hull using a file, router, saw, jigsaw, or with other means. In some embodiments, the serrations SOS are placed every ⅜ th  of an inch around the hole contour  504 . 
     As seen in  FIG. 5D , a boat hull patch anchor  510  is placed on the inside surface of the hole. The boat hull patch anchor  510  is placed with the fabric layer away from the hull. The boat hull patch anchor  510  may be trimmed to the approximate shape, with overlap, of the hole. In some embodiments, the boat hull patch anchor may be molded to the shape of the interior of the hull, or other suitable shape, using a heat source. In some embodiments, the boat hull patch anchor is easily molded to an appropriate shape, typically to follow the contours of the inside of the boat hull, using a heat gun. In some embodiments, the boat hull patch anchor retains its new molded shape after cooling. In some embodiments, the overlap will be 1–4 inches of overlap along the interior of the hull. In some embodiments, the boat hull patch anchor is fastened to the inside of the boat hull using adhesives. In some embodiments, the boat hull patch anchor is fastened to the inside of the boat hull using a 2 part epoxy or an epoxy resin sealer paste. In some embodiments, the boat hull patch anchor is fastened to the inside of the boat hull using the same casting resin that may later be used in the patching process. The resin adhering the boat hull patch anchor to the interior of the hull may be allowed to set, or to cure, prior to proceeding. In some cases, there may not be access from the inside of the hull to place the boat hull patch anchor into position. In such cases, the boat hull patch anchor may be inserted through the hull from the outside to gain its position inside the hull. In such cases, the boat hull patch anchor may be held in place during bonding to the inside surface of the hull. In some cases, this may be done using a loop of wire or other suitable material that may be punched through the fabric layer at the bottom of one of the holes in the plate, and then looped back by punching through another hole, for example, so that the boat hull patch anchor can be pulled from the outside in order to apply pressure during bonding. The loop of wire may then be remove after the boat hull patch anchor has bonded to the inside of the boat hull. 
     As seen in  FIG. 5E , the hole in the boat hull is filled with a patch  511 . The patch  511  is placed into the hole and held from going through the hole by the boat hull patch anchor. In some embodiments of the present invention, the patch  511  is a composite of fiberglass and resin. In some embodiments, the fiberglass consists of chopped fibers. In some embodiments, the fiberglass consists of fiberglass cloth. In some embodiments, a single compound, such as resin or other material, is used.. In some embodiments, a polyester marine fiberglass resin is used, such as Evercoat® Premium Marine Resin. In some embodiments, the patch  511  fills the holes in the surface of the boat hull patch anchor plate. In some embodiments, the resin soaks into the fabric layer on the back side of the boat hull patch anchor. 
     After curing, the patch  511  has repaired the hole in the hull. The boat hull patch anchor becomes an integral part of the patched hull. There is no need for subsequent removal of the boat hull patch anchor. In addition, the patch anchor is not vulnerable to rotting or degradation due to environmental conditions. 
     As evident from the above description, a wide variety of embodiments may be configured from the description given herein and additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is, therefore, not limited to the specific details and illustrative examples shown and described. Accordingly, departures from such details may be made without departing from the spirit or scope of the applicant&#39;s general invention.