Strake Structure and Method for Building Bonded Lapstrake Boats

Abstract

An improved method for building a lapstrake boat 240 includes an improved strake structure 152 having a wide rabbet 182 running the length of said strake's lower edge 164 and inside face and having a selected rabbet width which defines a joint overlap region with a bond receiving gap 210 . The strake's rabbet width is preferably three times the plank's thickness 180 along most of its length but may taper. A plurality of temporary tie receiving holes 220 are bored through the thickness of the strake, and entirely within the rabbet segment of the strake for coaxial alignment with adjacent holes 224 in the adjacent strake. Adjacent strakes 150, 152 are aligned and tied together so that the wide rabbet segment 182 in the bottom edge of one adjoining strake 152 overlaps and is tied to a selected surface area on the outside face of the adjoining strake 150.

1 . A method for building lapstrake boats from wood or plastic strakes without use of a strongback or mold comprising the steps of:
 (a) providing a design for a lapstrake boat hull with a plurality of strakes forming port and starboard sides;   (b) determining two-dimensional shapes for said plurality of strakes, each said strake having a top edge, a bottom edge, and inside and outside faces separated by a plank thickness;   (c) fabricating said strakes in accordance with said two-dimensional shapes;   (d) cutting a rabbet along the bottom edge and inside face of each said strake in said hull design, with the exception of a bottom strake on each side of said hull, at the intersection of said strake's bottom edge and inside face; said rabbet having a selected rabbet width at least twice as wide as the strake's thickness;   (e) drilling first pairs of spaced temporary tie receiving holes through the thickness of at least a first strake, said first pairs of holes being located in and defined through the rabbet of said first strake;   (f) drilling second pairs of spaced temporary tie receiving holes through the thickness of a second strake, said second pairs of holes being located below the top edge of said second strake in alignment with said first pairs of holes when said first and second strakes are assembled;   (e) positioning said first and second strakes together so that a portion of the top edge and a portion of the outside face of said second strake fits into and is in contact with the rabbet in the bottom edge of said first strake in such a manner that a portion of said first strake adjacent to said rabbet overlaps the outside face of said second strake, adjoining;   (f) binding said first and second strakes to one another with temporary ties passing through corresponding pairs of holes in said first strake rabbet and said second strake top edge; and   (g) bonding said first and second strakes using a cementitious matter, whereby said first and second strakes are attached to each other.   
     
     
         2 . The method for building a lapstrake boat hull as in  claim 1 , wherein bonding adjacent strakes includes applying epoxy. 
     
     
         3 . The method for building a lapstrake boat hull as in  claim 1 , further including adding a transom, frames, stringers, and bulkheads to complete the hull. 
     
     
         4 . The method for building a lapstrake boat hull as in  claim 1 , wherein cutting a rabbet includes cutting it to a width at least three times as wide as the strake's thickness. 
     
     
         5 . The method for building a lapstrake boat hull as in  claim 1 , wherein multiple strakes are positioned together and adjacent strakes are bound together using temporary ties to form sides of said boat hull. 
     
     
         6 . The method for building a lapstrake boat hull as in  claim 5 , wherein fabricating said strakes includes fabricating them from plywood panels. 
     
     
         7 . The method for building a lapstrake boat hull as in  claim 5 , wherein fabricating said strakes includes fabricating them from plastic panels. 
     
     
         8 . A method for building a lapstrake boat hull as in  claim 5 , wherein the step of drawing a lapstrake boat hull with a plurality of strakes forming port and starboard sides includes configuring a desired hull to include both convex and concave cross sectional shapes with a reverse curve in a cross-section, wherein a joint between adjoining strakes transitions from a rabbeted cross-section to a conventional stitch-and-glue cross-section, and wherein the length of the transition is related to how quickly the hull sections shift from convex to concave to provide a hull shape which snugly receives and supports a wine-glass shaped boat hull transom. 
     
     
         9 . An improved strake structure configured for building a boat having a lapstrake hull, comprising:
 (a) an elongated strake having a top elongated edge opposite a bottom elongated edge;   (b) an inside face and outside face separated by a strake thickness;   (c) a rabbet segment along said strake's lower edge and inside face, said rabbet segment having a selected width from said lower edge and a selected rabbet segment thickness, the rabbet width being at least twice as wide as said strake thickness; and   (d) wherein the rabbet segment includes at least a first array of single tie receiving rabbet holes through the rabbet segment thickness and corresponding pairs of temporary tie receiving holes through the top edge of an adjacent strake.   
     
     
         10 . The improved strake structure of  claim 9 , wherein the rabbet width is at least three times as wide as said strake thickness, and said rabbet segment has a second array of tie receiving rabbet holes spaced from said first tie receiving rabbet holes to provide a plurality of pairs of temporary tie receiving holes through the rabbet segment thickness. 
     
     
         11 . The improved strake structure of  claim 10 , wherein said rabbet extends along the full length of a strake for a convex hull. 
     
     
         12 . The improved strake structure of  claim 10 , wherein said rabbet extends along a portion of the length of a strake for a convex/concave hull. 
     
     
         13 . The improved strake structure of  claim 9 , wherein said rabbet extends along a portion of the length of a strake for a convex/concave hull constructed from a plurality of strakes with reverse curve (i.e., concave) segments in hull sections and the width of a rabbet overlap joint area defined between adjacent strakes varies and tapers along the length of selected planks and defines a transition from a rabbeted cross-section to a conventional stitch-and-glue cross-section having a transition length; and
 wherein the transition length is related to how quickly the hull sections shift from convex to concave to provide a wine-glass shaped boat hull transom.   
     
     
         14 . The improved strake structure of  claim 9 , wherein the strake is made from six millimeter thick marine grade plywood and the rabbet width is at least eighteen millimeters, and said rabbet segment's array of tie receiving rabbet holes are spaced from said strake's bottom edge. 
     
     
         15 . A method of joining adjacent wood or plastic planks in a structure, comprising:
 (a) providing first and second planks each having a plank thickness and each being shaped to the design of a desired structure;   (b) cutting a rabbet along a bottom edge of each of said first and second planks, wherein said rabbet defines a rabbet segment having a selected width from said bottom edge and a selected rabbet segment thickness, the rabbet segment width being at least twice as wide as the plank thickness;   (c) drilling a first array of aligned tie-receiving through bores along a top edge of each of said first and second planks and corresponding second array of aligned tie-receiving through bores along the rabbet segment of each of said first and second planks;   (d) positioning first and second planks side by side with the top edge of said first plank abutting the rabbet segment of said second plank, with said first array of aligned tie-receiving through bores in said top edge of said first plank in coaxial alignment with said corresponding second array of aligned tie-receiving through bores in the rabbet segment of said second plank; and   (e) inserting temporary ties through said coaxially aligned tie-receiving through bores and through said first and second planks to secure said first and second planks in abutting relationship to define a bond receiving gap between said first plank and said second plank's rabbet segment.   
     
     
         16 . The method of  claim 15 , further including filling said bond receiving gap with a bonding agent and bonding said first and second planks. 
     
     
         17 . The method of  claim 16 , further including repeating the steps of positioning, tying, and bonding additional planks to form said structure.