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.

Description

[0001]This application is a continuation of and claims priority to International Application No. PCT / US2014 / 061713, filed on Oct. 22, 2014, entitled “Improved Strake Structure and Method for Building Bonded Lapstrake Boats,” which claims priority from U.S. Provisional Application No. 61 / 894,300, filed Oct. 22, 2013, entitled “Improved Strake Structure and Method for Building Bonded Lapstrake Boats”, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTIONField of the Invention[0002]The present invention relates, in general, to methods for building boats, and more specifically to the construction of lapstrake planked boat hulls and to improved methods of construction of such hulls.Discussion of the Prior Art[0003]Traditional methods for building wooden boats include a procedure known as lapstrake planking, a method which has been used for thousands of years. Like most wooden boats, lapstrake boats are built of planks, or strakes, which comprise th...

AI Technical Summary

Benefits of technology

The present invention provides an inexpensive and easy-to-assemble strake structure and an improved method for building lapstrake boats. Compared to the structure and method of U.S. Pat. No. 6,142,093, the improved strake structure and method have three significant advantages: B. STITCHING WIRE PLACEMENT. The wire stitches are placed within the rabbet to hold the hull together temporarily while the epoxy is applied. By shifting the location of the wire holes to be contained entirely within the rabbeted area, the possibility of distortion is removed and the wire stitches align and hold adjacent planks better.

Problems solved by technology

(a) It is time consuming and costly to construct a strongback and molds for each type of boat built; often, as much time is required to build the strongback and molds as to assemble the hull;

b) The shape of each strake is determined by holding it against the molds. Each pair of planks, one for the port and one for the starboard side, are individually shaped and fit to the molds. This is a time consuming and exacting process demanding substantial skill on the builder's part; and

(c) A rolling, or constantly varying, bevel must be cut in the edge of each of the strakes. This method is time consuming and exacting, and it requires considerable skill on the part of the builder.

(a) It requires a boatbuilder possessing substantial skill, artistry, and experience, since the overall shape of the hull is largely determined by “eye” as it is being built, rather than by the molds;

(b) A rolling, or constantly varying, bevel must be cut or planed into each strake in order to attach the next strake. This is time consuming and exacting, and it requires considerable skill on the part of the builder;

(c) The shape of each strake is determined by eye and must be fitted to the boat without the use of molds to guide the builder. Each pair of planks, one for the port side and one for the starboard side, are individually cut to fit without the aid of the molds. This is also a time consuming process demanding substantial skill on the builder's part; and

(d) In practice, this method limits the hull shapes that can be built.

(a) The hull is not the lapstrake construction that is favored by many boat builders for reasons of aesthetics as well as for reasons of functionality and economy;

(b) This method demands extensive use of fiberglass and resins, which results in increased cost and increased environmental impact; and

(c) Fiberglass reinforced joints require additional sanding and finishing, particularly if the hull is to be finished with varnish or other clear coating, which many owners desire for aesthetic reasons.

(a) It is difficult to hold such overlapped strakes in alignment since the forces required in bending and twisting the strakes tot the desired hull shape cause them to slip prior to being bonded. The plastic rivets must flex in order to accommodate the changes in angle between the strakes as the hull is assembled, and this flexibility makes it difficult, if not impossible, to precisely align the strakes;

(b) Given the large number of strakes in some designs, the accumulated error caused by changes, or errors, in each strakes' position may result in hull shapes substantially different than those the designer envisioned;

(c) The rivets must be placed with great precision to assure the most accurate possible alignment of the strakes;

(d) The lack of accuracy in strake alignment limits this method to boats with little bend in the strakes and does not allow designs containing substantial twist in the strakes, such as might be used in powerboats with both flare and tumblehome in the hulls, for example; and

(e) The amount of overlap between the strakes may not be consistent, which is detrimental to the aesthetics of the boat.

The self-aligning nature of the narrow rabbet at the strake edge simplified assembly of the hulls with this method, but it was discovered that the narrow edges of the strakes were deformed when the ties were tightened.

It was eventually discovered that the lapstrake of the '093 patent was also not as strong as might be needed for some applications, and the method had a limiting effect on the hull shapes which could be made, since the overlapping rabbet area of the strake, where an adhesive or a bonding agent is to be applied, was suited to making only convex hull shapes.

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