Ships – Building
Reexamination Certificate
2002-08-07
2003-05-20
Swinehart, Ed (Department: 3617)
Ships
Building
C114S061300
Reexamination Certificate
active
06564737
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to hull design and construction and in particular to the creation of original hull designs and the construction based on them. More particularly, the invention relates to a method for systemizing the creation of an original lines drawing in a way that permits the hull-defining frames to be drawn from a single template and the physical frames to be constructed from a single template, so as to shorten the time required at both the design and construction stages for any type of frame-based watercraft that is not a reproduction or facsimile of an earlier vessel. Furthermore, the use of the single template to define the curve along the entire length of the hull results in less turbulent, and hence more rapid, passage of the resulting boat through the water.
2. Description of the Prior Art
An original hull has a shape not previously in existence. It is based on drawings created specifically for the vessel of which it is a part, which is therefore an original vessel. Designing and constructing an original vessel are time- and labor-intensive undertakings; hence, the high cost of owning a original vessel, and the relatively small number of boatyards specializing in original boat design and construction.
Although mention of unique vessels often conjures up wooden sailing craft, originally vessels currently being built are by no means limited to that type of watercraft or to that material. At any event, decisions regarding type and material are usually, though not always, made before the designer and the builder of the craft have been hired. Typically, the designer will have as givens, in addition to the type and material, the overall length and beam (width) of the vessel. Starting with those parameters, and usually the load-bearing capacity of the original vessel to be created, the designer relies on his experience, education, and instinct (his design sense) to produce the drawing that will serve as the vessel's blueprint. This is the “lines drawing,” the lines including the sheer line (defining the top of the hull, where the hull joins the deck), and the hull's bottom line (which incorporates the keel line, where the hull joins the keel, if there is to be a keel), and the water line. They also include a number of the hull's longitudinal contours as well as the (related) shape of the hull's transverse cross-sections at many locations (“stations”) along the length of the vessel. These cross-sectional shapes define the shapes of the frames that will form the skeleton of the vessel. The more complex the hull shape, the more such cross-sections are necessary to define the design for later construction. The lines drawing, in combination with a table of offsets numerically specifying the locations of particular points within the hull, defines the new hull. It is typically drawn to a scale of 1:24 (half-inch to the foot) and, when complete, expanded to a full scale (“lofted”) version. In the case of traditional wooden-boat construction, this lofted version is painted on the floor of the boat builder's shop.
Among boat builders and designers, important term and practice is “fairing,” or “making fair” the lines of a design. Also, the lines of an existing boat can be described as “fair” or “not fair.” This refers to the smoothness of the lines, and also to their relative monotonicity. A sheer line is fair if it makes a continuous sweep from one end of the vessel to the other, typically sinking as it progresses from the stem to midships, then rising again as it progresses the rest of the way to the stern. It is not fair, however, if during this sweep it falls and rises repeatedly and/or for no logical reason.
One of the reasons for the traditional of transferring the scale lines drawing to a full-size version is to check for the fairness of the lines. Irregularities not visible on a small scale may show up in the full-scale drawing.
The physical hull is built up starting with construction of its skeleton, the series of frames oriented perpendicularly to, and deployed along, the hull's longitudinal axis. The shape of each frame is defined by the shape-given the hull at that station during the design stage. Working from the full-scale drawing, the builder constructs each of the full-scale frames. When the building material is wood, one may make molded frames by bending a single piece of wood bent to the proper shape using a mold, which in turn was made using the full-scale drawing. Alternatively, one may make sawed frames out of a single large piece of wood or, more commonly, several pieces of wood affixed to one another and then the composite sawed to the proper shape. For the latter approach, a full scale drawing of the individual frame may be made on plywood or the like to serve as an outline for the sawing. Once constructed, each frame is placed at the proper station in the hull taking shape overhead as the construction progresses.
The number of frames needed depends on the requirements of the vessel; typically it is several score. Although there is a relationship between the frames determined by the architect's drawing, there is no simple way of determining the shape of one frame from the shape of another frame, even a neighboring one. The drawing and construction of frames contributes significantly to the total time, and hence expense, of building a newly designed vessel. The need to derive and construct each frame as a separate undertaking is one of the factors that makes the construction phase so lengthy.
For more than 100 years, extending down to the present time, the method just described is the way that original hulls have been created. For all that time, much of the cost of producing hulls has come from this frame by frame by frame approach. Although a hull, once designed and constructed, can form the mold for repetitive and relatively inexpensive copying, originality of design is a good that has always driven the market for new boats, especially where sailing craft and other sporting boats are concerned. It is, however, a good that is difficult to acquire because of the high cost of producing unique boats.
Therefore, what is needed is a method to produce original hulls in a manner requiring less time than the method now in use. What is further needed is a method that is more efficient both at the design stage and at the construction stage of original hulls. What is yet further needed is such a method that can be implemented in the boat-building craft as it is presently constituted.
SUMMARY OF THE INVENTION
The object of the invention is to introduce an approach to the creation of hull designs that allows the designs to be more efficiently created. It is a further object of the invention that the designs thus created permit the hull-construction based on them to be carried out with less effort and time than is the case with current hull designs. Finally, it is an object of the invention that the efficiencies made available by the new approach be immediately adaptable by existing naval architects and boat shops that produce either wooden or non-wooden vessels.
The present invention meets its objectives by a reversal of the traditional approach to hull design. Instead of first creating the lines drawing and then determining from that drawing the shape of the individual frames, the design approach of the present invention involves generating the lines drawing from the shape of a single curve, a Single Frame Curve (SFC), which can also be referred to as a Master Curve. Then, during the physical construction of the hull, the Single Frame Curve is used to generate all of the frames for all of the stations, each of the individual frame shapes being found along a segment of the Master Frame. Because of the single-frame approach made possible by the present invention, only one frame curve need be designed, only one frame mold need be constructed, and—because all frames are just different segments of the same curve (that of the Single Frame Curve)—there is less chance of error in the lo
Bohan Thomas L.
Mathers Patricia M.
Swinehart Ed
LandOfFree
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