WO2007054562A1

WO2007054562A1 - Method to design and produce sails

Info

Publication number: WO2007054562A1
Application number: PCT/EP2006/068344
Authority: WO
Inventors: Alberto Fiorenzi; Gian Mauro Maneia
Original assignee: Alberto Fiorenzi; Gian Mauro Maneia
Priority date: 2005-11-14
Filing date: 2006-11-10
Publication date: 2007-05-18
Also published as: ITUD20050188A1

Abstract

Method to design and produce a sail (11) comprising a plurality of panels (21-25) and provided with at least a reinforcement structure (27) made with a plurality of reinforcement elements (26). The method comprises in sequence a first step in which the three-dimensional geometric shape of the sail (11) is defined or acquired, and a second step, in which the reinforcement structure (27) is defined, directly on the three-dimensional surface of the sail (11), exactly localizing the position of each individual reinforcement element (26) with respect to the cutting position of the panels (21-25), to the perimeter of the sail (11) and to the other reinforcement elements (26).

Description

METHOD TO DESIGN AND PRODUCE SAILS

* * * * *

FIELD OF THE INVENTION

The present invention concerns a method firstly to design, preferably with the aid of an electronic calculator or computer, and then to produce one or more sails, or parts thereof, in which, staring from a geometric design of the sail in its entirety, the individual panels or sail cloths which make up the sail itself are designed. The method according to the present invention also allows to dispose reinforcement elements on each of the panels, along determinate preferential load lines, so that, when the different panels are made solid with each other, said reinforcement elements are perfectly aligned with each other, also in the joining zones between each panel and the adjacent one.

BACKGROUND OF THE INVENTION

It is a well-consolidated practice to define the three- dimensional geometry of sails through CAD programs. The procedure common to all said programs consists in a first step in which the general sizes of the sail are defined and inserted into the computer, such as for example the length of the sides, that is, the fore leech, the after leech and foot, or other equivalents. Then, the shape, curved or rectilinear, which is to be given to each of the sides that make up the outer perimeter of the sail, is then associated with said sizes.

Then the wing profile of the sail is defined, by means of attributing and positioning the depth, in an adequate number of cross sections, until the desired shape is achieved.

Then the accessory elements, if any, are positioned, such as for example the slats, reefs and reinforcement elements. Normally, in the state of the art, the design method concludes with the division of the sail into two or more panels or sail cloths, according to numerous possibilities, depending on the type of the individual sail, and with the definition of the cut of each panel; the cut is then performed manually, or by means of cutting machines with a numerical control (CNC).

It is therefore the task of known computer programs to develop, starting from a complex three-dimensional surface, a series of plane panels which, after being taken from rolls of fabric, are then assembled together by the sailmaker, according to various methods, until the finished sail is achieved. It is known that the joining zones between the panels are the most critical for the sail, and are the parts most subject to breakages or tears.

Typically, the panels have straight edges and more or less curved edges, so as to attribute the desired three- dimensional form, starting from plane elements. The progressive abandonment of traditional fabrics in favor of fiber-reinforced composite materials, with sails having bigger and bigger panels, and less numerous, consisting of laminated materials, makes it necessary to have a greater curvature of the edges, where the joins are made, and this introduces new problems. Moreover, in order to guarantee the correct transfer of loads between two adjacent panels, the reciprocal position of the reinforcement elements must be calculated with maximum accuracy, something which does not occur in the state of the art. In fact, it is consolidated practice to design the distribution of the reinforcement elements directly on plane panels positioned located adjacent to each other, so as to guarantee a certain correspondence between the reinforcement elements of adjacent panels.

However, the deeper the wing profile desired, the worse is the result obtainable after assembly, because the curvature of the edges of the panels is very accentuated. On the contrary the method according to the present invention completely solves this technical problem.

In fact, a purpose of the present invention is to perfect a method to design and produce a sail, or parts thereof, which is simple and reliable, and which also allows to dispose reinforcement elements on each of the panels, along determinate preferential load lines, in such a manner that, when the different panels are made solid with each other, said reinforcement elements are perfectly aligned with each other, also in the joining zone between one panel and the adjacent one, and despite the curvature, even accentuated, of said panels.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purpose, a method according to the present invention comprises at least a first step in which the three-dimensional geometric form, that is, the geometry, of the sail is defined or acquired, and a second step during which the reinforcement structure is defined, consisting of a plurality of reinforcement elements, directly on the three-dimensional surface of the sail, exactly localizing the position of each individual reinforcement element with respect to the cutting position of the panels, to the perimeter of the sail and to the other reinforcement elements.

The method according to the present invention is therefore able to generate the so-called machine sequence (CNC) after the reinforcement structure has been defined, for which it is sufficient to define, or have available, the geometry of the sail. On the contrary, it is not necessary to perform any type of a priori analysis, as this is only an option.

The second step is performed by calculating first of all the intersections between the reinforcement elements and the edges of the sail in the three-dimensional space, also identifying on every individual reinforcement element a high number of control points, of which the position is calculated in curvilinear coordinates on the complex surface of the sail.

During the operation to calculate the shape taken, in the plane, by the three-dimensional panels when considered individually, it is thus possible to calculate the position taken by each of the reinforcement elements on the plane panel.

Once the shape of each plane panel and the position of each reinforcement element thereon has been defined, for the production or manufacture of the sail, each plane panel is cut manually or, advantageously, with cutting machines numerically controlled by means of a computer (CNC).

The operation to assemble the panels thus made, for example by means of sewing and/or heat welding, will lead to the perfect transmission of the loads between adjacent panels, and to a perfect correspondence between the position defined during the design stage and the position taken on by the reinforcement elements in the finished sail .

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a first flow chart representing the different steps of the method according to the present invention; - fig. 2 is a second flow chart representing the individual sub-steps that make up the design step of the reinforcement structure, according to the method in fig. 1;

- fig. 3 is a third flow chart representing the individual sub-steps that make up the design step of the machine sequence (CNC), according to the method in fig. 1;

- fig. 4 is a fourth flow chart representing the individual sub-steps that make up the analysis step of a sail designed according to the method in fig. 1;

- fig. 5 is a perspective view of a whole sail, during the design step, using the method in fig. 1;

- fig. 6 is a plane view of the sail in fig. 5, divided into five panels; - fig. 7 is a perspective view of the sail in fig. 6;

- fig. 8 is an enlarged detail of the two lower panels of the sail in fig. 6;

- fig. 9 is a perspective view of the two panels in fig. 8, joined together. DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

With reference to fig. 1, we shall now describe a method 10 according to the present invention to design a sail 11 (fig. 5), triangular in shape, in this case a jib, which has three tops, respectively A, B and C, defining respectively the tack corner 12, the head corner 13 and the clew or sheet corner 14, and three sides, respectively foot or base 15, which connects the top A with the top C, the fore leech or reef 16, which connects the top A with the top B, and the after leech 17 which connects the top B with the top C.

In this case the sail 11 comprises five panels or sail cloths 21, 22, 23, 24 and 25 which are joined together in a known manner, for example by stitching or gluing the relative adjacent edges. Each panel 21-25 comprises a plurality of reinforcement elements which, in their entirety, achieve a reinforcement structure 27. For simplicity of explanation, the reinforcement structure 27 is only shown schematically and comprises only some reinforcement elements 26, mostly in the lower panels 21 and 22 (figs. 5 to 9). An example of a complete reinforcement structure is shown in the application for an Italian patent of industrial invention UD2004A000175, filed on 09.09.2004, by the present Applicant.

The method 10 (fig. 1) begins with a starting step 31, which activates a control panel 32 from which, if there is assent to a question 33 as to whether a sail is to be designed/produced, and to a question 34 as to whether a geometry of the sail is to be designed/defined, we move to a step 35 to define the three-dimensional geometry of the sail, for the moment without the reinforcement structure 27. Step 35 occurs in any known manner.

Subsequently, if there is assent to a question 36 as to whether a geometry of the sail exists, and to the question 37 as to whether a reinforcement structure of the sail is to be designed/defined, we move to a step 38 to define the reinforcement structure 27. Step 38 is described in detail hereafter, with reference to fig. 2.

Once the reinforcement structure 27 of the sail 10 is complete, if there is a negative response to a question 39, as to whether a structural analysis is to be effected, or a fluid-dynamic code (FDC) is to be used, to analyze the flow of air on the sail, and if there is assent to a question 40 as to whether a CNC is to be created, that is, for a machine with numerical control, we move to a step 41, which creates a file of data which contain the instructions and information to produce the individual panels 21-25 with a

CNC machine. Step 41 is described in detail hereafter, with reference to fig. 3.

On the contrary, if there is a negative reply to question

40, we proceed to a question 42 as to whether the method is to be abandoned, and if the answer is affirmative, we arrive at a step 43 ( end-of-method).

On the contrary, if there is an affirmative reply to question 39, we move to a step 44 to analyze the sail 11 just designed, including the reinforcement structure 27, and/or perform a FDC analysis or another of the possible analyses. Step 44 is described in detail hereafter, with reference to fig. 4.

At the end of the possible step 44, if there is an affirmative answer to question 45, as to whether the design is to be modified in the light of the results of the analysis just done, we return to question 37, otherwise, in the event of a negative answer, we return to question 40. Moreover, if there was a negative reply to question 33, we proceed to question 46, which asks whether we want to proceed with an analysis of a photographic image of the sail 11 and, in the event of an affirmative answer, a step

47 is performed, to analyze the photographic image on the sail 11, in any known manner. With reference to figs. 2, 5, 8 and 9, we shall now describe step 38 in detail.

A necessary condition to proceed with designing the reinforcement structure 27 is the presence of a valid mathematical representation of the geometry of the sail 11 and its surface.

The disposition of the reinforcement elements 26 is for example described in the afore-mentioned patent application UD2004A000175. Step 38 comprises a starting sub-step 38A followed by a question 38B, which asks if we want to load into the program data relating to groups of reinforcement elements 26 already existing, because they have been previously calculated and memorized. If affirmative, with a sub-step 38C we load said data or import them from the relative memory. If negative, we proceed to a question 38D which asks if we want to edit or create new groups of reinforcement elements 26; if affirmative, we proceed to a question 38E which asks if it is a primary reinforcement structure. If there is an affirmative answer to question 38E too, we proceed to a sub-step 38F to define the primary reinforcement structure 27.

The designer, as provided in a sub-step 38G, associated with sub-step 38F, in order to program the disposition of at least a group of reinforcement elements 26 that make up the primary reinforcement structure 27, cannot do otherwise than perform the following operations:

1 ) attribute a name to the group of reinforcement elements 26 he is creating; 2) insert the position of the pressure center (CE) on the surface of the sail 11, using curvilinear coordinates on the three-dimensional geometry. In the absence of a previous fluid-dynamic analysis, the CE point can be positioned, in a first approximation, at 30% along the direction of the chords and at 30% along the direction of the fore leech 16. This value can be corrected and modified at any moment, in the light of subsequent analyses. When this has been done, the three curves x, y and z, also called generatrixes, are automatically generated; these have their common origin in CE and pass through the tops A, B and C of the sail 11, as provided in the above-cited patent application UD2004A000175; 3) select two only of these curves in order to generate the group of reinforcement elements 26, for example curve x with direction CE-tack point 12 and curve z with direction CE-clew point 14; 4) identify the portion of these curves that will be divided into points of passage of the reinforcement elements 26. For example, considering the curve x with direction CE-tack point 12 and attributing the percentage value 0 (zero) to the first point of passage, the percentage value 100 to the last point of passage, the whole portion of curve x comprised between CE and tack point 12 will be divided. Instead, by attributing a value greater than 100, the segment of curve x that will be divided will also comprise a portion of curve outside the surface of the sail 11; 5) define the number of reinforcement elements 26. The value inserted indicates to the program into how many segments the portion of curve considered has to be divided, in order to identify the points of passage of the reinforcement elements 26. The proportion between the various segments can be uniform or adjustable through known mathematical functions;

6) attribute material. To every individual reinforcement element 26 it is possible to attribute its own constituent material, selecting from a list of possibilities. The choice of a material attributes the chemical-physical properties of the reinforcement element 26, such as for example the linear density, the longitudinal elastic modulus, the Poisson modulus, which will be used possibly during the structural, aero elastic and fluid-dynamic analyses. On this point it is important to note that the design of the reinforcement structure 27 does not constitute a simple geometric construction, but the attribution of a precise elastic behavior to the sail 11 consisting of all the structural elements 26. It is clear that this result cannot be obtained by designing the structure on plane panels, or simply by defining a geometric disposition. In particular, the position and disposition of each individual reinforcement element 26 are calculated so as to take into account the fact that the panels 21-25 are plane when they are cut, but become curved when they are coupled with the adjacent panel. For example, it must be certain that the points E' and F' on the curved edge of the first panel 21 and the points E" and F" on the straight edge of the second panel 22 correspond to the points E and F (figs. 8 and 9), identified by the intersection between two reinforcement elements 26 and the cut between the first panel 21 and the second panel 22 on the three-dimensional surface of the sail 11.

The distance, understood as the curvilinear integral in the space between points E and F, will be equal to the distance understood as the curvilinear integral in the plane between points E' and F' and between points E" and F".

In the same way the total length of the reinforcement element 26 comprised between points H and I on the three- dimensional surface of the sail 11 will be equal to the length of the reinforcement element 26 comprised between points H' and I' on the surface of the first panel 21. The distances between points L and M and between points M and N are also calculated in the same way, considering that these points must correspond to points L', M' and respectively N' on the surface of the first panel 21.

After adding one or more groups of reinforcement elements 26, so as to complete the primary reinforcement structure 27, it is also possible to define other reinforcement elements 26, of a secondary type, in a sub-step 38H connected with question 38E.

For simplicity of explanation, we have chosen to identify on the contour of the sail 11 an edge portion as a starting zone for a group of reinforcement elements 26 and on the same edge, or on another edge, an edge portion as an arrival zone of the group of reinforcement elements 26.

The designer, as provided in a sub-step 381, associated with sub-step 38H, in this case must operate in the following sequence:

1) attribute a name, different from the previous ones, to the group of reinforcement elements 26 which are being created; 2) identify the starting edge of the four available (base 15, fore leech 16, head 13, after leech 17);

3) identify the arrival edge of the four available (base 15, fore leech 16, head 13, after leech 17);

4) identify the portion of these curves that will be divided into points of passage of the reinforcement elements 26;

5) define the number of reinforcement elements 26;

6) attribute the material. It is also possible, if necessary, to curve the reinforcement elements 26 belonging to a group by modifying some control points disposed on the edge of the same group.

A sub-step 38L automatically verifies if the designer has carried out the programmed teachings, for example those contained in the above-cited patent application

UD2004A000175, and prevents the disposition of reinforcement elements 26 that are not in conformity. In the event of a negative check, we pass to a sub-step 38M where the designer is informed of the error and made to return to sub-step 38H for correction.

After having repeated these operations, until the reinforcement structure 27 is completely defined, it is possible to save in a memory the groups of reinforcement elements 26 individually or in small blocks, according to their future use. This saving occurs in a sub-step 38R, only if there is assent to question 38N, if they are to be saved as a production model, and to question 38P, if a valid primary structure exists. If there is a negative reply to question 38P, there is a sub-step 38Q in which the designer is informed of the need to create said valid primary structure.

The parametric nature of the program allows to adapt structures designed for a certain geometry of a particular sail to other sails of different geometries.

The last passage, in a sub-step 38S, consists in associating definitively the geometric shape of the sail 11 to the overall structural design, thus making it possible to create the machine sequence (CNC) in step 41, which will lead to the practical embodiment of the sail 11.

This passage too is subordinate to the presence of a primary reinforcement structure 27 and to the fact that the requirements described above have been met. Step 38 ends with an exit sub-step 38U, if there is a negative reply to question 38T, as to whether it is desired to continue with the design of the reinforcement structure 27. With reference to fig. 3, we shall now describe step 41 in detail.

Step 41 comprises a starting sub-step 4IA, followed by a sub-step 4 IB in which an electronic document or file is loaded into a memory, with all the data relating to the geometry of the sail 11 and to the cut of the panels 21-25, and also to the reinforcement structure 27.

There then follows a sub-step 41C to set the user's parameters and a sub-step 4ID to transform the panels 21-25 from three-dimensional to plane. In a sub-step 4 IE the files are created for the CNC machine, in any known manner, which are transmitted or transferred in a sub-step 4 IF to the site of the producer of the sail 11, or of the individual panels 21-25.

Step 41 ends with an exit sub-step 4IG. The files transmitted by the sub-step 4 IF are received by an input device 50, which also receives the data arriving from the CNC machine 51. The overall data are then transferred to a memory 52 so that they can be used.

With reference to fig. 4, we shall now describe in detail step 44 which, as we have seen, is optional.

In step 44, which comprises a starting sub-step 44A, the designer finds integrated into the same program, or in any case in the same environment, all the functions now present on the market as independent elements, up-dated in the light of the increased calculating capacities of modern processors.

A great advantage of the present invention is that it has developed instruments with common logics with regard to, for example, the generation, management and modification of the geometries, data formats input and output, models that describe the structural response.

In the state of the art, a difficult problem to solve is the interaction between analysis instruments of different nature, which often cancels out the advantages that can be obtained in terms of calculating speed due to the necessary and complex human intervention to export a model from one system to the other. According to the present invention, on the contrary, while guaranteeing the possibility of importing geometric data from other systems, such as for example the three- dimensional forms of the sails or hulls, all the analysis operations are performed according to common modes, developed for the purpose.

Moreover, unknown functions have been developed in the present invention.

For example we have introduced a system to measure the weight/surface ratio of the sail 11, which with this technology is extremely variable from zone to zone of the sail 11.

In a sub-step 44c, if an affirmative answer has been given to a question 44C as to whether to calculate the density of the fibers that make up the reinforcement elements 26, a first instrument of structural analysis is activated, which bases its effectiveness on the consolidated practice of designers who size traditional sails using materials on rolls of differing grams per square meter. The material on the roll, distributed by the biggest producers, is characterized by a specific unit of measurement, which is dpi (denier per inch).

This value is calculated by adding the value of linear density (denier) of all the yarns present in a strip of material one inch wide and directed in one of the main directions of the fabric (warp and weave).

It is then automatic to calculate the number of deniers per square inch, considering all the yarns present in a square with one-inch sides.

These values are deliberately constant in a traditional material on the roll, so the sail-maker can choose to use a fabric with a greater quantity of fiber in the more stressed zones and a lighter material where the loads are lower .

The instrument for counting the dpi divides the surface of the sail 11 into a large number of quadrilateral elements, calculates the area and then calculates how many yarns are present on every individual quadrilateral element.

The type of material that makes up the count ( linear density) of the yarn is associated with every reinforcement element 26, among the approximately 3,000 present that make up the reinforcement structure 27; it is thus possible to calculate the total sum of deniers on the quadrilateral element and to divide by the area of the latter in order to obtain the deniers per square inch.

It is also possible to carry out an analysis in the two standard directions, identified by the curvilinear coordinates u (along the chords of the profile) and v (in the direction of the head 13) on the surface of the sail

11.

The result of the analysis made in sub-step 44C is shown on screen, in a sub-step 44D, as a color map superimposed on the surface of the sail 11, so that it is possible to associate the measured value of dpi with the shade of color. In a sub-step 44F, if an affirmative answer has been given to a question 44E as to whether to perform an aero elastic analysis on the sail 11 just designed, a second analysis instrument is activated, called SPIDER SIMl, which is an aero elastic solver based on the finished elements method (FEM) to analyze the structural response coupled with a fluid-dynamic code (FDC) to analyze the flow of air on the surface of the sail 11.

A balanced solution is sought starting from the initial conditions chosen, such as wind speed and angle, regulation of the sail 11, regulation of the mast.

Since the elastic response of the material to the action of the wind causes a variation in the shape of the sail 11, and hence a variation in the aerodynamic stresses on the sail 11, the only way to solve the problem is an iterative cycle of fluid-dynamic and elastic calculations which follow each other until the difference between two successive solutions is reduced to negligible values.

In this case we say that the calculation process has reached convergence, and the last solution constitutes a balanced condition, therefore a precise field of tensions and deformations corresponds to a given form in the final use of the sail 11.

By analyzing these data, the designer can for example decide to increase the quantity of reinforcement elements 26 in the zones that are excessively deformed, or reduce the quantity in the less stressed zones.

The designer can also decide to modify the orientation of the fibers of the reinforcement elements 26, or change the type of material, thus optimizing the sail 11 in terms of weight and strength.

The result of the analysis made in sub-step 44F is shown on screen, in a sub-step 44G. In a sub-step 441, if an affirmative answer has been given to a question 44H as to whether to perform an analysis on the fluid-dynamic and turbulence effects on the sail 11 just designed, a third analysis instrument is activated, called SPIDER SIM2, which is a last generation fluid-dynamic code which offers the designer the possibility to check the performance of an isolated sail, or in combination with another sail, to consider the influence of the mast and the deck on the flow, and to assess the effect of turbulence and wake.

All this while analyzing the attendant conditions, variable over time, such as for example the increase or decrease in wind speed, angle variations or other.

If the main purpose of the aero elastic analysis is the correct sizing of the structure, in this case the search is intended to identify the best aerodynamic forms, allowing for example to design an optimized sail for a precise wind intensity, or a sail that guarantees very similar performances even when confronted by very strong variations in wind intensity.

The result of the analysis performed in sub-step 441 is shown on screen, in a sub-step 44L.

In a sub-step 44N, if an affirmative answer has been given to a question 44M as to whether to perform an analysis on the prediction of the behavior of a boat using the sail 11 just designed, a fourth analysis instrument is activated, the so-called Velocity Prediction Program (VPP), of a known type, which is an instrument that provides a prediction of the boat's speed, according to the speed and direction of the wind. The VPP is based on a search for a balanced condition through an iterative cycle to calculate the hydrodynamic performances of the hull and the aerodynamic performances of the sails. The mathematical formulas used to describe the physical phenomena are of the approximate type, generally taken from experiments in test tanks or wind tunnels, this characteristic guaranteeing a considerable calculation speed but not very accurate results.

The result of the analysis performed in sub-step 44N is shown on screen, in a sub-step 44P.

In a sub-step 44R, if an affirmative answer has been given to a question 44Q as to whether to perform an aero/hydro dynamic analysis on the sail 11 just designed, a fifth analysis instrument is activated, that is, an aero/hydrodynamic solver, of a known type, which provides results of the same type as the VPP, but differing in the calculation mode. In this case, the balanced solution is sought by resolving with every cycle the equations that regulate the fluid dynamics, both with regard to the hydrodynamic part, and also with regard to the fluid-dynamic part.

A typical set of results comprises: speed of the boat; angle of list; angle of drift; the force on the sail plane; the list moment and all the other sizes that univocally identify the trim of the boat for a given wind condition.

Finally, the correctness of the calculations performed can be verified by means of a photographic analysis of the sail 11 in use.

The procedure in this case entails the acquisition of a number of photographs correlated by data on the wind conditions (angle, absolute speed, apparent speed).

From the photographs taken it is possible to trace the geometry assumed by the sail 11 and to compare for example the numerical data with the forms in use as provided by the calculation codes.

Alternatively, it is possible to assess the performance of the real sail 11 by subjecting its geometry to fluid- dynamic calculation, and comparing the result with ideal sails of different shape.

The result of the analysis performed in sub-step 44R is shown on screen, in a sub-step 44S.

Step 44 ends with an exit sub-step 44U, if an affirmative answer is given to a question 44T as to whether to exit from the step of analyzing the sail 11 just designed.

The production or manufacture of the sail 11 thus designed comprises a step in which the reinforcement elements 26 are disposed on a first plane film, larger than the individual panel 21-25 to be cut, according to the predefined configuration. Subsequently, the first film and the reinforcement elements 26 are covered with a second film, to form a sandwich that is then subjected to laminating, in a known manner. Then the panel 21-25 is cut to size.

According to a variant, less practical but in any case feasible, it is possible to cut to size the first and the second film, before using them to form the sandwich with the reinforcement elements 26.

After making the individual plane panels 21-25, they are connected to each other by means of any known technique, making sure that the reinforcement elements 26 of one panel are perfectly aligned with those of the adjacent panel. It is clear that modifications and/or additions of steps or sub-steps may be made to the method 10 as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to a specific example, a person of skill in the art shall certainly be able to achieve many other equivalent forms of methods to design and produce a sail, or parts thereof, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

1. Method to design and produce a sail (11) comprising a plurality of panels (21-25) and provided with at least a reinforcement structure (27) made with a plurality of reinforcement elements (26), characterized in that it comprises in sequence a first step (35) in which the three- dimensional geometric shape of said sail (11) is defined or acquired, and a second step (38), in which said reinforcement structure (27) is defined, directly on the three-dimensional surface of said sail (H), exactly localizing the position of each individual reinforcement element (26) with respect to the cutting position of said panels (21-25), to the perimeter of said sail (11) and to the other reinforcement elements (26).

2. Method as in claim 1, characterized in that in said second step (38) a calculation operation is performed by means of which the intersections are calculated between said reinforcement elements (26) and the edges of said sail (11) in three-dimensional space.

3. Method as in claim 2, characterized in that, in said calculation operation, a determinate number of control points (L, M, N) are also identified, on each individual reinforcement element (26), whose position is calculated in curvilinear coordinates on the complex surface of said sail (11).

4. Method as in claim 2 or 3, characterized in that during said calculation operation, for said panels (21-25) considered three-dimensionally, the position assumed by each of said reinforcement elements (26) on the corresponding plane panel (21-25) is calculated.

5. Method as in any claim hereinbefore, characterized in that, once the shape of each of said plane panels (21-25) and the position of each reinforcement element (26) thereon have been defined, for the production or manufacture of said sail (11) the method proceeds to make each panel (21- 25), disposing said reinforcement elements (26) on a first film and then covering them with a second film, in order to form a sandwich which is subsequently laminated.

6. Method as in claim 5, characterized in that said first and said second films are initially larger than the corresponding panel (21-25) and in that said sandwich is cut to size after laminating.

7. Method as in claim 5, characterized in that each of said first and second films are cut to size before making said sandwich with said reinforcement elements (26).

8. Method as in any claim hereinbefore, characterized in that it also comprises a third step (41) in which a machine sequence (CNC) is generated in order to cut said panels (21-25) and to dispose said reinforcement elements (26).

9. Method as in any claim hereinbefore, characterized in that it also comprises a fourth step (44) in which one or more of the following analyses are optionally performed: a) analysis of the density of said reinforcement elements (26) in said sail (11); b) aero elastic behavior of said sail (11); c) fluid-dynamic behavior and turbulence effects of said sail (11); d) verification of speeds obtainable with said sail (11); e) aero/hydrodynamic analyses on the performances of the boat on which said sail (11) is to be mounted.