MASTING FOR SAILBOATS

Abstract: A masting for sailboats, which comprises: at least three poles (3, 5, 5), the lower end of which are fitted in the bridge or deck of the boat (1), while the upper ends are connected between them to form the vertex (7) of an ideal pyramid whose corners are formed by the poles themselves; and a plurality of stays (11, 9) in tension between said vertex (7) and an anchoring point on the boat, the sails being borne by said stays.

Description: In the traditional sailboats, both single and multihull, the masting consists of a mast disposed on the longitudinal axis of the hull, which is supported by a plurality of shrouds and stays with eventually the aid of one or more pairs of crosstrees. This masting exhibits a series of structural and aerodynamic drawbacks. Under rest condition, the mast is compressed by symmetrical forces imposed by the rigging, while the shrouds and the stays are uniformly tensioned. Under wind-blowing condition, vice-versa, only the windward rigging is acted upon, resulting heavily tensile-stressed, while the leeward rigging is partially unloaded or even in slack condition, that is, released from the tension it is subject when at standstill. As a consequence, under wind blowing condition, the mast is under a combined compression and bending stress, while the stress over the rigging is distributed only over a portion thereof, with consequent overstressing of the windward shrouds and of the hull at the anchorage points of same shrouds. The structural problems related to the masting of traditional type are even greater in the case of multihull boats. In fact, in the catamarans, for example, the mast is borne by the structure connecting the two floats, while the shrouds are applied to the same floats. As the mast is under compression, the connection structure between the floats is stressed by high bending moments dinamically varying during the navigation. This gives rise to frequent breaks of said connection structure. A similar thing occurs whith the trimarans, in which the mast is supported by the central float and the shrouds are anchored to the side floats. The connection structures are still subject to high bending moments of dynamic nature during the navigation. A masting arrangement is known (EP-A-0 126 679) which partly overcomes the above mentioned problems. This masting arrangement comprises four poles the lower ends of which are connected to the floats of a catamaran, while the upper ends are conneted to each other to form a vertex of an ideal pyramid whose corners are formed by the poles themselves. A stay is anchored between said vertex and a boom, the latter being supported by a short central mast. The boom and the stay support a central sail. According to this known masting arrangement, also a jib may be provided, which is anchored to the deck of the boat and to the vertex formed by the masts. The way in which this stay is anchored to the deck is not described. Even though this known arrangement solves the above mentioned structural problems, it still has some drawbacks. For example, the use of a short mast supporting a central boom makes it compulsory to attach the main sails in correspondence of the boat central axis, as it is the case in more traditional masting arrangements providing one single central mast. This implies heavy restraints as far as the aerodynamic solutions of the sails are concerned. For example, with traditional masting, as well as with the arrangement described in EP-A-0 126 679 the possible minimum value of the angle between the boat route and the real direction of the wind is about 45° (corresponding to the angle taken up by the boat during a close-hauled sailing). A smaller angle between the wind real direction and the boat route is not feasible. Moreover, the number of sails which can be used is limited. Also, the presence of the boom reduces the useful space on the deck and is dangerous for the people on the boat, as it is subject to sudden oscillations due to the change of wind direction and/or to the change of route direction. The object of the invention is to provide a masting arrangement for sailboats which does not have the above mentioned limitations in the sail distribution, while permitting a wide range of possible riggings. Starting from the arrangement described in EP-A-0 126 679, according to the invention the solution to the above mentioned problems is obtained with a masting arrangement as defined in the preamble of the annexed main claim, further characterized in that the anchoring point of the stays on the boat is formed by stay-anchoring means movably mounted on rails applied on the deck of the boat, transversely to the hull axis. In a particularly advantageous embodiment of the masting arrangement according to the invention, said rails are arranged in such a way that they can be used also for the anchoring of the sheets of the sails. In an advantageous development of the invention, longitudinal sheet rails are disposed on the deck. In a possible embodiment of the masting arrangement, the poles can be moved on guides applied to the boat, to permit a displacement of the masting vertex. Further advantageous features and possible embodiments of the masting arrangement according to the invention are set out in the appended claims. The drawing shows schematically a non limiting exemplification of the invention. In the drawings: Fig. 1 shows, in schematic side view, the application of the masting, according to the invention, to a single-hull boat. Figs. 2 and 3 show schematic views on lines II-II and III-III of Fig. 1; Fig. 4 shows a schematic plan view of a sails system obtainable by the masting according to the invention; Fig. 5 shows a possible sails disposition for close-hauled sailing; Fig. 6 shows a modified embodiment of the masting of Fig. 3; Fig. 7 shows a cross-section of a pole having a streamline profile; Fig. 8 shows a plan view of a possible disposition of the sails when sailing with the wind; Figs 9 and 10 show possible dispositions of rails for manoeuvring the sails; Figs. 11 and 12 show a masting for large-size boats; Fig. 13 shows a further embodiment of the masting; Figs. 14; 15; and 16 show possible embodiments of the vertex, respectively rigid and with feasible articulated joint. Figs. 1 to 3 show the application of the invention to a single-hull boat. As it appears from the drawing, three poles 3, 5, 5 are applied to the hull, the first pole of which being anchored abaft and thesecond ones in correspondence of point 7 wherein said poles meet to make up an ideal pyramid (with triangular base, in this case), of which the poles themselves form the corners, or afore with respect to said point 7. The masting comprises also a plurality of stays anchored, at one end, to the vertex 7 formed by poles 3, 5, 5, and at the other end, to suitable points of the bridge or deck of the boat in a manner described lateron. Figs. 1 to 3 show to of these stays indicated by 9 and 11, respectively. The stays may also be in number far greater than two. In the configuration of Fig. 4, in which the poles have been omitted for sake of clarity, five stays are provided, whose anchoring points indicated by 13, 15, 17, 19 and 21, respectively, are lined up along the longitudinal axis of the hull. To each stays 13 to 21, sails 23, 25, 27, 29, 31 - shown by their profile - are applied, which can be maneuvered by means of sheets likewise the traditional jibs of the sailing boats of known type. It is not necessary yet that the stays be anchored at points lined up along the boat axis, as shown in Fig. 4. In Fig. 5 a solution is shown in which two stays are anchored at points 33 and 35, respectively, being not lined up along the hull axis. Said stays support sails 37, 39 indicated by their profile. This disposition is particularly advantageous as it allows a close-hauled sailing with an angle between the boat route - indicated by arrow fI - and the wind real direction - indicated by arrow fV - significantly small, and surely smaller than that allowed by the traditional mastings with central mast. In fact, it is known that the wind entry angle with respect to the leading edge of the sails, that is, the angle between the direction of the apparent wind and the chord of same sails, cannot go below a predetermined minimum value, beyond which the fluid stream becomes detached from the sail with consequent turbulence or suppression of the aerodynamic force exerted on the sails. In the traditional mastings, the sails (in particular the spanker and the jib, as used when the boat is close hauled) are necessarily applied along the longitudinal axis of the boat, as the spanker is held by the mast and the jib by the bow stay. The attachment edges of the sails and, correspondingly, the so-called tack points, result thus lying on the symmetry plan of the hull. Since the angle between the direction of the apparent wind and the plane on which the sails attachement edges lie, cannot, for the above stated reasons, go below a predetermined value (corresponding to an angle of about 45° between the direction of real wind and the boat route), and since the boat advancement direction coincides with the straight line joining the jiib and spanker tack points, it thus follows that - in the traditional boats - the angle between the boat advancement direction and the wind real direction cannot go below the above mentioned minimum value of approximately 45°. By the masting according to the invention, on the contrary, since the straight line joining the tack points must not necessarily be parallel to the axis of symmetry of the hull, it is possible to reduce the angle between the advancement direction and the real wind down to far lower values than 45°. In the schematic design of Fig. 5, for example, the plane on which the attachment edges of the sails lie, is indicated by its trace A on the horizontal, which corresponds to the straight line on which the tack points are lying and are coincident, in the plan view, with the trace of stays 33 and 35. The angle "β" between said trace and the wind real direction fV is again at least 45°, owing to the above stated reasons of fluid dynamics, but the angle between fV and fI is much smaller. The possibility of distributing more sails as shown in Fig. 4 allows also to obtain - the wind being equal - the same force as that obtainable by a traditional masting while employing sails of far more limited height, with consequent reduction of the moment tending to turn the hull over. This greater aerodynamic force is achieved owing to a dual effect obtainable through the masting according to the invention. In fact, the possibility of distributing more stays 13, 15, 17, 19, 21 and relevant sails 23, 25, 27, 29, 31 provides, firstly, a larger sail area to rely on; secondly, for an increase of spaces between two contiguous sails (indicated by X in Fig. 4), wherein the exploitation of the wind stream is maximum. In practice, the possibility of having a high number of anchoring points for the stays, and the lack of a central mast allow the boat to be rigged in many different ways thereby obtaining, for every wind condition, a sails distribution which achieves an ideal aerodynamic exploitation of the available wind. Fig. 8 shows, in plan view and without poles for sake of Drawing clarity, a possible disposition of the sails for sailing before the wind. As it results from said figure, in order to move forward before the wind, sails 28, 30, 32, 34 may be disposed in a butterfly arrangement - by means of booms - that is, projecting very far with respect to the hull, which sails are supported by suitable stays 20, 22, 24, 26. Advantageously, the fore sails 28, 30 are larger than the rear sails 32, 34. By a disposition of the illustrated type, it is possible to achieve large sail areas even without spinnaker, which is a rather dangerous sail and difficult to be operated. In this way, the drawback deriving from the use of the spinnaker, whose sail area cannot be gradually adjusted, is avoided. On the contrary, by providing more sails 28, 30, 32, 34, the sail area can be easily regulated with graduality. The anchoring points of the stays on the deck or bridge of the boat is obtained, according to the invention by providing a set of rails 38, 40 as shown in Fig. 9, on each of which stays-anchoring means (38A, 40A) can be fixed in the desired location. On each rail a number of anchoring means may be provided, apt to be blocked at suitable positions along the relevant rail. As it appears from the drawing, the rails 40 are less spaced apart than rails 38. In this way, the rails 40 may be advantageously used also as sheet rails by providing blocks sliding on said rails for the movement of the sheets. By using openable blocks, it is possible to make the corresponding sheet shift from one to the other of rails 40 according to the navigation requirements. The operation of shifting the sheet from the block of one rail 40 to the block of a second rail 40, adjacent to the first one, corresponds to the movement of the same sheet along a rail disposed lengthwise to the hull. Fig. 10 shows another possible disposition of rails 42 for the stays anchoring means 42A and of rails 44 for the sheets manoeuvring, said rails 44 being in this case longitudinal. The masting according to the invention allows the boat's deck to be fully cleared when the boat is at anchor. In fact, it is sufficient to release the stays from the respective anchoring points and retain them along the poles to make the whole deck easily accessible. In addition, the presence of a high number of poles makes the boat more visible both to radar and optical means. The poles may be applied at non fixed points of the boat. Fig. 6 shows a schematic plan view of a single-hull boat, in which the poles 5 are applied on guides 77 and can be moved according to arrow f thereby determining a displacement of the vertex 7 with respect to the hull along the axis thereof, and a lowering or lifting of said vertex to/from same hull. Poles 3, 5, 5 are suitably hinged both at the vertex and at the point where they are connected to the hull, to allow these movements. In order to reduce the aerodynamic resistance of the poles during the navigation, provision may be made for fitting streamline profiles onto the poles. Fig. 7 shows a cross-section view of a pole 81 on which an aerodynamic profile developed in the shape of a cylindrical surface is fitted, having the cross-section shown in Fig. 7 and a height approximately equal to the whole longitudinal development of the corresponding pole. The profile 83 is rotatively mounted with respect to the pole axis, for example with the aid of ball-bearings, so as to allow the orientation according to the direction in which the wind is blowing. Fig. 7 shows a cross-section of a pole having a high resistance to combined compression and bending stress. Said pole, in fact, has an outer cylindrical sheath with circular cross-section 85 and an internal cross-shaped portion 87. The masting according to the invention allows also to get rid of the boom which is a source of frequent accidents during navigation due to abrupt movements the boom is subject to as a consequence of the changes in the wind direction with respect to the boat. As for boats of great length are concerned, it is possible to predispose a high number of stays thereby obtaining a very large sail area with poles disposition of the type shown in Figs. 11 and 12. In this disposition, to the hull 1 - or to the deck thereof - two poles 92 are applied converging into a vertex 93, and three poles 94, 94, 98 converging into vertex 95, the two vertices 93 and 95 being joined by a further pole 96. In this way, the stays may be applied throughout the length of the horizontal pole 96, instead of at a single point, and are anchored to the deck by way of rails as described above. Fig. 13 shows a modified embodiment of the masting according to the invention. In this embodiment, to the hull 1 a masting is combined, consisting of six poles 105 symmetrically disposed with respect to the central part of the boat and converging into a vertex 107. The function and the use of this masting are similar to those described for the other embodiments. The rails 38, 40 have been omitted for the sake of clarity. Fig. 14 shows a feasible embodiment of the vertex 207 designed to provide relative angular positions between the poles converging thereto, such as those indicated by 3, 5, 5. The vertex consists, in this case, of a member made up of laminar gussets 206 which stiffen the seats 203, 205, 205 for said poles, relative to each other. Figs. 15 and 16 show a possible embodiment wherein an articulated joint is provided jointing three poles at the vertex of the masting made up of poles 3, 5, 5 of Figs. 1 to 3 or 6 or 9 or 10 said poles being connected to the same hull in different points thereof or to hulls of different dimensions. According to said Figs. 15 and 16, where the poles are numbered 49, 51, 53, the pole 51 is articulated at its lower part to the hull according to a trasverse axis along which a pivot pin 353 is provided. This pole 51 is articulated by means of a collar 357 to a trasverse axis of a cylindrical body 355. The body 355 makes up, at the two sides of the collar 357, the seats for two spherical joints 359, 359 for the upper ends of the two poles 49 and 51. The centres of said spherical joints lie on the trasverse axis defined by the cylindrical body 355. In this way, relative inclinations may be obtained between poles 49, 51 and 53, the poles 53 being able to move along the longitudinal vertical axis of symmetry of the boat. The rear pole 3, 98 may also be replaced by a pair of respectively aft and fore stays disposed along the plane of symmetry of the hull. The drawing shows only an exemplification of the invention, which may vary in the forms and dispositions.

Claims: 1. Masting arrangement for sailboats comprising at least three poles (3, 5, 5; 41, 43, 45, 47; 49, 51, 53; 92, 94, 96, 98; 105) the lower ends of which are connected to the deck of the boat (1; 59; 63), while the upper ends are conneted to each other to form a vertex (7; 93, 95; 107; 207; 307) of an ideal pyramid whose corners are formed by the poles themselves; at least one stay (11; 15, 17, 19, 21; 33, 35; 20, 22, 24, 26) in tension between said vertex (7) and an anchoring joint on the boat; and at least one sail (23, 25, 27, 29, 31; 37, 39; 28, 30, 32, 34) borne by said stay; characterized in that said anchoring point on the boat is formed by stay-anchoring means (38A, 40A, 42A) movably mounted on rails (38, 40, 42) applied on the deck of the boat, transversely to the hull axis. 2. Masting arrangement according to claim 1, characterized in that said rails are arranged in such a way that they can be used also for the anchoring of the sheets of the sails. 3. Masting arrangement according to claim 1 or 2, characterized in that longitudinal sheet rails (44) are disposed on the deck. 4. Masting arrangement according to one or more of the preceding claims, characterized in that a first one (3; 53; 98) of said poles is applied abaft in correspondence of the boat longitudinal axis, and that the other two poles (55; 49, 51; 94) are applied, symmetrically to the longitudinal axis of the boat, in correspondence of the vertex (7) formed by the same poles or afore said vertex. 5. Masting arrangement according to one or more of the preceding claims, characterized in that said poles (5) can be moved on guides (77) applied to the boat, to permit a displacement of the masting vertex (7). 6. Masting arrangement according to one or more of the preceding claims, characterized in that said poles have a cross-section exhibiting a high compression-bending resistance. 7. Masting arrangement according to one or more of the preceding claims, characterized in that around said poles streaming profiles (83) are applied, which can rotate according to the wind direction. 8. Masting arrangement according to one or more of the preceding claims, characterized in that said poles form variable angles. 9. Masting arrangement according to claim 8, characterized in that a joint is provided having spherical articulations (359) for the two side poles (49, 51) and an articulation (355, 357) with a transversal axis which passes through the centers of said spherical articulations for the pole (53) which at its lower end is articulated at the hull around a transersal axis (353). 10. Masting according to claim 1, characterized in that it comprises further two poles (92), the lower ends of which are anchored to the deck of the boat and the upper ends converge into a further vertex (93) at a level corresponding to the level of the vertex (95) of the ideal pyramid, a horizontal pole (96) being provided for connecting said further vertex (93) to said vertex (95) of the ideal pyramid, the stays being anchored to said horizontal pole (96).

Inventors: BIAGIOLI, MARIO
Applicants: BIAGIOLI, MARIO
Application year: 1988
Main classification: B63B15
IPC codes: B63B15