Sail for a sail-powered craft, and corresponding craft

Abstract

Sail for a sail-powered craft, and corresponding craft The invention relates to a sail (10) for a sail-powered craft (1), said sail being intended to be mounted along a mast (6). The sail (10) has an aerodynamic cross-section comprising, on the one hand, a peripheral contour (12) comprising a leading edge (14), a trailing edge (16), and two adjacent surfaces (18) each extending between the leading edge and the trailing edge; and on the other hand, an interior space surrounded by the peripheral contour (12) and configured to accommodate the mast (6).The sail (10) comprises at least one longitudinal inflatable envelope (20) comprising two walls, inner and outer, facing each other, said two walls each comprising a textile sheet and being connected to each other by a multitude of connecting threads distributed over the entire surface of said sheets and of substantially equal lengths, forming a structure, preferably closed or sealed, suitable for being inflated, and at least part of the peripheral contour (12) is formed by said at least one inflatable envelope (20). The invention also relates to a sail- or hybrid-powered craft, comprising such a sail (10). Figure for the abstract: Fig. 1.

Description

Title of the invention: Sail for a sail-powered craft, and corresponding craft Technical field

[0001] The present invention relates to the field of sails for sail-powered vehicles, in particular inflatable sails having an aerodynamic profile. Prior art

[0002] In the field of sailing, the propulsion of the ship is classically ensured by one or more simple sails made of stretched canvas.

[0003] However, it is known to use thick-profile sails, whose performance is superior to that of simple sails. Among the thick-profile tracks, a distinction is thus made between rigid wings and flexible wings.

[0004] Rigid wings are extremely complex mechanical assemblies whose manufacturing cost limits their use to high-level competition. In addition, this type of wing does not allow the reduction in sail area required for cruise ships.

[0005] Flexible wings are wings made of a double canvas, hoisted on a spar and stretched by rigid elements (battens or cambers as in document FR2556310) to maintain a thick profile. This type of wing has the major disadvantage of deformations of the profile between the rigid elements. In addition, the disadvantages of tension forces of the classic sail persist: it is indeed necessary to strongly stretch the canvas from top to bottom to best maintain the chosen aerodynamic profile.

[0006] Patent FR 3 008 382 B1 discloses a wing-shaped sail arranged vertically and composed of a front part including the leading edge and a rear part including the trailing edge, each part being made of a piece of double-walled textile whose warp threads of the fabric are linked to the weft threads facing each other. By varying the length of these linking threads during weaving, the spacing between the two walls makes it possible to create a defined sail profile. These pieces of double-walled textile are closed by a fabric glued and sewn at the top and bottom of the generated profile, the whole made airtight by coating with an elastomeric resin. The maintenance of the profile thus obtained is ensured by the inflation of the sail, this air pressurization being independent of the static or dynamic pressure of the air circulating around this profile.

[0007] However, such a sail has several drawbacks. First of all, the manufacture of such double textile pieces, with warp threads cooperating with the weft threads of the two facing walls, is complex, particularly when these connecting threads have variable lengths depending on the shape of the required aerodynamic profile (the two walls with non-parallel faces). Such three-dimensional weaving requires significant and costly adaptations to current weaving machines. In addition, excessive tension in one of the threads can lead to the tearing of a weft thread, creating a hole or a tear in one of the walls, affecting the airtightness of the sail and consequently its rigidity and therefore its aerodynamic performance.

[0008] Document FR 3 073 817 relates to a wing-shaped sail with an aerodynamic profile comprising, between its leading edge and its trailing edge, at least one closed flexible envelope comprising, between its front end on the leading edge side and its rear end on the trailing edge side, a first side wall and a second side wall. Said side walls are spaced apart from each other, and provide between them an interior space capable of being inflated to form a rigid profile. The interior space of the envelope is equipped with rows of wires, extending from its front end on the leading edge side to its rear end on the trailing edge side. The wires are held alternately on the inner face of the first side wall and the inner face of the second side wall of the envelope by means of fixing by gluing or welding. Said glued or welded wires ensure the maximum spacing between the two side walls in the inflated state of the envelope.Each row of wires is arranged in a crenellated pattern, in the form of crenellations whose apexes correspond to the bonding or welding areas on the inner faces of the side walls of the envelope.

[0009] Such a wing-shaped sail thus has, in the inflated state, a rigid, non-deformable profile. Said connecting threads are independent of the warp threads and the weft threads of the textile material which can form the envelope walls of the sail.

[0010] However, the manufacture of such sails, with connecting threads cooperating with each of the two facing walls, is also complex, in particular because the length of the connecting threads varies according to the shape of the required aerodynamic profile. Such three-dimensional manufacturing therefore also requires expensive machines. Presentation of the invention

[0011] The present invention aims to solve the various technical problems stated above. In particular, the present invention aims to propose a sail, in particular an inflatable sail, for a sail-powered craft, in the form of an aerodynamically profiled wing, which is simpler to manufacture while remaining robust. The present invention also aims to propose an inflatable sail for a sail-powered craft, the aerodynamic profile of which can be modified simply, on command.

[0012] Thus, according to one aspect, a sail for a sail-powered craft is proposed, said sail being intended to be mounted substantially vertically along a mast of said machine, in which the sail extends in a longitudinal direction and has an aerodynamic cross-section comprising a peripheral contour and an interior space surrounded by the peripheral contour and configured to accommodate the mast. The peripheral contour comprises: a leading edge, a trailing edge, and two adjacent surfaces, or side walls, each extending between the leading edge and the trailing edge. The sail comprises at least one longitudinal inflatable envelope comprising two walls, inner and outer, facing each other, said two walls each comprising a textile sheet and being connected together by a multitude of connecting threads distributed over the entire surface of said sheets and of substantially equal lengths, forming a structure, preferably closed or sealed, suitable for being inflated. At least part of the peripheral contour is formed by said at least one inflatable envelope.

[0013] The structure of the inflatable sail according to the present invention thus comprises at least one volume formed from a “dropstitch” type material which is an initially substantially planar material. The volume makes it possible in particular to obtain at least a portion of the surface, or skin, of the inflatable sail with the desired aerodynamic profile. Such dropstitch materials are conventionally used to manufacture, for example, stand-up paddle boards. They are in particular simpler to use and to shape than the materials of the prior art having a distance between the opposite walls which varies along the profile of the sail, because, in the present invention, the dropstitch material forms all or part of the surface of the aerodynamic profile, and not all or part of the aerodynamic volume, as in the prior art.Thus, only the outer walls of the inflatable envelope according to the present invention contribute to the aerodynamic shape of the sail: the inner walls are oriented towards the interior space of the sail.

[0014] Thus, unlike the sails of the prior art for which the inflatable volume was delimited by the two opposite surfaces of the wing-shaped sail and forms the aerodynamic profile of the sail, the inflatable volume of the sail according to the present invention is located only on all or part of the peripheral contour. In other words, the inflatable volume of the sail according to the present invention forms only the entirety or part of the surface of the sail, the interior volume delimited by the sail being mainly a non-inflated interior space. Such an inflatable structure in the form of a skin makes it possible in particular to use inflatable materials whose opposite walls are substantially spaced by the same distance. In the sail according to the present invention, the inflatable envelope forming all or part of the peripheral contour of the sail is a substantially flat envelope which maintains substantially the same thickness along the profile of the sail.

[0015] Preferably, said at least one inflatable envelope is patronized in a manner to be formed, in particular so that the outer wall of said inflatable envelope forms at least part of each adjacent surface, and preferably the leading edge, of the peripheral contour.

[0016] The inflatable envelope may advantageously extend from the leading edge of the sail and along at least a portion of each adjacent surface, in the direction of the trailing edge. Obtaining the desired aerodynamic shape for the leading edge and the portions of each adjacent surface may in particular be obtained by patterning the initial flat material intended to form the inflatable envelope. Patterning the flat material to obtain an aerodynamic contour proves to be simpler to produce than a three-dimensional volume with an aerodynamic profile. In particular, specific cutouts on at least one of the opposite walls of the initial flat material may be sufficient to obtain an aerodynamic contour, while keeping the same distance between the two opposite walls, whereas 3-dimensional profiled materials require constant adjustment of the distance (and therefore the length of the connecting threads) between the two opposite walls.

[0017] Thus, at least one of said opposite walls of the inflatable envelope comprises at least one cutout, preferably made in the longitudinal direction, and a sealing means connecting, preferably edge to edge, the sides of the cutout together. Said at least one cutout is positioned and dimensioned in the inflatable envelope so as to obtain the cross section of the sail with the desired aerodynamic profile.

[0018] Consequently, and despite the use of an inflatable envelope formed from a dropstitch material, i.e. substantially flat, to form the peripheral contour of the sail, the latter nevertheless has an aerodynamic curved profile thanks to a specific pattern. Thus, at least one of the walls of the dropstitch material comprises one or more cutouts which, after re-closing, allow a modification of the planar geometry of the dropstitch material, and in particular to obtain a curvature of the peripheral contour allowing the obtaining of a desired three-dimensional cross-section for the sail.

[0019] Indeed, the dropstitch material is conventionally a planar material, with two main planar walls parallel to each other connected by threads and a peripheral wall. Unlike the sails of the prior art, it is not the variation in the length of the connecting threads connecting the opposite walls, but the specific patterning of one or more inflatable dropstitch envelopes, which makes it possible to obtain the desired curved aerodynamic cross-section of the sail according to the present invention.

[0020] Preferably, the sail comprises a single inflatable envelope, said single inflatable envelope being shaped so as to form the leading edge and at least a portion of each adjacent surface of the peripheral contour.

[0021] In order to simplify the inflation and deflation of the sail, but also its assembly, the sail may comprise a peripheral contour, or skin, formed at least in part by a single inflatable volume.

[0022] Preferably, the inflatable envelope is designed by modifications of the surface of one of the walls relative to the other, in particular by local modifications such as cutouts, removal of portions or superpositions.

[0023] According to one embodiment, the shaping of the dropstitch material may comprise, in addition to one or more cuts, a removal of a portion of at least one wall of the dropstitch material, and preferably a removal of a portion of the inner wall.

[0024] Alternatively, the shaping of the dropstitch material may comprise, in addition to one or more cuts, a superposition of the edges of the cut of at least one wall of the dropstitch material, and preferably a superposition of the edges of a cut of the inner wall forming the peripheral contour of the sail.

[0025] It is thus possible to obtain an inner wall with a smaller surface area than that of the outer wall, so that they remain substantially parallel to each other along the entire peripheral perimeter.

[0026] Preferably, the sail also comprises a longitudinal flap, preferably inflatable and more preferably distinct from said at least one inflatable envelope, positioned adjacent to said at least one inflatable envelope so as to form a part of the peripheral contour comprising the trailing edge.

[0027] In such an embodiment, the inflatable sail comprises, in addition to the aerodynamic profile, a steerable flap at the trailing edge. Said flap may in particular be inflatable and mounted adjacent to the inflatable envelope so as to form, with the inflatable envelope, the peripheral contour of the sail. Thus, despite its inflatable and hollow appearance, the sail according to the present invention can retain advanced functionalities such as the aerodynamic profile and the steerable trailing edge in order to make it versatile and usable in multiple applications.

[0028] Preferably, the flap is mounted to pivot about a longitudinal axis positioned in a longitudinal plane comprising the leading edge and the trailing edge of the sail, for example said flap being connected to said at least one inflatable envelope by a pivot connection, and the sail also comprises a control means, preferably inflatable, mounted between said at least one inflatable envelope and the longitudinal flap, and configured to pivot the flap relative to said at least one inflatable envelope.

[0029] The flap can be mounted on the inflatable envelope by a pivot connection, and be controlled by one or more inflatable elements arranged between the flap and the inflatable envelope. This keeps a sail whose different elements are inflatable, while having movable elements, notably the flap, to modify the aerodynamic profile of the sail.

[0030] Preferably, the control means comprises two inflatable longitudinal elements mounted on either side of the longitudinal plane comprising the leading edge and the trailing edge of the sail.

[0031] The control means may comprise two adjacent inflatable elements, the inflation of one of the two elements making it possible to move one edge of the flap away from the corresponding edge of the inflatable envelope, and therefore to pivot the flap relative to the inflatable envelope. Such control means thus make it possible to pivot the flap, while remaining inflatable and space-saving.

[0032] Preferably, the sail comprises several connecting means distributed along the longitudinal direction of the sail, and secured to said at least one inflatable envelope.

[0033] In order to maintain the sail on the mast, and more particularly the inflatable envelope relative to the mast, the sail may comprise connecting means positioned regularly along the longitudinal direction of the sail, to mechanically connect it to the mast and transmit to it the forces exerted on the sail.

[0034] Preferably, the sail also comprises one or more connecting means, preferably rigid, for example made of composite material, mounted in the interior space and configured to cooperate with the mast and at least part of the peripheral contour, preferably said at least one inflatable envelope.

[0035] The connecting means may take the geometric shape of the cross-section of the interior space of the sail. They may thus be in the form of rigid plates distributed along the longitudinal direction of the sail, and extending into the space left free between the mast and the inflatable envelope.

[0036] According to another aspect, there is also provided a sail propulsion element comprising a sail as described above, a mast and a means of inflating, and possibly deflating, said at least one inflatable envelope.

[0037] According to another aspect, there is also provided a sail-powered or hybrid vehicle, comprising at least one hull and at least one sail-powered element as described above. Brief description of the drawings

[0038] [Fig-1] [Fig.l] schematically represents a sail-powered craft equipped with a sail according to the present invention, seen from above;

[0039] [Fig.2] [Fig.2] represents a perspective view of the sail according to the present invention;

[0040] [Fig.3] [Fig.3] schematically represents the stages of production of the inflatable envelope of the sail according to the present invention;

[0041] [Fig.4] [Fig.4] shows, in an enlarged form, the connection between the envelope inflatable and the sail flap according to the present invention; and

[0042] [Fig.5] [Fig.5] represents a perspective view of the shutter according to the present invention. Description of the embodiments

[0043] [Fig.l] schematically illustrates an example of a sail-powered craft 1 according to the present invention, seen from above. The craft 1, for example a boat such as a monohull, comprises a hull 2 ​​and a sail propulsion element 4 allowing movement of the craft 1 thanks to the energy provided by the wind.

[0044] The sail propulsion element 4 extends substantially in a longitudinal direction D (see [Fig.2]) which is substantially perpendicular to the upper surface of the hull 2 ​​and which is substantially parallel, or even coincident, with the mast 6. The sail 10, which also extends in the longitudinal direction D, can thus have an invariable cross-section along said longitudinal direction D. In this case, the sail 10 can have a generally cylindrical shape. Alternatively, the sail 10 can have a cross-section whose dimensions vary, for example continuously, along the longitudinal direction D, preferably which decrease as one moves away from the hull 2. In this case, the sail 10 can have a generally conical or frustoconical shape.

[0045] The sail propulsion element 4 thus comprises a mast 6, an inflation (and possibly deflation) means 8 and a sail 10 according to the present invention. In particular, the sail 10 being at least partially inflatable, the inflation means 8 can make it possible to hoist, at least partially, or to lower, at least partially, the sail 10. Alternatively, the sail 10 can be hoisted or lowered along the mast 6 by halyards, or can be hoisted or lowered by connection with a telescopic mast 6 which can be deployed or retracted on command.

[0046] The mast 6, on which the sail 10 is mounted, allows the forces exerted by the wind on the sail 10 to be transmitted to the hull 2 ​​to move the machine 1 forward.

[0047] The sail 10 is an inflatable sail, but having the aerodynamic profile of a wing. The sail 10 thus has, in cross-section, a peripheral contour 12 which is chosen to have an aerodynamic shape. The peripheral contour 12 comprises a leading edge 12, a trailing edge 14, and two adjacent surfaces 18, or side walls, connecting the leading edge 12 to the trailing edge 14. The peripheral contour 12, and in particular the two adjacent surfaces 18 which are distant from each other and not parallel to each other, therefore delimits the volume of the sail 10.

[0048] As can be seen in the embodiment illustrated in [Fig.l], the sail propulsion element 4, and in particular the sail 10, may have, in particular at rest, a plane of symmetry formed by a longitudinal plane P passing through the leading edge 12, the mast 6 and the trailing edge 16.

[0049] [Fig. 2] illustrates more precisely the internal structure of the sail 1. The sail 10 comprises on the one hand an inflatable envelope 20, delimiting in particular an interior space 22, and on the other hand a flap 24. The inflatable envelope 20 and the flap 24 are both longitudinal, of cylindrical and / or truncated cone shape, in the longitudinal direction D.

[0050] In the embodiment illustrated in [Fig.2], the inflatable envelope 20 forms in particular the leading edge 12 of the sail 10, as well as a significant portion of the adjacent surfaces 18 of the peripheral contour 12. The flap 24 forms, for its part, the trailing edge 16, as well as a smaller portion of the adjacent surfaces 18 of the peripheral contour 12.

[0051] The interior space 22, surrounded by the inflatable envelope 20, and possibly by the flap 24, is not an inflatable volume of the sail 10. It allows in particular to position the mast 6 inside the sail 10, and may include in particular connecting means 26 mechanically connecting the mast 6 to the peripheral contour 12 of the sail 10, in order to transmit the forces exerted on the sail 10, to the hull 6. The connecting means 26 may include plates having the shape of the cross-section of the interior space, and distributed along the mast 6. The connecting means 26 may be rigid, for example made of composite material, and come into contact with both the mast 6 and with at least a portion of the inflatable envelope 20.

[0052] For its part, the flap 24 can be mounted on the inflatable envelope 20 by one or more pivot connections 28 (see figures 4 and 5) extending substantially in the direction D.

[0053] Thus, and unlike the sails of the prior art, only the peripheral contour 12 of the sail 10 is formed, at least in part, by an inflatable envelope 20, while the interior space remains free and non-inflatable. The peripheral contour 12 can then be produced with an inflatable envelope of substantially constant thickness, that is to say from a substantially flat inflatable material such as dropstitch material, as will be described below.

[0054] Thus, and as illustrated in [Fig. 3], the inflatable envelope 20 comprises two opposite walls, substantially parallel to each other: an inner wall 20a and an outer wall 20b. Said walls 20a, 20b each comprise a textile sheet and are connected to each other by a multitude of connecting threads distributed over the entire surface of said sheets, forming a structure suitable for being inflated. A peripheral wall, at the ends, is mounted on the peripheral periphery of each of the inner 20a and outer 20b walls of the inflatable envelope 20, in order to connect them together and form a closed volume.

[0055] To obtain the desired shape for the cross-section of the sail 10, the inflatable envelope 20 was specifically patterned. [Fig. 3] thus illustrates the inflatable envelope 20 in the initial flat configuration (on the right), and the inflatable envelope 20 in the final aerodynamic configuration (on the left) after finalizing the pattern.

[0056] Thus, to obtain the desired curvature, the inner wall 20a is patterned with longitudinal cutouts, distributed over the width of the inner wall 20a, to remove for example portions of inner walls. The removal of such portions, the surface area of ​​which is chosen as a function of the area of ​​the inflatable envelope 20 in order to obtain the desired curvature, makes it possible to reduce the surface area of ​​the inner wall 20a relative to the outer wall 20b. Once the portions of inner walls have been cut out, the edges of the cutouts are then joined together, for example edge to edge, with a sealing means, for example a waterproof strip glued or welded to said edges of the inner wall 20a.

[0057] An inflatable envelope 20 is then obtained, the interior volume of which is again closed, and the walls 20a, 20b of which are connected to each other by connecting wires of the same length, while presenting an aerodynamic profile.

[0058] Such an inflatable envelope 20 is therefore easier to obtain, and less expensive because flat dropstitch materials are widespread and conventional for those skilled in the art, while maintaining the performance of an aerodynamic profile wing.

[0059] The flap 24 may also be an inflatable element of the sail 10. The flap 24 may have the shape of a cylinder with a triangular base, or of a truncated pyramid with a triangular base. One side of the triangle (base) is intended to face the ends of the inflatable envelope 20, while the other two sides are intended to form the trailing edge 16.

[0060] In order to orient the flap 24 relative to the rest of the sail 10, the sail 10 may comprise inflatable longitudinal elements 30, for example bladders extending in the longitudinal direction. The inflatable longitudinal elements 30 may be two in number and mounted between the inflatable envelope 20 and the flap 24, for example on the base of the triangle of the flap 24, each on one side of the pivot connection 28. Thus, by selectively inflating one of the inflatable longitudinal elements 30, it becomes possible to move a portion of the flap 24 away from the inflatable envelope 20, and therefore to pivot it. The inflatable longitudinal elements 30 thus form, with corresponding inflation means (not shown), a control means 32 making it possible to orient the flap 24 of the sail 10, while remaining an inflatable and deflatable element like the rest of the peripheral contour 12.

[0061] As illustrated in [Fig.4], the flap 24 may comprise a base (side opposite the ends of the inflatable envelope 20) formed by a dropstitch material, while the other two sides of the triangular section of the flap 24 are formed by single walls closing the triangular section and forming the trailing edge 16. In order to shape the triangular flap 24 whose interior volume is not inflated, the flap 24 may also comprise a cylindrical inflatable element mounted in the flap 24, near the trailing edge 16.

[0062] A pivot connection 28 in the form of a flexible wall connects the flap 24 to the inflatable envelope 20 at the longitudinal plane P. The two inflatable elements 30 of the control means 32 are mounted on either side of said flexible wall to allow rotation of the flap 24 around the pivot connection 28.

[0063] [Fig. 5] illustrates a perspective view of the longitudinal flap 24 according to another embodiment. Unlike the inflatable envelope 20 or the first embodiment illustrated in [Fig. 4], the flap 24 of [Fig. 5] may be a volume delimited by a single sealed peripheral wall, to be fully inflated, and not by a dropstitch material. In order to have a regular triangular cross-section all along the flap 24, non-sealed intermediate walls integral with the inner face of the peripheral wall may be provided, at regular intervals, inside the inflatable volume.

[0064] Pivot connection means 28 may be provided in individual form, for example in the form of hooks configured to cooperate with loops and distributed along the longitudinal direction D, to connect the flap 24 to the inflatable envelope 20. The two inflatable elements 30 of the control means 32 are mounted on either side of said individual connection means.

[0065] An inflation valve 24a is provided on the flap 24 in order to inflate it.

[0066] Inflation valves 30a are provided for each inflatable element 30 of the control means 32.

[0067] Thus, with the sail according to the present invention, it becomes possible to obtain an aerodynamic profile delimited by a peripheral contour formed from a substantially flat inflatable material. It therefore becomes simpler and less expensive to produce an inflatable sail, in particular of large size, while retaining the possibility of having an adjustable flap at the trailing edge.

Claims

Claims

1. Sail (10) for a sail-powered craft (1), said sail being intended to be mounted substantially vertically along a mast (6) of said craft, in which the sail (10) extends in a longitudinal direction (D) and has an aerodynamic cross-section comprising: - a peripheral contour (12) comprising: - a leading edge (14), - a trailing edge (16), and - two adjacent surfaces (18) each extending between the leading edge and the trailing edge, - and an interior space (22) surrounded by the peripheral contour (12) and configured to accommodate the mast (6), characterized in that the sail (10) comprises at least one longitudinal inflatable envelope (20) comprising two walls, inner (20b) and outer (20a), facing each other, said two walls (20a,20b) each comprising a textile sheet and being connected to each other by a multitude of connecting threads distributed over the entire surface of said sheets and of substantially equal lengths, forming a structure, preferably closed or sealed, suitable for being inflated, and in that at least part of the peripheral contour (12) is formed by said at least one inflatable envelope (20).,

2. A sail (10) according to claim 1, wherein said at least one inflatable envelope (20) is patterned so as to form at least a portion of each adjacent surface (18), and preferably the leading edge (14), of the peripheral contour (12).

3. A sail (10) according to claim 1 or 2, comprising a single inflatable envelope (12), said single inflatable envelope being patterned so as to form the leading edge (14) and at least a portion of each adjacent surface (18) of the peripheral contour (12).

4. Sail (10) according to claim 2 or 3, in which the inflatable envelope (20) is shaped by modifications of the surface of one of the walls relative to the other, in particular by local modifications such as cutouts, removal of portions or superpositions.

5. Sail (10) according to any one of the preceding claims, also comprising a longitudinal flap (24), preferably inflatable and more preferably distinct from said at least one inflatable envelope (20), positioned adjacent to said at least one inflatable envelope (20) so as to form a part of the peripheral contour (12) comprising the trailing edge (16).

6. Sail (10) according to the preceding claim, wherein the flap (24) is pivotally mounted about a longitudinal axis positioned in a longitudinal plane comprising the leading edge (14) and the trailing edge (16) of the sail, for example said flap being connected to said at least one inflatable envelope by a pivot connection (28), and wherein the sail (10) also comprises a control means (32), preferably inflatable, mounted between said at least one inflatable envelope (20) and the longitudinal flap (24), and configured to pivot the flap (24) relative to said at least one inflatable envelope (20).

7. Sail (10) according to the preceding claim, in which the control means (32) comprises two inflatable longitudinal elements (30) mounted on either side of the longitudinal plane (P) comprising the leading edge (14) and the trailing edge (16) of the sail.

8. Sail (10) according to any one of the preceding claims, also comprising one or more connecting means (26), preferably rigid, for example made of composite material, mounted in the interior space (22) and configured to cooperate with the mast (6) and at least part of the peripheral contour (12), preferably said at least one inflatable envelope (20).

9. Sailing propulsion element (4) comprising a sail (10) according to any one of the preceding claims, a mast (6) and a means of inflating (8), and possibly deflating, said at least one inflatable envelope (20).

10. Machine (1) with sail or hybrid propulsion, comprising at least one hull (2) and at least one sail propulsion element (4) according to the preceding claim.

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