PROPULSION DEVICE FOR A SHIP WITH AT LEAST ONE HOLE WING WITH A LONGITUDINAL AXIS INTENDED TO EXTEND VERTICALLY

Description

Technical field of the invention

[0001] The present invention relates to the technical field of propulsion devices for ships which include at least one wing having a longitudinal axis intended to extend vertically. State of the art

[0002] Environmental constraints, and the increasing cost of fossil fuels, are forcing shipbuilders to offer partial alternatives to thermal propulsion.

[0003] In this sense, documents FR2847009, FR3035861, WO-2021 / 158106, US-4 630 997, US-2020 / 115019 and FR-2 811 030 describe wind thrusters which include an elongated hollow body, suction zones provided along the peripheral wall of this hollow body and associated suction means.

[0004] The suction at the peripheral wall of the propeller helps to limit the separation of the airflow from the wall of the propeller.

[0005] In order to produce a lift force directed to one side or the other of the ship, these wind thrusters generally use a flap system which is mounted movable to close off symmetrically arranged suction zones respectively.

[0006] However, the orientation of the lift force is not always optimal with current flap systems.

[0007] Indeed, the shuttering achieved with current shutter systems is not entirely effective.

[0008] Suction phenomena may then occur outside the initially planned suction zones, leading to a loss of efficiency of the suction means.

[0009] There is therefore a need for new wind turbines with improved lift force orientation and efficiency. Presentation of the invention

[0010] In order to remedy the aforementioned drawback of the prior art, the present invention proposes a propulsion device for a ship, comprising at least one hollow wing having a longitudinal axis intended to extend vertically.

[0011] This hollow wing includes: an envelope that defines an internal volume and includes a rear section with two openwork areas, which two perforated zones are in fluidic communication with said internal volume and are arranged symmetrically on either side of a longitudinal plane of symmetry, suction means for generating an aspirated airflow intended to pass through said perforated zones and directed towards said internal volume, and closing means adapted to alternately close one of said two perforated zones, which closing means comprise: at least one closing element adapted to close at least one of said two perforated zones, operating means adapted to operate said at least one closing element relative to at least one of said two perforated zones, which operating means are structured to operate said at least one closing element between two positions: an open position, in which said at least one closing element is retracted relative to at least one of said two perforated zones,and a closed position, in which said at least one closing device is deployed opposite said perforated area.

[0012] And said at least one obturating device consists of a flexible flap.

[0013] Said means of operation comprise a chassis equipped with support means which cooperate with said at least one flexible flap.

[0014] And said support means are structured to maneuver said flexible flap within said frame between said two positions, advantageously without friction phenomena between said flexible flap and said casing, namely: said opening position, in which said flexible flap is moved away from said envelope and retracted in relation to at least one of said two perforated areas, and said closing position, in which said flexible flap is deployed in relation to said envelope and fits said perforated area.

[0015] Such a structure offers a wind turbine whose lift force orientation and efficiency are improved compared to the state of the art.

[0016] According to the invention, the support means comprise at least one rotating roller, which is moved in translation around said envelope and which cooperates with said at least one flexible flap to define two strands: an active strand, intended to conform to said envelope, and an inactive strand, away from said envelope, which at least one roller advantageously comprises an axis of rotation which extends parallel to said longitudinal axis.

[0017] According to a preferred embodiment, said at least one flexible flap comprises two lateral edges, namely: a first fixed lateral border, attached to said envelope, between said two openwork areas, and a second movable lateral border, attached to said support means.

[0018] Other non-limiting and advantageous features of this embodiment according to the invention, taken individually or in all technically possible combinations, are as follows: said first fixed lateral border is secured at said longitudinal symmetry plane; the support means comprise at least one roller which consists of a return roller, cooperating with said at least one flexible flap to define the two strands: the active strand, extending between the first lateral border and said return roller, and the inactive strand, extending between said return roller and said second lateral border; the second movable lateral border is advantageously secured with traction means which are movable in translation and which are intended to maintain said at least one flexible flap under tension; preferably, the closing means comprise at least two flexible flaps intended to cooperate respectively with said two perforated zones, and the traction means consist of connecting means which join the second movable lateral borders of said two flexible flaps;The support means comprise at least one roller, which consists of a winding roller, cooperating with said at least one flexible flap to define the two strands: the active strand, extending between the first lateral edge and said winding roller, and the inactive strand, wound around said winding roller, and of which said second lateral edge is secured to said winding roller; the two lateral edges advantageously comprise rods and are assembled with complementary profiles.

[0019] Other non-limiting and advantageous characteristics of the product according to the invention, taken individually or in all technically possible combinations, are as follows: The chassis cooperates with drive means for the translational movement of said chassis around the circumference of said envelope, and which drive means are structured to coordinate, on the one hand, said translational movement of said chassis and, on the other hand, said movement of said flexible flap between said opening and closing positions, advantageously without friction phenomena between said flexible flap and said envelope; preferably, the drive means comprise at least one drive element coupled with pinions, and at least one toothed ring, which are distributed between said envelope and said chassis; the closing means comprise at least two flexible flaps, each intended to close one of said two open areas respectively; said chassis carries an aerodynamic flap, for example V-shaped, forming the trailing edge of said hollow wing;said envelope comprises: a front part, forming the leading edge of the wing, and a rear part, provided with the perforated areas; said at least one flexible flap is chosen from among flexible membranes and roller flaps.

[0020] The present invention also relates to a ship equipped with a propulsion device according to the invention.

[0021] Of course, the different features, variants and embodiments of the invention can be combined with each other in various ways as long as they are not incompatible or mutually exclusive. Detailed description of the invention

[0022] Furthermore, various other features of the invention become apparent from the attached description made with reference to the drawings which illustrate non-limiting embodiments of the invention and where: [ Fig. 1] is a general and perspective view of a ship equipped with a propulsion device according to the invention; [ Fig. 2 ] is an isolated, perspective view of a hollow wing belonging to the propulsion device according to the invention; [ Fig. 3 ] is a partial, perspective view of a section of a hollow wing whose sealing means comprise two flexible flaps (flexible membranes), each cooperating with a return roller; [ Fig. 4 ] is a top view of the hollow wing section illustrated on the figure 3 ; Fig. 5 ] is a partial view of the hollow wing section according to the figure 4 illustrating in more detail the methods of sealing; [ Fig. 6 ] is an isolated, perspective view of the shuttering methods illustrated on the figures 3 to 5 ; Fig. 7] is a partial, perspective view of a section of a hollow wing whose closing mechanism comprises two flexible flaps, each cooperating with a winding roller; [ Fig. 8 ] is a partial view of the hollow wing section according to the figure 7 illustrating in more detail the methods of sealing; [ Fig. 9 ] is an isolated, perspective view of the shuttering methods illustrated on the figures 7 and 8 ; Fig. 10 ] is a partial, perspective view of a section of a hollow wing whose closing means include two flexible flaps (roller shutters), each cooperating with a return roller; [ Fig. 11 ] is an isolated, perspective view of the shuttering methods illustrated on the Figure 10 .

[0023] It should be noted that, in these figures, the structural and / or functional elements common to the different variants may have the same references.

[0024] The present invention thus relates to a propulsion device 1 for a ship N ( figure 1 ).

[0025] By "ship" we mean in particular a boat intended for maritime navigation, preferably large, decked boats intended for sea transport, preferably cargo ships.

[0026] The propulsion device 1 according to the invention comprises at least one hollow wing 2, preferably several hollow wings 2, which is erected on the ship N.

[0027] The hollow wing 2 according to the invention is intended to generate a lift force which is used to participate in the propulsion of the ship N. Thus, the hollow wing 2 is of the wind turbine type and is mounted on the ship N so that the airflow flows around this hollow wing 2 to generate a propulsive force.

[0028] In general, such a hollow wing 2 has a longitudinal axis 2' designed to extend vertically.

[0029] As depicted on the figures 2 and following, the hollow wing 2 comprises: an envelope 3 which delimits an internal volume 31 and which comprises two perforated zones 32, suction means 4 (shown schematically on the figure 2 ), to generate an aspirated airflow which travels through the openwork areas 32 and along the internal volume 31, and closure means 5, adapted to alternately close the openwork areas 32 (taking into account in particular the orientation of the airflow flowing around the hollow wing 2). Envelope

[0030] Envelope 3, for example, is made of a material chosen from steel, aluminum, or a composite material.

[0031] Preferably, the envelope 3 has a cross-section, perpendicular to the longitudinal axis 2' and horizontal, having an oval or elliptical shape.

[0032] In general, this envelope 3 advantageously comprises two front parts 3a, 3b: a rear part 3a, and a front part 3b, advantageously forming a leading edge of the hollow wing 2.

[0033] In other words, the two parts 3a, 3b extend longitudinally and over the height of the envelope 3, on either side of the longitudinal axis 2'.

[0034] The two parts 3a, 3b each advantageously present a section in the shape of a semi-oval or semicircle, separated by a small axis passing through the longitudinal axis 2'.

[0035] The envelope 3 also has two longitudinal ends 3c, 3d, defining its height ( figure 2 ) : a lower longitudinal end 3c, intended to be fixed to the ship N and to be oriented downwards, and an opposite upper longitudinal end 3d, intended to be oriented upwards and at a distance from the ship N.

[0036] The envelope 3 also includes two opposite surfaces 3e, 3f ( figures 3 and following): an interior surface 3e, delimiting the internal volume 31, and an exterior surface 3f, opposite, oriented outwards and participating in generating the lift force.

[0037] Furthermore, the rear part 3a of the envelope 3 includes the two perforated areas 32.

[0038] The two openwork zones 32 are in fluidic communication with the internal volume 31.

[0039] Each perforated zone 32 advantageously includes a plurality of through orifices, allowing the circulation of an airflow.

[0040] The through orifices thus advantageously open at the level of the two opposite surfaces 3e, 3f of the envelope 3.

[0041] The openwork areas 32 are thus intended to be traversed by an airflow, flowing between the internal volume 31 and the outside (between the two opposite surfaces 3e, 3f of the envelope 3).

[0042] The two openwork zones 32 are further arranged symmetrically on either side of a longitudinal plane of symmetry P of the envelope 3 ( figure 3 ).

[0043] Each openwork zone 32 extends advantageously over the entire height of the envelope 3, on one side of the longitudinal plane of symmetry P of the envelope 3.

[0044] The upper longitudinal end 3d of the envelope 3 is further terminated here by a terminal wing 35, extending in a plane perpendicular to the longitudinal axis 2'. This terminal wing 35 helps to stabilize the airflow and limit turbulence in the upper part of the envelope 3.

[0045] This wing 35 includes in particular a V-shaped leading edge, extending cantilevered on either side of envelope 3. Suction methods

[0046] The aspiration means 4, schematically illustrated on the figure 2 are designed to generate an aspirated airflow that is capable of passing through the perforated areas 32.

[0047] The suction means 4 then generate an aspirated airflow which is directed towards the internal volume 31, from the outside.

[0048] In other words, the aspirated airflow travels from the outer surface 3f, to the inner surface 3e, of the envelope 3.

[0049] For this purpose, the suction means 4 advantageously include a fan having an axis of rotation which is parallel to the longitudinal axis 2' of the hollow wing 2.

[0050] The fan is advantageously located connected to the internal volume 31 and at the lower longitudinal end 3c of the casing 3. Methods of sealing

[0051] The sealing means 5 are adapted to alternately seal one of the two openwork areas 32, to create the load-bearing capacity.

[0052] As depicted on the figures 3 and following, the means of closure 5 include: at least one shuttering element 51, adapted to shutter at least one of said two openwork areas 32, operating means 52, adapted to operate said at least one shuttering element 51 relative to at least one of said two openwork areas 32, which comprise a frame 521 equipped with support means 522 cooperating with said at least one flexible flap 51.

[0053] In this case, said at least one sealing element 51 consists here of a flexible flap 51.

[0054] In general, said at least one flexible flap 51 is advantageously chosen from: flexible membranes 51 ( figures 3 to 9 ), for example made from a material chosen from neoprene rubbers, polyurethanes, polyester elastomers, which may be woven or non-woven, and roller shutters 51 ( Figures 10 And 11), comprising a plurality of pivoting blades 511 (for example made of plastic, metallic or composite material).

[0055] The width of the pivoting blades 511 is advantageously chosen according to the diameters of the outer surface 3f of the envelope 3 (and where applicable said at least one roller 5221 described thereafter).

[0056] Two pivoting blades 511 are advantageously connected by a hinge structure, permitting one degree of rotational freedom advantageously parallel to the longitudinal axis 2'.

[0057] Preferably, the shuttering means 5 comprise at least two flexible flaps 51 which are intended to cooperate respectively with the two openwork areas 32.

[0058] In other words, the shuttering means 5 comprise at least two flexible flaps 51, each intended to respectively seal one of said two openwork areas 32.

[0059] For this purpose, these flexible flaps 51 are then advantageously placed on either side of the longitudinal symmetry plane P.

[0060] In other words, each flexible flap 51 is designed to close off one of the two perforated areas 32: a first flexible flap 51 is intended to close a first openwork area 32, on a first side of the longitudinal symmetry plane P of the envelope 3, and a second flexible flap 51 is intended to close a second openwork area 32, on a second side of the longitudinal symmetry plane P of the envelope 3.

[0061] Furthermore, said at least one flexible flap 51 advantageously comprises two lateral edges, namely: a first fixed lateral border 51d, attached to the envelope 3, between the two openwork areas 32, and a second mobile lateral border 51e, attached to the support means 522.

[0062] Preferably, the two lateral edges 51d, 51e have 51j rods and are assembled with complementary profiles 5225 belonging to the support means 522.

[0063] For example, the first fixed side edge 51d is joined with a complementary profile 5225d which is fixed to the envelope 3. Preferably, the first fixed side edge 51d is joined at the longitudinal symmetry plane P.

[0064] The second movable lateral border 51e is intended to be maneuvered so as to maneuver said at least one closing device 51 in relation to an openwork area 32.

[0065] In general, the operating means 52 are structured to maneuver said at least one closing device 51 between two positions: an opening position (illustrated for example on the figure 3), wherein said at least one obturating member 51 is retracted relative to at least one of said two perforated zones 32 (here relative to the perforated zone 32 which is located at the bottom on the figure 3 ), and a closed position (illustrated for example on the figure 3 ), wherein said at least one shuttering member 51 is deployed opposite said perforated area 32 (here on the perforated area 32 which is located at the top of the figure 3 ).

[0066] And the support means 522 are structured to maneuver the flexible flap 51 within the frame 521 between the two positions, namely: the open position, in which the flexible flap 51 is moved away from the envelope 3 and retracted in relation to at least one of said two perforated areas 32, and the closed position, in which the flexible flap 51 is deployed in relation to the envelope 3 and fits into a perforated area 32.

[0067] In general, said at least one flexible shutter 51 is protected within the frame 521, in the open position, in the closed position and during the maneuver between these two positions.

[0068] Preferably, the support means 522 are structured to maneuver the flexible flap 51 within the frame 521, between the two aforementioned positions, without friction phenomena between this flexible flap 51 and the envelope 3. In other words, the flexible flap 51 is maneuvered, between the two aforementioned positions, without sliding phenomenon relative to the envelope 3.

[0069] Such a structure is particularly interesting for limiting, or even eliminating, wear phenomena caused by friction of the flexible flap 51 on the surface of the envelope 3 during maneuvers between the two positions mentioned above.

[0070] For this purpose, the support means 522 advantageously include at least one rotating roller 5221, which is moved in translation around the envelope 3.

[0071] This translational maneuver is advantageously carried out along a stroke following the envelope 3, and in particular its rear part 3a.

[0072] This roller 5221 cooperates advantageously with said at least one flexible flap 51 to define two strands: an active strand 51a, intended to fit the envelope 3, and an inactive strand 51b, away from this same envelope 3.

[0073] Said at least one roller 5221 advantageously comprises a rotation axis 5221' which extends parallel to the longitudinal axis 2' of the hollow wing 2.

[0074] Similarly, chassis 521 cooperates advantageously with engine means 524 (schematic on the figure 4 ), for the translational maneuver of the chassis 521 on the circumference of the envelope 3.

[0075] The 524 drive means, distributed between the envelope 3 and the chassis 521, include, for example: at least one drive unit which is coupled with gears, and at least one toothed ring.

[0076] The chassis 521 then follows a trajectory which is also parallel to the envelope 3, advantageously on an angular sector of the rear part 3a.

[0077] In this context, the support means 522 are advantageously structured to coordinate, on the one hand, the translational movement of the frame 521 and, on the other hand, the movement of the flexible shutter 51 between the opening and closing positions.

[0078] This coordinated movement advantageously avoids friction phenomena between the flexible flap 51 and the envelope 3.

[0079] In this case, advantageously, the evolution of the dimension in length of the active strand 51a is synchronized with the evolution of the dimension in displacement of the chassis 521.

[0080] For this purpose, in particular, the rotating roller 5221 is advantageously fixed within the frame 521. The movement of the roller 5221 is then caused by the movement of this frame 521 which is here driven by the motor means 524.

[0081] Furthermore, in general, the chassis 521 carries an aerodynamic flap 5211, for example in V, forming the trailing edge of the hollow wing 2.

[0082] The 5211 aerodynamic flap makes it possible to break the symmetry of the envelope 3 and thus increase the propulsive force generated.

[0083] This aerodynamic flap 5211 is oriented to one side or the other of the envelope 3, with respect to the longitudinal plane of symmetry P of the envelope 3, according to the direction of the wind.

[0084] The fluid flow around the hollow wing 2 is then accelerated on one side and slowed down on the other side, which strengthens the propulsive force. Methods of implementation

[0085] According to a first embodiment described below in connection with the figures 3 to 6 Or 9 and 10 , the support means 522 comprise at least one roller 5221 which consists of a return roller 5221, cooperating with said at least one flexible flap 51 to define the two strands: the active strand 51a, extending between the first lateral border 51d and the return roller 5221, and the inactive strand 51b, extending between the return roller 5221 and the second lateral border 51e.

[0086] Preferably, the flexible flap 51 has a general dihedral shape, on either side of the return roller 5221.

[0087] In this first embodiment, the second lateral edge 51e, which is movable, is advantageously secured with traction means 525 which are movable in translation and which are intended to maintain said at least one flexible flap 51 under tension.

[0088] Preferably, the traction means 525 consist of linking means 525 which connect the second mobile lateral edges 51e of the two flexible flaps 51 present.

[0089] The connecting means 525 here advantageously consist of links 525a (for example metal cables) passing through return pulleys 525b.

[0090] These 525a links are advantageously equipped with a 525c spring element, designed to control tension forces.

[0091] According to a second embodiment described below in connection with the figures 7 to 9 , the support means 522 comprise at least one roller 5221 which consists of a winding roller 5221.

[0092] Said at least one winding roller 5221 cooperates with said at least one flexible flap 51 to define the two strands: the active strand 51a, extending between the first lateral border 51d and the winding roller 5221, and the inactive strand 51b, wound around the winding roller 5221, and of which said second lateral border 51e is secured with this winding roller 5221.

[0093] Said at least one winding roller 5221 is, for example, driven in rotation by: a spring element, ensuring a return by winding, or a gear.

[0094] In general, each embodiment can include a flexible shutter 51, advantageously chosen from flexible membranes 51 and roller shutters 51. Functioning

[0095] In practice, the closing means 5 are maneuvered around the hollow wing 2 so as to alternately close one of the two openwork areas 32 according to the direction of the airflow and so as to create lift.

[0096] In this case, the closing position has the advantage of offering a configuration in which said at least one flexible flap 51 is deployed opposite an openwork area 32 and pressed against the envelope 3, to obtain optimal sealing and to eliminate (or at least significantly limit) leaks.

[0097] Simultaneously, the suction means 4 are implemented so as to generate an aspirated airflow which is able to pass through the openwork area 32 "free" with respect to the sealing means 5.

[0098] More specifically, the flexible shutter 51 is advantageously moved from its open position to its closed position, by the implementation of the operating means 52. In the presence of two symmetrical flexible shutters 51, the second flexible shutter 51 follows an inverse movement, from its closed position to its open position.

[0099] During this movement towards the closed position, the flexible flap 51 is advantageously maneuvered so that its active strand 51a gradually extends from its mobile roller 5221.

[0100] In this case, according to the first embodiment, the first flexible flap 51 undergoes a translational movement relative to the first mobile roller 5221 so that its active strand 51a lengthens at the same time as its inactive strand 51b shortens.

[0101] For this, the movement of the chassis 521 causes a displacement of the first roller 5221 which moves away from the first fixed lateral edge 51d, and which presses the first flexible flap 51 against the first openwork area 32.

[0102] Simultaneously, the second flexible flap 51 undergoes a translational movement relative to the second mobile roller 5221 so that its active strand 51a decreases at the same time as its inactive strand 51b lengthens.

[0103] For this, the movement of the chassis 521 causes a displacement of the second roller 5221 which moves closer to the first fixed lateral edge 51d.

[0104] According to the second embodiment, the first flexible flap 51 undergoes an unwinding movement relative to the first mobile roller 5221 so that its active strand 51a lengthens at the same time as its inactive strand 51b shortens.

[0105] For this, the movement of the chassis 521 causes a displacement of the first roller 5221 which moves away from the first fixed lateral edge 51d, and from which the first flexible flap 51 unwinds.

[0106] Simultaneously, the second flexible flap 51 undergoes a winding movement relative to the second mobile roller 5221 so that its active strand 51a decreases at the same time as its inactive strand 51b winds up.

[0107] For this, the movement of the chassis 521 causes a displacement of the second roller 5221 which moves closer to the first fixed lateral edge 51d.

[0108] In practice, in the case where the wind direction is incident on the hollow wing 2 on a first side of the envelope 3 which has a first openwork area 32, the closing means 5 are operated so that this first openwork area 32 is closed by said at least one flexible flap 51.

[0109] In this closed position, said at least one shutter flap 51 is deployed opposite this first perforated area 32 and pressed against the envelope 3.

[0110] This closing position ensures optimal sealing of this first openwork zone 32 opposite.

[0111] The second openwork zone 32 (on the second side of the envelope 3) is then free, generating the airflow drawn through this second openwork zone 32.

[0112] In this case, the support 53 in the form of an aerodynamic flap is also oriented at the level of the first side of the envelope 3.

[0113] The fluid flow around the hollow wing 2 is then further accelerated on one side and slowed down on the other side, which further increases the propulsive force.

[0114] Of course, various other modifications can be made to the invention within the scope of the attached claims.

Claims

1. Propulsion device for a vessel, comprising at least one hollow wing (2) having a longitudinal axis (2') intended to extend vertically, which hollow wing (2) comprises: - an envelope (3) which delimits an internal volume (31) and which comprises a rear part (3a) comprising two perforated zones (32), which two perforated zones (32) are in fluid communication with said internal volume (31) and are arranged symmetrically on either side of a longitudinal plane of symmetry (P), - suction means (4), for generating a flow of sucked air which is intended to pass through said perforated zones (32) and which is directed towards said internal volume (31), and - shutter means (5), adapted to alternately close one of said two perforated zones (32), which shutter means (5) comprise: - at least one shutter member (51), adapted to close at least one of said two perforated zones (32), - operating means (52), adapted to operate said at least one shutter member (51) relative to at least one of said two perforated zones (32), which operating means (52) are structured to operate said at least one shutter member (51) between two positions: - an open position, in which said at least one shutter member (51) is retracted relative to at least one of said two perforated zones (32), and - a closed position, in which said at least one shutter member (51) is deployed facing said perforated zone (32), said at least one shutter member (51) consisiting in a flexible flap (51), said operating means (52) comprising a frame (521) equipped with support means (522) which cooperate with said at least one flexible flap (51), and said support means (522) being structured to maneuver said flexible flap (51) within said frame (521) between said two positions, namely : - said open position, in which said flexible flap (51) is spaced from said envelope (3) and retracted relative to at least one of said two perforated zones (32), and - said closed position, in which said flexible flap (51) is deployed facing said envelope (3) and conforms to said perforated zone (32), characterized in that said support means (522) comprise at least one rotary roller (5221), which is maneuvered in translation around said envelope (3) and which cooperates with said at least one flexible flap (51) to define two strands: - an active strand (51a), intended to conform to said envelope (3), and - an inactive strand (51b), spaced from said envelope (3).

2. Propulsion device according to claim 1, wherein said at least one roller (5221) comprises an axis of rotation (5221') which extends parallel to said longitudinal axis (2').

3. Propulsion device according to claim 1 or 2, wherein said support means (522) are structured to maneuver said flexible flap (51) within said frame (521) between said two positions, without friction phenomena between said flexible flap (51) and said envelope (3).

4. Propulsion device according to any of the claims 1 to 3, wherein said at least one flexible flap (51) has two side edges, namely: - a fixed first side edge (51d) secured to said envelope (3), between said two perforated zones (32), and - a movable second side edge (51e) secured to said support means (522).

5. Propulsion device according to claim 4, wherein the support means (522) comprise at least one roller (5221) which consists of a return roller (5221), cooperating with said at least one flexible flap (51) to define the two strands: - the active strand (51a), extending between the first side edge (51d) and said return roller (5221), and - the inactive strand (51b), extending between said return roller (5221) and said second side edge (51e).

6. Propulsion device according to claim 5, wherein the movable second side edge (51e) is secured to traction means (525) which are movable in translation and which are intended to maintain said at least one flexible flap (51) in tension.

7. Propulsion device according to claim 4, wherein the support means (522) comprise at least one roller (5221) which consists of a winding roller (5221), cooperating with said at least one flexible flap (51) to define the two strands: - the active strand (51a), extending between the first side edge (51d) and said winding roller (5221), and - the inactive strand (51b), wound around said winding roller (5221), and of which said second side edge 51e is secured to said winding roller (5221).

8. Propulsion device according to any of the claims 1 to 7, wherein the frame (521) cooperates with motor means (524), for the translational maneuvering of said frame (521) on the circumference of said envelope (3), and which operating means (52) are structured to coordinate, on the one hand, said translational movement of said frame (521) and, on the other hand, said movement of said flexible shutter (51) between said open position and said closed position, preferably without friction phenomena between said flexible flap (51) and said envelope (3).

9. Propulsion device according to any of the claims 1 to 8, wherein the shutting means (5) comprise at least two flexible flaps (51) which are each intended to respectively close one of said two perforated zones (32).

10. Propulsion device according to according to any of the claims 1 to 9, wherein said frame (521) carries an aerodynamic flap (5211), for example V-shaped, forming the trailing edge of said hollow wing (2).

11. Propulsion device according to according to any of the claims 1 to 10, wherein said envelope (3) comprises: - a front part (3b) forming the leading edge of the wing, and - a rear part (3a) provided with perforated zones (32).

12. Propulsion device according to according to any of the claims 1 to 11, wherein said at least one flexible shutter (51) is chosen from flexible membranes (51) and rolling shutters (51).

13. Vessel equipped with a propulsion device according to according to any of the claims 1 to 12.