Sail propulsion element, sail-propelled vehicle

Abstract

The present invention relates to a sail propulsion element comprising a mast (3), an inflatable or non-inflatable sail (1) consisting essentially of two adjacent faces (5) substantially fluid-tight, said two adjacent faces (5) being joined together along their periphery to form at least one closed cavity between them, said sail comprising an upper part (6), a lower part (7), a leading edge (8) and a trailing edge (9), said sail including a variable camber forming a bulge along its length, a conduit arranged between the inside and the outside of the sail cavity, and at least one means for injecting air into said cavity, said sail having a profile which, when inflated, remains permanently symmetrical regardless of the movement of said propulsion element or the direction or strength of the wind, a headboard (10) arranged in the upper part of the sail, and a sail receptacle (11) arranged in the lower part of the sail between the leading and trailing edges. The element according to the invention is characterized in that the mast is located forward of the centre of aerodynamic thrust of the sail, that the mast is free to rotate 360° or not, and that the sail is provided with at least one means for maintaining a slight pressure on the sail.

Description

[Technical field]

[0001] The present invention relates to inflatable sails and is in the field of sail propulsion or hybrid sail propulsion. [Background technology]

[0002] A reminder of some definitions used below is set out below. Reefing: Consists of reducing the surface area of ​​a sail by furling a portion of it from the bottom so as to adapt it to the wind strength. Reefing can be done manually or automatically. Reefing band: A partially reinforced horizontal zone to which reefing turning blocks can be attached, for example by means of grommets or pulleys. There are as many reefing bands as there are possible reefing surface area of ​​the sail. Lazy jacks: Devices that guide a sail to perform the reefing and dropping actions of the sail. Boom: A horizontal spar near the base of the mast that holds and allows a particular sail to point. The boom can also receive a sail when it is dropped. Luffing: A luffing sail is one that is underhauled and therefore partially deflated. A well-trimmed sail should be at its luffing limit. If the sail is properly filled, luffing will not occur and you can sail close to the wind. Leading edge: The front part of a dynamic profile (wing, propeller, etc.) where the fluid separates into two streams. Trailing edge: The distinctive part of any profile (wing, keel, rudder blade, etc.) that is exposed on either side to the flow of fluid (air, water, etc.) - the part facing away from the sense of direction, i.e. the part aft when viewed in the direction of the flow. Headboard: The upper edge of a sail that conforms to the upper contour of an inflatable sail. Dropping: Consists of lowering a sail. Hoisting: Consists of raising a sail. Rigging: The collection of fixed and movable parts on a sailboat-type boat that enables it to be propelled and steered using the power of the wind. Sail receptacle: In addition to receiving a dropped sail, it can incorporate other functions such as reacting to tension supplied by the sail or housing other actuators, energy storage sensors, and control modules used in the operation of the sail. Hydrodynamic drag: The frictional force between the boat and the water. The more drag there is, the more the boat slows down. Aerodynamic drag: The component of force experienced by an object moving through a fluid that acts in a direction opposite to the direction of movement. In accordance with the present invention, a sail generates aerodynamic drag. Aerodynamic lift: The component of force acting perpendicular to the direction of motion of an object moving through a fluid. In accordance with the present invention, a sail generates aerodynamic lift. Relative or apparent wind: The vector sum of the wind caused by the boat's specific speed and the actual wind speed. Aerodynamic resultant: The vector sum of the aerodynamic lift and aerodynamic drag forces. Sail Angle of Incidence: The angle between the plane of the sail profile and the relative wind direction. Sail Angle: The angle between the plane of the sail profile and the axis of the boat.

[0003] (prior art) A sail propulsion element with an inflatable sail having a symmetrical profile is known from document WO2017 / 221117A1. The propulsion element comprises an inflatable sail consisting essentially of two substantially fluid-tight adjacent faces joined together along their periphery to form at least one closed cavity. The element further comprises a conduit arranged between the inside and the outside of the cavity and a means for injecting air into the cavity. When inflated, the sail has a profile that remains permanently symmetrical, regardless of the movement of the element or the wind direction or strength. The sail of the document is constantly inflated while being used for sailing.

[0004] Unfortunately, such soft sails have the drawback of not providing suitable inflation levels for the various stages of their use, especially the hoisting and dropping stages. Specifically, unlike hard sails, soft sails do not have a clearly defined position during these stages of handling (hoisting and dropping). During these stages, it is important to keep the sail close to the axis of symmetry of the sail profile, to avoid the sail dropping into the water or getting caught in nearby elements, or collapsing in a poorly defined area and becoming unable to be packed compactly. Furthermore, it is important to maintain a slight pressure on the sail during the dropping or reefing stages to prevent the sail from becoming luffing, which could reduce the life of the sail.

[0005] Furthermore, if the automated sail handling device, i.e., the controls, sensors, actuators or electrical energy supply components, suffer an electronic or electrical failure, the sails described herein may not be properly secured.

[0006] A device for hydraulically adjusting a retractable boat sail is also known from document CN107878720A. This sail is made of two parts, a lower part and an upper part, which can be rotated around the mast independently of each other depending on the sailing conditions or wind direction. The device automatically adjusts the angle of attack of each of the two parts of the sail depending on the wind. The retractability of the sail ensures the safety of the boat under adverse sailing conditions. However, the retractability of the sail requires the correct operation of electronic automation devices. No alternative means in case of failure are provided. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2017 / 221117 [Patent Document 2] China Patent Publication No. 107878720 Summary of the Invention

[0008] Therefore, there remains a need for a continuous or discontinuous inflatable sail, or a non-inflatable sail, or a tension sail, or a hard sail with an asymmetric profile, which, in the event of an electronic failure by the automatic handling device, can remain in a safe position, safe for the sail and for the crew on board, while at the same time minimizing the forces generated by the lift of the inflatable sail. To achieve this, the sail must be able to position itself (and / or be manually positioned) facing the wind, so as to greatly reduce the generation of aerodynamic lift and have only aerodynamic drag. This allows for reduced forces on the rigging and the boat, and also allows for a completely safe operation.

[0009] One subject of the invention is a sail propulsion element comprising a mast, an inflatable or non-inflatable sail consisting essentially of two adjacent surfaces substantially fluid-tight joined along their periphery to form at least one closed cavity between them, said sail including an upper part, a lower part, a leading edge and a trailing edge, the sail including a variable camber forming a bulge along its entire length, an air conduit arranged between the inside and the outside of the cavity of the sail, at least one means for injecting air into the cavity, the inflated sail having a profile that remains permanently symmetrical regardless of the movement of the propulsion element or the direction or strength of the wind, a headboard arranged on the upper part of the sail, and a sail receptacle arranged between the leading and trailing edges of the lower part of the sail.

[0010] The propulsion element according to the invention is characterized in that the mast is located forward of the centre of aerodynamic propulsion of the sail, that the mast is free to rotate 360° or not, and that the sail is provided with at least one means for maintaining a slight pressure on the sail.

[0011] Preferably, according to the invention, the mast is made to rotate by the system for adjusting the angle of incidence of the sails and is free to rotate when the mast is no longer driven by said system. In this way, the mast is rotated using an automatic handling system acting on the system for adjusting the angle of incidence of the sails and is left free to rotate even in the event of a failure or accident or when the automatic handling system is deliberately deactivated. The mast can therefore rotate multiple times on its own. An accident or failure means, for example, a loss of power to the mast drive motor or to the electronic components of the automatic handling system or the mast rotation torque reaching a preset limit value. In such a case, the mast is left free to rotate and the sails can be placed facing the wind, reducing the forces on the rigging and the boat.

[0012] The sail propulsion element according to the invention offers various advantages: the centre of aerodynamic thrust is clearly distinguished from the mast and is located sufficiently far from it towards the stern of the boat. The positioning of the mast forward of the centre of aerodynamic thrust of the sail means that the resultant aerodynamic forces on the sail in all circumstances will orient the sail towards the relative wind, except when the relative wind is zero. Furthermore, the sail can be kept fully inflated, for example thanks to a passive air inlet on the leading edge, thereby maintaining the sail's profile and thus preventing it from luffing even without active supply. In a situation where the relative wind is zero (and therefore the sail cannot inflate), the sail will not luff. In such an electronics failure situation, luffing of the sail will cause the sail to crack (in the sense of slapping) and thus generate high loads, with the risk of destroying the sail or the mast. Finally, in case of electronics failure, the sail can be used in manual mode very quickly and easily, thus increasing the ability to make it safe and therefore safe for the boat and the crew.

[0013] Preferably, the centre of aerodynamic thrust of the sail is 0-10m away from the mast.

[0014] Preferably, the means for maintaining pressure is an air intake opening arranged facing the relative wind, by means of which an internal pressure maintained by the relative wind can be maintained in the sail.

[0015] Preferably, during said rotation of the mast, energy and commands are transmitted using devices that do not impede the rotation.

[0016] Preferably, the device that does not hinder rotation is selected from a revolute joint or a cable bearing chain, where it is recognized that the rotational freedom is not infinite but is limited to a number of rotations.

[0017] Preferably, the intake opening includes a movable closure flap.

[0018] Preferably, at least one guide line, consisting of one or more parts, is disposed in the closed cavity of the sail for sail hoisting and dropping operations, said guide line extending from the leading edge to the trailing edge of the sail through the headboard and sail receptacle.

[0019] Preferably, when a guide line is present, it is in one piece and fixedly attached to a sail receptacle on the trailing edge and movable by rollers on the leading edge, or movable by rollers in a sail receptacle on the trailing edge and fixedly attached to the leading edge, with the guide line being positioned along the headboard so that it can move over at least one pulley between the trailing and leading edges.

[0020] Preferably, when a guideline is present, it consists of two parts, the first part on the trailing edge side being fixed or movable on a pulley on the headboard and movable by a roller in a receptacle, and the second part on the leading edge side being fixed or movable on a pulley on the headboard and movable by a roller in a receptacle.

[0021] Another subject of the invention is a vehicle with sail or hybrid propulsion comprising at least one sail propulsion element as described herein above, a hull and a mast fixed to said hull but still rotatable, characterized in that the mast is arranged in the cavity of the inflatable sail described above.

[0022] By vehicle is meant any craft, with or without wheels, that moves on land, water, ice, snow, or mud.

[0023] Preferably, the sails are oriented manually or automatically according to wind direction and vehicle heading to optimize thrust along the axis of the boat or to achieve the desired thrust while limiting force, pressure and heel to acceptable values.

[0024] If the mast cannot rotate infinitely - for example it can easily rotate twice in one direction on itself without jamming, by using a cable bearing chain - then it will have to rotate in the opposite direction to get back into the correct position for the sail.

[0025] A hybrid propulsion vehicle according to the present invention means sail propulsion combined with another propulsion source, such as propulsion using a propeller driven by an electric motor or an internal combustion engine, and has batteries, hydrogen (with fuel cells), natural gas or fuel oil as energy storage sources.

[0026] The invention is illustrated by the following figures, which are schematic and are not necessarily drawn to scale. [Brief description of the drawings]

[0027] [Figure 1] 1 shows the projection of various physical forces applied to a vessel, for example of the motorsail boat type, and in particular the resulting aerodynamic forces. [Diagram 2] FIG. 1 is a schematic cross-sectional view of a sail propulsion element according to the invention arranged on a boat hull. [Figure 3A] 2 shows a schematic view from above of the position of a propulsion element according to the invention according to different relative wind angles; [Figure 3B] 2 shows a schematic view from above of the position of a propulsion element according to the invention according to different relative wind angles; [Figure 3C] 2 shows a schematic view from above of the position of a propulsion element according to the invention according to different relative wind angles; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Before describing in more detail, with the aid of the figures mentioned above, the sail propulsion elements which form the subject of the present invention, a reminder of some hydrodynamic and aerodynamic definitions is given below.

[0029] A sail-propelled vehicle (hereafter referred to as a sailboat or vessel) is in contact with air and water. From a physical point of view, the main factors are the hydrodynamic and aerodynamic forces acting on the hull, sails and appendages (centerboard, keel, rudder, propeller).

[0030] As shown in Figure 1, aerodynamic forces (or sail thrust) are the result of air being deflected by at least one sail. Aerodynamic forces are related to the sail and the position and strength of the relative wind. Drag is in the direction of the relative wind, and lift is perpendicular to the relative wind, which is not always perpendicular to the sail. For example, at 0°, a symmetrical profile produces no lift, since the air travels exactly the same distance across the outer and inner arcs. At this point, it produces only drag.

[0031] The aerodynamic forces generated by a sail can also be resolved, in the frame of reference of the boat rather than the sail, into a sail thrust force (along the axis of the boat's travel) and a drift force (perpendicular to the axis of the boat) which can cause the boat to heel (heel is the lateral tilt of the board as caused by an external phenomenon such as wind).

[0032] Hydrodynamic forces are the result of the friction of water against the hull and centerboard or keel and various underwater appendages. Their direction depends on the opposing aerodynamic forces, the propulsive forces in hybrid mode, sea conditions and currents. The longitudinal component is called hydrodynamic drag and the transverse component is called side force, anti-heeling force or hydrodynamic lift. The direction and strength of hydrodynamic forces do not depend only on aerodynamic forces. For surface vessels (boats) operating in hybrid mode (wind and another energy source), the hydrodynamic forces are highly dependent on the vessel speed generated by the engine or motor propulsion, e.g. sea conditions and currents.

[0033] When the force of the sail is greater than the hydrodynamic force, the boat will accelerate. When the force of the sail is less than the hydrodynamic force, the boat will slow down. Additionally, if the aerodynamic force is greater but toward the rear of the boat, the boat will slow down. If the hydrodynamic force is in the direction of the boat's travel (due to the presence of a strong current), the boat (a sailboat) will accelerate.

[0034] By optimizing the trim of the sail, the boat (sailboat) will achieve maximum performance in terms of sail thrust in the direction of travel. Specifically, by optimizing the angle of the sail with respect to the relative wind and the direction of travel of the boat, and by trimming the surface area of ​​the sail, the boat can achieve the maximum level of sail thrust along the axis of the boat. In addition to this, there can be additional trimmings, including varying the internal pressure of the sail. This allows the boat to increase its speed, while at the same time reducing the consumption of other energy sources in favor of sail power, while maintaining the same speed.

[0035] FIG. 1 again illustrates each of the above defined parameters with a unique specific reference number, all as listed below. a: Lift b: Drag force c: aerodynamic resultant force d: Aerodynamic thrust (along the axis of the ship) e: aerodynamic drift force f: relative wind g: Relative angle between wing and boat axis (e.g. 15°) h: angle between relative wind and boat axis (e.g. 30°) i: Propeller thrust j: Haru k: Sale l: Mast m: center of aerodynamic thrust n: Propeller o: Sensor in fixed part (hull reference frame) p: Sensor of moving part (sail reference frame) The information given in FIG. 1 allows the transition from sensors in the hull reference frame to sensors in the sail reference frame and vice versa.

[0036] Figure 2 shows a sail propulsion element according to the invention mounted on a boat of sailboat type in operating position. The element comprises a sail, with the general reference 1, mounted on the hull 2 ​​of the boat. The element comprises a mast 3, the foot 4 of which is fixed to the hull 2 ​​while allowing a rotational movement. The mast 3 is free-standing. The mast 3 is connected to the hull 2 ​​by means of a support (not shown) intended to absorb the loads of physical forces and leave a degree of rotational freedom. The loads are measured at the support. The sail 1 comprises two adjacent faces 5 (only one is visible in the figure) connected to each other to form a closed cavity. The material used for the two adjacent faces 5 must have limited permeability to reduce air consumption and to allow the various loads involved to react and transmit. In some cases it may be necessary to apply various treatments to the material, for example to ensure a certain fire or UV resistance and / or antistatic treatment.

[0037] The sail 1 has multiple cambers (not shown) evenly distributed over its height (higher in the lower part of the sail and lower in the upper part). The height of the camber is often tied to the length of the chord of the profile.

[0038] The camber gives it a concertina-like appearance. The sail 1 includes an upper portion 6, a lower portion 7, a leading edge 8 and a trailing edge 9. At least one air inlet 18 is located, for example, in the lower portion 7 of the sail 1. Another air inlet 30 may also be located in the surface of the leading edge 8. At least one active means 7a for injecting air into the sail cavity is located in the continuation of the air conduit so that air can be injected into the sail cavity. The sail further comprises a headboard 10 located in the upper portion 6 and a sail receptacle 11 located in the lower portion 7 between the leading edge 8 and the trailing edge 9. The receptacle 11 is for receiving all or part of the sail when it is dropped. The receptacle 11 may comprise various actuators and sensors to facilitate manual or automatic operation of hoisting or dropping the sail 1.

[0039] The sail propulsion element according to the invention comprises a guide line 12 arranged in a cavity of the sail 1. This guide line is intended to guide the sail 1 during the hoisting and dropping operation and during the reefing operation. This line 12 extends substantially around the circumference of the sail 1. The guide line 12 is fixed removably or non-removably, but is not movable at an end 13 close to the intersection between the trailing edge 9 and the sail receptacle 11. The line then extends towards the upper part 6 of the sail 1 and runs along the headboard 10 between the trailing edge 9 and the leading edge 8. This guide line 12 can move along the headboard 10 with the help of at least two pulleys or other rotation block systems (not shown), one located on each side of the mast 3. This guide line 12 is adjacent to the leading edge 8 and towards the sail receptacle 11, and is fixed on the sail receptacle 11 by means of rollers 19 substantially at the leading edge 8. The guide line 12 can be pulled up towards the release cleat when manually actuated, whereas in the automated version the guide line 12 is wound on automatic rollers.

[0040] The guide line 12 has a length of about 50 m for a sail having a total surface area of ​​approximately 100 m2 and has a tension of about 50 to 250 N depending on the application to which it is put during the various drop and hoist operations.

[0041] The mast 3 can be telescopic or fixed. If the mast 3 is telescopic, the headboard 10 is fixed to the last element of the telescopic mast 3 and can maintain a degree of rotational freedom relative to the mast or with the last element of the mast rotating. If the mast 3 is telescopic, it is made up of various elements that slide sequentially relative to each other to extend and retract. In the absence of reefing (as in the case of a transport vessel), it is possible to extend the elements forming the telescopic mast one after the other or all at the same time.

[0042] When the mast 3 is fixed, only the headboard 10 can move along the mast 3. The sail 1 is fixed to the headboard 10 and rises or falls with it. The headboard can be free to rotate, can be prevented from rotating, or can be prevented from rotating up to a certain load value. It is also possible to feedback control the angular position of the headboard to control the twist of the sail. In particular, since the wind speed is not the same at all altitudes, it can be advantageous to adjust the angle of incidence of the sail at different altitudes to accommodate different changes in the relative wind.

[0043] It is also possible to combine a telescoping mast 3 with a headboard 10 that slides along the mast 3 .

[0044] The headboard 10 is sufficiently rigid to be able to impart the physical forces present between the various line ropes and the mast 3, and to withstand the weight of the sail when the sail is uninflated. According to various embodiments of the present invention, the headboard 10 can be free to rotate around the mast 3 as desired, can be prevented from rotating around the mast 3, can be prevented from rotating around the mast 3 up to a maximum limiting torque value to limit the load to an acceptable value (the maximum acceptable value will depend on the configuration of the system and the components to be protected by the safety system), or alternatively can be feedback controlled to control the twist of the sail.

[0045] The mast 3 is connected and fixed to the hull 2 ​​using a mast support 14, the purpose of which is to react the various physical forces between the sail and the boat whilst leaving the mast some freedom to rotate so that it can be positioned at the correct angle to the relative wind.

[0046] At the foot of the mast 3, i.e. at the hull 2, there is a system 15 for adjusting the incidence angle, which makes it possible to command the sail 1 to rotate by rotating the mast 3 and all the steering parts fixed to said mast 3. This system 15 may in particular consist of a motor. This system 15 makes it possible for the sail 1 to rotate about the axis of rotation of the mast 3 and thus to command the desired incidence angle of the sail 1. This incidence setting system may also be fixedly mounted to the mast 3, for example on a "nest" (or sail receptacle), the motor driving, via a pinion, a ring gear fixed to the hull.

[0047] It will be recalled that by measuring the angle of incidence, the angular positioning of sail 1 relative to the axis of the boat can be determined. Such a device allows sail 1, hull 2 ​​and the relative wind to be placed in one and the same reference frame, regardless of where the wind is measured on sail 1 or on hull 2. Such a system simplifies sailing in automatic mode.

[0048] The sail propulsion element according to the invention, arranged on the hull of the boat, can also be combined with a torque limiter, known to be arranged at the foot of the mast 3 and to limit the maximum torque that the sail 1 can transmit to the hull 2.

[0049] The propulsion element according to the invention, arranged on the hull of the boat, may further comprise an electronic control system 16 arranged in the sail receptacle 11. A rotary electric joint 17 may be added in the hull at the lower base of the mast 3. This joint 17 allows the transmission of power and electric commands between the hull 2 ​​and the lower part 7 of the sail 1, without limiting the number of rotations around the mast 3 that the sail can perform. The joint 17 may also be replaced by a conventional suitable cable-bearing chain. If the power used to operate the sail element according to the invention is, for example, hydraulic or pneumatic, a rotary hydraulic or pneumatic joint may be used.

[0050] Among the various measurement sensors there may be sensors measuring the loads transmitted from the sail 1 to the hull 2, sensors measuring the loads in the transverse axis of the hull 2, sensors measuring the loads in the longitudinal axis of the hull 2, sensors measuring the pressure in the internal cavity of the sail 1, and sensors measuring the relative wind speed and angle. This last measurement may be made equally on the sail 1 or on the hull 2. If the sensor is placed on the part fixed to the mast 3, it measures the loads along the longitudinal and transverse axes of the sail 1.

[0051] The sail 1 may further include a sail neutralizer (not shown) stored in the sail receptacle 11 or headboard 10. Such a neutralizer, when deployed upward from the bottom of the sail or downward from the top of the sail, encapsulates the sail and reduces its volume by evacuating internal air, preventing the sail from luffing and reducing its windage.

[0052] 3A, 3B and 3C differ from one another by having different sail incidence angles.

[0053] In Figure 3A the relative wind is along the axis of the sail, in Figure 3B the sail axis is at an angle to the relative wind direction substantially equal to 15°, and in Figure 3C the sail axis is at an angle to the relative wind direction that is symmetrical to and equal to the angle depicted in Figure 3B.

[0054] 3A, 3B and 3C the sail 1 has a substantially symmetrical profile. The mast 3 is represented by a circle. The relative wind is represented by an arrow 23.

[0055] Figure 3A depicts the sail 1 in a stable position facing the wind 23. The various loads are in balance: the aerodynamic lift is zero (being identical on both sides of the wing due to the symmetrical profile of the wing) and there is only a drag force 24 that keeps the sail 1 on an axis parallel to the axis of the relative wind.

[0056] Figure 3B depicts a sail 1 with its axis at an angle of about 15° to the direction of the relative wind. The axis of rotation of the mast 3 is offset towards the front of the profile with respect to the centre of aerodynamic thrust 25 along the axis of symmetry of the profile. Figure 3B shows that the torque generated by the aerodynamic forces at a certain distance from the centre of rotation of the mast 3 tends to return the sail to a position facing the relative wind, and the symmetrical profile of the sail allows the sail to remain stable.

[0057] Due to the offset between the rotation point of the mast 3 and the propulsion centre 25, the propulsion element of the invention is able to hold the sail 1 in position in situations of large as well as small angular deviations from the wind direction. Such an offset between the rotation point of the mast 3 and the centre 25 means that the sail 1 can be made to return towards its neutral position, i.e. facing the wind, when it deviates from said position. Such an offset makes it possible to improve sailing safety, since the sail automatically returns to a suitable and optimal position with respect to the relative wind direction, thus minimising the load and keeping the sail facing the wind. However, this distance must be minimised so as not to excessively increase the forces required to turn the sail.

[0058] Figure 3C is a symmetrical view of Figure 3B with respect to the axis of the relative wind. The same applies as in Figure 3B. EXAMPLES

[0059] The following examples are presented for illustrative purposes only and are not limiting. The following table collates various possible implementations. TIFF2024522097000002.tif179150

[0060] The outer layer of the sail, also called the body, is made of a woven fabric, including the outer layer, which is in contact with the outside air, and the inner layer. This fabric is a polyester fabric coated with polyurethane. The basis weight of this fabric is approximately 100 m 2 110g / m for sail area 2 It is.

[0061] The upper side of the sail may be secured with hook and loop fasteners of the Velcro type. The joints between the outer part of the sail and the ribs (internal joints) and between the components of the outer part may be achieved by fusion or adhesive joints or other joining means (e.g. zip fasteners which may ensure load transfer whilst ensuring a sufficiently low level of permeability to be compatible with existing inflation systems). [Explanation of symbols]

[0062] 1 Sale 3 Mast 5 Adjacent Surfaces 6 Upper part 7 Lower part 8 Leading Edge 9 Trailing Edge 10 Headboard 11 Sail Receptacle

Claims

1. A sail propulsion element, comprising: a. a mast (3); b. an inflatable sail (1) consisting essentially of two adjacent substantially fluid-sealed surfaces (5) joined along their periphery and forming at least one closed cavity between said two adjacent surfaces, said sail including an upper portion (6), a lower portion (7), a leading edge (8) and a trailing edge (9), said sail including various cambers forming a bulge along its entire length; c. at least one air duct disposed between the inside and the outside of said cavity of said sail; d. at least one means for injecting air into said cavity, said inflated sail having a profile that remains permanently symmetric regardless of the movement of said propulsion element or the direction and strength of the wind; e. a headboard (10) disposed on the upper portion (6) of said sail (1); f. a sail receptacle (11) disposed between said leading edge (8) and said trailing edge (9) of the lower portion (7) of said sail; wherein in the sail propulsion element comprising the above, said mast is located in front of the center of the aerodynamic propulsion force of said sail, said mast does not rotate freely 360°, and said sail includes at least one means for maintaining a slight pressure on said sail. This is a characteristic sail propulsion element.

2. The element according to claim 1, wherein the center of the aerodynamic propulsion force of said sail (1) is separated from said mast (3) by a length of 0 to 10 m.

3. The element according to claim 1, wherein the means for maintaining said pressure is an air intake opening disposed facing the relative wind.

4. The element according to claim 1, wherein during the rotation of said mast, energy and command are transmitted using a device that does not impede the rotation.

5. The element according to claim 4, wherein the device that does not impede the rotation is selected from a rotary joint or a cable bearing chain.

6. The element according to claim 3, wherein said air intake opening includes a movable closing flap.

7. At least one guideline consisting of one or more parts is arranged in the closed cavity of the sail for the hoist and drop operation of the sail, and the guideline extends from the leading edge to the trailing edge of the sail through the headboard and the sail support, the element according to any one of claims 1 to 6.

8. A mobile body for sail propulsion or hybrid propulsion, comprising at least one element according to claim 1, a hull, and a mast (3) fixed to the hull but still rotatable, wherein the mast (3) is arranged in the cavity of the inflatable sail. A mobile body characterized by that.

9. The mobile body according to claim 7, characterized in that the sail (1) is oriented according to the wind direction and according to the running direction of the mobile body manually or automatically.

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