Wing sail structure for wind-assisted propulsion arrangement for marine vessels

Abstract

The invention relates to a wing sail structure (100) for a wind-assisted propulsion arrangement (10) of a marine vessel (1). The wing sail structure (100) comprises a wing sail frame (101) comprising a rigid or semi-rigid main wing sail (110) and a flap (120) having an airfoil shape, and at least one upper (130) and lower (140) coupling the main wing sail and the flap. The wing sail structure further comprises a base (20) arranged to be fixed to the body (3) of the vessel (1) and with respect to which the wing sail frame is rotatable. The flap (120) is rotatable about a second longitudinal axis of rotation such that the flap and its flap centerline (FCL) are in an inclined position relative to the main wing sail centerline (MCL). The second axis of rotation is arranged laterally offset from the main wing sail centerline (MCL). In this manner, only one axis of rotation is required for tilting the flap.

Description

Technical Field

[0001] The present disclosure relates to a wingsail structure for a wind assisted propulsion arrangement of a marine vessel and to a method of operating a wind assisted propulsion arrangement comprising a wingsail structure as defined in the appended claims. Background Art

[0002] Sails have long been known as a means of ship propulsion. Traditionally, flexible sails have been mounted on masts to harness the power of the wind and propel ships. Modern commercial ships typically use fossil fuels and combustion engines to propel ships. It has been proposed to use wind propulsion to reduce the overall consumption of fossil fuels. For this purpose, rigid sails can be used. The amount of power generated is related to a large number of interrelated factors, but wing area and other geometric aerodynamic characteristics are the main performance indicators. Possible geometric settings can be achieved by combining the main wing with flaps, which can generate large propulsion forces under given wing sizes compared to wings without flaps. For example, by adjusting the camber formed by the main wing sail and flaps, a highly efficient wing sail arrangement and structure can be obtained, which can generate a large amount of propulsion forces under given its absolute size. When the aerodynamic propulsion force from the wing sail is not expected or the force should be limited, ship stability, ship safety and operability should be considered. This increases the complexity and challenge of using rigid wing sails as ship propulsion devices. In addition, ship performance is related to the prevailing wind strength and direction. Due to the statistical distribution of wind strength for example, it is clear that during most of the time the wind speed is quite moderate. Therefore, the wing characteristics should be configured such that the wingsail can exploit low wind speeds and at the same time be able to cope with the less frequently occurring high wind speeds in a safe manner.

[0003] The use of rigid sails has been discussed in the prior art. For example, US10906620B2 discloses a retractable double wing profile having a shape for a corresponding front flap and a rear flap, the shape being traversed by the foremast while being able to rotate about the axis defined thereby. In a variant, the flaps are constructed as rigid frames which are telescopically nested in series.

[0004] US10906620B2 also discloses a variant of a retractable double wing profile, in which the front and rear wing profiles are composed of a rigid frame, which is traversed by the corresponding mast. The rigid frame can be rotated around the wing profile and retracted. Therefore, the rigid wing profile can be retracted, that is, by folding the wing profile telescopically along the mast to a non-propelling position. However, telescopic nesting can lead to wear of the frame, and this in turn can lead to problems with assembly with the frame when the frame is nested. In the event of damage to the frame, it may be difficult to retract the sail, whereby the construction may be subject to forces exerted by the wind when propulsion by the wing sail is not desired.

[0005] Despite the known rigid wing sail solutions, there is still room for improvement. Summary of the invention

[0006] In the context of the present invention, it has been noted that reefing of large rigid or semi-rigid wing sails is laborious. It has been realized that due to the height and large overall area of ​​such rigid wing sails, there are problems in finding a suitable way or reefing and storing the wing sail when it is not in use on a marine vessel.

[0007] In view of the drawbacks and limitations of the prior art solutions, the object of the present invention is to provide a marine vessel with a wind-assisted propulsion arrangement which at least partially solves the problems of the known solutions, in particular problems related to the robustness of the wingsail structure, the arrangement of the wingsail structure in a neutral non-propulsive position in a robust and space-saving manner, and the easy maintenance and servicing of the wingsail structure.

[0008] It has been noted that in conjunction with a large rigid wing sail, it may be advantageous not to use a conventional mast when reefing. Instead, the wing sail is arranged to be tilted to a non-propulsive position. However, due to the large size of the wing sail, it should be ensured that the wing sail can be retracted in a compact manner when the wing sail is in a non-propulsive position, for example when the vessel is docked. In addition, the structure of the wing sail needs to be reinforced in a suitable manner to provide a robust construction.

[0009] The above objects are achieved by the present invention as defined in the attached independent claims.

[0010] Therefore, the present invention relates to a wing sail structure for a wind-assisted propulsion arrangement of a marine vessel, and includes a wing sail frame, which is rotatably connected to a base via a first longitudinal rotation axis. The wing sail frame includes a main wing sail and a rear flap, each of which has an airfoil shape, and includes a rigid or semi-rigid sidewall extending between a top end and a bottom end, and has a leading edge and a trailing edge. The main wing sail has a main wing sail centerline, and the rear flap has a flap centerline, which extends between the corresponding leading edge and the trailing edge in a cross-sectional view. The wing sail frame further includes at least one coupling component connecting the main wing sail and the rear flap. The flap is arranged to rotate around a second longitudinal rotation axis so that the flap and its flap centerline are in an inclined position relative to the main wing sail centerline. The second rotation axis is arranged to laterally deviate from the main wing sail centerline. The second rotation axis can be located outside the periphery defined by the sidewall of the main wing sail. Similarly, the second rotation axis can be arranged to laterally deviate from the flap centerline. Furthermore, the second axis of rotation may be arranged outside a perimeter defined by the side walls of the flap.Furthermore, the second axis of rotation may be connected to at least one coupling component.

[0011] By means of this configuration, several advantages can be obtained. Since the second axis of rotation is arranged to be laterally offset from the mainsail centre line, it is possible to bring the flap into close proximity with the mainsail when the flap is folded towards the mainsail. In this way, the space required during folding can be reduced. In addition, only one point of rotation is required for the tilting of the flap relative to the mainsail. Furthermore, when the second axis of rotation is located outside the perimeter defined by the side walls of the mainsail and / or the flap, the point of rotation is separated from the body of the mainsail and / or the flap, which can improve the robustness and functionality of the structure and facilitate maintenance. Furthermore, when the second axis of rotation is connected to at least one coupling component, the structure will be robust and can be simplified.

[0012] The main wing sail and the flap suitably have a distance or slot between the trailing edge of the main wing sail and the leading edge of the flap. This improves the aerodynamic performance of the wing sail structure.

[0013] Each of the main wing sail and the rear flap may further include a support frame extending longitudinally along the length of the respective main wing sail and the rear flap. The support frame may be arranged inside the respective main wing sail and the flap, whereby the support frame may be mainly located inside the side walls of the respective main wing sail and the flap. However, the support frame may extend outside the extension of the side walls, for example at the end portion and the bottom portion of the main wing sail and the flap. The support frame provides structural stability for the wing sail frame.

[0014] At least one of the supporting frames may have a hollow structure. Alternatively, at least one of the supporting frames may have a wall-like structure. The supporting frames may have the same type of structure adapted to the size of the corresponding mainsail or flap. Alternatively, the supporting frame structures in the mainsail and flap may be different. For example, the supporting frame associated with the mainsail may have a hollow structure, and the supporting frame associated with the flap may have a wall-like structure. Regardless of the type of supporting frame, according to a variation, it may be connected to the inner surface of the side wall of the corresponding mainsail and flap. The hollow structure and / or the wall-like structure provide a reduced weight for the frame and provide a less rigid construction. Therefore, the frame will have a certain degree of flexibility.

[0015] At least one coupling member may be fixed to the respective frame structures of the main wing sail and the flap. In this way, a more robust construction may be provided.

[0016] At least one coupling part may be associated with the respective bottom and / or top end of the main wing sail and the flap. The coupling part may comprise a first cantilever part connected to the flap and a second cantilever part connected to the main wing sail. The first cantilever part and the second cantilever part may be connected to each other via a second axis of rotation. In this way, the second axis of rotation provides an articulated connection between the cantilever parts, whereby only one axis of rotation may be provided in a robust manner for tilting the flap relative to the main wing sail.

[0017] The first cantilever part and the second cantilever part can be fixed to the corresponding frame structure of the flap and the main wing sail in a non-rotatable manner. The rotation of the flap relative to the main wing sail can be provided by the second rotation axis. Therefore, a robust construction is provided.

[0018] The flap may be configured to rotate relative to the main wing sail by means of a movable lever arm movably fixed to the first and second cantilever parts. The movable lever arm is driven by means of at least one linear actuator or motor. The linear actuator may include, for example, a hydraulic cylinder.

[0019] Each of the bottom and / or top ends of the main wing sail and flaps may include a corresponding bottom cover plate and / or top cover plate. The cover plate may have an outer periphery that at least partially extends beyond the periphery of the side walls of the corresponding main wing sail and flaps. The supporting frames of the main wing sail and flaps may be connected to the corresponding bottom and / or top cover plates. The cover plate can be used to control airflow and prevent turbulence.

[0020] The second axis of rotation may be located laterally outside the area defined by the side walls of the mainsail and the flaps, ie outside the periphery of the mainsail and the flaps. In this way, a robust construction may be provided.

[0021] The wing sail structure can be configured so that the flap can be tilted to a neutral position, in which the flap centerline can be aligned with the main wing sail centerline or parallel to the main wing sail centerline but laterally spaced, and / or to a propulsion position, in which the flap centerline is tilted relative to the main wing sail centerline, and / or to a folded non-propulsion position, in which a side wall of the flap faces a side wall of the main wing sail. In this way, different propulsion positions can be provided by the rotation of the flap relative to the main wing sail, and in addition to the rotation of the entire wing sail frame. When the flap is rotated from the neutral position to the folded position, the rotation angle of the flap centerline is suitably at least 90°, or at least 120°, or at least 150° about the normal to the main wing sail centerline. Therefore, according to the present solution, the flap can be rotated beyond the degree required to provide camber in the propulsion position, and the flap can be folded toward the main wing sail using only one rotation axis.

[0022] The wingsail structure may further comprise a tilting arrangement configured to bring the wingsail frame from the standing folded position to a tilted position relative to the base. The tilting angle may vary and may be, for example, from 10° to 100°. Since the wingsail frame may be brought to the folded position before tilting the wingsail frame, stowing may be provided in a space-saving manner.

[0023] The wing sail frame may comprise at least one intermediate connecting component which is located between the upper and lower ends of the respective main wing sail and flap along their longitudinal extension. In this way, the structural stability of the connection between the main wing sail and the flap may be improved.

[0024] Furthermore, the present invention relates to a wind-assisted propulsion arrangement comprising at least one wing-sail structure as defined above, and to a marine vessel comprising such a wind-assisted propulsion arrangement. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features and advantages of the present invention will be described with reference to the accompanying drawings, in which:

[0026] Figure 1 A marine vessel comprising a wind-assisted propulsion arrangement in a standing deployed propulsion position is shown in a perspective view.

[0027] Figure 2a and 2b An embodiment of a flap tilt arrangement is shown from below in the standing deployed neutral position (I).

[0028] Figure 2c The standing propulsion position (II) is shown from below. Figure 2a and 2b An embodiment in which the flap is tilted leftward in a clockwise direction relative to the leading edge of the main wing sail.

[0029] Figure 2d The standing propulsion position (II) is shown from below. Figure 2a and 2b An embodiment in which the flap is tilted to the right in a counterclockwise direction relative to the leading edge of the main wing sail.

[0030] Figure 2e The folded standing position (III) is shown from below. Figure 2a and 2b An embodiment in which the flap is inclined through a left curve towards the sidewall on the right hand side relative to the leading edge of the mainsail.

[0031] Figure 3 An embodiment is shown in which a second axis of rotation of the rotary actuator is provided.

[0032] Figure 4a and 4b Another embodiment of a flap tilt arrangement is shown from below in the standing deployed neutral position (I).

[0033] Figure 4c The standing propulsion position (II) is shown from below. Figure 4a and 4b An embodiment in which the flap is canted to the left relative to the leading edge of the mainsail.

[0034] Figure 4d The standing propulsion position (II) is shown from below. Figure 4a and 4bAn embodiment in which the flap is canted to the right relative to the leading edge of the mainsail.

[0035] Figure 4e The folded standing position (III) is shown from below. Figure 4a and 4b An embodiment in which the flap is inclined through a left curve towards the sidewall on the right hand side relative to the leading edge of the mainsail.

[0036] Figure 5 The bottom end caps for the main wing sail and flaps are shown.

[0037] Figure 6 The wing structure is shown in a perspective view in a standing deployed propulsion position, wherein the main wing and the flap are connected by means of an intermediate connecting part which is located between the upper and lower ends of the respective main wing and flap in their longitudinal extension.

[0038] Figure 7 The wing sail structure of a wind assisted propulsion arrangement is shown in a perspective view in a folded and heeled horizontal position. DETAILED DESCRIPTION

[0039] In order to use the wind as a power for vessel propulsion, wingsails are formed so that they can generate sufficient propulsion force by themselves or together with the vessel's engines to overcome the vessel's resistance. In the present application, wingsails are generally defined as rigid or semi-rigid structures, which may be similar to aircraft wings and can be fixed on marine vessels in vertical or axial directions to provide propulsion force from the action of the wind. The configuration, size and number of wingsails are suitable for the vessel in question. In general, the stronger the resistance, the larger the wingsails and / or the greater the number of wingsails. When rigid wingsails are not used, for example due to bad weather, altitude restrictions on the selected route or during cargo operations, safety aspects should be ensured.

[0040] According to the present invention, a wing sail structure is provided, which includes a wing sail frame. The wing sail frame includes a main wing sail and a rear flap connected by means of at least one coupling component. The wing sail frame is rotatably connected to a base via a first longitudinal rotation axis. Each of the main wing sail and the rear portion has an airfoil shape. By the airfoil shape is meant the cross-sectional shape of the wing sail, the movement of which through the air can generate (significant) lift. The main wing sail and the rear flap include a rigid or semi-rigid sidewall extending between the top and the bottom, and have a leading edge and a trailing edge. The main wing sail has a main cross-sectional centerline MCL, and the rear flap has a rear flap cross-sectional centerline FCL, which extends between the corresponding leading edge and the trailing edge, and as shown below in the specification with reference to the accompanying drawings later. The flap is connected to the main wing sail via at least one coupling component. As described in more detail below, when the main wing sail and the flap are in a neutral position, the main centerline and the flap centerline can be aligned with each other or laterally deviated or spaced apart.

[0041] In addition to the entire frame being rotatable around the first longitudinal axis of rotation, the flap is also arranged to be rotatable around the second longitudinal axis of rotation alone. During rotation, the flap centerline can be rotated to an inclined position relative to the main wing sail centerline MCL from a neutral position (I), in which the flap centerline FCL is aligned with the main wing sail centerline MCL in sequence (i.e., one after the other), or arranged in sequence but laterally deviated or spaced apart from each other. Therefore, the flap and its centerline can be rotated to a propulsion position, in which the flap centerline FCL is tilted relative to the main wing sail centerline MCL. The tilt angle can be determined relative to a normal perpendicular to the main wing sail centerline MCL. When in the neutral position, the flap centerline FCL is positioned perpendicular to the normal. When tilted to the propulsion position, the flap is tilted in a counterclockwise or clockwise direction relative to the leading edge of the main wing sail about the normal and towards the normal. Therefore, the flap can be tilted to the left or right relative to the leading edge of the main wing sail. The tilt angle at the propulsion position is less than 90 ° towards the normal. The flap can also be rotated to a folded non-propelling position, in which a side wall of the flap faces a side wall of the main wing sail. The tilt angle when folded is at least 90°, or at least 120°, or at least 150° toward and across (i.e., about) the normal to the centerline MCL of the main wing sail.

[0042] According to the invention, the second rotation axis is arranged laterally offset from the main wingsail centre line MCL when the wingsail frame is in a neutral position.The second rotation axis may additionally be arranged laterally offset from the flap centre line FCL.

[0043] When the main wing and flap are in the neutral position, the main wing and flap are suitably separated by a slot. The slot defines the distance between the trailing edge of the main wing and the leading edge of the flap. In the neutral position, the slot extends in the same direction as the center lines MCL and FCL. When the slot is present in the neutral position of the main wing and flap, the main wing and flap do not overlap each other laterally when viewed in a cross-sectional view. In the neutral position, the slot or distance between the trailing edge of the main piece and the leading edge of the flap is suitable for the desired aerodynamic performance. This distance is substantially less than the length of the corresponding main wing and flap between the corresponding leading edge and trailing edge. The slot improves the aerodynamic performance of the wing frame and structure.

[0044] The second rotation axis can be connected to at least one coupling member to provide a robust structure. In this way, when the flap is folded onto the main wing sail, a more compact wing sail position can be obtained. Meanwhile, when in use, the flap can be tilted relative to the main wing sail to provide a camber to provide propulsion. The main wing sail cannot rotate independently relative to the flap centerline. Instead, the main wing sail rotates when the entire wing sail frame rotates. By providing a flap, the flap can rotate relative to the main wing sail around the axis of the main wing sail centerline MCL and optionally also the flap centerline FCL that deviates (that is, spaced apart) and optionally also has a flap centerline FCL, and may only use one rotation axis for the folding and tilting of the flap. In this way, when sailing, the flap can be tilted at different angles, and the flap can be folded toward the main airfoil using only one rotation point. This is a huge advantage, which simplifies the structure and control of the wing sail structure. It also allows hinges or lever arms to be vertically distributed between the main part and the flap to keep the flap toward the main airfoil.

[0045] In addition to the folding function provided by the second axis of rotation, it is also possible to adjust the amount of power generated by adjusting the camber formed by the main wing and the flaps. Since the flaps can be folded towards the main wing, the projected area of ​​the wing frame can be reduced. Therefore, the space required by the wing frame on the vessel is also reduced. When the main wing and the flaps are folded, the forces generated can be reduced. In this way, a minimum power configuration can be obtained under desired conditions, which can be important for vessel safety, structural integrity and maneuverability.

[0046] In order to prevent the wingsail from providing propulsion, the wingsail frame can be tilted horizontally towards the deck to a tilted position. By a "tilted" position is meant a position in which the wingsail frame is tilted towards a horizontal position and / or can lean towards the deck of the vessel or towards a support on the deck. The wingsail frame can be stowed in this position and this position is also referred to herein as the stowed position. In the tilted position and when the mainsail and flaps are in the folded position, space on the deck of the vessel can be saved compared to when the mainsail and flaps are not in the folded position. This is also shown in the accompanying drawings.

[0047] In order to provide the heeled position, the wingsail frame is tilted from a vertical standing position towards a horizontal position. The wingsail frame has a longitudinal axis, which extends in a vertical direction relative to the ship deck when the wingsail frame is in the standing position. Therefore, the wingsail frame is tilted relative to a horizontal rotation axis, which is perpendicular to the longitudinal axis and is therefore substantially horizontal or transverse relative to the ship deck. In the heeled position, the longitudinal axis of the wingsail frame may therefore be substantially horizontal. However, heeling wingsails require a large space on the deck of a marine vessel, which space may be difficult to find. Therefore, it is critical to minimize the required space allowing the wingsail arrangement to be installed as much as possible.

[0048] The wing sail structure including the wing sail frame and the base and the arrangement including one or more wing sail structures can be used in marine or maritime vessels, i.e. vessels used as means of water transportation. The main wing sail and the flap are basically made of rigid or semi-rigid materials and have an airfoil shape. Both the main wing sail and the flap have side walls, a leading edge and a trailing edge and a top and a bottom. In addition, the main wing sail has a main cross-sectional centerline MCL, and the rear flap has a flap cross-sectional centerline FCL, which extend between the corresponding leading edge and the trailing edge.

[0049] By "rigid" material is meant a material that may be a combination of several materials, which is not foldable and can support its own weight when leaning against parallel edges of such material. A "semi-rigid" material is a material that is partially rigid and has a certain degree of flexibility, but can still support its own weight when leaning against parallel edges of such material.

[0050] In the present application, by an "airfoil" shape is meant a wing profile having an aerodynamic shape when seen in cross section in the fore-aft direction, i.e. the direction from the leading edge to the trailing edge. An aerodynamic airfoil shape is advantageous because it makes it easier for air to pass through the wing sail. The shape may be asymmetric in said direction, but it may involve symmetric sections, or the shape may be a symmetric airfoil. The airfoil shape may be defined, for example, according to the NACA standardized series, but the shape is not limited thereto.

[0051] In order to better understand the invention of the present disclosure, it will now be described with reference to the accompanying drawings, which are provided to illustrate non-limiting example embodiments of the present invention. It should be noted that in the drawings, for the sake of clarity, not all reference symbols are added to all figures, but it will be clear to the skilled person that reference symbols related to structural details in one figure can be applied in a similar manner to other figures showing the same details.

[0052] refer to Figure 1 , shows a marine vessel 1 comprising a wind-assisted propulsion arrangement 10 having three wing sail structures 100. Each of the wing sail structures 100 comprises a wing sail frame 101, which is Figure 1 Schematically shown in the figure by a rectangle with dashed lines in combination with an intermediate wing sail frame 101. The wing sail frame 101 includes a main wing sail 110 and a rear flap 120, and at least one connecting member 140 connecting the main wing sail and the rear flap. Both the main wing sail 110 and the flap 120 are rigid or semi-rigid, meaning that there is a certain degree of flexibility. Figures 2a to 2e The wingsail frame also mentioned in this text is further shown from below in FIG.

[0053] The wingsail structure 100 further comprises a base 20 which can be fixed to the deck 3 (i.e. the body of the vessel 1). The wingsail frame 101 is rotatably connected to the base 20 via a first longitudinal rotation axis 111. The first rotation axis is configured to allow the entire wingsail frame to rotate relative to the base 20. Thus, the main wingsail rotates when the entire wingsail frame rotates. The first longitudinal rotation axis can be provided by any suitable means, such as an axle detachably attached to the base 20 or, for example, by a swivel ring. The base 20 is further associated with the wingsail frame 101 so that the base 20 supports the frame when the wingsail frame is in an upright vertical standing position, whether in a neutral non-propulsive position (I), or in a propulsive position (II) (where the flap is tilted relative to the main wingsail centerline MCL), or in a folded position (III). The base can also be associated with the wingsail frame when the wingsail frame is brought to a tilted position (IV).

[0054] exist Figure 1 The wing frame is arranged in the standing propulsion position (II) in the deployed standing position shown in FIG. The propulsion provided by the main wing and flaps can be changed by changing the camber (i.e., the convexity of the curve of the main wing and flap form from the leading edge of the main wing to the trailing edge of the flap, such as Figure 1 The camber curve C of the frontmost wing sail frame is changed. Figure 2a-2d As shown in , the convexity can be adjusted by adjusting the inclination of the flaps relative to the main wing sail. In the standing position, the longitudinal axis L of the wing sail structure (only shown in connection with one structure 100) is substantially parallel to a substantially vertical axis V, which is perpendicular to a horizontal axis H of the vessel 1. The horizontal axis H may extend substantially in the same direction as the deck floor. The wing sail structure also has an extension in a depth direction D, which is perpendicular to a plane formed by the two-dimensional longitudinal direction L and the transverse direction T. When the flaps are folded towards the main wing sail, the extension of the wing sail frame 101 decreases in the transverse direction T and increases in the depth direction D.

[0055] The main wing sail 110 and the flap 120 both have an airfoil shape. The main wing sail 110 has a leading edge 117, a trailing edge 118 ( Figure 2a ), top end 115 and bottom end 116 ( Figure 1 ), and side walls 211 and 212 extending therebetween ( Figure 2a ). In a similar manner, flap 120 has a leading edge 127 and a trailing edge 128 ( Figure 2a ) and the top end 125 and the bottom end 126 ( Figure 1 ), and side walls 221 and 222 extending therebetween ( Figure 2a ). Figure 2a , 2b, 3 and 4a and 4b, there is a slot 250 in the cross-sectional view, which defines the distance d between the main wing sail trailing edge 118 and the flap leading edge 127. For example, Figure 2b and 4b As shown in , the slot ensures that the main wing sail 110 and the flap 120 do not overlap laterally in a cross-sectional view when the main wing sail and the flap are arranged in a neutral position (I). The shape of the airfoil generally has a tapering shape from the leading edge towards the trailing edge.

[0056] The side walls 221 and 222 are integrally combined to form an airfoil shape having a leading edge 127 and a trailing edge 128. The side walls 221 and 222 may be formed by modules that are permanently or detachably attached to each other, and the modules together form an integrally combined wing sail or flap having an airfoil shape. The profiles of the wing sail and flap may be designed as different modular elements that may be combined to achieve wing sails of different sizes. The main wing sail and flap may include any suitable material, such as a moldable polymer material, a glass fiber material, a carbon fiber material and / or a composite material, but is not limited thereto.

[0057] The wingsail frame 101 further comprises at least one coupling member 140, which is Figure 1 In the example shown is a lower coupling member placed in association with the bottom end 116 of the main wing sail 110 and the bottom end 126 of the flap 120. The wing sail frame may additionally or alternatively include an upper coupling member 130 associated with the top end 115 of the main wing sail 110 and the top end 125 of the flap 120. The coupling members 130, 140 may have similar configurations on both the top and bottom, or the configurations may differ from each other. The coupling members 130, 140 are configured to connect the main wing sail 110 and the rear flap 120.

[0058] According to the invention, the flap 120 can be rotated about the second longitudinal rotation axis 112 to bring the flap into an inclined position relative to the main wing sail centerline MCL. In this way, when sailing, the flap can be tilted at different angles and it can be folded towards the main airfoil using only one rotation point. This simplifies the construction and control of the wing sail structure, which is a huge advantage compared to known solutions.

[0059] Figure 2a-2e A second longitudinal rotation axis 112 is shown which, in the example shown, is connected to at least one coupling member 140 and is arranged laterally offset from the main wing sail centerline MCL and also the flap centerline FCL. Figure 2a and Figure 2b , which shows the main wing sail 110 and the flap 120 in a neutral position (I), and wherein the rotation axis centerline RCL ( Figure 2a ) is parallel to and laterally spaced from the main wing sail centerline MCL and the flap centerline FCL. Figure 2aAs shown by arrows d1 and d2, there is a lateral distance between the rotation axis centerline RCL and the main wing sail centerline MCL. The lateral direction is a direction perpendicular to the extension of the centerlines MCL and FCL.

[0060] The coupling member 140 may include a first boom member 141 connected to the flap 120. The first boom member 141 may include a rod that is fixed to the flap 120 in a non-rotatable manner. The coupling member 140 may include a second boom member 142 connected to the main wing sail 110. The second boom member 142 may include a rod that is fixed to the main wing sail 110 in a non-rotatable manner. Then, the first boom member 141 and the second boom member 142 may be connected to each other via a second rotation axis 112, and the second rotation axis 112 provides an articulated connection. Therefore, the coupling member 140 rotatably connects the main wing sail 110 and the flap 120 relative to each other via the second rotation axis 112. By rotatably connecting means that the flap 120 can be rotated around the second longitudinal axis 112 to make the flap towards the main wing sail, so that the flap centerline FCL rotates relative to the main wing sail centerline MCL. When the wing sail frame is in a standing position (e.g., in a propulsion position), the longitudinal axis is parallel to the vertical axis L.

[0061] Figure 2c-2e The rotation of the flaps is shown in Figure 2b-2e , the center lines FCL and MCL of the flap 120 and the main wing sail 110 are shown with dotted lines. The normal N of the main wing sail center line MCL, i.e. the line perpendicular to the main wing sail center line MCL, is also shown and drawn to pass through the second rotation axis 112. The tilting of the flap can be shown as a rotation of the flap center line FCL relative to the normal N. When the flap 120 is tilted to the propulsion position (II) to form a camber C with the main wing sail 110, the flap center line FCL tilts from the neutral position (I) toward the normal N. The angle of tilt from the neutral position (I) toward the normal N is suitably less than 90°. The tilting can be relative to the leading edge 117 of the main wing sail (see Figure 2a ) to the left or right. Figure 2c and 2d Thus, the tilting can be performed toward either of the side walls 211, 212 of the main wing sail 110. Figure 2e As shown in , when the flap is folded to the folded position and rotated from the neutral position (I) to the folded position (III), the angle of inclination toward and across the normal N of the main wing sail centerline MCL is at least 90°, or at least 120°, or at least 150°. In this way, the wing sail can be stowed in a compact manner.

[0062] Rotation of flap 120 may be actuated in different ways. Figure 3An example of a rotary arrangement is shown comprising a rotary actuator 1121. The actuator may be used to rotate the flap 120 relative to the main wing sail 110 about the second axis of rotation 112. The actuator may be driven, for example, by means of an electric or hydraulic motor.

[0063] Figure 4a-4e Another example of a rotational arrangement 1121 for rotating the flap 120 relative to the main sail 110 is shown. Figure 4a-4e In addition, it is shown that the wing sail frame further includes a support frame 310, 320 extending longitudinally along the length of the corresponding main wing sail and the rear flap. The main wing sail support frame 310 is arranged in the main wing sail 110 inner side, and the flap support frame 310 is arranged in the flap 120 inner side. In the example shown, each support frame 310, 320 has a hollow structure and is connected to the inner surface of the side walls 211, 212, 221, 222 of the corresponding main wing sail 110 and the flap 120. The purpose of the frame structure is to provide support for the wing sail, and thereby provide a robust structure. The frame structure can be provided in a module, or as a one-piece structure. The frame structure can have a hollow structure, and is connected to the inner surface of the side walls of the corresponding main wing sail and the flap, and has a size that makes it fit in the corresponding main wing sail and the flap inner side. However, the support frame can have another shape, and can be, for example, a wall type structure. Such a structure can be used in a flap 120 that is smaller than the main wing sail, for example. In this way, the weight of the flap may be minimized while providing adequate support.

[0064] The rotating arrangement 1120 is associated with at least one lower attachment member 140, which in the illustration is associated with the bottom end 116 of the main wing sail 110 and the bottom end 126 of the flap 120. Figure 2a-2e In a similar manner as explained above, the coupling member 140 may additionally or alternatively be located at the tip 115 of the main wing sail or the tip 125 of the flap 120. Figure 4b Reference symbols (which apply similarly to all Figure 4a-4e), the coupling component 140 comprises a first cantilever component 141. The first cantilever component 141 of the coupling component 140 is rigidly connected (i.e., in a non-rotatable manner) to the flap 120 via the flap frame structure 320. The flap frame structure 320 extends a certain length outside the extension of the side walls 221, 222 of the flap 120 to provide a robust structure. The coupling component 140 comprises a second cantilever component 142, which is connected to the main wing sail frame structure 310 of the main wing sail 110 in a rigid and non-rotatable manner. The second cantilever component is connected to the first cantilever component via the second rotation axis 112 that provides an articulated connection. The coupling component connected to the flap and the main wing sail is configured to rotate the flap 120 relative to the main wing sail 110 by means of a movable lever arm 145, and the movable lever arm 145 is movably fixed to the first cantilever component 141 and the second cantilever component 142. The number of movable lever arms in the example shown is 2, but it can be more, or only 1. The movable lever arm 145 is driven by means of at least one linear actuator or motor 147 .

[0065] Figure 4b-4e An embodiment of a coupling component configured to rotate the flap relative to the main wing sail is shown. Figure 4b-4e In the embodiment, the flap 120 and the main wing sail 110 include a flap centerline FCL and a main centerline MCL. Figure 4b , wherein the main wing sail (110) and the flap (120) are in a neutral position (I), a slot 250 is present between the main wing sail 110 and the flap 120, wherein the main wing sail trailing edge 118 and the flap leading edge 127 have a distance (d) between them. In addition, the main centerline MCL and the flap centerline 127 are parallel to each other and are arranged at a lateral distance CLD from each other in a cross-sectional view. The slot 250 extends in the neutral position (I) in the same direction as the centerlines MCL and FCL, and the main wing sail 110 and the flap 120 do not overlap laterally in the neutral position (I). A normal N to the main wing sail centerline MCL also exists but is not shown. The inclination of the flap 120 providing the propulsion position (II) can be relative to the leading edge 117 of the main wing sail as shown in FIG. Figure 4c To the left, or to the right (see Figure 4d ). Therefore, the tilting can be performed toward any one of the side walls 211, 212 of the main wing sail 110. Figure 2e In a similar manner as shown in Figure 4e The folded position in Figure 4b The neutral position (I) of Figure 4e In the folded position (III), the inclination angle is at least 90°, or at least 120°, or at least 150° towards and across (ie, about) the normal N to the main wing centerline MCL. In this way, the wing can be folded in a compact manner.

[0066] Figure 5 An embodiment of a wing sail frame is shown in which the bottom end 116 of the main wing sail 110 includes a bottom end cap 1160. The top end 115 may include a top end cap (not shown) in a similar manner. The bottom end cap 1160 has an outer perimeter that at least partially extends beyond the perimeter of the main wing sail formed by the side walls 211, 212 of the main wing sail 110 and the flap 120. The flap 120 may include a bottom end cap 1260 in a similar manner.

[0067] The bottom end plate 1160,1260 with a larger periphery than the periphery of the main wing sail and flap defined by the corresponding sidewalls is provided to control airflow and prevent turbulence. According to a variation, the second axis of rotation 112 may be connected to the bottom end plate and / or the top end plate. It may be laterally located outside the area defined by the sidewalls of the main wing sail and flap (i.e., the periphery defined by the sidewalls of the main wing sail and flap in a cross-sectional view). The support frames 310 and 320 of the main wing sail and flap may be arranged to be connected to the corresponding bottom end plates 1160 and 1260.

[0068] Figure 6 Another embodiment of the invention is shown. In addition to the lower attachment part 140, in the example 3 shown, the wing sail also comprises at least one intermediate attachment part 150 shown, which is located between the upper end 115, 125 and the lower end 116, 126 of the respective main wing sail 110 and flap 120 in the longitudinal extension of the main wing sail 110 and flap 120. This further improves the robustness of the structure.

[0069] The wingsail structure 100 may further comprise a tilting arrangement (not shown) configured to move the wingsail frame from a standing position to a tilted position, for example from a folded standing position (III) to a tilted position (IV) relative to the base 20 . Figure 7The wingsail frame is shown in a tilted stowed position (III, IV). The wingsail frame can be tilted to a substantially horizontal position, wherein the side wall between the leading edge and the trailing edge faces the deck of the vessel. Alternatively, the wingsail frame can be tilted to a vertical position, wherein the leading edge or the trailing edge faces the deck of the vessel. However, the tilt angle can vary, and for example, the tilt angle can be from 10 to 100°, more commonly up to 90°, relative to the deck of the vessel, which corresponds to a substantially horizontal position relative to the deck. In order to provide a tilted position, when the wingsail frame is in a standing position, the wingsail frame 101 having a longitudinal axis L extending in a vertical direction V is tilted around a transverse rotation axis. The transverse rotation axis RT is perpendicular to the longitudinal axis L and is therefore substantially horizontal. The arrow RT shows the direction of tilting relative to the rotation axis. In the tilted position, the longitudinal axis L of the wingsail frame can therefore be substantially parallel or nearly parallel to the horizontal axis H. Alternatively, the tilt angle can be less than 90°, and the longitudinal axis L can be correspondingly tilted at an angle less than 90° relative to the horizontal axis. Furthermore, as indicated by arrows RH, the wingsail frames 101 may be tilted in a horizontal plane. In this way, when the wingsail frames are in a tilted position, they may also be arranged tilted relative to each other. This may facilitate the folding of the wingsail frames. The tilting may be achieved by a tilting arrangement included in the wingsail structure 100.

[0070] In general, the main wing sail, flaps and upper and lower coupling devices may include a suitable arrangement, which is configured to provide a rotational movement relative to the axis of rotation, and may include, for example, a shaft, a bearing (e.g., a roller bearing) and a drive device. The rotation of the wing sail frame, the main wing sail and / or the flaps may be controlled by combining, for example, an electrically controllable device to each axis of rotation. Then, a control unit may be connected to a drive arrangement to adjust the rotation of the wing sail frame, the main wing sail and / or the flaps. The degree of rotation of the wing sail frame, the main wing sail and / or the flaps is adapted to the prevailing ambient conditions. For the rotation arrangement of the main wing sail and the flaps and each vertical axis of rotation in the vertical axis of rotation, a stop device may be arranged so that the degree of rotation is angularly limited to a certain extent. By limiting the degree of rotation, uncontrolled rotation of parts of the wing sail frame may be avoided, for example, in the case of changes in prevailing wind / weather conditions.

[0071] The wind assisted propulsion arrangement 10 may be operated according to a method comprising the following steps:

[0072] - controlling the degree of rotation of the wingsail frame 101 and / or flap 120 from the neutral position (I) to the thrust position (II) to provide camber;

[0073] - folding the flaps towards the mainsail to provide a folded standing position (III);

[0074] - Heeling the wingsail frame (101) towards the body of the vessel to provide a heeled position (IV).

[0075] The detailed description and drawings are intended to facilitate understanding of the embodiments of the present invention, but do not limit the scope of the present invention, which is limited by the appended claims.

Claims

1. A wingsail structure (100) for wind-assisted propulsion of a marine vessel (1), the wingsail structure (100) comprising a wingsail frame (101), the wingsail frame (101) being rotatably connected to a base (20) via a first longitudinal rotation axis (111), wherein the wingsail frame (101) comprises: a main wing sail (110) and a rear flap (120), each having an airfoil shape and comprising rigid or semi-rigid sidewalls (211, 212; 221, 222) extending between a top end (115; 125) and a bottom end (116; 126) and having a leading edge (117; 127) and a trailing edge (118; 128), wherein the main wing sail (110) has a main wing sail centerline (MCL) and the rear flap has a flap centerline (FCL) extending, in a cross-sectional view, between the respective leading edge (117; 127) and trailing edge (118; 128), At least one connecting member (140) connecting the main wing sail (110) and the rear flap (120), wherein The flap (120) is arranged to be rotatable about a second longitudinal rotation axis (112) to bring the flap and its flap centerline (FCL) to an inclined position relative to the mainsail centerline (MCL), and wherein The second rotation axis (112) is arranged laterally offset from the mainsail centerline (MCL).

2. The wing sail structure (100) according to claim 1, wherein: The second rotation axis (112) is connected to the at least one coupling member (140).

3. The wing sail structure (100) according to claim 1 or claim 2, wherein: Each of the main wing sail (110) and the rear flap (120) further comprises a support frame (310; 320) extending longitudinally along the length of the respective main wing sail and rear flap, the support frame being arranged inside the respective main wing sail (110) and flap (120).

4. The wingsail structure (100) according to claim 3, wherein: At least one of the support frames (310, 320) has a hollow structure and is connected to the inner surface of the side wall (211, 212; 221, 222) of the corresponding main wing sail (110) and / or flap (120).

5. The wing sail structure according to claim 3 or claim 4, wherein: The at least one coupling member is fixed to respective frame structures (310; 320) of the main wing sail (110) and the flap (120).

6. A wingsail structure according to any one of the preceding claims, wherein: The at least one coupling member (140) is associated with respective bottom ends (116; 126) and / or top ends (115; 125) of the main wing sail (110) and the flap (120), and comprises a first cantilever member (141) connected to the flap (120) and a second cantilever member (142) connected to the main wing sail (110), and wherein the first cantilever member (141) and the second cantilever member (142) are connected to each other via the second rotation axis (112).

7. The wing sail structure according to claim 6, wherein: The first cantilever part (141) and the second cantilever part (142) are fixed to the corresponding frame structures (320; 310) of the flap (120) and the main wing sail (110) in a non-rotatable manner.

8. A wing sail structure according to any one of claims 6 or claim 7, wherein the flap (120) is configured to be rotatable relative to the main wing sail (110) by means of a movable lever arm (145) movably fixed to the first cantilever part (141) and the second cantilever part (142), and wherein the movable lever arm (145) is driven by means of at least one linear actuator (147) or a motor.

9. The wingsail structure (100) according to any one of the preceding claims, wherein: Each of the bottom and / or top ends of the main wing sail and the flap comprises a corresponding bottom end cover plate (1160; 1260) and / or top end cover plate, wherein the bottom end cover plate and / or the top end cover plate have an outer periphery that at least partially extends beyond the periphery of the side walls (211, 212; 221, 222) of the corresponding main wing sail (110) and flap (120).

10. The wingsail structure (100) according to any one of the preceding claims, wherein: The second axis of rotation (112) is located laterally outside a region defined by the side walls of the main wing sail and / or the flap.

11. The wingsail structure (100) according to any one of the preceding claims, wherein: The flaps are configured to tilt: - to a neutral position (I) in which the flap centre line (FCL) is aligned with the mainsail centre line (MCL), - to a thrust position (II) in which the flap centre line (FCL) is inclined relative to the mainsail centre line (MCL), and / or - to a folded, non-propelled position (III), in which a side wall of the flap faces a side wall of the mainsail.

12. The wingsail structure (100) according to claim 11, wherein: When the flap is rotated from the neutral position (I) to the folded position (III), the rotation angle of the flap centerline (FCL) with respect to the normal (N) relative to the main wing sail centerline (MCL) is at least 90°, or at least 120°, or at least 150°.

13. The wingsail structure (100) according to any one of the preceding claims, wherein: The wingsail structure (101) further comprises a tilting arrangement (300) configured to move the wingsail frame (101) from a standing position (I-III) to a tilted position (IV) relative to the base.

14. The wingsail structure (100) according to any one of the preceding claims, wherein: The wing sail frame (101) comprises at least one intermediate connecting part (150) which is located between the upper end (115; 125) and the lower end (116; 126) of the main wing sail (110) and the flap (120) along their longitudinal extension.

15. The wingsail structure (100) according to any one of the preceding claims, wherein: The main wing sail (110) and the rear flap (120) are separated by a slot (250).

16. A wind-assisted propulsion arrangement (10) comprising at least one wingsail structure (100) according to any one of the preceding claims 1 to 15.

17. A marine vessel (1) comprising a wind-assisted propulsion arrangement (10) according to claim 16.

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