Wing sail structure for a wind-assisted propulsion assembly for marine vessels

Abstract

The present invention relates to a wing sail structure (100) for a wind-assisted propulsion assembly (10) of a marine vessel (1). The wing sail structure (100) includes a wing sail frame (101), and the wing sail frame (101) includes a rigid or semi-rigid main wing sail (110) and a flap (120) having an airfoil shape, and at least one upper and lower connecting member (130; 140) connecting the main wing sail and the flap. The wing sail structure further includes a base (20) arranged to be fixed to the main body (3) of the vessel (1), and the wing sail frame is rotatable relative to the base. The flap (120) is rotatable about a second longitudinal axis in order to bring the flap and its flap center line (FCL) to a position inclined with respect to the main wing sail center line (MCL). The second axis of rotation is arranged offset laterally to the main wing sail center line (MCL). Thus, only one axis of rotation is required to tilt the flap.

Description

Technical Field

[0001] The present disclosure relates to a wing sail structure for a wind assisted propulsion assembly of a marine vessel, and also to a method of operating a wind assisted propulsion assembly including a wing sail structure as defined in the appended claims.

Background Art

[0002] Sails have long been known as a means of propelling ships. Conventionally, flexible sails have been mounted on masts to utilize the power of the wind to propel ships. Modern merchant ships generally use fossil fuels and combustion engines to propel the vessel. To reduce the overall consumption of fossil fuels, the use of wind propulsion has been proposed. For this purpose, rigid sails can be used. The amount of power generated is related to a number of interrelated factors, but wing area and other geometric aerodynamic characteristics are the main performance indicators. Possible geometric setups can be achieved by combining a main wing with flaps, which can generate greater propulsion force for a given wing size compared to a wing without flaps. High-efficiency wing sail configurations and structures that can generate a large amount of propulsion force for a given absolute size can be obtained, for example, by adjusting the camber formed by the main wing sail and flaps. When the aerodynamic propulsion force from the wing sail is not desired, or when the force should be limited, the stability, safety, and operability of the ship should be taken into account. This adds complexity and challenges when using a rigid wing sail as a ship's propeller. In addition to this, ship performance is related to the dominant wind strength and direction. For example, due to the statistical distribution of wind strength, it is clear that the wind speed is fairly calm for most of the time. Therefore, the wing characteristics should be configured such that the wing sail can utilize low wind speeds and at the same time be able to handle higher wind speeds, which occur more rarely, in a safe manner.

[0003] The use of rigid sails has been discussed in the prior art. For example, U.S. Patent No. 10906620B2 discloses a reefable double airfoil that has shaped members for each of the front flap and the rear flap, which are traversed by a front mast, and on the one hand, can be oriented around the axis defined thereby. In a variant, the flap is constructed as a rigid box, which can be telescopically nested in series.

[0004] Also, U.S. Patent No. 10906620B2 discloses, in a variant, a reefable double airfoil, where the front airfoil and the rear airfoil are composed of rigid boxes traversed by their respective masts. The airfoils can rotate around them and can be reefed. Thus, the rigid airfoils can be reefed by telescopically collapsing the airfoils along the mast, i.e., can be brought to a non-propulsion position. However, telescopic nesting can cause wear of the box, and this can lead to problems associated with the fit of the boxes when nesting them. In the case of damage to the box, it may be difficult to retract the sail, and thereby, its construction may be subjected to forces exerted by the wind when propulsion by the wing sail is not desired.

[0005] Even if there are known rigid wing sail solutions, there is still room for improvement.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the context of the present invention, it has been noted that reefing large rigid or semi-rigid wing sails is demanding. Due to the height and large total area of such rigid wing sails, problems have been recognized when finding an appropriate way or when reefing and stowing the wing sails when the wing sails are not in use on board a marine vessel.

[0008] In view of the drawbacks and limitations of prior art solutions, an object of the present invention is to provide a marine vessel equipped with a wind-assisted propulsion assembly, which in particular addresses at least in part the problems associated with known solutions regarding the robustness of the wing sail structure, the arrangement of the wing sail structure in a neutral non-propulsion position in a robust and space-saving manner, and the easy maintenance and servicing of the wing sail structure.

[0009] It has been noted that it may be advantageous that a conventional mast is not used when reefing in relation to large rigid wing sails. Instead, the wing sail is arranged to be tilted to a non-propulsion position. However, due to the large size of the wing sail, it should be ensured that the wing sail can be stowed in a compact manner when the wing sail is in the non-propulsion position, for example when the vessel is at anchor. Additionally, the structure of the wing sail needs to be reinforced in an appropriate way to provide a robust construction.

Means for Solving the Problems

[0010] The above object is achieved by the present invention as defined in the appended independent claims.

[0011] Accordingly, the present invention relates to a wing sail structure for a wind-assisted propulsion assembly of a marine vessel. The present invention includes a wing sail frame, which is rotatably connected to a base via a first longitudinal axis of rotation. The wing sail frame includes a main wing sail and a rear flap, the main wing sail and the rear flap each having an airfoil shape and including a rigid or semi-rigid side wall portion extending between an upper end and a bottom end and having a leading edge and a trailing edge. The main wing sail has a main wing sail center line, and the rear flap has a flap center line, and their center lines extend between the respective leading edge and trailing edge in a cross-sectional view. The wing sail frame further includes at least one connecting member connecting the main wing sail and the rear flap. The flap is rotatably arranged about a second longitudinal axis of rotation in order to bring the flap and its flap center line to a position inclined with respect to the main wing sail center line. The second axis of rotation is arranged offset laterally from the main wing sail center line. The second axis of rotation can be positioned outside the periphery defined by the side wall portion of the main wing sail. Similarly, the second axis of rotation can be arranged offset laterally from the flap center line. Additionally, the second axis of rotation can be arranged outside the periphery defined by the side wall portion of the flap. Further, the second axis of rotation can be connected to at least one connecting member.

[0012] With this construction, several advantages can be achieved. Since the second axis of rotation is offset laterally from the centerline of the main wing sail, when the flap is folded towards the main wing sail, it is possible to bring the flap very close to the main wing sail. Thus, it is possible to reduce the space required during folding. Additionally, due to the inclination of the flap with respect to the main wing sail, only one point of rotation is required. Further, when the second axis of rotation is positioned outside the periphery defined by the side walls of the main wing sail and / or the flap, the point of rotation is separated from the main body of the main wing sail and / or the flap, which can improve the robustness and functionality of the structure and facilitate maintenance. Further, when the second axis of rotation is connected to at least one connecting member, the structure will become robust and can be simplified.

[0013] The main wing sail and the flap preferably 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.

[0014] Each of the main wing sail and the rear flap can further include a support frame extending longitudinally along the length of the respective main wing sail and rear flap. The support frame can be disposed inside the respective main wing sail and flap, whereby the support frame can be mainly positioned within the side walls of the respective main wing sail and flap. However, the support frame can extend outside the extension of the side wall, for example, at the end parts and bottom parts of the main wing sail and the flap. The support frame provides structural stability for the wing sail frame.

[0015] At least one of the support frames can have a hollow structure. Alternatively, at least one of the support frames can have a structure such as a wall. The support frames can have the same type of structure adapted to the size of each main wing sail or flap. Alternatively, the support frame structures may differ in the main wing sail and the flap. For example, the support frame associated with the main wing sail can have a hollow structure, and the support frame associated with the flap can have a structure such as a wall. Regardless of the type of support frame, according to a modification, it can be connected to the inner surface of the side wall portions of each main wing sail and flap. The hollow structure and / or the wall type structure provide a reduced weight for the frame and a less rigid construction. Thus, the frame will have a certain degree of flexibility.

[0016] At least one connecting member can be fixed to the respective frame structures of the main wing sail and the flap. In this way, a more robust construction can be provided.

[0017] At least one connecting member can be associated with the respective bottom ends and / or top ends of the main wing sail and the flap. The connecting member can include a first boom member connected to the flap and a second boom member connected to the main wing sail. The first boom member and the second boom member can be connected to each other via a second axis of rotation. In this way, the second axis of rotation provides a hinge-type connection between the boom members, whereby only one axis of rotation for tilting the flap relative to the main wing sail can be provided in a robust manner.

[0018] The first boom member and the second boom member can be fixed in a non-rotatable manner to the respective frame structures of the flap and the main wing sail. The rotation of the flap with respect to the main wing sail can be provided by the second rotation axis. Thus, a robust construction is provided.

[0019] The flap can be configured to be rotatable with respect to the main wing sail by a movable lever arm that is movably fixed to the first and second boom members. The movable lever arm is driven by at least one linear actuator or motor. The linear actuator can include, for example, a hydraulic cylinder.

[0020] Each of the bottom end and / or top end of the main wing sail and the flap can include a respective bottom end cover plate and / or top end cover plate. The cover plate can have an outer periphery that extends at least partially across the periphery of the side wall portion of each of the main wing sail and the flap. The support frames of the main wing sail and the flap can be connected to the respective bottom cover plate and / or top cover plate. The cover plate can be used for controlling the air flow and for preventing turbulence.

[0021] The second rotation axis can be positioned laterally outward, that is, outside the periphery of the main wing sail and the flap, of the area defined by the side wall portions of the main wing sail and the flap. In this way, a robust construction can be provided.

[0022] The wing sail structure can be configured such that the flap center line can be aligned with the main wing sail center line or be parallel to the main wing sail center line but at a lateral distance to a neutral position, and / or to a propulsion position where the flap center line is inclined with respect to the main wing sail center line, and / or to a folded non-propulsion position where one side wall portion of the flap faces one side wall portion of the main wing sail, the flap being able to be tilted. Thus, different propulsion positions can be provided by rotation of the flap with respect to the main wing sail and in addition by rotation of the entire wing sail frame. The angle of rotation of the flap center line is suitably at least 90°, or at least 120°, or at least 150° with respect to the normal of the main wing sail center line when the flap is rotated from the neutral position to the folded position. Thus, according to this solution, the flap can be rotated more than is required to provide a camber in the propulsion position, and the flap can be folded towards the main wing sail by using only one axis of rotation.

[0023] The wing sail structure can further include a tilting structure, which is configured to move from a folded position standing on the base with respect to the wing sail frame to a tilted position. The tilt angle can vary and can be, for example, from 10° to 100°. Since the wing sail frame can be brought to the folded position before tilting the wing sail frame, storage can be provided in a space-saving manner.

[0024] The wing sail frame can include at least one intermediate connecting member, and the at least one intermediate connecting member is positioned along the longitudinal extension of the main wing sail and the flap between the upper end and the lower end of each main wing sail and flap. In this way, it is possible to improve the structural stability of the connection between the main wing sail and the flap.

[0025] Furthermore, the present invention relates to a wind-assisted propulsion configuration including at least one wing sail structure as defined above, and also relates to a marine vessel including the wind-assisted propulsion configuration.

[0026] Further features and advantages of the present invention will be described with reference to the accompanying drawings.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 2d

Figure 2e

Figure 3

Figure 4a

Figure 4b

Figure 4c

Figure 4d

Figure 4e

Figure 5

Figure 6

Figure 7

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to utilize wind as power for ship propulsion, the wing sail is formed such that it can generate sufficient propulsion force to overcome the ship's resistance, either by itself or together with the ship's engine. In the present application, the wing sail is generally defined as a rigid or semi-rigid structure, which can be similar to the wings of an aircraft and can be fixed vertically or axially on an ocean ship to provide propulsion force from the action of the wind. The construction, size, and number of wing sails are adapted to the ship in question. Generally, the stronger the resistance, the larger the wing sail and / or the greater the number of wing sails. For example, when a rigid wing sail is not used, such as due to bad weather, due to height restrictions on the selected route, or during cargo operation, a safety mode should be guaranteed.

[0029] According to the present invention, a wing sail structure including a wing sail frame is provided. The wing sail frame includes a main wing sail and a rear flap, and the main wing sail and the rear flap are connected by at least one connecting member. 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 part has an airfoil shape. The airfoil shape means the cross-sectional shape of the wing sail whose movement through the air can generate a (considerable) lift force. The main wing sail and the rear flap include a rigid or semi-rigid side wall portion extending between an upper end and a bottom end, and have a leading edge and a trailing edge. The main wing sail has a main cross-sectional center line MCL, and the rear flap has a rear flap cross-sectional center line FCL, and these center lines extend between the respective leading edge and trailing edge, and are to be illustrated later in the description with reference to the attached drawings. The flap is connected to the main wing sail via at least one connecting member. The main center line and the flap center line can be aligned when the main wing sail and the flap are in a neutral position, or can be laterally offset from each other or placed at a distance, as will be described in more detail below.

[0030] In addition to the entire frame being rotatable about a first longitudinal axis of rotation, the flap is individually rotatably arranged about a second longitudinal axis of rotation. During rotation, the flap center line can be rotated relative to the main wing sail center line MCL from a neutral position (I) to an inclined position, where in the neutral position (I), the flap center line FCL is continuously (i.e., successively) aligned with or is continuously arranged but laterally offset or spaced apart from the main wing sail center line MCL. Thus, the flap and its center line can be rotated to a propulsion position, where the flap center line FCL is inclined relative to the main wing sail center line MCL. The angle of inclination can be determined with respect to a normal, which is perpendicular to the main wing sail center line MCL. When in the neutral position, the flap center line FCL is positioned perpendicular to the normal. When inclined to the propulsion position, the flap is inclined either counterclockwise or clockwise with respect to and towards the normal relative to the leading edge of the main wing sail. Thus, the flap can be inclined either to the left or to the right relative to the leading edge of the main wing sail, i.e., the flap can be inclined either to the left or to the right relative to the leading edge of the main wing sail. The angle of inclination in the propulsion position is less than 90° towards the normal. Also, the flap can be rotated to a folded non-propulsion position, where one side wall of the flap faces one side wall of the main wing sail. The angle of inclination when folding is at least 90°, or at least 120°, or at least 150° with respect to and passing through the normal of the main wing sail center line MCL, i.e., with respect to the normal of the main wing sail center line MCL.

[0031] According to the present invention, the second axis of rotation is arranged laterally offset from the main wing sail center line MCL when the wing sail frame is in the neutral position. The second axis of rotation can additionally be arranged laterally offset from the flap center line FCL.

[0032] The main wing sail and the flap are properly separated by a slot when the main wing sail and the flap are in their neutral positions. The slot defines the distance between the trailing edge of the main wing sail and the leading edge of the flap. The slot extends in the same direction as the center lines MCL and FCL in the neutral position. When the slot is present in the neutral positions of the main wing sail and the flap, the main wing sail and the flap do not laterally overlap each other when viewed in cross section. The slot or distance between the trailing edge of the main in the neutral position and the leading edge of the flap is adapted to the desired aerodynamic performance. The distance is generally smaller than the lengths of the respective main wing sail and flap between their respective leading and trailing edges. The slot improves the aerodynamic performance of the wing sail frame and structure.

[0033] The second axis of rotation can be connected to at least one connecting member to provide a robust construction. In this way, when folding the flap over the main wing sail, a more compact wing sail position can be obtained. At the same time, in use, the flap can be tilted relative to the main wing sail to provide a camber that provides propulsion. The main wing sail cannot rotate individually with respect to the flap center line. Instead, the main wing sail rotates when the entire wing sail frame rotates. By providing a flap (the flap is rotatable relative to the main wing sail about an axis that is offset from and optionally also from the main wing sail center line MCL and the flap center line FCL, i.e., spaced apart), it is possible to use only one axis of rotation to fold and tilt the flap. In this way, the flap can be tilted at different angles during sailing, while on the other hand, using only one rotation point, the flap can be folded towards the main airfoil. This is a great advantage as it simplifies the structure and control of the wing sail structure. It also allows the hinge or lever arm to be distributed vertically between the main wing sail and the flap and to hold the flap towards the main airfoil.

[0034] In addition to the folding function provided by the second axis of rotation, by adjusting the camber formed by the main wing sail and the flap, it is possible to adjust the amount of power generated. Since the flap can be folded towards the main wing sail, it is possible to reduce the projected area of the wing sail frame. Therefore, the space required by the wing sail frame is also reduced on board the ship. When the main wing sail and the flap are folded, the generated force can be reduced. In this way, a minimum power configuration can be obtained under the desired conditions, which may be important for the safety, structural integrity, and operability of the ship.

[0035] To prevent the propulsion provided by the wing sail, the wing sail frame can be tilted horizontally towards the deck to an inclined position. The "inclined" position means a position where the wing sail frame is inclined towards the horizontal position and / or can be inclined towards the deck of the ship or towards a support above the deck. The wing sail frame can be stored in this position, which is also referred to herein as the storage position. In the inclined position, as well as when the main wing sail and the flap are in the folded position, the space above the deck of the ship can be saved compared to the main wing sail and the flap that are not in the folded position. This is also illustrated in the accompanying drawings.

[0036] To provide an inclined position, the wing sail frame is inclined from a vertically upright position towards a horizontal position. The wing sail frame has a longitudinal axis which, when the wing sail frame is in the upright position, extends in a direction perpendicular to the ship's deck. Thus, the wing sail frame is inclined with respect to a horizontal axis of rotation which is perpendicular to the longitudinal axis and is thus essentially horizontal or transverse with respect to the ship's deck. In the inclined position, the longitudinal axis of the wing sail frame can thus be essentially horizontal. However, the inclined wing sail requires a large space above the deck of an ocean-going ship, which may be difficult to find. Therefore, it is essential to minimize the required space as much as possible in order to enable the installation of the wing sail assembly.

[0037] A wing sail structure (which includes a wing sail frame and a foundation), and an assembly including one or more wing sail structures can be used in an ocean-going or seagoing ship, i.e., a ship used as a means of waterborne transportation. The main wing sail and the flap are made substantially from a rigid or semi-rigid material and have an airfoil shape. Both the main wing sail and the flap have a side wall portion, a leading edge portion and a trailing edge portion, and an upper end portion and a bottom end portion. Further, the main wing sail has a main cross-sectional center line MCL and the rear flap has a flap cross-sectional center line FCL, and these center lines extend between the respective leading edge portion and trailing edge portion.

[0038] A "rigid" material means a given material which can be a composition of several materials, which is not foldable and can support its own weight when placed on parallel edges of such a material. A "semi-rigid" material is a given material which is partially rigid and has a certain degree of flexibility but can still support its own weight when placed on parallel edges of such a material.

[0039] The "airfoil" shape, as used in this application, means a wing profile having an aerodynamic shape when viewed in the front-to-back direction (i.e., from the leading edge direction to the trailing edge direction) in cross-section. The aerodynamic airfoil shape is advantageous because it allows air to pass more easily over the wing sail. The shape may be asymmetric in said direction, but it can also include a symmetric section or the shape can be a symmetric airfoil. The airfoil shape can be defined, for example, according to the NACA standardized series, but the shape is not limited thereto.

[0040] For a better understanding of the present invention of the present disclosure, it will now be described with reference to the accompanying drawings, which are provided to illustrate non-limiting exemplary embodiments of the present invention. It should be noted that in the drawings, not all reference signs are added to all the drawings for clarity, but it will be apparent to those skilled in the art that reference signs related to structural details in one drawing are applicable in a similar manner to other drawings showing the same details.

[0041] Referring to FIG. 1, an ocean vessel 1 including a wind-assisted propulsion structure 10 with three wing sail structures 100 is shown. Each of the wing sail structures 100 includes a wing sail frame 101, which is schematically shown in FIG. 1 by a rectangle with a dotted line in relation to the middle wing sail frame 101. The wing sail frame 101 includes a main wing sail 110, 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, which means that there is a certain degree of flexibility. The wing sail frame is further shown below in FIGS. 2a to 2e, which are also referred to herein.

[0042] The wing sail structure 100 further includes a base 20, which can be fixed to the deck 3 (i.e., the main body of the vessel 1). The wing sail frame 101 is rotatably connected to the base 20 via a first longitudinal rotation axis 111. The first rotation axis is configured to enable the rotation of the entire wing sail frame with respect to the base 20. Thus, the main wing sail rotates when the entire wing sail frame rotates. The first longitudinal rotation axis can be provided by any suitable means, for example, by a shaft removably attached to the base 20 or, for example, by a swivel ring. The base 20 is further associated with the wing sail frame 101 and is in a neutral non-propulsion position (I), or in a propulsion position (II) where the flap is inclined with respect to the main wing sail center line MCL, or in a folded position (III) when the wing sail frame is in an upright vertical position, or when the wing sail frame is tilted to a position (IV), it is configured to support the frame. Also, the base can be associated with the wing sail frame when the wing sail frame is taken to an inclined position (IV).

[0043] In the deployed upright position shown in FIG. 1, the wing sail frame is disposed in the upright propulsion position (II). The propulsion force provided by the main wing sail and the flap can be varied by changing the camber (i.e., the convexity of the curvature of the form of the main wing sail and the flap from the leading edge of the main wing sail to the trailing edge of the flap), as schematically illustrated by the camber curve C in relation to the foremost wing sail frame in FIG. 1. The convexity can be adjusted by adjusting the inclination of the flap with respect to the main wing sail, as shown in FIGS. 2a-2d. In the upright position, the longitudinal axis L of the wing sail structure (shown only in relation to one structure 100) is essentially parallel to the general vertical axis V, which is perpendicular to the horizontal axis H of the ship 1. The horizontal axis H can extend in substantially the same direction as the deck floor. Also, the wing sail structure has an extension in the depth direction D, which is perpendicular to the plane formed by the two-dimensional longitudinal L direction and the transverse T direction. The extension of the wing sail frame 101 decreases in the transverse direction T and increases in the depth direction D when the flap is folded towards the main wing sail.

[0044] Both the main wing sail 110 and the flap 120 have an airfoil shape. The main wing sail 110 has a leading edge 117, a trailing edge 118 (FIG. 2a), an upper end 115, a bottom end 116 (FIG. 1), and side walls 211 and 212 (FIG. 2a) extending therebetween. In a similar manner, the flap 120 has a leading edge 127, a trailing edge 128 (FIG. 2a), an upper end 125, a bottom end 126 (FIG. 1), and side walls 221 and 222 (FIG. 2a) extending therebetween. As shown in relation to FIGS. 2a, 2b, 3, and FIGS. 4a and 4b, there is a slot 250 that defines a distance d between the main wing sail trailing edge 118 and the flap leading edge 127 in a cross-sectional view. This slot ensures that the main wing sail 110 and the flap 120 do not laterally overlap in the cross-sectional view when the main wing sail and the flap are in the neutral position (I), as illustrated for example in FIGS. 2b and 4b. The shape of the airfoil generally has a tapered shape from the leading edge towards the trailing edge.

[0045] The side walls 221 and 222 are integrated with the leading edge 127 and the trailing edge 128 to form an airfoil shape. The side walls 221 and 222 can be formed from modules that are permanently or removably attached to each other, and the modules together form an integrated wing sail or flap having an airfoil shape. The profiles of the wing sail and the flap can be designed with different modular elements that can be combined to achieve wing sails of different sizes. The main wing sail and the flap can include, but are not limited to, any suitable materials such as moldable polymer materials, glass fiber materials, carbon fiber materials, and / or composite materials.

[0046] The wing sail frame 101 further includes at least one connecting member 140, and in the illustrated example of FIG. 1, the at least one connecting member 140 is a lower connecting member associated with and installed at the bottom end 116 of the main wing sail 110 and the bottom end 126 of the flap 120. The wing sail frame can additionally or alternatively include an upper connecting member 130 associated with the upper end 115 of the main wing sail 110 and the upper end 125 of the flap 120. The connecting members 130, 140 can have a similar construction at both the top and bottom, or the constructions can be different from each other. The connecting members 130, 140 are configured to connect the main wing sail 110 and the rear flap 120.

[0047] According to the present invention, the flap 120 is rotatable about a second longitudinal axis 112 in order to hold the flap in a position inclined with respect to the main wing sail center line MCL. In this way, the flap can be inclined at different angles during sailing, and it can be folded towards the main airfoil using only one rotation point. This simplifies the structure and control of the wing sail structure, which is a significant advantage compared to known solutions.

[0048] Figures 2a - 2e illustrate a second longitudinal axis of rotation 112 which, in the example shown, is connected to at least one connecting member 140 and is disposed offset laterally from the main wing sail center line MCL and also offset laterally from the flap center line FCL. This is illustrated in FIGS. 2a and 2b which show the main wing sail 110 and flap 120 in a neutral position (I). In FIGS. 2a and 2b, the axis of rotation center line RCL (FIG. 2a) is laterally spaced parallel from the main wing sail center line MCL and the flap center line FCL. Thus, as indicated by arrows d1 and d2 in FIG. 2a, there is a lateral distance between the axis of rotation center line RCL and the main wing sail center line MCL. The lateral direction is perpendicular to the extension of the center lines MCL, FCL.

[0049] The connecting member 140 can include a first boom member 141, and the first boom member 141 is connected to the flap 120. The first boom member 141 can include a bar, and the bar is fixed to the flap 120 in a non-rotatable manner. The connecting member 140 can include a second boom member 142, and the second boom member 142 is connected to the main wing sail 110. The second boom member 142 can include a bar, and the bar 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 can be connected to each other via a second rotation axis 112, and the second rotation axis 112 provides a hinge-type connection. Accordingly, the connecting member 140 rotatably connects the main wing sail 110 and the flap 120 to each other via the second rotation axis 112. Being rotatably connected means that the flap 120 can be rotated around the second longitudinal axis 112 in order to bring the flap towards the main wing sail so that the flap center line FCL is rotated with respect to the main wing sail center line MCL. The longitudinal axis is parallel to the vertical axis L when the wing sail frame is in an upright position (e.g., in a propulsion position).

[0050] The rotation of the flap is illustrated in FIGS. 2c to 2e. In FIGS. 2b to 2e, the center lines FCL and MCL of the flap 120 and the main wing sail 110 are illustrated by dotted lines. Also, the normal line N of the main wing sail center line MCL (i.e., the line perpendicular to the main wing sail center line MCL) is drawn and illustrated through the second rotation axis 112. The inclination of the flap can be illustrated as the rotation of the flap center line FCL with respect to the normal line N. When the flap 120 is inclined to the propulsion position (II) and forms the camber C together with the main wing sail 110, the flap center line FCL is inclined from the neutral position (I) toward the normal line N. The angle of inclination is preferably less than 90° from the neutral position (I) toward the normal line N. The inclination can be directed either to the left or to the right with respect to the leading edge 117 of the main wing sail (see FIG. 2a). This is illustrated in FIGS. 2c and 2d. Therefore, the inclination can be made toward either one of the side walls 211, 212 of the main wing sail 110. 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 is at least 90°, or at least 120° or at least 150° toward and through the normal line N of the main wing sail center line MCL, as illustrated in FIG. 2e. Thus, the wing sail can be stored in a compact manner.

[0051] The rotation of the flap 120 can be actuated in different ways. FIG. 3 shows an example of a rotation configuration including a rotary actuator 1121. The actuator can be used to rotate the flap 120 around the second rotation axis 112 with respect to the main wing sail 110. The actuator can be driven, for example, by an electric motor or a hydraulic motor.

[0052] Figures 4a - 4e show further examples of the rotating structure 1120 for rotating the flap 120 relative to the main wing sail 110. Figures 4a - 4e additionally show that the wing sail frame further includes support frames 310, 320 that extend longitudinally along the lengths of their respective main wing sails and rear flaps. The main wing sail support frame 310 is disposed inside the main wing sail 110, and the flap support frame 310 is disposed inside the flap 120. In the illustrated example, each of the support frames 310, 320 has a hollow structure and is connected to the inner surfaces of the side walls 211, 212, 221, 222 of their respective main wing sails and flaps. The purpose of the frame structure is to provide support for the wing sail, thereby providing a robust construction. The frame structure may be provided in modules or as a one-piece construction. The frame construction can have a hollow structure and can be connected to the inner surfaces of the side walls of their respective main wing sails and flaps and is dimensioned to fit inside their respective main wing sails and flaps. However, the support frames can have other shapes, for example, they can be wall-type structures. Such structures can be used, for example, inside the flap 120, which is smaller than the main wing sail. In this way, the weight of the flap can be minimized while sufficient support is provided.

[0053] The rotary structure 1120 is associated with at least one lower connecting member 140, and the at least one lower connecting member 140 is, in the illustration, associated with the bottom end 116 of the main wing sail 110 and the bottom end 126 of the flap 120. In a manner similar to that described in connection with FIGS. 2a-2e, the connecting member 140 can additionally or alternatively be positioned at the upper end 115 of the main wing sail or the upper end 125 of the flap 120. As shown in FIG. 4b with reference numerals (which apply equally to all of FIGS. 4a-4e), the connecting member 140 includes a first boom member 141. The first boom member 141 of the connecting member 140 is rigidly (i.e., in a non-rotatable manner) connected to the flap 120 via the flap frame structure 320. The flap frame structure 320 extends a specific length outside the extensions of the side walls 221, 222 of the flap 120 to provide a robust construction. The connecting member 140 includes a second boom member 142, and the second boom member 142 is connected to the main wing sail frame structure 310 of the main wing sail 110 in a rigid non-rotatable manner. The second boom member is connected to the first boom member via a second axis of rotation 112 that provides a hinged connection. The connecting member (which is connected to the flap and the main wing sail) is configured to rotate the flap 120 relative to the main wing sail 110 by a movable lever arm 145, and the movable lever arm 145 is movably fixed to the first and second boom members 141, 142. The number of movable lever arms in the illustrated example is two, but it can be more or only one. The movable lever arm 145 is driven by at least one linear actuator or motor 147.

[0054] Figures 4b - 4e show embodiments of a connecting member configured to rotate a flap relative to a main wing sail. In Figures 4b - 4e, the flap 120 and the main wing sail 110 include a flap center line FCL and a main center line MCL. As shown in Figure 4b (in Figure 4b, the main wing sail (110) and the flap (120) are in a neutral position (I)), there is a slot 250 between the main wing sail 110 and the flap 120, and the main wing sail trailing edge 118 and the flap leading edge 127 have a distance (d) therebetween. Additionally, the main center line MCL and the flap center line 127 are parallel to each other and are laterally displaced from each other by a distance CLD in a cross-sectional view. The slot 250 extends in the same direction as the center lines MCL and FCL in the neutral position (I), and the main wing sail 110 and the flap 120 do not laterally overlap in the neutral position (I). There is also a normal N to the main wing sail center line MCL, but it is not shown. The inclination of the flap 120 to provide a propulsion position (II) can be either to the left as in Figure 4c or to the right with respect to the leading edge 117 of the main wing sail (see Figure 4d). Thus, the inclination can be made towards either one of the side walls 211, 212 of the main wing sail 110. When the flap is folded to the folded position in Figure 4e and rotated from the neutral position (I) of Figure 4b to the folded position (III) of Figure 4e, the angle of inclination is in a manner similar to that shown in Figure 2e, towards and passing over the normal N to the main wing sail center line MCL, i.e., with respect to the normal N to the main wing sail center line MCL, at least 90°, or at least 120°, or at least 150°. In this way, the wing sail can be stored in a compact manner.

[0055] Figure 5 shows an embodiment of a wing sail frame, where the bottom end 116 of the main wing sail 110 includes a bottom end cover plate 1160. The upper end 115 can similarly include an upper end cover plate (not shown) in a similar manner. The bottom end cover plate 1160 has an outer peripheral portion that extends at least partially across the peripheral portion of the main wing sail formed by the side walls 211, 212 and the flap 120 of the main wing sail 110. In a similar manner, the flap 120 can include a bottom end cover plate 1260.

[0056] The bottom end plates 1160, 1260, which have a peripheral portion larger than the peripheral portion of the main wing sail and the flap defined by their respective side walls, provide control of the air flow and prevent turbulent flow. According to a modification, the second rotation axis 112 can be connected to the bottom end plate and / or the upper end plate. It can be positioned laterally outward of the area defined by the side walls of the main wing sail and the flap (i.e., the peripheral portion defined by the side walls of the main wing sail and the flap in a cross-sectional view). The support frames 310 and 320 of the main wing sail and the flap can be arranged connected to their respective bottom end plates 1160 and 1260.

[0057] Figure 6 illustrates a further embodiment of the present invention. In addition to the lower connecting member 140, the wing sail includes at least one shown intermediate connecting member 150 positioned along the longitudinal extension of the main wing sail 110 and the flap 120 between the upper ends 115, 125 and the lower ends 116, 126 of the respective main wing sail 110 and flap 120 in the illustrated example 3. This further improves the robustness of the structure.

[0058] The wing sail structure 100 can further include a tilting structure (not shown), and the tilting structure is configured to move the wing sail frame from an upright position to a tilted position, for example, from an upright position (III) folded with respect to the base 20 to a tilted position (IV). FIG. 7 shows the wing sail frame in the tilted storage positions (III, IV). The wing sail frame can be tilted to a substantially horizontal position, and in the substantially horizontal position, the side wall portion between the leading edge and the trailing edge faces the deck of the ship. Alternatively, the wing sail frame can be tilted to a vertical position, and in the vertical position, the leading edge or the trailing edge faces the deck of the ship. However, the tilt angle can vary, for example, it can be 10° to 100° with respect to the deck of the ship, and more generally, it can be up to 90°, which corresponds to a position substantially horizontal with respect to the deck. To provide the tilted position, the wing sail frame 101 having a longitudinal axis L extending in the vertical direction V when the wing sail frame is in the upright position is tilted around a transverse rotation axis. The transverse rotation axis RT is perpendicular to the longitudinal axis L and is thus essentially horizontal. The arrow RT indicates the direction of tilt with respect to the rotation axis. Thus, in the tilted position, the longitudinal axis L of the wing sail frame can be essentially parallel or substantially parallel to the horizontal axis H. Alternatively, the tilt angle can be less than 90°, and the longitudinal axis L can correspondingly be tilted at an angle less than 90° with respect to the horizontal axis. Further, the wing sail frame 101 can be tilted in a horizontal plane as illustrated by the arrow RH. In this way, the wing sail frames can also be tilted with respect to each other when they are in the tilted positions. This can facilitate the storage of the wing sail frames. Tilting can be achieved by a tilting structure configured within the wing sail structure 100.

[0059] Generally, the main wing sail, the flap, and the upper and lower connecting means can include a suitable arrangement configured to provide a rotational movement with respect to the axis of rotation, for example, including a shaft, bearings (e.g., roller bearings), and drive means. The rotation of the wing sail frame, the main wing sail, and / or the flap can be controlled, for example, by incorporating electrically controllable means into each axis of rotation. The control unit can then be connected to the drive assembly to adjust the rotation of the wing sail frame, the main wing sail, and / or the flap. The degree of rotation of the wing sail frame, the main wing sail, and / or the flap is adapted to the dominant ambient conditions. The rotational assembly, and each of the vertical axes of rotation of the main wing sail and the flap, can be arranged with stop means such 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 can be avoided, for example, in the case of changes in dominant wind / weather conditions.

[0060] The wind-assisted propulsion assembly 10 - controlling the degree of rotation of the wing sail frame 101 and / or the flap 120 from a neutral position (I) to a propulsion position (II) to provide a camber; - folding the flap towards the main wing sail to provide a folded upright position (III); - tilting the wing sail frame (101) towards the hull of the ship to provide a tilted position (IV) and can be operated according to a method including.

[0061] The detailed description and the drawings are aimed at facilitating the understanding of the embodiments of the present invention, but do not limit the scope of the present invention. The scope is limited by the appended claims.

Explanation of Signs

[0062] 1 Ship 3 Deck 10 Wind-assisted propulsion structure 20 Foundation 100 Wing sail structure 101 Wing sail frame 110 Main wing sail 111 First longitudinal rotation axis 112 Second longitudinal rotation axis 115 Upper end, upper side end 116 Bottom end, lower side end 117 Leading edge 118 Trailing edge 120 Rear flap 125 Upper end, upper side end 126 Bottom end, lower side end 127 Leading edge 128 Trailing edge 130 Upper connecting member 140 Connecting member 141 First boom member 142 Second boom member 145 Movable lever arm 147 Linear actuator, motor 150 Intermediate connecting member 211 Side wall part 212 Side wall part 221 Side wall part 222 Side wall part 250 Slot 300 Tilting structure 310 Main wing sail support frame 320 Flap support frame 1120 Rotating structure 1121 Rotary actuator 1160 Bottom end cover plate 1260 Bottom end cover plate C Camber curve CLD Lateral distance D Depth direction d Distance d1 Arrow d2 Arrow FCL Flap center line H Horizontal axis L Longitudinal direction MCL Main wing sail center line N Normal RCL Rotation axis center line RH Arrow RT Arrow T Transverse direction V Vertical axis (I) Neutral non-propulsion position (II) Inclined propulsion position (III) Folded position (IV) Tilted position

Claims

1. A wing sail structure (100) for wind-assisted propulsion of a marine vessel (1), said wing sail structure (100) comprising a wing sail frame (101), said wing sail frame (101) being rotatably connected to a foundation (20) via a first longitudinal axis of rotation (111), said wing sail frame (101) being a main wing sail (110) and a rear flap (120), said main wing sail (110) and said rear flap (120) each having an airfoil shape and including rigid or semi-rigid side wall portions (211, 212; 221, 222) extending between an upper end (115; 125) and a bottom end (116; 126), having a leading edge (117; 127) and a trailing edge (118; 128), said main wing sail (110) having a main wing sail center line (MCL), said rear flap having a flap center line (FCL), said center lines extending between said respective leading edges (117; 127) and trailing edges (118; 128) in a cross-sectional view, the main wing sail (110) and the rear flap (120), and at least one connecting member (140) connecting said main wing sail (110) and said rear flap (120) including, said rear flap (120) being rotatably arranged about a second longitudinal axis of rotation (112) in order to bring said rear flap and its said flap center line (FCL) to an inclined position with respect to the main wing sail center line (MCL), said second longitudinal axis of rotation (112) being laterally offset with respect to the main wing sail center line (MCL), the wing sail structure (100).

2. The wing sail structure (100) according to claim 1, wherein said second longitudinal axis of rotation (112) is connected to said at least one connecting member (140).

3. Each of the main wing sail (110) and the rear flap (120) further includes a support frame (310; 320) that extends longitudinally along the length of each of the main wing sail (110) and the rear flap (120), and is disposed inside each of the main wing sail (110) and the rear flap (120). The wing sail structure (100) according to claim 1 or 2.

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

5. The at least one connecting member is fixed to the respective frame structures (310; 320) of the main wing sail (110) and the rear flap (120). The wing sail structure (100) according to claim 3 or 4.

6. The at least one connecting member (140) is associated with the respective bottom end portions (116; 126) and / or the upper end portions (115; 125) of the main wing sail (110) and the rear flap (120), and is connected to the rear flap (120). A first boom member (141) and a second boom member (142) connected to the main wing sail (110), wherein the first boom member (141) and the second boom member (142) are connected to each other via the second longitudinal rotation axis (112). The wing sail structure (100) according to any one of claims 1 to 5.

7. The first boom member (141) and the second boom member (142) are fixed to the respective frame structures (320; 310) of the rear flap (120) and the main wing sail (110) in a non-rotatable manner. The wing sail structure (100) according to claim 6.

8. The rear flap (120) is configured to be rotatable with respect to the main wing sail (110) by a movable lever arm (145) movably fixed to the first boom member (141) and the second boom member (142), and the movable lever arm (145) is driven by at least one linear actuator (147) or a motor. The wing sail structure (100) according to claim 6 or 7.

9. Each of the bottom end and / or the upper end of the main wing sail and the rear flap includes a respective bottom end cover plate (1160; 1260) and / or an upper end cover plate, and the bottom end cover plate (1160; 1260) and / or the upper end cover plate has an outer peripheral portion that extends at least partially over the peripheral portion of the side wall portions (211, 212; 221, 222) of the respective main wing sail (110) and the rear flap (120). The wing sail structure (100) according to any one of claims 1 to 8.

10. The second longitudinal rotation axis (112) is positioned outwardly in the lateral direction of the area defined by the side wall portions of the main wing sail and / or the rear flap. The wing sail structure (100) according to any one of claims 1 to 9.

11. The rear flap is - up to a neutral position (I) where the flap center line (FCL) is aligned with the main wing sail center line (MCL), - up to a propulsion position (II) where the flap center line (FCL) is inclined with respect to the main wing sail center line (MCL), and / or - up to a folded non - propulsion position (III) where one side wall portion of the rear flap faces one side wall portion of the main wing sail configured to be inclined. The wing sail structure (100) according to any one of claims 1 to 10.

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

13. The wing sail structure (101) further includes a tilting structure (300), and the tilting structure (300) is configured to move the wing sail frame (101) from the upright position (I-III) with respect to the base to the tilted position (IV), the wing sail structure (100) according to any one of claims 1 to 12.

14. The wing sail frame (101) includes at least one intermediate connecting member (150), and the at least one intermediate connecting member (150) is positioned along the longitudinal extension of the main wing sail (110) and the rear flap (120) between the upper ends (115; 125) and the lower ends (116; 126) of the respective main wing sail and the rear flap, the wing sail structure (100) according to any one of claims 1 to 13.

15. The main wing sail (110) and the rear flap (120) are separated by a slot (250), the wing sail structure (100) according to any one of claims 1 to 14.

16. A wind-assisted propulsion structure (10) including at least one wing sail structure (100) according to any one of claims 1 to 15.

17. A marine vessel (1) including the wind-assisted propulsion structure (10) according to claim 16.

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