Propulsion unit and ship equipped with the propulsion unit

Abstract

Disclosed is a propulsion unit for propelling a vessel, the propulsion unit including a body configured to be disposed on a keel of the vessel and including a pivot point, a fin movably disposed relative to the body, and an actuator assembly for generating a heave motion of the fin relative to the body, the actuator assembly including at least one actuator, the fin arranged to pivot about the pivot point to generate a pitch motion of the fin when the at least one actuator couples to the pivot point to generate a heave motion of the fin.

Description

Technical Field

[0005]

[0001] The present disclosure relates to the field of ship propulsion systems. The present disclosure relates to a marine propulsion unit and a ship equipped with such a propulsion unit.

Background Art

[0002] It relates to the field of ship propulsion systems that convert the energy output from a ship's prime mover into forward motion. Depending on the type of ship and the services provided by the ship, fuel costs can account for 50 - 60% of the total operating costs of the ship. The screw propeller is the propulsion device mainly used in today's ships. The maximum achievable open-water efficiency with the latest screw propellers is about 70%. In the case of merchant ships, it is desirable to improve the efficiency of the propulsion system so as not to waste the energy supplied by the prime mover.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Therefore, there is a need for a propulsion system that reduces, alleviates, or addresses existing drawbacks and provides more efficient propulsion for a ship.

Means for Solving the Problems

[0004] Disclosed is a propulsion unit for propelling a ship. The propulsion unit includes a body configured to be disposed on the keel of the ship and including a pivot point, a fin movably disposed relative to the body, and an actuator assembly for generating a heave motion of the fin relative to the body and / or the keel. The actuator assembly includes at least one actuator. The fin is connected to the pivot point such that when at least one actuator generates a heave motion of the fin, the fin is arranged to generate a pitch motion of the fin by pivoting about the pivot point.

[0005] The advantage of this disclosure is that the hydrodynamic drag generated by the fins is less than that of conventional propulsion systems such as propellers driven by a shaft system moving underwater. The actuator of the propulsion unit provides a drive mechanism for generating the motion of the fins. This drive mechanism is simple and efficient, reducing the energy loss and maintenance requirements of the propulsion unit. The motion of the fins may be further controllable by the actuator so that the hydrodynamic properties of the fins can be adapted to improve the efficiency of the fins. Furthermore, the body of the propulsion system provides course stability to the ship containing the propulsion unit. This improves the efficiency of the propulsion unit.

[0006] A ship is disclosed having a propulsion unit for propelling the ship, as disclosed herein. The body is located on the keel of the ship. The fins are configured to perform pitching and / or heaving motions relative to the keel of the ship.

[0007] The advantages of this disclosure are that the ship's propulsion system is more efficient and has reduced maintenance requirements compared to conventional propulsion systems such as propellers driven by a shaft system moving underwater. Consequently, the ship's operating costs and emissions may be reduced by decreasing fuel consumption and downtime due to ship maintenance. Furthermore, the propulsion system body provides course stability to the ship, including the propulsion unit.

[0008] The above and other features and advantages of this disclosure will be readily apparent to those skilled in the art through the following detailed description of exemplary embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1A] Figure 1A shows an exemplary perspective view of a propulsion unit comprising a single actuator according to the present disclosure. [Figure 1B] Figure 1B shows an exemplary side view of a propulsion unit comprising a single actuator according to the present disclosure. [Figure 2A-2D]Figures 2A-2D show an exemplary overall design and motion pattern of a propulsion unit comprising a first actuator and a second actuator according to this disclosure. [Figure 3] Figure 3 shows an exemplary coupling for connecting fins to first and second actuators according to the present disclosure. [Figure 4] Figure 4 shows an exemplary body of the propulsion unit according to this disclosure. [Figure 5] Figure 5 is an exemplary graph showing the motion pattern of the fins of the propulsion system when the first and second actuators operate with a phase difference, according to the present disclosure. [Figure 6] Figure 6 shows an exemplary propulsion unit rotatably mounted on a ship according to the present disclosure. [Figure 7] Figure 7 shows an external perspective view of an exemplary ship equipped with an exemplary propulsion unit according to the present disclosure. [Figure 8] Figure 8 shows an inside perspective view of an exemplary ship equipped with an exemplary propulsion unit according to the present disclosure. [Figure 9] Figure 9 shows an exemplary propulsion unit according to the present disclosure, comprising first and second actuators positioned on the fins via a fixed pivot point. [Figure 10] Figure 10 shows an exemplary propulsion unit according to the present disclosure, comprising first and second actuators positioned on the fins via a fixed pivot point. [Figure 11] Figure 11 is an illustrative graph showing the motion patterns of fins in a propulsion system using different angle of attack profiles. [Modes for carrying out the invention]

[0010] Various exemplary embodiments and details are described below with reference to the relevant drawings. Note that the drawings may or may not be drawn to scale, and that elements of similar structure or function are represented by the same reference numerals throughout the drawings. Also note that the drawings are intended solely to facilitate the description of the embodiments. They are not intended to be an exhaustive description of the disclosure or to limit the scope of the disclosure. Furthermore, the illustrated embodiments do not necessarily have all the aspects or advantages shown. Aspects or advantages described in relation to a particular embodiment are not necessarily limited to that embodiment and may be implemented in any other embodiment even if they are not so illustrated or explicitly described.

[0011] These diagrams are schematic and simplified for clarity, and other details are omitted, but they provide details that are helpful in understanding the disclosure. Throughout, the same reference numbers are used for the same or corresponding parts.

[0012] A propulsion unit for propelling a ship is disclosed. The propulsion unit includes a body configured to be positioned on the keel of the ship and including a pivot point (such as a first pivot point), fins positioned to be movable relative to the body, and an actuator assembly for generating heave motion of the fins relative to the body. Heave motion may, as used herein, refer to the reciprocating motion of the fins, such as the linear vertical upward / downward motion of the fins relative to the body, when the propulsion unit is positioned on a ship. The actuator assembly includes at least one actuator. The fins are coupled to the pivot point so that, when at least one actuator generates heave motion of the fins, the fins pivot about the pivot point to generate pitch motion of the fins. Pitch motion of the fins as used herein refers to rotation about a transverse axis of the fins, such as an axis extending from a first tip to a second tip, for example, from the port tip to the starboard tip of the fin. The heave motion and / or pitch motion of the fins generate thrust for propelling the ship.

[0013] At least one actuator may be a linear actuator. The actuator may be a hydraulic, electric, or mechanical actuator. In one or more exemplary propulsion units, the actuator may be a hydraulic ram-type actuator. The propulsion unit may include at least one actuating rod. The actuator assembly may be connected to the fins via at least one actuating rod. The actuator assembly may be configured to actuate in a swinging pattern to generate swinging heave and pitch motions of the fins.

[0014] In one or more exemplary embodiments of the propulsion unit, the pivot point may be fixedly positioned on the main body. The propulsion unit may include a lever arm. The lever arm may be mounted on the pivot point so that it can pivot around the pivot point. Fins may be mounted on the pivot point via the lever arm. Since the fins can be mounted on a lever arm that is pivotably mounted on the pivot point, the fins can pivot around the pivot point.

[0015] In one or more exemplary embodiments of the propulsion unit, fins may be pivotably mounted on a lever arm. The propulsion unit may further include a pitch rod configured to change the pitch of the fins when an actuator generates a heave motion of the fins. The first end of the pitch rod may be pivotably mounted on the fins a short distance from the pivot point to which the fins are attached to the lever arm. The propulsion unit may include a crank, such as a bell crank, which has first and second arms and may be slidably mounted on the body of the propulsion unit a short distance from the respective ends of the first and second arms. The second end of the pitch rod may be pivotably mounted on the first end of the crank, and the actuator may be pivotably mounted on the second end of the crank. As the actuator reciprocates, the crank may rotate about the pivot point, so that a change in the position of the second arm of the crank changes the position of the second end of the pitch rod. This causes the first end of the pitch rod to change the position of the fins relative to the pivot point to which they are attached to the lever arm, thereby changing the pitch angle of the fins relative to the lever arm. The crank may further include a first contact surface and a second contact surface that are opposite to each other, and these contact surfaces may be configured to contact the upper and lower sides of the lever arm, respectively, to generate a heave motion of the fin. When the actuator is extended, the crank can pivot relative to the body, so the first contact surface of the crank contacts the upper side of the lever arm and pushes the lever arm downward. When the actuator is retracted, the crank can pivot in the opposite direction relative to the body, so the second contact surface of the crank contacts the lower side of the lever arm and pushes the lever arm upward.

[0016] In some exemplary embodiments, the pitch motion of the fin may also be generated by an actuator, which is a rotary actuator. In some exemplary embodiments of the propulsion unit, the actuator assembly may comprise a first actuator and a second actuator. The first actuator and the second actuator may be connected to the fin via a first pivot point and, optionally, a second pivot point, respectively. Thus, pivot points such as the first pivot point and / or the second pivot point can be movably positioned relative to the body. The positions of the pivot points and / or actuators connected thereto can be moved forward or backward on the fin body to optimize the torque induced in the fin.

[0017] The first and second actuators may be able to act independently of each other such that the phase difference between the heave motion and pitch motion of the fin is variable. Therefore, the first and second actuators can act in the same phase or in opposite phase. To generate pitch and heave motions that are in opposite phase, the actuators can act with a phase difference. By changing the phase difference, it becomes possible to adjust the maximum pitch angle of the fin. In one or more embodiments, the two actuators can be actuated by independently changing the amplitude of their movement or motion. Therefore, the first and second actuators can change the amplitude and / or phase of their movement or motion independently of each other. In this specification, the pitch angle is the angle of the fin with respect to the horizontal plane. When the first and second actuators act in the same phase, the relative positions of the first and second pivot points do not change, so the fin performs only heave motion. In other words, when the first and second actuators act in the same phase, they perform the same motion, so the pitch of the fin does not change, and the fin performs upward / downward motion without changing the angle of the fin with respect to the horizontal plane. When the first and second actuators operate in opposite phases, the relative positions of the first and second pivot points change, causing the fins to perform heave and pitch motions. In other words, when the first and second actuators operate in opposite phases, they perform different movements, changing the fin's pitch and causing it to move upward / downward while changing its angle with respect to the horizontal plane. Since the first and second actuators can operate independently, the fin's motion pattern can be adapted and optimized to increase the fin's lift and, therefore, the thrust it generates. By significantly changing and / or reversing the phase or amplitude of the first and / or second actuators, the fins can generate reverse thrust to push the ship backward. By individually controlling the phase difference and / or amplitude of the first and second actuators, precise control of the fin's motion can be achieved.Therefore, one or more exemplary embodiments disclosed herein provide a simple system that enables precise control of the movement of the fins.

[0018] In one or more exemplary embodiments of the propulsion unit, the fins may be slidably disposed inside the body. The fins can include a first fin portion, a second fin portion, and a connecting element for connecting the first fin portion and the second fin portion. The connecting element can include a first connecting rod and optionally a second connecting rod. The first fin portion and the second fin portion may be connected via the first connecting rod and the second connecting rod. The first connecting rod and the second connecting rod may be parallel and disposed at a first distance and a second distance respectively from the leading edges of the first and second fin portions. The first and second connecting rods can each have a first and a second end configured to be disposed inside the first and second fin portions respectively. The central portions of the first connecting rod and the second connecting rod may be disposed inside the body. The first fin portion and the second fin portion may be disposed on opposite sides of the body such that the body separates the first fin portion and the second fin portion. Thus, the first fin portion can be disposed on a first side such as the right side of the body, and the second fin portion can be disposed on a second side such as the left side of the body.

[0019] The first connecting rod can be connected to the first actuator, and the second connecting rod can be connected to the second actuator. The first connecting rod and the second connecting rod can be connected to their respective first and second actuators via the first and second operating rods, respectively. The first connecting rod can be connected to the first operating rod via the first freely rotatable pin connection. The second connecting rod can be connected to the second operating rod via the second freely rotatable pin connection. Thus, the first freely rotatable pin connection can constitute a first pivot point, and optionally, the second freely rotatable pin connection can constitute a second pivot point at which the fin is arranged to pivot.

[0020] At least one actuator can have one or more pin connections at its end, so that the actuator can be connected to the fin, the operating rod and / or the hull of the ship. Also, at least one operating rod can have one or more pin connections at its end, so that the actuator rod can be connected to the actuator and / or the fin. The pin connection allows the actuator to rotate freely at the connection point, so that the actuator can adjust its alignment relative to the lever arm and / or the ship during the pivoting movement of the fin about the pivot point. Thus, by including a pin connection in at least one actuator, no bending moment is transmitted.

[0021] In one or more exemplary embodiments, at least one actuator and / or at least one actuating rod may be constrained by one or more bearings, such as sliding bearings, so that it can move only in the longitudinal direction, such as the linear direction of at least one actuator, and therefore cannot rotate, thereby supporting bending moments in the actuator. At least one actuator and / or at least one actuating rod, for example, at least one of the first and second actuators, may be constrained so that it can be displaced only in the vertical direction. The vertical direction may correspond to the vertical direction of the ship when the propulsion unit is positioned on the ship. Displacement only in the vertical direction can be considered as the displacement of the actuator having no component in either the longitudinal or transverse direction of the ship. At least one of the first and second actuators may be configured to be displaced in the vertical direction. At least one of the first and second actuators may be constrained in the transverse and / or longitudinal directions. At least one actuator may be constrained so that it cannot pivot relative to the ship, such as relative to the hull of the ship. At least one actuator, such as at least one of the first actuator and the second actuator, can be constrained in a direction perpendicular to the extension direction of at least one actuator, for example, in a direction perpendicular to the extension direction of at least one of the first actuator and the second actuator.

[0022] One or more bearings may be located within the body of the propulsion unit and / or within the hull of the ship. One or more bearings may be located around the outer circumference of at least one actuator and / or at least one actuating rod. One or more bearings may be configured to support forces acting on at least one actuator and / or at least one actuating rod in a direction perpendicular to the linear direction of motion of at least one actuator, for example, in the vertical direction when the propulsion unit is mounted on the ship. Restricting the movement of at least one actuator and / or at least one actuating rod in the longitudinal direction facilitates sealing of at least one actuator and / or at least one actuating rod relative to the ship. Since at least one actuator and / or at least one actuating rod cannot rotate relative to each other and / or relative to the hull of the ship, simpler and less expensive seals may be used compared to solutions in which at least one actuator and / or at least one actuating rod can rotate relative to the ship. Restricting the movement of at least one actuator and / or actuating rod improves the controllability of the fin movement, making it possible to precisely control the motion of the fin. By restricting the movement of at least one actuator and / or actuating rod, it is possible to prevent the fin from swinging back and forth during the heave and / or pitch motion of the fin relative to the ship's hull.

[0023] In one or more exemplary propulsion units, the propulsion unit comprises a plurality of actuators and / or actuating rods, for example, a first actuator and / or actuating rod, a second actuator and / or actuating rod, and a third actuator and / or actuating rod, and so on. One of the plurality of actuators and / or actuating rods may be constrained so that the actuator and / or actuating rod cannot rotate relative to the hull of the ship. The other actuators and / or actuating rods of the plurality of actuators and / or actuating rods may be configured to pivot relative to the hull of the ship while performing heave and / or pitch motion of the fin. By being configured to pivot relative to each of the plurality of actuators and / or actuating rods, the fin can change its angle of attack relative to each of the plurality of actuators and / or actuating rods. The fin may be connected to the plurality of actuators and / or actuating rods, for example, via their respective pivot points.

[0024] As the fins perform a pitching motion, the distance between the first and second pivot points, as seen from a horizontal plane such as a plane perpendicular to the longitudinal extension of the actuarial rod, changes. To allow for this change in the distance between the first and second pivot points as seen from the horizontal plane, at least one of the pivot points can be connected to the fin via a sliding joint. The sliding joint may be, for example, an elongated slot in which the pivot point can be slidably positioned.

[0025] At least one of the first and second connecting rods, such as the first connecting rod, may have first and second elongated slots located at opposite ends of the connecting rod, respectively. The elongated slots may have longitudinal extensions perpendicular to the longitudinal axis of at least one of the first and second connecting rods. The elongated slots may be located inside the first and second fin portions, respectively. The first and second elongated slots may be connected to pins or rods fixedly located inside the first and second fin portions, respectively, so that the pins or rods are slidably positioned within the elongated slots of at least one of the first and second connecting rods. The first and second fin portions may also have elongated slots, which may receive the first and / or second connecting rods, allowing the first and / or second connecting rods to slide within the elongated slots relative to the first and second fin portions. Therefore, the first connecting rod and / or the second connecting rod can be slidably positioned inside the first and second fin portions in a direction perpendicular to the longitudinal axis of at least one of the first and second connecting rods, so that the distance of the first connecting rod and / or the second connecting rod from the leading edge can be varied. By varying the distance of the first connecting rod and / or the second connecting rod from the leading edge, the distance between the first and second pivot points as seen from the horizontal plane can be varied by the pitch motion of the fins. This allows the first and second actuators to perform purely vertical motion to generate both the pitch motion and heave motion of the fins. The positions of the first and second connecting rods, and therefore the positions of the connection points to the first and second actuators, can be depending on the implementation and can move along the cord of the fin body, so that the connection points to the first and second actuators are positioned to optimize the torque induced on the fins.

[0026] The first actuating rod and / or the second actuating rod (or at least its central portion) can be located inside the body. Therefore, the body can be provided with a first through-slot and / or a second through-slot for receiving the first connecting rod and / or the second connecting rod, respectively. The first and / or second through-slots allow the first and second connecting rods to protrude through the body and be slidably positioned within the first and second through-slots. The first and second connecting rods can be connected to the first actuating rod and the second connecting rod inside the body. The first and second through-slots have longitudinal extensions in the vertical direction of the body, allowing the first and second connecting rods to perform vertical movements and generate pitch and heave motions of the fins. The first and second through-slots may include openings at their respective apical ends. If these openings are located at the apex of the first and second through-slots, the first and second actuators and / or the first and second actuation rods can protrude into the main body and be connected to the connecting rods. The openings at the apex of the first and second through-slots may extend upward within the main body and / or hull of the ship and may be sealed above the waterline.

[0027] The propulsion unit may include a rudder. In one or more exemplary embodiments, the body may be configured to be fixedly positioned on the keel of the ship, and the rudder may be pivotably positioned on the skeg. When the body is fixedly positioned on the keel, it may constitute the ship's skeg. In this specification, the skeg refers to the stern extension of the ship's keel. The skeg can provide the ship with course stability. The body may have a rudder mounted on its centerline. The rudder may be attached to the body via a rudder head member located at the trailing edge of the body. The rudder head member is a vertical shaft through which the turning force of the steering device can be transmitted to the rudder. Thus, the rudder head member can provide a pivot point for the rudder, and the rudder may be positioned on the body pivotably around that pivot point.

[0028] In one or more exemplary embodiments, the body may include a rudder head for rotatably positioning the body on the keel of the ship. Thus, the body may be configured to rotate and function as a rudder. The rudder head may be hollow to accommodate one or more actuators and / or at least one actuating rod. One or more actuators and / or at least one actuating rod may be located inside the rudder head. The rudder head may be equipped with bearings, such as rotary bearings, for rotatably positioning the rudder head on the keel of the ship. The rudder head may constitute a bearing raceway of the bearing. To prevent water from entering the ship due to the hollow rudder head, the rudder head may be sealed. A rudder head constituting one of the bearing raceways may extend above the waterline of the ship so that the rudder head may be sealed above the waterline. Sealing the rudder head above the waterline allows for the use of simpler and less expensive seals compared to when the rudder head is sealed below the waterline of the ship.

[0029] The body may include a hollow tube projecting from the body on the side of the body facing the ship or keel. A first actuating rod and / or a second actuating rod may be located within the hollow tube. If the body is located in the ship's keel, the hollow tube may be configured to project into the ship, such as inside the ship's hull. If the body is fixedly located in the ship's keel, the hollow tube may be a steel pipe welded to the ship's hull. If the body is rotatably located in the ship's keel, the rudder head may be hollow and constitute a hollow tube. The hollow tube may include a first end positioned to project into the ship's hull and a second end positioned inside and / or within the ship's body. Thus, the first end of the hollow tube is located further away from the body and / or fin than the second end of the hollow tube. Therefore, the first end of the hollow tube may be referred to herein as the distal end of the hollow tube. The body may be fully or partially open to the water surrounding the ship. To allow the movement of the actuator, actuator rod, and / or connecting rod within the body, the body includes openings such as slots for receiving the actuator, actuator rod, and / or connecting rod. Therefore, water may enter the body through these openings. To prevent water from entering the ship's hull, the hollow tube may include a seal, which can seal the actuator and / or actuator rod to the hollow tube when the seal is located at a first end, such as the distal end of the hollow tube. The hollow tube may also include a flanged connection for receiving the seal. Seals between the actuator and the hull plating can be particularly complex and difficult if the seal is located below the ship's waterline. By providing the hollow tube on the body so that it protrudes into the ship's hull, and positioning the seal at a first end, such as the distal end of the hollow tube inside the ship's hull, the seal can be moved upward so that the connections between the actuator and the ship's hull, and / or between the operating rod and the ship's hull, can be located above the ship's waterline. This allows the connections between the actuator and the ship's hull and / or between the actuating rod and the ship's hull to be sealed using less complex and less expensive seals.The first actuator and / or the second actuator may be sealed internally to prevent water from entering the ship through the actuator.

[0030] In one or more exemplary propulsion units, the first actuator and the second actuator and / or the first actuating rod and the second actuating rod may be located within the same hollow tube. In one or more exemplary embodiments of the propulsion unit, the body may include first and second hollow tubes, for example, when the body is fixedly positioned on the keel of a ship. The first actuator and the second actuator and / or the first actuating rod and the second actuating rod may be located within their respective hollow tubes. The first actuator and / or the first actuating rod may be located within the first hollow tube, and the second actuator and / or the second actuating rod may be located within the second hollow tube.

[0031] In one or more exemplary propulsion units, the propulsion unit, such as an actuator assembly, includes a third actuator such that the propulsion unit comprises at least three actuators. The at least three actuators may be positioned between the hull of the ship and the fins. The at least three actuators are configured to provide heave and pitch motion of the fins relative to the hull of the ship. At least one of the three actuators may be configured to perform motion in the vertical direction of the body only. The other actuators may be configured to perform motion in the vertical and longitudinal directions of the body. The motion of the at least one actuator configured to perform motion in the vertical direction only may be constrained by a support. The support can prevent the at least one actuator and / or at least one actuation rod configured to perform motion in the vertical direction only from moving in any direction other than vertical.

[0032] In one or more exemplary propulsion units, at least two of the first, second, and third actuators may be actuated in correlation to variably adjust the pitch angle and / or heave of the fins, for example, by acting simultaneously with respect to each other. For example, to change the pitch of the fins, two of the three actuators may act simultaneously with respect to each other, for example by being retracted or extended with respect to each other, thereby changing the vertical distance between the respective pivot points to which the two actuators are connected. Since one of the actuators does not need to be displaced, the fins can pivot around the pivot point to which the non-displaced actuator is connected to the fins. To perform the heave motion of the fins, all three actuators may act simultaneously.

[0033] To control the heave and pitch motion of the fins, a first actuator, a second actuator, and a third actuator can be controlled individually. The first, second, and third actuators may be connected to the body of the propulsion unit (or the ship's hull) and / or the fins via their respective pivot points. The pivot points of the fins may be positioned at respective distances from the leading edge of the fins, such that the first, second, and third actuators act on the fins at their respective distances from the leading edge. For example, the first actuator may be positioned closer to the leading edge of the fin than the second and third actuators. The second actuator may be positioned closer to the leading edge of the fin than the third actuator, but further from the leading edge than the first actuator. The third actuator may be positioned further from the leading edge than both the first and second actuators.

[0034] The third actuator may be of the same type as the first and second actuators, or of a different type. In one or more exemplary propulsion units, the third actuator may be a water hammer pump type actuator. The third actuator may be an actuating rod. The third actuator may be connected to the fin at a distance from the first and second actuators in the longitudinal direction, such as the forward / stern direction of the ship. The first actuator, the second actuator, and / or the third actuator may be connected to the fin and / or the ship's hull via one or more fixed pivot points. Fixed pivot points as used herein mean that the pivot point is fixedly positioned relative to the fin, the ship's hull, and / or the body of the propulsion unit, such that it is not slidable. In one or more exemplary propulsion units, these pivot points may be pin joints fixed to the fin and / or the body of the propulsion unit and / or the ship's hull. By fixing the first and second pivot points within the fin, the stability and / or controllability of the fin can be improved, so that the fin pitch can be controlled with improved precision. Furthermore, by eliminating sliding joints, such as pivot points that are slidably positioned, within the fins, friction induced in the system can be reduced, thereby improving the efficiency of the propulsion unit. Reducing the number of moving parts in the propulsion unit located underwater further reduces the risk of corrosion and potential seizure of moving parts, as well as potential system malfunctions. This can improve the performance of the propulsion unit.

[0035] These displacements, for example, the displacements of each actuator such as the first actuator, second actuator, and / or third actuator, may be controlled so that one of the actuators performs only vertical displacement, without any forward and / or aft motion components, such as in the longitudinal direction of the ship. By constraining the movement of one of the three actuators, the motion of the fins can be controlled in a more precise manner. For example, by preventing the ship from swinging forward / backward while the fins are performing heave and / or pitch motion, the efficiency of the propulsion unit is improved because forward / backward swinging of the fins can change the pitch angle of the fins.

[0036] The displacement of the actuator can be controlled to adjust the heave and pitch based on the state of the water surrounding the fin, for example, based on the velocity of incoming water, such as the velocity of water reaching the leading edge of the fin. This allows the fin's motion to be adapted to improve the performance of the propulsion unit based on the current state of the water surrounding the fin. The actuator can be controlled based on, for example, multiple angle of attack profiles depending on the water state. For example, an exemplary first angle of attack profile may be optimized for open water. An exemplary second angle of attack profile may be optimized for operation in the wake behind the ship. A propulsion unit according to this disclosure, such as a propulsion unit including two or more actuators, can continuously adapt the heave and / or pitch of the fin, so that the fin's motion can be adjusted to more or less countless angle of attack profiles. Multiple angle of attack profiles can be determined using computational fluid dynamics (CFD) codes in conjunction with optimization routines to optimize the motion pattern and / or the fin's geometric shape based on a given water state, such as a given inflow of water to the fin.

[0037] In one or more exemplary propulsion units, the propulsion unit may include a control system which may be configured to optimize and control motion patterns, such as the displacement of actuators of different angle-of-attack profiles based on the detected angle of attack of the fins. In one or more exemplary propulsion units, the control system may control motion patterns in real time, for example by using machine learning. The control system may receive information about the state of the fins, such as the water flow around the fins, information about the fin pitch and / or heave, such as the pitch angle, and the heave and / or velocity of the fin motion, such as the pitch and / or heave velocity. The control system may use the received information to optimize the fin pitch motion and / or heave motion and improve the efficiency of the propulsion unit.

[0038] In one or more exemplary propulsion units, at least one of the actuators may be laterally offset from one or more other actuators to absorb torsional moments on the fins that may be induced, for example, by waves. In this specification, laterally means along the transverse axis of the fin, such as along an axis extending from the starboard side to the port side of the ship. This can further improve the performance of the fins. In one or more exemplary propulsion units, at least one of the actuators may be offset from one or more other actuators by a distance in the range of 50 to 500 mm, such as in the range of 100 to 200 mm.

[0039] In one or more exemplary propulsion units, such as when the propulsion unit includes a third actuator, the fins may include a third connecting rod. The third actuator may be pivotably connected to the third connecting rod. The third connecting rod may be connected to the third actuator via a third actuating rod. The third actuating rod may be located inside the body of the propulsion unit. The first fin portion and the second fin portion may be connected via the third connecting rod. The first connecting rod, the second connecting rod, and the third connecting rod may be positioned parallel to each other and at first, second, and third distances, respectively, from the leading edges of the first and second fin portions.

[0040] In one or more exemplary propulsion units, the body may include a third through-slot, which allows the third connecting rod to protrude through the body and to be slidably positioned within the third through-slot.

[0041] Fins can have an elliptical planar shape. In some embodiments, such as one or more exemplary propulsion units, fins can have an elliptical planar shape with a high aspect ratio. The aspect ratio of a fin is the ratio of its width to its mean chord. The width of a fin is the distance from the tip of one fin to the tip of another. The chord is an imaginary straight line connecting the leading edge and trailing edge of the fin. The aspect ratio is equal to the square of the wingspan divided by the wing area. Therefore, long and narrow fins have a high aspect ratio, while short and wide fins have a low aspect ratio. The lift-to-drag ratio of a fin increases with the aspect ratio, so a higher aspect ratio of a fin can improve the performance and efficiency of the fin, potentially improving the ship's fuel consumption. The lift-to-drag ratio, also known as the L / D ratio, is the amount of lift generated by the fin divided by the hydrodynamic drag caused by moving through a viscous fluid such as water. The shape and / or planar shape of the fins can be modified, for example, based on the shape of the ship's hull, to reduce the drag of the fins.

[0042] Fins may include winglets. Winglets are endplates positioned at the tip of a fin and may extend perpendicular to the fin's main wing, or at least substantially perpendicular. Winglets can improve the efficiency of a fin by reducing its hydrodynamic drag. Fin drag can be reduced by the partial recovery of tip vortex energy. Winglets can increase the lift generated at the fin tip by smoothing the water flow across the fin near its tip, thereby reducing the lift-induced drag caused by vortices around the fin tip. A reduction in lift-induced drag improves the fin's lift-to-drag ratio, which in turn improves the fin's efficiency. Winglets can also improve fin efficiency by shifting the confluence of low-pressure and high-pressure water regions away from the fin's surface, thereby reducing the interference between laminar water flow and vortices near the fin tip. Vortices around the fin tip can generate turbulence that originates at the leading edge of the fin tip and propagates to the rear of the fin and into the in-ship fin. This turbulence may prevent the water flow above the small triangular section of the outboard fin from becoming laminar, potentially destroying the lift generated by the fin in that region. Winglets move the region where the vortex forms away from the fin surface, as the center of the resulting vortex is located at the tip of the winglet. Since fins perform an upward / downward motion, which can also be called an up / down stroke, while the propulsion unit is operating, winglets can be positioned above and below the fin. Because the lift on the fin can be reversed between the upstroke and downstroke, positioning winglets above and below the fin increases the efficiency of the fin in both the upstroke and downstroke.

[0043] The stroke of a fin, such as the displacement of a heave motion, may depend on the size of the ship and / or the ship's draft. The larger the ship and / or the deeper the draft, the greater the stroke can be. Increasing the fin stroke can increase the efficiency of the fin and, therefore, the efficiency of the propulsion unit. In one or more exemplary propulsion units, the stroke may be in the range of 3 to 20 meters, such as in the range of 5 to 15 meters.

[0044] Furthermore, a ship is disclosed having a propulsion unit for propelling the ship according to this disclosure. The ship includes a keel. The body of the propulsion unit may be located on the ship's keel. Fins are configured to perform pitch and heave motions relative to the ship's keel. In one or more exemplary embodiments, the ship may have multiple propulsion units, such as when the ship has several engines.

[0045] In one or more exemplary embodiments, the body can be fixedly positioned to the keel of the ship. This firmly attaches the body to the hull and reduces the hydrodynamic drag of the body.

[0046] In one or more exemplary embodiments, the body can be rotatably mounted on the ship's keel. This integrates the body and rudder components into a single unit, allowing the entire unit to rotate like a rudder. This can improve the ship's maneuverability.

[0047] Figures 1A and 1B show a propulsion unit 1 for propelling a ship 100 according to one or more exemplary first embodiments of this specification. In one or more exemplary embodiments shown herein, the propulsion unit 1 comprises a single actuator for generating heave and pitch motions. The actuator acts on a lever arm, which is attached to a pivot point at one end and to a fin at the other end. When the actuator acts on the lever arm to generate heave motion, the rotation of the lever arm around the pivot point generates pitch motion of the fin.

[0048] Figure 1A shows a side view of one or more exemplary first embodiments of the propulsion unit 1. The propulsion unit 1 includes a body 2, which is configured to be positioned on the keel 101 of a ship 100, and includes a pivot point 5a, a fin 3 positioned movably relative to the body 2, and an actuator assembly 4 for generating heave motion of the fin 3 relative to the body 2, the actuator assembly 4 including an actuator 4a. The fin 3 is connected to the pivot point 5a via a lever arm 7, so that when the actuator 4a generates heave motion of the fin 3, the fin 3 pivots about the pivot point 5a, thereby generating pitch motion of the fin 3. In one or more exemplary first embodiments herein, the first end of the lever arm 7 is connected to the pivot point 5a, and the second end of the lever arm 7 is connected to the fin 3. The pivot point 5a is fixedly positioned on the body 2. The pivot point 5a may be a pin-fixed rotation point. The pivot point 5a may be positioned inside the body 2 so that the lever arm 7 can be connected to a pivot point on the inside of the body 2. Therefore, the main body 2 may include a slot 2a that opens toward the rear end of the main body 2, allowing the lever arm 7 to protrude through the main body 2 and perform heave and pitch movements relative to the main body 2. Because the slot 2a is open, it is configured to be in contact with the water surrounding the ship 100 during operation.

[0049] The actuator assembly 4 includes a single actuator 4a for generating the heave and pitch motion of the fins 3. The propulsion unit 1 and / or the actuator assembly 4 may include an actuation rod 9. The actuator 4a can be connected to the lever arm 3 via the actuation rod 9. The actuation rod 9 can be connected to the lever arm 7 a short distance from the pivot point 5a. Thus, the actuator 4a exerts a force on the lever arm 7 via the actuation rod 9 at a distance from the pivot point 5a, and this force generates a torque in the lever arm 7 around the pivot point 5a.

[0050] Actuator 4a, also called the first actuator 4a, may be a linear actuator that performs a linear motion. Actuator 4a may be positioned to perform vertical (up / down) motion. Since the lever arm 7 is connected to the pivot point 5a, the linear vertical motion of actuator 4a rotates the lever arm 7 about the pivot point 5a. The rotation of the lever arm 7 about the pivot point 5a causes the fin 3, which is attached to the end of the lever arm 7 opposite the pivot point 5a, to rotate about the pivot point 5a, thereby performing heave and pitch motions relative to the hull of the ship 100. The pitch of the fin 3 is directly dependent on the heave of the fin 3, since the pivot motion of the lever arm 7 during the heave motion of the fin 3 generates the pitch of the fin 3. Therefore, the pitch and heave of the fin 3 are always in phase with each other. The actuating rod 9 can be connected to the lever arm 7 via the second pivot point 5b, so that the actuating rod 9 and the lever arm 7 can rotate relative to each other. This allows the angle between the linear actuator 4a and the lever arm 7 to change during the heave and pitch movements of the lever arm 7 and the fin 3. When the actuating rod 9 is connected to the lever arm 7 via a second pivot point 5b, the pivot point 5a may be referred to as the first pivot point 5a.

[0051] The actuator 4a may be configured to operate in an oscillating pattern, thereby generating oscillating heave and pitch motions of the fin 3. The oscillating heave and pitch motions may include upward and downward strokes. The upward stroke refers to the movement of the actuator 4a pulling the fin 3 towards the ship 10. The downward stroke refers to the movement of the actuator 4a pulling the fin 3 away from the ship 10. In Figure 1A, the lever arm 7 and the fin 3 are shown in upper positions, such as the end position of the upward stroke.

[0052] As the fin 3 performs a pitching motion, the distance between the first pivot point 5a and the second pivot point 5b, as seen from a horizontal plane such as a plane perpendicular to the longitudinal extension of the actuating rod 9, changes. To allow for this change in the distance between the first pivot point 5a and the second pivot point 5b as seen from the horizontal plane, the second pivot point 5b can be connected to the lever arm 7 via a sliding joint 7a. The sliding joint 7a may be, for example, an elongated slot in which the second pivot point 5b can be slidably positioned. Thus, the second pivot point 5b can be movably positioned relative to the fin 3.

[0053] The fin 3 includes a winglet 15. The winglet 15 is an end plate positioned on the tip of the fin 3 and extends perpendicular to the main wing of the fin 3, or at least substantially perpendicular. The winglet 15 improves the efficiency of the fin 3 by reducing the hydrodynamic drag of the fin 3. The winglet 15 may be provided on the top and / or bottom sides of the fin 3. In one or more embodiments shown herein, the winglet 15 is provided on both the top and bottom sides of the fin 3. This improves the efficiency of the fin 3 in both its upward and downward strokes.

[0054] The propulsion unit 1 may further include a rudder 6. The main body 2 may be rotatably positioned relative to the ship 100 so that the main body 2 can function as a rudder 6. Thus, the fin 3 is positioned to rotate with the rudder 6. The main body 2 may be positioned in the ship via a rudder head member. The rudder head member may be hollow to accommodate the actuator 4a and / or the actuation rod 9. Thus, the actuator 4a and / or the actuation rod 9 can be connected to the lever arm 7 via the hollow rudder head member. The rudder head member may be rotatably positioned in the ship 100 via a bearing, such as a rotary bearing. The rudder head member may constitute a bearing raceway of the bearing. To prevent water from entering the ship through the hollow rudder head member, the rudder head member may need to be sealed. A rudder head member constituting one of the bearing raceways may extend above the waterline of the ship 100 so that the rudder head member can be sealed above the waterline. Sealing the rudder head member above the waterline allows for the use of simpler and less expensive seals compared to when the rudder head member is sealed below the waterline. However, the propulsion unit 1 may be fixed to the ship 100. If the propulsion unit 1 is fixed to the ship 100, the ship 100 may be equipped with a conventional rudder 6 positioned behind the fin 3.

[0055] Figure 1B shows a perspective view of a propulsion unit 1 for propelling a ship 100 according to one or more exemplary embodiments shown in Figure 1A. As can be seen from the figure, the body 2 is positioned on the keel 101 of the ship 100. The lever arm 7 is pivotally connected to the body 2 via a pivot point 5a (not shown in Figure 1B) located inside the body 2. The second end of the lever arm 7 is connected to a fin 3. The body 2 includes a slot 2a, which opens toward the rear end of the body 2, allowing the lever arm 7 to perform vertical movement relative to the body 2. The lever arm 7 is connected to an actuator 4a (not shown in Figure 1B) via an actuating rod 9. The actuating rod 9 can perform linear vertical movements such as up / down movements, which are transmitted to the fin 3 via the lever arm 7. In Figure 1B, the lever arm 7 and the fin 3 are shown in upper positions, such as the end position of the upward stroke.

[0056] Fin 3 has an elliptical planar shape, such as a high aspect ratio elliptical planar shape. The aspect ratio of a fin is the ratio of its width s to its average code c. Therefore, a fin with a high aspect ratio planar shape means that fin 3 is long and narrow. Since the lift-to-drag ratio of a fin increases with the aspect ratio, the high aspect ratio fin 3 disclosed herein can improve the performance and efficiency of fin 3 and improve the fuel consumption of the ship. The lift-to-drag ratio, also known as the L / D ratio, is the amount of lift generated by the fin divided by the hydrodynamic drag caused by its movement through a viscous fluid such as water. The shape of code c and / or the planar shape of fin 3 can be implementation-dependent and can be modified, for example, based on the shape of the hull of ship 100, to reduce the hydrodynamic drag of fin 3.

[0057] As can be seen in Figure 1B, according to one or more first embodiments of the propulsion unit 1 shown herein, the winglets 15 are provided on both the top and bottom sides of the fin 3, thereby improving the efficiency of the fin 3 in both upward and downward strokes.

[0058] The propulsion unit 1 according to one or more exemplary first embodiments of this specification has a simple layout that includes only one actuator for performing heave motion and pitch motion, and therefore has high mechanical efficiency and low maintenance requirements.

[0059] Figures 2A to 2D show a propulsion unit 1 and a motion pattern of the propulsion unit 1 according to one or more exemplary second embodiments of this specification. The actuator assembly 4 includes an actuator 4a, which may also be called a first actuator 4a, and a second actuator 4b. A pivot point 5a (not shown in Figures 2A to 2D) is connected to the second actuator 4b such that the pivot point 5a is movably positioned relative to the body 2. Since the first actuator 4a and the second actuator 4b are operable independently of each other, the phase difference between the heave motion and the pitch motion of the fin 3 is variable. The first actuator 4a and the second actuator 4b may be linear actuators. Thus, the pitch motion and heave motion of the fin 3 can be controlled independently of each other. The fin 3 is movably positioned on the body 2. The fin 3 includes a first fin portion 3a and a second fin portion 3b, a first connecting rod 8a (not shown in Figures 2A to 2D), and a second connecting rod 8b (not shown in Figures 2A to 2D). The first fin portion 3a and the second fin portion 3b are connected via a first connecting rod 8a and a second connecting rod 8b. The first connecting rod 8a and the second connecting rod 8b can form structural elements of the fin 3. The body 2 includes a first through slot 13a and a second through slot 13b for receiving the first connecting rod 8a and the second connecting rod 8b of the fin 3. The first through slot 13a and the second through slot 13b allow the first connecting rod 8a and the second connecting rod 8b to protrude through the body 2 in the short direction. The first connecting rod 8a and the second connecting rod 8b are slidably positioned within the first through slot 13a and the second through slot 13b, respectively. The first through-slot 13a and the second through-slot 13b have longitudinal extensions in the short direction of the main body 2, which allows the first connecting rod 8a and the second connecting rod 8b of the fin 3 to perform perpendicular movement relative to the main body 2, thereby enabling the fin 3 to perform heave and pitch movements relative to the main body 2.The first actuator 4a and the second actuator 4b may be connected to the first connecting rod 8a and the second connecting rod 8b, respectively. When the propulsion unit 1 is positioned on the ship 100 to accommodate the actuators 4a and 4b, the first through slot 13a and the second through slot 13b may be open at their apex ends, such as the ends of the first through slot 13a and the second through slot 13b facing the ship 100. Thus, the actuators 4a and 4b can extend through the body 2 in the vertical direction and be connected to the first connecting rod 8a and the second connecting rod 8b that project through the body 2 in the short direction.

[0060] The propulsion unit 1 disclosed herein may further comprise a rudder 6. The body 2 may be configured to be fixedly positioned on the ship 100, such as on the keel 101 of the ship 100, and the rudder 6 may be pivotally positioned on the skeg 2. The rudder 6 may be mounted on the centerline of the body 2. The rudder 6 may be attached to the body 2 via a rudder head member positioned at the trailing edge of the body 2.

[0061] Figure 2A shows the fins 3, including fin portions 3a and 3b of the propulsion unit 1, at the apex position in an exemplary motion pattern for moving the fins 3. In this exemplary motion pattern, the first actuator 4a and the second actuator 4b act in phase difference. The apex position of the fins 3 corresponds to the peak of the movement of the fins 3, such as when the fins 3 reach the end position during an upward stroke. At this position, both the first and second actuators are in the upper position, and the fin portions 3a and 3b are positioned horizontally such that the pitch angle is 0°.

[0062] Figure 2B shows the fin 3 of the propulsion unit 1 during its downward stroke. Both the first actuator 4a and the second actuator 4b are moving downward, applying a downward heave motion to the fin 3. However, the second actuator 4b begins its downward stroke before the first actuator 4a begins its downward stroke. As a result, the leading edge 10 of the fin 3, such as fin portions 3a and 3b, moves downward before the trailing edge 16 moves downward, causing the fin 3 to have a pitch angle with respect to a horizontal line having the first notation. The pitch angle may have a positive or negative sign, depending on the definition of the coordinate system. In the examples shown in Figures 2B and 5 of this specification, this pitch angle, for example, the pitch angle having the first notation, corresponds to a positive pitch angle.

[0063] Figure 2C shows that the fin 3 of the propulsion unit is in the bottom position during an exemplary motion pattern for moving the fin 3. The bottom position of the fin 3 corresponds to the bottom point of the fin 3's movement, such as when the fin 3 reaches the end position during a downward stroke. At this position, both the first and second actuators are in the lower position, and the fin portions 3a and 3b are positioned horizontally such that the pitch angle is 0°.

[0064] Figure 2D shows the fin 3 of the propulsion unit 1 during an upward stroke of the fin, an exemplary motion pattern for moving the fin 3. An upward heave motion is applied to the fin 3 by both the first actuator 4a and the second actuator 4b moving upward. The second actuator 4b starts its downward stroke before the first actuator 4a, and therefore also starts its upward stroke before the first actuator 4a. As a result, the leading edge 10 of the fin 3, such as fin portions 3a and 3b, moves upward before the trailing edge 16 moves upward, and the fin 3 has a pitch angle with respect to a horizontal line having second reference numeral. In the examples shown in Figures 2D and 5 of this specification, this pitch angle corresponds to a negative pitch angle.

[0065] Figure 3 shows a coupling for connecting the fin 3 to the first actuator 4a and the second actuator 4b according to one or more exemplary second embodiments of this specification. The first connecting rod 8a and the second connecting rod 8b of the fin 3 are parallel and positioned at a first and second distance, respectively, from the leading edges 10 of the first fin portion 3a and the second fin portion 3b of the fin 3.

[0066] The first connecting rod 8a is connected to the first actuator 4a, and the second connecting rod 8b is connected to the second actuator 4b. The first connecting rod 8a and the second connecting rod 8b can be connected to the first actuator 4a and the second actuator 4b, respectively, via the first actuating rod 9a and the second actuating rod 9b. The first actuator 4a and the second actuator 4b can be connected to the first connecting rod 8a and the second connecting rod 8b, respectively, via the first actuating rod 9a and the second actuating rod 9b, for example, via a freely rotating pin coupling. The first actuating rod 9a and the second actuating rod 9b may, for example, include through holes at their respective lower ends, through which the first connecting rod 8a and the second connecting rod 8b can be inserted, respectively. Therefore, the translational motion from the first actuator 4a and the second actuator 4b can be transmitted to the first connecting rod 8a and the second connecting rod 8b via the first operating rod 9a and the second operating rod 9b, respectively.

[0067] However, the rotation of the pin connection allows the first connecting rod 8a and the second connecting rod 8b to rotate freely within the first operating rod 9a and the second operating rod 9b, respectively. As a result, the rotation of the pin connection between the operating rod and the connecting rod constitutes a pivot point. In the example shown in Figure 3, the connection between the second operating rod 9b and the second connecting rod 8b constitutes the first pivot point 5a, and the connection between the first operating rod 9a and the first connecting rod 8a constitutes the second pivot point 5b. Therefore, the fin 3 can rotate relative to the operating rods 9a and 9b in order to change the pitch of the fin 3.

[0068] When the fin 3 performs a pitching motion to compensate for changes in the distance between the first and second connecting rods 8a and 8b as seen from the horizontal plane, one of the first connecting rod 8a and the second connecting rod 8b may be movably positioned within the first fin portion 3a and the second fin portion 3b. In one or more exemplary embodiments, the second connecting rod 8b may comprise first and second elongated guide portions 17 that are movably positioned within the fin portion and located at opposing ends of the connecting rod 8b. The first and second elongated guide portions 17 may have longitudinal extensions perpendicular to the longitudinal axis of at least one of the first and second connecting rods. The first and second elongated guide portions 17 may be configured to be located inside the first fin portion 3a and the second fin portion 3b, respectively. The first and second elongated guide portions 17 may be configured to guide a first pin 18 fixedly positioned inside the first fin portion 3a and a second pin 18 fixedly positioned inside the second fin portion 3b, respectively. The first and second elongated guide portions 17 may be elongated slots, elongated bearings, or tracks configured to guide the first and second pins 18, respectively. Thus, the pins 18 can be slidably positioned within the elongated slots 17 of the second connecting rod 8b.

[0069] In one or more exemplary embodiments, the first and second pins 18 may alternatively be located at opposing ends of one of the first connecting rod 8a and the second connecting rod 8b, and the elongated guide portions may be located inside the first fin portion 3a and the second fin portion 3b. The second connecting rod 8b may, for example, include the first and second pins 18 located at opposing ends of the connecting rod 8b. The first and second elongated guide portions 17 located inside the first fin portion 3a and the second fin portion 3b may have longitudinal extensions perpendicular to the width s of the first fin portion 3a and the second fin portion 3b. The first and second pins 18 may be arranged to slidably engage with the first and second elongated guide portions 17, respectively, which are fixedly located inside the first fin portion 3a and the second fin portion 3b. Furthermore, if the first fin portion 3a and the second fin portion 3b include an elongated slot 19 for receiving the second connecting rod 8b, the second connecting rod 8b can slide back and forth inside the elongated slot 19 in a direction perpendicular to the longitudinal axis of the second connecting rod 8b, thereby allowing the distance between the second connecting rod 8b and the leading edge portion 10 to be changed. This enables the actuating rod 9b and / or actuator 4b to perform purely vertical motion during the pitching motion of the fin 3.

[0070] Figure 4 shows the main body 2, which includes a first through slot 13a and a second through slot 13b for receiving the first connecting rod 8a and the second connecting rod 8b of the fin 3. The first connecting rod 8a and the second connecting rod 8b protrude through the main body 2 in the short direction. The first connecting rod 8a and the second connecting rod 8b are slidably positioned within the first through slot 13a and the second through slot 13b, respectively. The first connecting rod 8a and the second connecting rod 8b can also protrude through through holes at the lower ends of the first operating rod 9a and the second operating rod 9b, respectively. The first through slot 13a and the second through slot 13b have longitudinal extensions in the short direction of the main body 2, allowing the first connecting rod 8a and the second connecting rod 8b to perform vertical up / down motion within the through slots 13a and 13b, respectively. When the propulsion unit 1 is positioned in the ship 100, the first through slot 13a and the second through slot 13b are open at the apex end, such as the end facing the ship 100, allowing the first actuation rod 9a and the second actuation rod 9b to enter the through slots 13a and 13b from a vertical direction. If the open ends of the first through slot 13a and the second through slot 13b can be joined to holes in the ship's hull above them, the actuation rods will be able to move vertically within the hull of the ship 100 where the actuator assembly is to be positioned.

[0071] Figure 5 shows a graph illustrating an exemplary motion pattern of the fin 3 when the first actuator 4a and the second actuator 4b are actuated by a phase difference. Curve h2 shows that the first actuator rod 9a extends from an intermediate stroke position, such as the midpoint between the peak and trough of the first actuator rod's movement. Curve h1 shows that the second actuator rod 9b extends from an intermediate stroke position. Curve theta shows the corresponding pitch angle of the fin with respect to the horizontal in degrees. The actuators actuate by a phase difference to produce pitch and heave motions that are out of phase. By changing this phase difference, it is possible to adjust the maximum pitch angle of the fin 3 during the heave motion. As can be seen from the graph, the second actuator rod 9b performs its motion slightly ahead of the second actuator rod 9a. As can be seen, the pitch angle of the fin is maximum when the first and second actuator rods 9a and 9b are at the midpoint of their strokes and moving in the same direction, such as during the downward stroke at t=0 and the upward stroke at t=3. The first and second actuation rods are located at end positions, such as the peak or base point of movement, when t=1.5 and t=4.5, respectively.

[0072] Figure 6 discloses one or more exemplary third embodiments of a propulsion unit 1, in which the body 2 is configured to be rotatably positioned on a ship 100. The propulsion unit 1 disclosed herein is similar to the propulsion unit 1 disclosed in relation to Figures 2A to 2D, 3 and 4. The body 2 includes a rudder head 11 for rotatably positioning the body 2 on the keel 101 of the ship 100. The rudder head 11 is positioned on the top side of the body 2, such as the side facing the bottom of the ship 100 when the body 2 is attached to the ship 100. Thus, the body 2 can be configured to rotate around the rudder head 11 and function as a rudder 6. The rudder head 11 may be hollow to accommodate one or more actuators 4a, 4b and / or first actuation rods 9a and / or second actuation rods 9b. One or more actuators 4a, 4b and / or first actuating rods 9a and / or second actuating rods 9b may be positioned inside the rudder head 11 so as to be able to move vertically inside the rudder head 11. The rudder head 11 may be equipped with bearings, such as rotary bearings, to rotatably position the rudder head on the keel 101 of the ship 100. In some embodiments, the rudder head 11 may constitute a raceway of a bearing, such as an inner ring of a bearing.

[0073] Figure 7 discloses a ship 100 comprising a propulsion unit 1 for propelling the ship 100, according to one or more exemplary second embodiments disclosed herein. The ship 100 includes a keel 101. The body 2 of the propulsion unit 1 may be located at the bottom of the ship 100, such as the keel 101 of the ship 100. The fins 3a, 3b are configured to perform pitch and heave motions relative to the bottom of the ship 100, such as the keel 101 of the ship 100. When the fins 3, 3a, 3b perform heave and pitch motions, thrust is generated to propel the ship 100. In the exemplary embodiment shown in Figure 7, the propulsion unit 1 comprises two actuators for generating the heave and pitch motions of the fins 3, 3a, 3b. Thus, the motion pattern of the fins 3 can be precisely controlled to match the hull and the load on the fins 3 in the boundary layer of the hull. In this specification, the body 2 is fixedly positioned on the ship 100, such as the keel 101 of the ship 100, and can thus constitute the skeg of the ship 100. The propulsion unit further comprises a rudder attached to the trailing edge of the body 2. However, in one or more embodiments, the ship 100 may comprise propulsion units according to one or more exemplary first and third embodiments disclosed herein.

[0074] Figure 8 shows an internal perspective view of an exemplary vessel 100 equipped with an exemplary propulsion unit 1 according to this disclosure. The body 2 is fixedly mounted to the vessel, and the first actuator 4a and the second actuator 4b are located inside the vessel 100. The propulsion unit 1 shown in Figure 8 has a sealing arrangement to prevent water from entering the vessel, according to one or more exemplary embodiments of this specification. For the first actuator 4a and the second actuator 4b to generate the heave and pitch motion of the fins 3, 3a, the hull and body include openings for receiving the first and second actuators 4a, 4b and / or the first and second actuating rods 9a, 9b. These openings are open to the water surrounding the vessel 100. To prevent water from entering the vessel through the openings, the body may include one or more hollow tubes 12; 12a, 12b projecting from the body into the vessel 100. The first actuating rod 9a and / or the second actuating rod 9b and / or the first actuator 4a and / or the second actuator 4b may be located within one or more hollow tubes 12;12a, 12b. One or more hollow tubes 12;12a, 12b may be steel pipes welded to the hull of the ship 100. One or more hollow tubes 12;12a, 12b may include a first end, such as a distal end, that is positioned to project into the hull of the ship 100, and a proximal end that is positioned within the body 2 of the ship 100. The first end of one or more hollow tubes 12;12a, 12b, such as the distal end, may be configured to extend above the waterline of the ship 100. To prevent water from entering the hull of the ship 100 through the opening, one or more hollow tubes 12;12a, 12b may each include a seal 20 positioned at the distal end of one or more hollow tubes 12;12a, 12b. One or more hollow tubes 12;12a, 12b may include a flanged connector for receiving the seal 20. A less complex and less expensive seal can be used by positioning one or more hollow tubes 12;12a, 12b on the main body 2 so as to project into the hull of the ship 100, with the seal 20 positioned at the distal end of one or more hollow tubes 12;12a, 12b above the waterline of the ship 100.

[0075] Figure 9 shows an exemplary propulsion unit 1 according to the present disclosure. The exemplary propulsion unit 1 comprises two actuators 4, such as a first actuator 4a and a second actuator 4b. The motion of one of the two actuators 4, for example, the second actuator 4b, is constrained so that it can be displaced only in a vertical direction, such as along the vertical axis of the ship, such as by being extended or retracted. The exemplary propulsion unit 1 includes one or more support surfaces 21 for constraining the motion of the second actuator 4b. One or more support surfaces may be roller pivots and / or sliding bearings. One or more support surfaces 21 may be fixedly positioned on the hull of the ship or on the body of the propulsion unit 1. One or more support surfaces 21 may be configured to prevent the second actuator 4b from pivoting relative to the hull of the ship. By constraining the motion of the second actuator 4b, the pivot point 5b connecting the second actuator 4b to the fin 3 can only be displaced in a vertical direction and therefore can only perform heave motion. Nevertheless, the ability of the fin 3 to pivot around the pivot point 5b allows for changes in the pitch of the fin 3. The motion of the fin 3 can be precisely controlled by constraining the movement of one of the actuators, such as the second actuator 4b. For example, the fin 3 can be prevented from swinging forward / backward while performing heave and / or pitch motion. The first actuator 4a does not need to be constrained so that it can pivot relative to the hull of the ship when the first actuator is extended and / or retracted. In one or more exemplary propulsion units 1, the two actuators 4a;4b may be positioned at an angle to each other such that their extension directions are not parallel. For example, the first actuator 4a may be positioned at an angle to the vertical axis of the ship. The first pivot point 5a and the second pivot point 5b may be fixedly positioned within the fin 3, such as not being slidably positioned. In other words, the fin 3 can pivot around the first pivot point 5a and the second pivot point 5b. However, the first pivot point 5a and / or the second pivot point 5b do not necessarily have to be slidably positioned relative to the fin 3.The first pivot point 5a and the second pivot point 5b may be pin joints in one or more exemplary propulsion units. By fixing the first and second pivot points within the fin 3, the stability and / or controllability of the fin 3 can be improved, allowing the pitch of the fin 3 to be controlled with improved precision. Furthermore, by fixing the first and second pivot points 5a and 5b within the fin 3, friction induced in the propulsion system can be reduced because there is no sliding motion at one or more connection points between the actuators 4a and 4b and the fin 3. Reducing the number of moving parts of the propulsion unit 1 located underwater further reduces the risk of corrosion and potential seizure of moving parts, as well as potential system malfunctions. This can improve the performance of the propulsion unit.

[0076] Figure 10 shows an exemplary propulsion unit 1 according to the present disclosure. The exemplary propulsion unit 1 shown in Figure 10 comprises three actuators 4, such as a first actuator 4a, a second actuator 4b, and a third actuator 4c. The first actuator 4a, the second actuator 4b, and the third actuator 4c may be connected to a fin via their respective pivot points, for example, a first pivot point 5a, a second pivot point 5b, and a third pivot point 5c. In the exemplary propulsion unit 1 disclosed in Figure 10, one of the three actuators 4, for example, the second actuator 4b, is configured to be displaced vertically, such as along the vertical axis of the ship, e.g., extended or retracted. One of the three actuators 4, for example, the second actuator 4b, may be restricted in the short and / or longitudinal direction so that one of the three actuators cannot be displaced in the short and / or longitudinal direction, such as along the short and / or longitudinal axis of the ship, e.g., extended or retracted. In this specification, being configured to displace only vertically means that the second actuator does not move forward and / or aft of the ship when the actuator is extended and / or retracted. The limited displacement of the second actuator 4b, which is only vertical, can be achieved by controlling the extension and / or retraction of actuators 4a, 4b, and 4c, respectively. By providing a third actuator in the propulsion unit 1, the motion of the fins can be precisely controlled without using a support surface to prevent fin movement in the forward and / or aft directions. By not using a support surface to control the motion of the fins, friction between the support surface and at least one actuator can be reduced, thereby reducing losses in the propulsion unit. Furthermore, the absence of a support surface located in water reduces the number of moving elements of the propulsion unit located in water. The reduction in moving parts of the propulsion unit located in water further reduces the risk of corrosion and potential seizure of moving parts, as well as potential system failures. This can improve the performance of the propulsion unit.

[0077] By constraining the movement of the second actuator 4b, the pivot point 5b connecting the second actuator 4b to the fin 3 can only be displaced vertically, thus enabling only heave motion. The fin 3 is configured to pivot around the pivot point 5b, allowing for changes in its pitch. By constraining the movement of one of the three actuators, for example by limiting the movement of the second actuator 4b, the movement of the fin 3 can be precisely controlled. For example, the fin 3 can be prevented from swinging forward / backward while performing heave motion and / or pitch motion. The first actuator 4a and / or the third actuator 4c do not need to be constrained so that they can pivot relative to the hull of the ship when the first actuator 4a and / or the third actuator 4c are extended and / or retracted. In one or more exemplary propulsion units 1, the three actuators 4a, 4b, and 4c may be arranged at an angle to each other such that the extension directions of the three actuators 4a, 4b, and 4c are not parallel to each other. Actuators 4a, 4b, and 4c, such as water hammer pump type actuators, can be positioned on the hull of the ship, so that the actuators are not opposed to each other, such as when the forces acting on actuators 4a, 4b, and 4c act in opposite directions. One or more of the actuators 4a, 4b, and 4c can be positioned such that one or more of the actuators 4a, 4b, and 4c can absorb forces in the longitudinal direction and vertical direction of the ship. Forces acting in the longitudinal direction may be, for example, longitudinal thrust. For example, the first actuator 4a can be positioned at a first angle with respect to the vertical axis of the ship, the second actuator 4b can be positioned at a second angle, such as parallel to the vertical axis of the ship, and the third actuator can be positioned at a third angle with respect to the vertical axis of the ship. The first pivot point 5a, the second pivot point 5b, and the third pivot point 5c may be fixed relative to the fin 3, such as not being slidably positioned. In other words, fin 3 can pivot around the first pivot point 5a, the second pivot point 5b, and the third pivot point 5c.By positioning two of the actuators, such as the first actuator 4a and the third actuator 4c, at an angle other than zero with respect to the vertical axis, the first actuator 4a and the third actuator 4c can compensate for changes in the distance between the first pivot point 5a, the second pivot point 5b, and the third pivot point as seen from a horizontal plane, such as a plane perpendicular to the vertical axis of the ship, when the pitch angle of the fin 3 changes. The first pivot point 5a, the second pivot point 5b, and the third pivot point 5c may be pin joints in one or more exemplary propulsion units. By fixing the first pivot point 5a, the second pivot point 5b, and the third pivot point 5c within the fin 3, the stability and / or controllability of the fin 3 can be improved, so that the pitch of the fin 3 can be controlled with improved precision.

[0078] To provide the pitch and / or heave motion of the fin 3, two or more of the actuators 5a, 5b, and 5c can be actuated in a correlated manner so that the displacements of the actuators 5a, 5b, and 5c are controlled in a correlated manner. For example, to change the pitch of the fin 3, the first actuator 5a can be extended while the third actuator 5c is retracted. This causes the leading edge 10 of the fin 3 to be lowered and the trailing edge 16 of the fin 3 to be raised as the fin 3 pivots around the second pivot point 5b. To raise the leading edge 10 and lower the trailing edge 16 of the fin 3, the first actuator 5a can be retracted while the third actuator 5c is extended. To change the heave of the fin 3, all actuators can be actuated in a correlated manner. By simultaneously retracting the first actuator 4a, the second actuator 4b, and the third actuator 4c, the fin 3 can be raised so that the distance between the fin 3 and the hull of the ship decreases. By simultaneously extending the first actuator 4a, the second actuator 4b, and the third actuator 4c, the fin 3 can be lowered so that the distance between the fin 3 and the ship's hull increases. By independently controlling the displacements, such as the extension and / or retraction rates, of the first actuator 4a, the second actuator 4b, and the third actuator 4c, a combined motion of pitch and heave of the fin 3 can be generated. This makes it possible to continuously adjust the heave and / or pitch of the fin 3 of the propulsion unit 1 to countless angle of attack profiles. This improves the performance of the propulsion unit 1, since the angle of attack of the fin 3 relative to the incoming water is a critical factor for the performance of the propulsion unit 1. The heave and / or pitch of the fin 3 can be controlled to increase the efficiency of the fin 3 based on the conditions of the water surrounding the fin, for example, based on the velocity of the incoming water, such as the velocity of the water reaching the leading edge 10 of the fin 3. The displacements of actuators 5a, 5b, and 5c may be controlled, for example, such that all forces acting on actuators 5a, 5b, and 5c can be absorbed as either tension or compression in one or more of the actuators 5a, 5b, and 5c.The displacements of actuators 5a, 5b, and 5c may be controlled such that only vertical displacement is performed by one of the actuators, such as the second actuator 5b, without any forward and / or aft motion components, such as in the longitudinal direction of the ship.

[0079] Figure 11 shows a graph illustrating two different angle of attack profiles to control the motion of fin 3, such as heave and / or pitch, based on the water conditions surrounding fin 3, such as the velocity of incoming or outgoing water. This graph shows the pitch angle of fin 3 during one reciprocating motion, such as during one stroke of the fin. The dotted line in Figure 11 shows the angle of attack profile optimized for a fin operating with a single propeller, such as when the propulsion unit is simulated without a ship. The solid line shows the angle of attack profile optimized for operation in a wake behind a ship. Instead of water flow moving along the longitudinal axis of the ship, the ship's hull can bend the water flow vector upward along the rise at the stern of the ship. This creates a flow field with vertical and aft components. Also, the boundary layer of the hull can decelerate the water flow, so the strength of the water flow is below the velocity of freely flowing water without the influence of the ship's hull. The angle of attack profile shown by the dotted line takes into account the influence of the ship on the water flowing to fin 3 when determining the optimal angle of attack profile for the fin. By adapting the angle of attack profile to the water conditions surrounding the ship, for example by optimizing it, the efficiency of the propulsion unit can be significantly improved.

[0080] It should be noted that the features mentioned in the embodiments described in Figures 1 to 11 are not limited to these specific embodiments. Therefore, any features related to the sealing of fins, one or more actuators, and / or contained therein, mentioned in relation to one or more exemplary first embodiments of Figures 1a-1b, such as the dimensions of the fins and the type of actuator or sealing solution, are also applicable to one or more exemplary second embodiments described in relation to Figures 2 to 5, and / or exemplary embodiments described in relation to Figures 9 to 11, and vice versa.

[0081] Furthermore, it should be noted that, as used herein, the vertical axis relates to an imaginary line passing vertically through the ship and through its center of gravity, the transverse axis or short axis is an imaginary line crossing the ship horizontally and through its center of gravity, and the longitudinal axis is an imaginary line passing horizontally through the ship's length and through its center of gravity, parallel to the waterline. Similarly, as used herein, the vertical plane relates to an imaginary plane passing vertically through the ship's width, the transverse plane or short plane is an imaginary plane crossing the ship horizontally, and the longitudinal plane is an imaginary plane passing vertically through the ship's length.

[0082] Embodiments of the products (propulsion unit and ship) described herein are as follows:

[0083] Item 1. A propulsion unit (1) for propelling a ship, The above-mentioned vessel is configured to be positioned on the keel and comprises a body (2) including a pivot point (5a), A fin (3) is movably positioned relative to the main body (2), An actuator assembly (4) for generating heave motion of the fin (3) relative to the main body (2), wherein the actuator assembly (4) has at least one actuator (4a, 4b), Includes, The propulsion unit (1) is configured such that the fin (3) is connected to the pivot point (5a) so that when at least one actuator (4a, 4b) generates the heave motion of the fin (3), the fin (3) pivots around the first pivot point (5a) and generates the pitch motion of the fin (3).

[0084] Item 2. The propulsion unit (1) according to Item 1, wherein at least one actuator (4a, 4b) is a linear actuator.

[0085] Item 3. The propulsion unit (1) according to any one of the preceding items, wherein the propulsion unit (1) includes at least one actuation rod (9, 9a, 9b), and the actuator assembly (4) is connected to the fin (3) via the at least one actuation rod (9, 9a, 9b).

[0086] Item 4. The propulsion unit (1) described in any one of the preceding items, wherein the actuator assembly (4) is configured to generate oscillating heave motion and pitch motion of the fin by operating in an oscillating pattern.

[0087] Item 5. The pivot point (5a) is a propulsion unit (1) described in any one of the preceding items, which is fixedly positioned on the main body (2).

[0088] Item 6. The propulsion unit (1) according to Item 5, wherein the propulsion unit (1) includes a lever arm (7), and the fin (3) is attached to the pivot point (5a) via the lever arm (7).

[0089] Item 7. The actuator assembly (4) includes a first actuator (4a) and a second actuator (4b), The propulsion unit (1) according to any one of items 1 to 4, wherein the pivot point (5a) is connected to the second actuator (4b), so that the pivot point (5a) is movably positioned relative to the main body (2).

[0090] Item 8. The propulsion unit (1) as described in Item 7, wherein the first actuator (4a) and the second actuator (4b) are operable independently of each other, and the phase difference between the heave motion and the pitch motion of the fin (3) is variable.

[0091] Item 9. The fin (3) includes a first fin portion (3a), a second fin portion (3b), a first connecting rod (8a), and a second connecting rod (8b), The first fin portion (3a) and the second fin portion (3b) are connected via the first connecting rod (8a) and the second connecting rod (8b), The propulsion unit (1) according to item 7 or 8, wherein the first connecting rod (8a) and the second connecting rod (8b) are parallel and positioned at a first distance and a second distance, respectively, from the leading edge (10) of the first fin portion (3a) and the second fin portion (3b).

[0092] Item 10. The propulsion unit (1) according to Item 9, wherein the main body (2) includes a first through slot (13a) and a second through slot (13b), so that the first connecting rod (8a) and the second connecting rod (8b) can protrude through the main body (3) and be slidably positioned within the first through slot (13a) and the second through slot (13b).

[0093] Item 11. The propulsion unit (1) according to item 9 or 10, wherein the first connecting rod (8a) is connected to the first actuator (4a) and the second connecting rod (8b) is connected to the second actuator (4b).

[0094] Item 12. The propulsion unit (1) according to Item 11, wherein the first connecting rod (8a) and the second connecting rod (8b) are connected to the first actuator (4a) and the second actuator (4b) via the first operating rod (9a) and the second operating rod (9b), respectively.

[0095] Item 13. The first operating rod (9a) and the second operating rod (9b) are located inside the main body (2) and constitute the propulsion unit (1) as described in Item 12.

[0096] Item 14. The actuator assembly (4) includes a third actuator (4c), as described in any one of items 7 to 13, of the propulsion unit (1).

[0097] Item 15. The propulsion unit (1) as described in Item 14, wherein at least two of the first actuator (4a), the second actuator (4b), and the third actuator (4c) are operable in correlation to variably adjust the pitch angle and / or heave of the fin (3).

[0098] Item 16. The fin (3) includes a third connecting rod, The first fin portion (3a) and the second fin portion (3b) are connected via the third connecting rod. The propulsion unit (1) according to item 14 or 15, as it is dependent on any one of items 9 to 12, wherein the first connecting rod (8a), the second connecting rod (8b), and the third connecting rod are arranged in parallel and at a first distance, a second distance, and a third distance, respectively, from the leading edge (10) of the first fin portion (3a) and the second fin portion (3b).

[0099] Item 17. The propulsion unit (1) as described in Item 16, wherein the body (2) includes a third through slot (13c), thereby enabling the first connecting rod (8c) to protrude through the body (3) and to be slidably positioned within the third through slot (13c).

[0100] Item 18. The propulsion unit (1) according to item 16 or 17, wherein the third connecting rod (8c) is connected to the third actuator (4c).

[0101] Item 19. The propulsion unit (1) as described in Item 18, wherein the third connecting rod (8c) is connected to the third actuator (4c) via the third operating rod (9c).

[0102] Item 20. The third operating rod (9c) is the propulsion unit (1) described in Item 19, which is located inside the main body (2).

[0103] Item 21. A propulsion unit (1) according to any one of items 7 to 20, wherein at least one of the first actuator (4a) and the second actuator (4b) is configured to be displaced vertically.

[0104] Item 22. The propulsion unit (1) according to Item 21, wherein at least one of the first actuator (4a) and the second actuator (4b) is constrained in a direction perpendicular to the extension direction of at least one of the first actuator (4a) and the second actuator (4b).

[0105] Item 23. A propulsion unit (1) according to item 21 or 22, wherein at least one of the first actuator (4a) and the second actuator (4b) is constrained in the short direction and / or the longitudinal direction.

[0106] Item 24. The propulsion unit is a propulsion unit (1) as described in any one of the preceding items, including a rudder (6).

[0107] Item 25. The propulsion unit (1) as described in Item 24, wherein the body (2) is configured to be fixedly positioned on the keel of the ship, and the rudder (6) is pivotably positioned on the body (2).

[0108] Item 26. The main body (2) includes a rudder head member (11) for rotatably positioning the main body (2) on the keel of the ship, The propulsion unit (1) according to item 24, wherein the one or more actuators (4a, 4b) and / or the at least one actuation rod (9, 9a, 9b) are located inside the rudder head member (11), and the body (2) is configured to function as the rudder (6).

[0109] Item 27. The main body (2) includes a hollow tube (12) that protrudes from the main body (2) onto the side of the main body (2) facing the keel, The first operating rod (9a) and / or the second operating rod (9b) are arranged inside the hollow tube (12). The hollow tube (12) is configured to protrude into the ship when the main body (2) is positioned on the keel of the ship, as described in any one of the preceding items, the propulsion unit (1).

[0110] Item 28. The propulsion unit (1) according to Item 27, wherein the hollow tube (12) includes a seal (14) positioned at the distal end of the hollow tube (12) to seal the first actuation rod (9a) and / or the second actuation rod (9b) against the hollow tube (12).

[0111] Item 29. The propulsion unit (1) according to item 27 or 28, wherein the rudder head member (11) is hollow and constitutes the hollow tube (12).

[0112] Item 30. The propulsion unit (1) described in any one of the preceding items, wherein the fin (3) has an elliptical planar shape.

[0113] Item 31. The fin (3) is a propulsion unit (1) as described in any one of the preceding items, including a winglet (15).

[0114] Item 32. The main body (2) is positioned on the keel (101) of the ship (100), A ship (100) comprising a propulsion unit (1) for propelling the ship (100) according to any one of items 1 to 31, wherein the fin is configured to perform pitch and heave motions relative to the keel (101) of the ship (100).

[0115] Item 33. The ship (100) described in Item 32, wherein the main body (2) is fixedly positioned on the keel (101).

[0116] Item 34. The ship (100) according to item 32, wherein the body (2) is rotatably positioned on the keel (101).

[0117] The use of terms such as "first," "second," "third," and "fourth," "primary," "secondary," and "tertiary" does not imply a specific order, but is included to identify individual elements. Furthermore, the use of terms such as "first," "second," "third," "fourth," "primary," "secondary," and "tertiary" does not indicate any order or importance; rather, these terms are used to distinguish one element from another. It should be noted that terms such as "first," "second," "third," "fourth," "primary," "secondary," and "tertiary" are used throughout the specification and are merely for labeling purposes, and are not intended to indicate any specific spatial or temporal order. Furthermore, the labeling of the first element does not imply the existence of the second element, and vice versa.

[0118] Note that "comprising" does not necessarily exclude the existence of elements or steps other than those exemplified.

[0119] Note that the terms "a" or "an" preceding an element do not exclude the possibility of multiple such elements existing.

[0120] While features are shown and described, it is understood that they are not intended to limit the claimed disclosure, and it will be clear to those skilled in the art that various changes and modifications can be made without departing from the scope of the claimed disclosure. Therefore, the specification and drawings are considered illustrative rather than limiting. The claimed disclosure is intended to encompass all alternatives, modifications, and equivalents. According to embodiment (1), a propulsion unit (1) for propelling a ship, The above-mentioned vessel is configured to be positioned on the keel and comprises a body (2) including a pivot point (5a), A fin (3) is movably positioned relative to the main body (2), An actuator assembly (4) for generating heave motion of the fin (3) relative to the main body (2), wherein the actuator assembly (4) has at least one actuator (4a, 4b), Includes, The fin (3) is connected to the pivot point (5a), and when the at least one actuator (4a, 4b) generates the heave motion of the fin (3), the fin (3) is arranged to pivot around the pivot point (5a) and generates the pitch motion of the fin (3), which is the propulsion unit (1). According to embodiment (2), the at least one actuator (4a, 4b) is a linear actuator. According to embodiment (3), the propulsion unit (1) includes at least one actuation rod (9, 9a, 9b), and the actuator assembly (4) is connected to the fin (3) via the at least one actuation rod (9, 9a, 9b). According to embodiment (4), the actuator assembly (4) is configured to generate a oscillating heave motion and pitch motion of the fin by operating in an oscillating pattern. According to embodiment (5), the pivot point (5a) is fixedly positioned on the main body (2). According to embodiment (6), the propulsion unit (1) includes a lever arm (7), and the fin (3) is attached to the pivot point (5a) via the lever arm (7). According to embodiment (7), the actuator assembly (4) includes a first actuator (4a) and a second actuator (4b), The pivot point (5a) is connected to the second actuator (4b), thereby allowing the pivot point (5a) to be movably positioned relative to the main body (2). According to embodiment (8), the first actuator (4a) and the second actuator (4b) are operable independently of each other, and the phase difference between the heave motion and the pitch motion of the fin (3) is variable. According to embodiment (9), the fin (3) includes a first fin portion (3a), a second fin portion (3b), a first connecting rod (8a), and a second connecting rod (8b), The first fin portion (3a) and the second fin portion (3b) are connected via the first connecting rod (8a) and the second connecting rod (8b), The first connecting rod (8a) and the second connecting rod (8b) are arranged parallel to each other and at a first distance and a second distance, respectively, from the leading edge (10) of the first fin portion (3a) and the second fin portion (3b). According to embodiment (10), the main body (2) includes a first through slot (13a) and a second through slot (13b), which allows the first connecting rod (8a) and the second connecting rod (8b) to protrude through the main body (3) and to be slidably arranged within the first through slot (13a) and the second through slot (13b). According to embodiment (11), the first connecting rod (8a) is connected to the first actuator (4a), and the second connecting rod (8b) is connected to the second actuator (4b). According to embodiment (12), the first connecting rod (8a) and the second connecting rod (8b) are connected to the first actuator (4a) and the second actuator (4b) respectively via the first operating rod (9a) and the second operating rod (9b). According to embodiment (13), the first operating rod (9a) and the second operating rod (9b) are arranged inside the main body (2). According to embodiment (14), the actuator assembly (4) includes a third actuator (4c). According to embodiment (15), at least two of the first actuator (4a), the second actuator (4b), and the third actuator (4c) are operable in correlation to variably adjust the pitch angle and / or heave of the fin (3). According to embodiment (16), the fin (3) includes a third connecting rod, The first fin portion (3a) and the second fin portion (3b) are connected via the third connecting rod. The first connecting rod (8a), the second connecting rod (8b), and the third connecting rod are arranged parallel to each other and at a first distance, a second distance, and a third distance, respectively, from the leading edge portions (10) of the first fin portion (3a) and the second fin portion (3b). According to embodiment (17), the main body (2) includes a third through slot (13c), which allows the first connecting rod (8c) to protrude through the main body (3) and to be slidably positioned within the third through slot (13c). According to embodiment (18), the third connecting rod (8c) is connected to the third actuator (4c). According to embodiment (19), the third connecting rod (8c) is connected to the third actuator (4c) via the third operating rod (9c). According to embodiment (20), the third operating rod (9c) is located inside the main body (2). According to embodiment (21), at least one of the first actuator (4a) and the second actuator (4b) is configured to be displaceable in the vertical direction. According to embodiment (22), at least one of the first actuator (4a) and the second actuator (4b) is constrained in a direction perpendicular to the extension direction of at least one of the first actuator (4a) and the second actuator (4b). According to embodiment (23), at least one of the first actuator (4a) and the second actuator (4b) is configured to be constrained in the short direction and / or the long direction. According to embodiment (24), the propulsion unit includes a rudder (6). According to embodiment (25), the main body (2) is configured to be fixedly positioned on the keel of the ship, The rudder (6) is pivotably positioned on the main body (2). According to embodiment (26), the main body (2) includes a rudder head member (11) for rotatably positioning the main body (2) on the keel of the ship, The one or more actuators (4a, 4b) and / or the at least one actuation rod (9, 9a, 9b) are located inside the rudder head member (11). The main body (2) is configured to function as the rudder (6). According to embodiment (27), the main body (2) includes a hollow tube (12) that protrudes from the main body (2) onto the side of the main body (2) facing the keel, The first operating rod (9a) and / or the second operating rod (9b) are arranged inside the hollow tube (12). The hollow tube (12) is configured to protrude into the ship when the main body (2) is positioned on the keel of the ship. According to embodiment (28), the hollow tube (12) includes a seal (14) positioned at the distal end of the hollow tube (12) to seal the first operating rod (9a) and / or the second operating rod (9b) to the hollow tube (12). According to embodiment (29), the rudder head member (11) is hollow and constitutes the hollow tube (12). According to embodiment (30), the fin (3) has an elliptical planar shape. According to embodiment (31), the fin (3) includes a winglet (15). According to embodiment (32), the main body (2) is positioned on the keel (101) of the ship (100), The fin (3) is configured to perform pitch and heave motions relative to the keel (101) of the ship (100). According to embodiment (33), the main body (2) is fixedly positioned on the keel (101). According to embodiment (34), the main body (2) is rotatably positioned on the keel (101). [Explanation of Symbols]

[0121] 1. Propulsion Unit 2 Main unit 3 fins 3a First fin section 3b Second fin section 4 Actuator Assembly 4a Actuator, First Actuator 4b Second actuator 5a Pivot point, first pivot point 5b Second pivot point 6. Rudder 7 Lever 8a First Connecting Rod 8b Second connecting rod 9. Operating rod 9a First operating rod 9b Second operating rod 10 Front edge 11 Rudder stock 12 hollow tube 13a First penetration slot 13b Second penetration slot 14 stickers 15 Winglets 16 Trailing edge 17 narrow slots 18 pins 19 narrow slots 20 stickers 21 Support surface 100 ships 101 Kiel

Claims

1. A propulsion unit (1) for propelling a ship, The above-mentioned ship's keel is configured to be positioned on the ship's keel and comprises a body (2) including a pivot point (5b), A fin (3) is movably positioned relative to the main body (2), An actuator assembly (4) for generating heave motion of the fin (3) relative to the main body (2), wherein the actuator assembly (4) has at least one actuator (4a, 4b), Includes, The fin (3) is connected to the pivot point (5b), and when the at least one actuator (4a, 4b) generates the heave motion of the fin (3), the fin (3) is arranged to pivot about the pivot point (5b) and generates the pitch motion of the fin (3). The actuator assembly (4) includes a first actuator (4a) and a second actuator (4b), The pivot point (5b) is connected to the second actuator (4b), thereby allowing the pivot point (5b) to be movably positioned relative to the main body (2). The first actuator (4a) and the second actuator (4b) are operable independently of each other, and the phase difference between the heave motion and the pitch motion of the fin (3) is variable. The fin (3) includes a first fin portion (3a), a second fin portion (3b), a first connecting rod (8a), and a second connecting rod (8b). The first fin portion (3a) and the second fin portion (3b) are connected via the first connecting rod (8a) and the second connecting rod (8b), The first connecting rod (8a) and the second connecting rod (8b) are arranged parallel to each other and at a first distance and a second distance, respectively, from the leading edge (10) of the first fin portion (3a) and the second fin portion (3b). Propulsion unit (1).

2. The propulsion unit (1) according to claim 1, wherein at least one actuator (4a, 4b) is a linear actuator.

3. The propulsion unit (1) according to claim 1 or claim 2, wherein the actuator assembly (4) is configured to operate in a swinging pattern to generate the swinging heave motion and pitch motion of the fins.

4. The propulsion unit (1) according to any one of claims 1 to 3, wherein the actuator assembly (4) includes a third actuator (4c).

5. The propulsion unit (1) according to claim 4, wherein at least two of the first actuator (4a), the second actuator (4b), and the third actuator (4c) are operable in correlation to variably adjust the angle of the pitch motion and / or the heave motion of the fin (3).

6. The fin (3) includes a third connecting rod (8C), The first fin portion (3a) and the second fin portion (3b) are connected via the third connecting rod (8C), The propulsion unit (1) according to claim 1, wherein the first connecting rod (8a), the second connecting rod (8b), and the third connecting rod (8C) are arranged parallel to each other and at a first distance, a second distance, and a third distance, respectively, from the leading edge portions (10) of the first fin portion (3a) and the second fin portion (3b).

7. The propulsion unit (1) according to claim 6, wherein the third connecting rod (8c) is connected to the third actuator (4c) of the actuator assembly (4).

8. The propulsion unit (1) according to claim 7, wherein the third connecting rod (8c) is connected to the third actuator (4c) via a third operating rod (9c).

9. The propulsion unit (1) according to claim 8, wherein the third operating rod (9c) is located inside the main body (2).

10. The main body (2) includes a hollow tube (12) that protrudes from the main body (2) onto the side of the main body (2) facing the keel, A first operating rod (9a) connecting the first actuator (4a) of the actuator assembly (4) and the first connecting rod (8a) of the fin (3), and / or a second operating rod (9b) connecting the second actuator (4b) of the actuator assembly (4) and the second connecting rod (8b) of the fin (3), are arranged within the hollow tube (12). The propulsion unit (1) according to any one of claims 1 to 9, wherein the hollow tube (12) is configured to protrude into the ship when the main body (2) is positioned on the keel of the ship.

11. The propulsion unit (1) according to claim 10, wherein the hollow tube (12) includes a seal (14) positioned at the distal end of the hollow tube (12) to seal the first operating rod (9a) and / or the second operating rod (9b) to the hollow tube (12).

12. The main body (2) is positioned on the keel (101) of the ship (100), A ship (100) comprising the propulsion unit (1) according to any one of claims 1 to 11, wherein the fin (3) is configured to perform the pitch motion and the heave motion relative to the keel (101) of the ship (100).

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