Propulsion unit and vessel comprising the same

Abstract

A propulsion unit for propelling a vessel is disclosed. The propulsion unit comprises a main body configured to be arranged at a keel of the vessel and comprising a pivot point, a fin movably arranged relative to the main body, and an actuator assembly for generating a heave motion of the fin relative to the main body. The actuator assembly comprises at least one actuator. The fin is connected to the pivot point such that the fin is arranged to pivot around the pivot point when the at least one actuator generates the heave motion of the fin, thereby generating a pitch motion of the fin.

Description

[0001] This disclosure relates to the field of propulsion systems for ships. Specifically, it relates to a propulsion unit for a ship and a ship including the propulsion unit. Background Technology

[0002] The field of propulsion systems for ships involves converting the energy output of a ship's prime mover into forward motion. Depending on the type of vessel and the services it provides, fuel costs can account for as much as 50% to 60% of a ship's total operating costs. Propellers are the primary propulsion device used on ships today. Modern propellers can achieve a maximum open-water efficiency of approximately 70%. For commercial shipping, there is a desire to improve the efficiency of propulsion systems to avoid wasting the energy provided by the prime mover. Summary of the Invention

[0003] Therefore, a propulsion system is needed that mitigates, alleviates, or resolves existing shortcomings and provides more efficient ship propulsion.

[0004] A propulsion unit for propelling a vessel is disclosed. The propulsion unit includes: a body configured to be disposed at the keel of the vessel and including a pivot point; fins movably arranged relative to the body; and an actuator assembly for generating heave motion of the fins relative to the body and / or the keel. The actuator assembly includes at least one actuator. The fins are connected to the pivot point such that the fins are arranged to pivot about the pivot point when the at least one actuator generates heave motion of the fins, thereby generating pitch motion of the fins.

[0005] One advantage of this disclosure is that the hydrodynamic drag generated by the fins is less than that generated by common propulsion systems, such as propellers driven by shafts moving in water. The actuator of the propulsion unit provides a drive mechanism for generating the motion of the fins, which is simple, efficient, and reduces energy loss and maintenance requirements of the propulsion unit. The motion of the fins can also be controlled by the actuator, allowing the hydrodynamic characteristics of the fins to be adapted to improve fin efficiency. Furthermore, the main body of the propulsion system provides directional stability to the vessel including the propulsion unit. Therefore, the efficiency of the propulsion unit is improved.

[0006] A vessel is disclosed, comprising a propulsion unit for propelling the vessel as disclosed herein. The main body is arranged to the keel of the vessel. The fins are configured to perform pitch and / or heave movements relative to the keel of the vessel.

[0007] One advantage of this disclosure is that, compared to common propulsion systems such as propellers driven by shafts moving in water, the propulsion system of this vessel is more efficient and requires less maintenance. Therefore, fuel consumption and downtime due to maintenance can be reduced, which lowers operating costs and emissions. Furthermore, the main body of the propulsion system provides directional stability to the vessel including the propulsion unit. Attached Figure Description

[0008] The above and other features and advantages of this disclosure will be readily apparent to those skilled in the art from the following detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

[0009] Figure 1A An exemplary perspective view of a propulsion unit including a single actuator according to this disclosure is shown.

[0010] Figure 1B An exemplary side view of a propulsion unit including the single actuator according to this disclosure is shown.

[0011] Figures 2A to 2D An exemplary overall design and motion pattern of a propulsion unit including a first actuator and a second actuator according to this disclosure are shown.

[0012] Figure 3 An exemplary connection for connecting fins to a first actuator and a second actuator according to this disclosure is shown.

[0013] Figure 4 An exemplary body of the propulsion unit according to this disclosure is shown.

[0014] Figure 5 This is an exemplary graph illustrating the motion modes of the fins of a propulsion system when the first and second actuators operate under phase shift conditions, according to the present disclosure.

[0015] Figure 6 An exemplary propulsion unit for rotatably mounted on a ship, according to the present disclosure, is shown.

[0016] Figure 7 An external perspective view of an exemplary vessel including an exemplary propulsion unit according to this disclosure is shown.

[0017] Figure 8 An internal perspective view of an exemplary vessel including an exemplary propulsion unit according to this disclosure is shown.

[0018] Figure 9 An exemplary propulsion unit according to this disclosure includes a first actuator and a second actuator arranged to the fins via a fixed pivot point.

[0019] Figure 10 An exemplary propulsion unit according to this disclosure is shown, comprising a first actuator and a second actuator arranged to the fins via a fixed pivot point, and

[0020] Figure 11 This is an exemplary graph illustrating the motion patterns of the fins in a propulsion system using different angle-of-attack profiles. Detailed Implementation

[0021] Various exemplary embodiments and details are described below, with reference to the accompanying drawings where applicable. It should be noted that the drawings may be drawn to scale or not, and that elements having similar structures or functions are indicated by the same reference numerals throughout the drawings. It should also be noted that the drawings are intended only to facilitate the description of embodiments. They are not intended as an exhaustive description of this disclosure or as a limitation on the scope of this disclosure. Furthermore, the illustrated embodiments need not possess all the aspects or advantages shown. Aspects or advantages described in connection with a particular embodiment are not necessarily limited to that embodiment and may be practiced in any other embodiment, even if not so shown or so explicitly described.

[0022] For clarity, the accompanying drawings are schematic and simplified, and they show only details that aid in understanding this disclosure, while other details are omitted. Throughout, the same reference numerals are used for the same or corresponding parts.

[0023] A propulsion unit for propelling a vessel is disclosed. The propulsion unit includes: a body configured to be disposed at the keel of a vessel and including a pivot point (such as a first pivot point); fins movably disposed relative to the body; and an actuator assembly for generating heave motion of the fins relative to the body. Heave motion may herein refer to reciprocating motion of the fins, such as linear vertical upward / downward movement of the fins relative to the body when the propulsion unit is disposed on the vessel. The actuator assembly includes at least one actuator. The fins are connected to the pivot point such that the fins are arranged to pivot about the pivot point when at least one actuator generates heave motion of the fins, thereby generating pitch motion of the fins. Pitch motion of the fins herein refers to rotation of the fins about their transverse axis, such as about an axis extending from a first tip of the fin to a second tip of the fin (such as from the port side tip of the fin to the starboard side tip of the fin). Heave motion and / or pitch motion of the fins generate thrust for propelling the vessel.

[0024] At least one actuator may be a linear actuator. The actuator may be a hydraulic, electric, or mechanical actuator. In one or more example propulsion units, the actuator may be a plunger-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 operate in an oscillating mode, thereby generating oscillating heave and pitch motions of the fins.

[0025] In one or more example embodiments of the propulsion unit, a pivot point may be fixedly arranged to the body. The propulsion unit may include a joystick arm. The joystick arm may be attached to the pivot point such that the joystick arm can pivot about the pivot point. Fins may be attached to the pivot point via the joystick arm. Because the fins may be attached to the joystick arm that is pivotally attached to the pivot point, the fins can pivot about the pivot point.

[0026] In one or more example embodiments of the propulsion unit, the fins may be pivotally arranged to a control lever arm. The propulsion unit may also include a pitch lever configured to change the pitch of the fins when an actuator generates heave motion of the fins. A first end of the pitch lever may be pivotally arranged to the fins at a distance from a pivot point where the fins are attached to the control lever arm. The propulsion unit may include a crank (such as a double-arm crank) having a first arm and a second arm, respectively pivotally arranged to the body of the propulsion unit at a distance from the ends of the first and second arms. A second end of the pitch lever may be pivotally arranged on the first end of the crank, and an actuator may be pivotally arranged to the second end of the crank. During reciprocating motion of the actuator, the crank may rotate about the pivot point, thereby changing the position of the second arm of the crank, and consequently changing the position of the second end of the pitch lever. This causes the first end of the pitch lever to change its position relative to the pivot point connecting the fins to the control lever arm, resulting in a change in the pitch angle of the fins relative to the control lever arm. The crank may further include a first contact surface and a second contact surface, the first and second contact surfaces facing each other and configured to contact the upper and lower sides of the control lever arm, respectively, to generate a heaving motion of the fins. When the actuator is extended, the crank is pivotable relative to the body such that the first contact surface of the crank contacts the upper side of the control lever arm and pushes the control lever arm downward. When the actuator is retracted, the crank is pivotable relative to the body in the opposite direction such that the second contact surface of the crank contacts the lower side of the control lever arm and pushes the control lever arm upward.

[0027] In some example embodiments, the pitch motion of the fins can also be generated by an actuator acting as a rotary actuator. In some example embodiments of the propulsion unit, the actuator assembly may include a first actuator and a second actuator. The first and second actuators may be connected to the fins via a first pivot point and an optional second pivot point, respectively. The pivot points (such as the first and / or second pivot points) can therefore be movably arranged relative to the body. The positions of the pivot points and / or the actuators connected thereto can be moved forward or backward on the fin body such that they are positioned to optimize the torque they induce on the fins.

[0028] The first and second actuators can operate independently of each other, such that the phase difference between the heave and pitch movements of the fin is variable. The first and second actuators can therefore operate in phase or out of phase. To produce out-of-phase pitch and heave movements, the actuators can operate with a phase difference. Changing the phase difference allows adjustment of the fin's maximum pitch angle. In one or more embodiments, the two actuators can be operated by independently changing the amplitude of their travel or movement. The first and second actuators can therefore independently change the amplitude and / or phase of their travel or movement. The pitch angle referred to herein is the angle of the fin relative to the horizontal plane. When the first and second actuators operate in phase, the fin only undergoes heave movements because the relative positions of the first and second pivot points do not change. In other words, when the first and second actuators operate in phase, they make the same movement, so the pitch of the fin remains unchanged, and the fin moves up / down without changing the angle of the fin relative to the horizontal plane. When the first and second actuators operate out of phase, the fins undergo heave and pitch movements due to the change in the relative positions of the first and second pivot points. In other words, when the first and second actuators operate out of phase, they move differently, thus changing the pitch of the fins and causing them to move up / down while altering their angle relative to the horizontal plane. Since the first and second actuators can operate independently, the fin's motion pattern can be tuned and optimized to increase lift and thus increase thrust generated by the fins. By significantly altering and / or reversing the phase or amplitude of the first and / or second actuators, the fins can generate reverse thrust to reverse the vessel. Precise control of the fin motion can be achieved by individually controlling the phase difference and / or amplitude of the first and second actuators. Therefore, one or more example embodiments disclosed herein provide a simple system that allows for precise control of fin motion.

[0029] In one or more example embodiments of the propulsion unit, fins may be slidably arranged within the body. The fins may 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 may include a first link and optionally a second link. The first fin portion and the second fin portion may be connected via the first link and the second link. The first link and the second link may be arranged in parallel and at corresponding first and second distances from the leading edges of the first fin portion and the second fin portion. The first link and the second link may have corresponding first and second ends configured to be disposed within the first fin portion and the second fin portion, respectively. The central portions of the first link and the second link may be disposed within 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 may be disposed on a first side of the body (e.g., the starboard side), and the second fin portion may be disposed on a second side of the body (e.g., the port side).

[0030] A first link can be connected to a first actuator, and a second link can be connected to a second actuator. The first and second links can be connected to the respective first and second actuators via a first actuation rod and a second actuation rod, respectively. The first link can be connected to the first actuation rod via a first free-rotating pin connection. The second link can be connected to the second actuation rod via a second free-rotating pin connection. The first free-rotating pin connection thus forms a first pivot point, and optionally, the second free-rotating pin connection forms a second pivot point, with fins arranged to pivot about both the first and second pivot points.

[0031] At least one actuator may include one or more pin connections at its end for connecting the actuator to a fin, an actuating rod, and / or the hull of the vessel. At least one actuating rod may also include one or more pin connections at its end for connecting the actuating rod to the actuator and / or to the fin. The pin connections allow the actuator to rotate freely at the connection point, thereby allowing the actuator to adjust its alignment with the control lever arm and / or the vessel during pivoting movements of the fin about a pivot point. At least one actuator including pin connections therefore cannot bear any bending moment.

[0032] In one or more example embodiments, at least one actuator and / or at least one actuating rod may be constrained, for example, by one or more bearings (such as sliding bearings) to move only in the longitudinal direction, such as in the direction of linear actuation of at least one actuator, so that it cannot rotate and thus can support bending moments in the actuator. At least one actuator and / or at least one actuating rod (such as at least one of a first actuator and a second actuator) 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 arranged on the ship. Displacement only in the vertical direction herein 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 actuator and the second actuator may be configured to displace in the vertical direction. At least one of the first actuator and the second actuator 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 a first actuator and a second actuator) may be constrained in a direction perpendicular to the extension direction of at least one actuator, such as in a direction perpendicular to the extension direction of at least one of the first actuator and the second actuator.

[0033] One or more bearings may be arranged in the body of the propulsion unit and / or in the hull of the vessel. One or more bearings may be arranged circumferentially around 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 actuation direction of at least one actuator (such as in the vertical direction when the propulsion unit is mounted to the vessel). Restricting the movement of at least one actuator and / or at least one actuating rod to the longitudinal direction contributes to the sealing of at least one actuator and / or at least one actuating rod relative to the vessel. 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 vessel, simpler and less expensive seals can be used compared to solutions where at least one actuator and / or at least one actuating rod can rotate relative to the vessel. Restraining the movement of at least one actuator and / or at least one actuating rod improves the controllability of fin movement and allows for precise control of fin motion. Restraining the movement of at least one actuator and / or actuator rod can prevent the fins from oscillating back and forth during their heave and / or pitch movements relative to the ship's hull.

[0034] In one or more example propulsion units, the propulsion unit includes a plurality of actuators and / or actuator rods, such as, for example, a first actuator and / or actuator rod, a second actuator and / or actuator rod, and a third actuator and / or actuator rod. One of the plurality of actuators and / or actuator rods may be constrained to prevent rotation of said actuator and / or actuator rod relative to the hull of the vessel. Other actuators and / or actuator rods may be configured to pivot relative to the hull of the vessel during heave and / or pitch movements of the fins. The fins may be configured to pivot relative to each of the plurality of actuators and / or actuator rods, such that the fins can change their angle of attack relative to each of the plurality of actuators and / or actuator rods. The fins may be connected to the plurality of actuators and / or actuator rods, for example, via respective pivot points.

[0035] When the fin performs a pitching motion, the distance between the first pivot point and the second pivot point changes when viewed from a horizontal plane (such as a plane perpendicular to the longitudinal extension of the actuating rod). To allow for this change in the distance between the first and second pivot points when viewed from the horizontal plane, at least one of the pivot points can be connected to the fin via a sliding joint. The sliding joint can be, for example, an elongated slot, in which the pivot point can be arranged for slidable movement.

[0036] At least one of the first and second links (such as the first link) may include a first elongated slot and a second elongated slot respectively disposed at opposite ends of the link. The elongated slots may have a longitudinal extension in a direction perpendicular to the longitudinal axis of at least one of the first and second links. The elongated slots may be disposed within the first fin portion and the second fin portion respectively. The first and second elongated slots may be respectively connected to a pin or rod fixedly disposed within the first and second fin portions, such that the pin or rod is slidably disposed within the elongated slot of at least one of the first and second links. The first and second fin portions may also include elongated slots for receiving the first and / or second links, thereby allowing the first and / or second links to slide relative to the first and second fin portions within the elongated slots. The first and / or second links can therefore be slidably disposed within the first and second fin portions in a direction perpendicular to the longitudinal axis of at least one of the first and second links, such that the distance of the first and / or second links from the leading edge can vary. By changing the distance of the first link and / or the second link from the leading edge, the distance between the first pivot point and the second pivot point, viewed from the horizontal plane, can vary with the pitch motion of the fin. Therefore, the first actuator and the second actuator can perform purely vertical motion to generate both pitch and heave motions of the fin. The positions of the first and second links, and therefore the positions of the connection points of the first and second actuators, can depend on the implementation and can move along the chord of the fin body, such that the connection points of the first and second actuators are positioned to optimize the torque induced on the fin.

[0037] The first actuating rod and / or the second actuating rod (or at least their central portions) may be disposed within the body. Therefore, the body may include a first through slot and / or a second through groove for receiving the first link and / or the second link, respectively. The first through slot and / or the second through groove allows the first and second links to protrude through the body and be slidably disposed within the first and second through slots. The first and second links may be connected internally to the first actuating rod and the second link. The first and second through slots have longitudinal extensions in the vertical direction of the body to allow vertical movement of the first and second links to generate pitch and heave motion of the fins. The first and second through slots may each include openings at their top ends. The openings at the top ends of the first and second through slots allow the first and second actuators and / or the first and second actuating rods to protrude into the body to connect to the links. The openings at the top of the first and second through slots can extend upward into the hull of the main body and / or the vessel, and can be sealed above the waterline of the vessel.

[0038] The propulsion unit may include a rudder. In one or more example embodiments, the body may be configured to be fixedly arranged to the keel of a vessel, and the rudder may be pivotally arranged to the stern fin. When the body is fixedly arranged to the keel, it may constitute the stern fin of the vessel. The stern fin, as used herein, refers to the stern extension of the keel of a vessel. The stern fin provides directional stability to the vessel. The body may have a rudder mounted on its centerline. The rudder may be attached to the body via a rudder stock arranged at the aft edge of the body. The rudder stock is a vertical axis through which the rotational force of the steering gear is transmitted to the rudder. The rudder stock can therefore provide a pivot point for the rudder, about which the rudder may be pivotally arranged to the body.

[0039] In one or more example embodiments, the body may include a rudder stock for rotatably arranging the body to the keel of a vessel. The body can thus be configured to rotate and function as a rudder. The rudder stock 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 arranged inside the rudder stock. The rudder stock may include bearings (such as swivel bearings) for rotatably arranging the rudder stock to the keel of the vessel. The rudder stock may form a bearing race of the bearing. To prevent water from entering the vessel through the hollow rudder stock, the rudder stock may be sealed. The rudder stock forming one of the bearing races may extend above the waterline of the vessel, allowing the rudder stock to be sealed above the waterline. Sealing the rudder stock above the waterline allows for the use of simpler and cheaper seals compared to sealing the rudder stock below the waterline of the vessel.

[0040] The main body may include a hollow tube projecting from the main body on the side facing the ship or the keel. A first actuating rod and / or a second actuating rod may be arranged within the hollow tube. When the main body is arranged to the keel of the ship, the hollow tube may be configured to project into the ship, such as into the interior of the ship's hull. When the main body is fixedly arranged to the keel of the ship, the hollow tube may be a steel pipe welded to the hull of the ship. When the main body is rotatably arranged to the keel of the ship, the rudder stock may be hollow and may constitute a hollow tube. The hollow tube may include a first end arranged to project into the hull of the ship and a second end arranged in and / or on the hull of the ship. The first end of the hollow tube is therefore positioned further away from the main body and / or fins 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 main body may be fully or partially open to the water around the ship. To allow movement of the actuator, actuator rod, and / or linkage within the body, the body includes openings (such as slots) for receiving the actuator, actuator rod, and / or linkage. Water can therefore surge in through these openings in the body. To prevent water from entering the ship's hull, the hollow tube may include a seal disposed at a first end (such as the distal end) of the hollow tube for sealing the actuator and / or actuator rod relative to the hollow tube. The hollow tube may include a flanged connector for receiving the seal. If the seal is disposed below the ship's waterline, sealing between the actuator and the hull can be particularly complex and difficult. By providing a hollow tube protruding into the ship's hull on the body, and arranging a seal at a first end (such as the distal end) of the hollow tube inside the ship's hull, the seal can be moved upwards such that the connection between the actuator and the ship's hull and / or between the actuator rod and the ship's hull can be disposed above the ship's waterline. Therefore, the connection between the actuator and the ship's hull and / or between the actuator rod and the ship's hull can be sealed using less complex and cheaper seals. The first actuator and / or the second actuator can be internally sealed to prevent water from entering the ship through the actuator.

[0041] In one or more example propulsion units, a first actuator and a second actuator and / or a first actuating rod and a second actuating rod may be arranged in the same hollow tube. In one or more example embodiments of the propulsion unit, such as when the body is fixedly arranged on the keel of a ship, the body may include a first hollow tube and a second hollow tube. The first actuator and the second actuator and / or the first actuating rod and the second actuating rod may be arranged in corresponding hollow tubes. The first actuator and / or the first actuating rod may be arranged within the first hollow tube, and the second actuator and / or the second actuating rod may be arranged within the second hollow tube.

[0042] In one or more example propulsion units, the propulsion unit (such as an actuator assembly) includes a third actuator, such that the propulsion unit includes at least three actuators. The at least three actuators may be arranged between the hull and the fins of the vessel. The at least three actuators are configured to provide heave and pitch movements of the fins relative to the hull of the vessel. At least one of the three actuators may be configured to move only in the vertical direction of the main body. The other actuators may be configured to move in both the vertical and longitudinal directions of the main body. The at least one actuator configured to move only in the vertical direction may have its movement constrained by a support. The support may prevent the at least one actuator and / or at least one actuating rod configured to move only vertically from moving in any other direction besides the vertical direction.

[0043] In one or more example propulsion units, at least two of the first, second, and third actuators can operate in relation to each other, such as simultaneously and relative to each other, to variably adjust the pitch angle and / or heave of the fins. For example, to change the pitch of the fins, two of the three actuators can operate simultaneously and relative to each other, such as retracting or extending relative to each other, to change the vertical distance between the respective pivot points to which the two actuators are connected. One of the actuators can remain stationary, allowing the fins to pivot about the pivot point to which the stationary actuator is connected. For heave motion of the fins, all three actuators can operate simultaneously.

[0044] To control the heave and pitch movements of the fins, a first, second, and third actuator can be controlled individually. The first, second, and third actuators can be connected to the main body of the propulsion unit (or to the hull of a ship) and / or to the fins via corresponding pivot points. The pivot points of the fins can be arranged at corresponding distances from the leading edge of the fin, such that the first, second, and third actuators act on the fins at corresponding distances from the leading edge. For example, the first actuator can be arranged closer to the leading edge of the fin than the second and third actuators. The second actuator can be arranged closer to the leading edge of the fin than the third actuator but farther from the leading edge than the first actuator. The third actuator can be arranged farther from the leading edge than both the first and second actuators.

[0045] The third actuator can be of the same type as or different from the first and second actuators. In one or more example propulsion units, the third actuator can be a hydraulic plunger-type actuator. The third actuator can be an actuating rod. The third actuator can be connected to the fin at a distance from the first and second actuators in the longitudinal direction of the vessel (e.g., forward / rearward). The first, second, and / or third actuators can be connected to the fins and / or the hull of the vessel via one or more fixed pivot points. A fixed pivot point, as used herein, means a pivot point that is fixedly (e.g., non-sliply) arranged to the fins, to the hull of the vessel, and / or to the body of the propulsion unit. In one or more example propulsion units, the pivot point can be a pin joint fixed to the fins and / or to the body of the propulsion unit and / or to the hull of the vessel. By fixing the first and second pivot points within the fins, the stability and / or controllability of the fins can be improved, allowing for increased precision control of the fin pitch. Furthermore, by eliminating sliding joints (such as slidably arranged pivot points) within the fins, friction introduced into the system can be reduced, thereby improving the efficiency of the propulsion unit. Reducing the number of moving parts in the underwater propulsion unit further reduces the risk of corrosion and potential jamming of moving parts, as well as potential system failures. Therefore, the performance of the propulsion unit can be improved.

[0046] The displacements (such as corresponding displacements) of the actuators (such as the first actuator, the second actuator, and / or the third actuator) can be controlled, for example, such that one of the actuators only makes a vertical displacement with no motion component in the forward and / or aft (such as the longitudinal direction) of the ship. By constraining the movement of one of the three actuators, the movement of the fins can be controlled in a more precise manner. For example, oscillations of the fins in the forward / aft direction of the ship can be prevented during heave and / or pitch movements, which improves the efficiency of the propulsion unit because oscillations of the fins in the forward / aft direction can change the pitch angle of the fins.

[0047] The displacement of the actuator can be controlled to adjust heave and pitch based on the conditions of the water surrounding the fins, such as the velocity of the incoming water, like the velocity of the water encountering the leading edge of the fin. Therefore, the movement of the fins can be adapted to increase the performance of the propulsion unit based on the current conditions of the water surrounding the fins. The actuator can be controlled, for example, based on multiple angle-of-attack curves that depend on the water conditions. For example, a first example angle-of-attack curve can be optimized for open water. A second example angle-of-attack curve can be optimized for operation in the wake behind the ship. According to currently disclosed propulsion units (such as propulsion units comprising two or more actuators), the heave and / or pitch of the fins can be continuously adapted, and thus the movement of the fins can be adjusted to more or less an infinite number of angle-of-attack curves. Multiple angle-of-attack curves can be determined, for example, using computational fluid dynamics (CFD) code with optimization routines to optimize the movement pattern and / or fin geometry based on given water conditions (such as a given inflow of water to the fin).

[0048] In one or more example propulsion units, the propulsion unit may include a control system configured to optimize and control the actuator's movement pattern (such as displacement) for different angle-of-attack curves based on detected fin angles of attack. In one or more example propulsion units, the control system may control the movement pattern in real time, for example, by using machine learning. The control system may receive information about fin conditions (such as water flow around the fins), and information about fin pitch and / or heave (such as fin pitch angle, heave, and / or movement speed, such as pitch and / or heave rate). The control system may use the received information to optimize the fin pitch and / or heave motion to improve the efficiency of the propulsion unit.

[0049] In one or more example propulsion units, at least one of the actuators may be laterally offset from one or more other actuators in order to absorb torsional moments on the fins that may be caused, for example, by waves. Laterally, as used herein, means along the lateral axis of the fin, such as along an axis extending from the starboard side of the vessel to the port side. This can thus further improve the performance of the fins. In one or more example propulsion units, at least one of the actuators may be laterally offset from one or more other actuators by a distance ranging from 50 mm to 500 mm (e.g., from 100 mm to 200 mm).

[0050] In one or more example propulsion units, such as when the propulsion unit includes a third actuator, the fins may include a third link. The third actuator may be pivotally connected to the third link. The third link may be connected to the third actuator via a third actuation rod. The third actuation rod may be disposed within the body of the propulsion unit. The first fin portion and the second fin portion may be connected via the third link. The first link, the second link, and the third link may be arranged in parallel and at corresponding first, second, and third distances from the leading edges of the first and second fin portions.

[0051] In one or more example propulsion units, the body may include a third through slot for allowing a third link to protrude through the body and be slidably disposed within the third through slot.

[0052] Fins can have an elliptical planar shape. In some embodiments, such as in one or more example 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 span to its mean chord. The span of a fin is the distance from one fin tip to another. The chord is an imaginary straight line connecting the leading and trailing edges of the fin. The aspect ratio is equal to the square of the wingspan divided by the fin 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 increasing aspect ratio, so fins with a high aspect ratio can improve fin performance and efficiency, thereby improving the fuel economy of the vessel. The lift-to-drag ratio (also known as the L / D ratio) is the lift generated by the fin divided by the hydrodynamic drag generated by its movement through a viscous fluid (such as water). The chord shape and / or planar shape of the fin can be varied, for example, based on the shape of the vessel's hull to reduce fin drag.

[0053] Fins can include winglets. Winglets are endplates arranged at the tips of the fins and can extend in a direction perpendicular to or at least substantially perpendicular to the principal plane of the fin. Winglets can improve fin efficiency by reducing the hydrodynamic drag of the fin. Fin drag can be reduced by partially recovering the energy of the tip vortex. Winglets smooth the water flow near the tip that could increase lift generated at the fin tip, which reduces drag caused by lift generated by vortices around the fin tip. Reducing lift-induced drag improves the lift-to-drag ratio of the fin. This improves fin efficiency. Winglets can also improve fin efficiency by moving the confluence of low-pressure and high-pressure water regions away from the fin surface, thereby reducing the interference of vortices on laminar water flow near the fin tip. Vortices around the fin tip can generate turbulence that originates at the leading edge of the fin tip and propagates backward and inward toward the fin. This turbulence can stratify the water flow above the small triangular cross-section of the outer fin, which can disrupt the lift generated by the fin in that area. The winglets move the vortex-forming area away from the fin surface, as the center of the generated vortex is now located at the tip of the winglet. Since the fins move up and down during the propulsion unit's operation (which can also be referred to as the up and down strokes), the winglets can be arranged on both the upper and lower sides of the fin. Because lift is reversible on the fin between the up and down strokes, arranging winglets on both the upper and lower sides of the fin can improve the fin's efficiency in both the up and down strokes.

[0054] The stroke of the fins (such as the displacement of heave motion) can depend on the size of the vessel and / or its draft. Larger vessels and / or deeper vessels can have a greater stroke. Increasing the stroke of the fins can improve their efficiency, and thus the efficiency of the propulsion unit. In one or more example propulsion units, the stroke can range from 3 meters to 20 meters, such as from 5 meters to 15 meters.

[0055] Furthermore, a vessel including a propulsion unit for propelling a ship according to this disclosure is disclosed. The ship includes a keel. The body of the propulsion unit may be disposed to the keel of the ship. Fins are configured to perform pitch and heave movements relative to the keel of the ship. In one or more exemplary embodiments, the ship may include multiple propulsion units, such as when the ship includes several engines.

[0056] In one or more example embodiments, the body can be fixedly arranged to the keel of the vessel. Thus, the body is securely attached to the hull and the hydrodynamic drag of the body is reduced.

[0057] In one or more example embodiments, the body can be rotatably arranged to the keel of the vessel. The body and rudder components can thus be integrated into a single unit, and the entire unit can be rotated like a rudder. This can improve the vessel's maneuverability.

[0058] Figure 1A and Figure 1B A propulsion unit 1 for propelling a vessel 100 according to one or more first example embodiments shown herein is illustrated. In one or more example embodiments shown herein, the propulsion unit 1 includes a single actuator for generating heave and pitch motions. The actuator acts on a control lever arm, which is attached to a pivot point at a first end and to fins at the other end. When the actuator applies heave motion to the control lever arm, pitch motion of the fins is generated by rotation of the control lever arm about the pivot point.

[0059] Figure 1A A side view of one or more first exemplary embodiments of a propulsion unit 1 is shown. The propulsion unit 1 includes: a body 2 configured to be disposed at the keel 101 of a vessel 100 and including a pivot point 5a; fins 3 movably disposed relative to the body 2; and an actuator assembly 4 for generating heave motion of the fins 3 relative to the body 2, the actuator assembly 4 including an actuator 4a. The fins 3 are connected to the pivot point 5a via a lever arm 7 such that the fins 3 are arranged to pivot about the pivot point 5a when the actuator 4a generates heave motion of the fins 3, thereby generating pitch motion of the fins 3. In one or more first exemplary embodiments herein, a first end of the lever arm 7 is connected to the pivot point 5a, and a second end of the lever arm 7 is connected to the fins 3. The pivot point 5a is fixedly disposed to the body 2. The pivot point 5a may be a pin-type rotation point. The pivot point 5a may be disposed inside the body 2 such that the lever arm 7 may be connected to the pivot point inside the body 2. Therefore, the main body 2 may include a slot 2a opening toward the rear end of the main body 2, allowing the control lever arm 7 to protrude through the main body 2 and to perform heave and pitch movements relative to the main body 2. Since the slot 2a is open, it is configured to contact the water around the vessel 100 during operation.

[0060] Actuator assembly 4 includes a single actuator 4a for generating heave and pitch movements of fin 3. Propulsion unit 1 and / or actuator assembly 4 may include an actuator rod 9. Actuator 4a may be connected to joystick arm 3 via actuator rod 9. Actuator rod 9 may be connected to joystick arm 7 at a distance from pivot point 5a. Actuator 4a thus applies a force to joystick arm 7 via actuator rod 9 at a distance from pivot point 5a, the force generating a torque on joystick arm 7 about pivot point 5a.

[0061] Actuator 4a (also referred to as first actuator 4a) can be a linear actuator that performs linear motion. Actuator 4a can be arranged to perform vertical (up / down) motion. Since the control arm 7 is connected to pivot point 5a, the linear vertical motion of actuator 4a causes the control arm 7 to rotate about pivot point 5a. The rotation of the control arm 7 about pivot point 5a causes the fin 3 (attached to the end of the control arm 7 opposite to pivot point 5a) to rotate about pivot point 5a and thus perform heave and pitch movements relative to the hull of vessel 100. Since the pitch of the fin 3 is generated by the pivoting motion of the control arm 7 during the heave motion of the fin 3, the pitch of the fin 3 is directly dependent on the heave of the fin 3. Therefore, the pitch and heave of the fin 3 are always in phase with each other. Actuator 9 can be connected to control arm 7 via second pivot point 5b, thereby allowing actuator 9 and control arm 7 to rotate relative to each other. This allows the angle between the linear actuator 4a and the joystick arm 7 to change during the heave and pitch movements of the joystick arm 7 and the fin 3. When the actuator 9 is connected to the joystick arm 7 via the second pivot point 5b, the pivot point 5a may be referred to as the first pivot point 5a.

[0062] Actuator 4a can be configured to operate in oscillating mode, thereby generating oscillating heave and pitch motions of fin 3. The oscillating heave and pitch motions can include an upward stroke and a downward stroke. The upward stroke refers to the movement of actuator 4a pulling fin 3 towards the vessel 10. The downward stroke refers to the movement of actuator 4a pushing fin 3 away from the vessel 10. Figure 1A In the diagram, the control lever arm 7 and the fin 3 are shown in an upper position, such as at the end of an upward stroke.

[0063] When the fin 3 pitches, the distance between the first pivot point 5a and the second pivot point 5b changes when viewed from a horizontal plane (such as a plane perpendicular to the longitudinal extension of the actuator 9). To allow this change in distance from the horizontal plane, the second pivot point 5b can be connected to the control arm 7 via a sliding joint 7a. The sliding joint 7a can be, for example, an elongated slot in which the pivot point 5b can be arranged for slidable movement. The second pivot point 5b can therefore be movably arranged relative to the fin 3.

[0064] The fin 3 includes winglets 15. Winglets 15 are end plates disposed at the tip of the fin 3 and extend in a direction perpendicular to or at least substantially perpendicular to the principal plane of the fin 3. Winglets 15 improve the efficiency of the fin 3 by reducing its hydrodynamic drag. Winglets 15 may be disposed on the top and / or bottom sides of the fin 3. In one or more embodiments shown herein, winglets 15 are disposed on both the top and bottom sides of the fin 3. Therefore, the efficiency of the fin 3 is improved in both its upward and downward strokes.

[0065] The propulsion unit 1 may also include a rudder 6. The body 2 may be rotatably arranged to the vessel 100 such that the body 2 can function as the rudder 6. Therefore, the fins 3 are arranged to rotate together with the rudder 6. The body 2 may be arranged to the vessel via a rudder stock. The rudder stock may be hollow to accommodate an actuator 4a and / or an actuator rod 9. The actuator 4a and / or actuator rod 9 can thus be connected to the control arm 7 via the hollow rudder stock. The rudder stock may be rotatably arranged to the vessel 100 via a bearing (such as a swivel bearing). The rudder stock may form the bearing housing of the bearing. To prevent water from entering the vessel through the hollow rudder stock, it may be necessary to seal the rudder stock. The rudder stock forming one housing of the bearing housing may extend above the waterline of the vessel 100, allowing the rudder stock to be sealed above the waterline. Sealing the rudder stock above the waterline allows for the use of simpler and cheaper seals compared to sealing it below the waterline. However, the propulsion unit 1 may also be fixedly arranged to the vessel 100. When the propulsion unit 1 is fixed to the ship 100, the ship 100 may include a conventional rudder 6 arranged behind the fins 3.

[0066] Figure 1B It shows that according to Figure 1A A perspective view of a propulsion unit 1 for propelling a vessel 100, shown in one or more example embodiments. It can be seen that the main body 2 is arranged on the keel 101 of the vessel 100. The control lever arm 7 is connected via a pivot point 5a arranged inside the main body 2. Figure 1B (Not shown) is pivotally connected to the body 2. The second end of the joystick arm 7 is connected to the fin 3. The body 2 includes a slot 2a opening toward the rear end of the body 2 to allow vertical movement of the joystick arm 7 relative to the body 2. The joystick arm 7 is connected to the actuator 4a ( (not shown) via an actuator rod 9) Figure 1B (Not shown in the image). The actuator 9 can perform linear vertical movement (such as up / down movement), which is transmitted to the fin 3 via the lever arm 7. Figure 1B In the diagram, the control lever arm 7 and the fin 3 are shown in an upper position, such as at the end of an upward stroke.

[0067] 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 span s to its mean chord c. Therefore, a fin with a high aspect ratio planar shape means that fin 3 is long and narrow. The lift-to-drag ratio of a fin increases with the increase of the aspect ratio, thus the high aspect ratio fin 3 disclosed herein improves the performance and efficiency of fin 3, thereby improving the fuel economy of the ship. The lift-to-drag ratio (also referred to as the L / D ratio) is the lift generated by the fin divided by the hydrodynamic drag generated by its movement through a viscous fluid (such as water). The shape of the chord c and / or the planar shape of fin 3 can be determined by the implementation and can be changed, for example, based on the shape of the hull of the ship 100 to reduce the hydrodynamic drag of fin 3.

[0068] like Figure 1B As can be seen, according to one or more first embodiments of the propulsion unit 1 shown herein, winglets 15 are disposed on the top and bottom sides of the winglet 3 to improve the efficiency of the winglet 3 in both the upward and downward strokes.

[0069] The propulsion unit 1 according to one or more first example embodiments of this document has a simple layout, including only one actuator for heave and pitch movements, thus having high mechanical efficiency and low maintenance requirements.

[0070] Figures 2A to 2D The propulsion unit 1 and its motion modes according to one or more second example embodiments of this document are shown. The actuator assembly 4 includes an actuator 4a (which may also be referred to as a first actuator 4a) and a second actuator 4b. Pivot point 5a ( Figures 2A to 2D (Not shown in the image) is connected to the second actuator 4b, such that the pivot point 5a is movably arranged relative to the body 2. The first actuator 4a and the second actuator 4b can operate independently of each other, such that the phase difference between the heave and pitch movements of the fin 3 is variable. The first actuator 4a and the second actuator 4b can be linear actuators. The pitch and heave movements of the fin 3 can therefore be controlled independently of each other. The fin 3 is movably arranged to the body 2. The fin 3 includes a first fin portion 3a and a second fin portion 3b, a first link 8a (… Figures 2A to 2D (not shown in the image) and the second link 8b ( Figures 2A to 2D(Not shown in the image). The first fin portion 3a and the second fin portion 3b are connected via a first link 8a and a second link 8b. The first link 8a and the second link 8b can form structural elements of the fin 3. The body 2 includes a first through groove 13a and a second through groove 13b for receiving the first link 8a and the second link 8b of the fin 3. The first through groove 13a and the second through groove 13b allow the first link 8a and the second link 8b to protrude through the body 2 in the lateral direction. The first link 8a and the second link 8b are slidably arranged in the first through groove 13a and the second through groove 13b, respectively. The first through groove 13a and the second through groove 13b have longitudinal extensions in the lateral direction of the body 2, thereby allowing the first link 8a and the second link 8b of the fin 3 to move vertically relative to the body 2, thereby allowing the fin 3 to perform heave and pitch movements relative to the body 2. A first actuator 4a and a second actuator 4b can be connected to the first link 8a and the second link 8b, respectively. To accommodate actuators 4a and 4b, when the propulsion unit 1 is arranged on the vessel 100, the first through slot 13a and the second through slot 13b can have openings at their top ends, such as at the ends of the first through slot 13a and the second through slot 13b facing the vessel 100. Actuators 4a and 4b can therefore extend through the body 2 in the vertical direction and can be connected to a first link 8a and a second link 8b that protrude through the body 2 in the transverse direction.

[0071] The propulsion unit 1 disclosed herein may also include a rudder 6. The main body 2 may be configured to be fixedly arranged to the vessel 100, such as to the keel 101 of the vessel 100, and the rudder 6 may be pivotally arranged to the stern fin 2. The rudder 6 may be mounted to the centerline of the main body 2. The rudder 6 may be attached to the main body 2 via a rudder stock arranged at the trailing edge of the main body 2.

[0072] Figure 2A The diagram illustrates the fins 3 (such as fin portions 3a and 3b) of the propulsion unit 1 in a top position during an exemplary motion mode for moving the fins 3. In this exemplary motion mode, the first actuator 4a and the second actuator 4b operate with a phase difference. The top position of the fins 3 corresponds to the top of the fin 3's stroke, such as when the fins 3 reach the end position during an upward stroke. In this position, both the first and second actuators are in the upper position, and the fin portions 3a and 3b are arranged horizontally, such as having a pitch angle of 0°.

[0073] Figure 2BThe diagram illustrates the fin 3 of the propulsion unit 1 during the downward stroke of fin 3. Both the first actuator 4a and the second actuator 4b move downwards, thus applying a downward heave motion to fin 3. However, the second actuator 4b begins its downward stroke before the first actuator 4a begins its downward stroke. This causes the leading edge 10 of fin 3 (such as fin portions 3a and 3b) to move downwards before the trailing edge 16, resulting in a pitch angle of fin 3 relative to the horizontal plane with a first sign. Depending on the definition of the coordinate system, the pitch angle can have a positive or negative sign. In this document... Figure 2B and Figure 5 In the example shown, the pitch angle (such as the pitch angle with the first sign) corresponds to a positive pitch angle.

[0074] Figure 2C The image shows the fin 3 of the propulsion unit in the bottom position during an exemplary motion mode for moving the fin 3. The bottom position of the fin 3 corresponds to the bottom of the stroke of the fin 3, such as when the fin 3 reaches the end position during the downward stroke. In this position, both the first actuator and the second actuator are in the lower position, and the fin portions 3a and 3b are arranged horizontally, such as having a pitch angle of 0°.

[0075] Figure 2D The diagram illustrates the fin 3 of the propulsion unit 1 during the upward stroke of the fin in an exemplary motion mode for moving the fin 3. Both the first actuator 4a and the second actuator 4b move upward, thereby applying an upward heave motion to the fin 3. Since the second actuator 4b begins its downward stroke before the first actuator 4a begins its downward stroke, it will also begin its upward stroke before the first actuator 4a. This causes the leading edge 10 of the fin 3 (such as fin portions 3a and 3b) to move upward before the trailing edge 16 moves upward, resulting in a pitch angle of the fin 3 relative to the horizontal plane with a second sign. In this document... Figure 2D and Figure 5 In the example shown, this pitch angle corresponds to a negative pitch angle.

[0076] Figure 3 A connection for connecting fin 3 to a first actuator 4a and a second actuator 4b according to one or more second example embodiments of the present invention is shown. The first link 8a and the second link 8b of fin 3 are arranged in parallel and are spaced from the leading edges 10 of the first fin portion 3a and the second fin portion 3b of fin 3 by a corresponding first distance and a second distance.

[0077] A first link 8a is connected to a first actuator 4a, and a second link 8b is connected to a second actuator 4b. The first link 8a and the second link 8b can be connected to the respective first actuator 4a and second actuator 4b via a first actuating rod 9a and a second actuating rod 9b, respectively. The first link 4a and the second link 4b can be connected to the first link 8a and the second link 8b via the first actuating rod 9a and the second actuating rod 9b (e.g., via a free-rotating pin connection), respectively. 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 link 8a and the second link 8b can be inserted. Translational movement from the first actuator 4a and the second actuator 4b can therefore be transmitted to the first link 8a and the second link 8b via the first actuating rod 9a and the second actuating rod 9b, respectively.

[0078] However, the rotary pin connection allows the first link 8a and the second link 8b to rotate freely within the first actuating link 9a and the second actuating link 9b, respectively. The rotary pin connection between the actuating link and the link thus constitutes the corresponding pivot point. Figure 3 In the example shown, the connection between the second actuating rod 9b and the second connecting rod 8b constitutes a first pivot point 5a, and the connection between the first actuating rod 9a and the first connecting rod 8a constitutes a second pivot point 5b. The fin 3 can therefore rotate relative to the actuating rods 9a and 9b to change the pitch of the fin 3.

[0079] To compensate for the change in distance between the first link 8a and the second link 8b when the fin 3 performs pitching motion, one of the first link 8a and the second link 8b may be movably arranged within the first fin portion 3a and the second fin portion 3b. In one or more example embodiments, the second link 8b is movably arranged within the fin portion and may include a first elongated guide portion and a second elongated guide portion 17 arranged at opposite ends of the link 8b. The first elongated guide portion and the second elongated guide portion 17 may have longitudinal extensions in a direction perpendicular to the longitudinal axis of at least one of the first link and the second link. The first elongated guide portion and the second elongated guide portion 17 may be configured to be arranged within the first fin portion 3a and the second fin portion 3b, respectively. The first elongated guide portion and the second elongated guide portion 17 may be configured to guide a first pin 18 fixedly arranged within the first fin portion 3a and a second pin 18 fixedly arranged within the second fin portion 3b, respectively. The first elongated guide portion and the second elongated guide portion 17 can be elongated slots, elongated supports, or tracks configured to guide the first pin 18 and the second pin 18, respectively. The pin 18 can therefore be slidably arranged within the elongated slot 17 of the second link 8b.

[0080] In one or more example embodiments, the first pin and the second pin 18 may alternatively be arranged at opposite ends of one of the first link 8a and the second link 8b, and an elongated guide portion may be arranged inside the first fin portion 3a and the second fin portion 3b. The second link 8b may, for example, include the first pin and the second pin 18 arranged at opposite ends of the link 8b. The first elongated guide portion and the second elongated guide portion 17 arranged inside the first fin portion 3a and the second fin portion 3b may have longitudinal extensions in a direction perpendicular to the span s of the first fin portion 3a and the second fin portion 3b. The first pin 18 and the second pin 18 may be arranged to slidably engage the first elongated guide portion and the second elongated guide portion 17 respectively fixedly arranged inside the first fin portion 3a and the second fin portion 3b. The first fin portion 3a and the second fin portion 3b may further include an elongated slot 19 for receiving the second link 8b, thereby allowing the second link 8b to slide back and forth within the elongated slot 19 in a direction perpendicular to the longitudinal axis of the second link 8b, such that the distance between the second link 8b and the leading edge 10 can be varied. This allows the actuator 9b and / or the actuator 4b to perform purely vertical motion during the pitch motion of the fin 3.

[0081] Figure 4 The main body 2 is shown to include a first through groove 13a and a second through groove 13b for receiving a first link 8a and a second link 8b of the fin 3. The first link 8a and the second link 8b protrude laterally through the main body 2. The first link 8a and the second link 8b are slidably arranged within the first through groove 13a and the second through groove 13b, respectively. The first link 8a and the second link 8b may also protrude through through holes at the lower ends of the first actuating rod 9a and the second actuating rod 9b, respectively. The first through groove 13a and the second through groove 13b have longitudinal extensions in the lateral direction of the main body 2, thereby allowing the first link 8a and the second link 8b to move vertically up and down within the through grooves 13a and 13b, respectively. When the propulsion unit 1 is arranged on the vessel 100, the first through slot 13a and the second through slot 13b are open at their top ends (such as at the end facing the vessel 100) to allow the first actuating rod 9a and the second actuating rod 9b to enter the through slots 13a and 13b vertically. The open ends of the first through slot 13a and the second through slot 13b can be connected to holes in the hull of the vessel above them to allow the actuating rods to travel vertically to a location in the hull of the vessel 100 where the actuator assembly can be arranged.

[0082] Figure 5A graph illustrating an exemplary motion pattern of fin 3 when the first actuator 4a and the second actuator 4b operate with a phase shift is shown. Curve h2 shows the extension of the first actuator rod 9a from a mid-stroke position (such as the midpoint between the top and bottom of the stroke of the first actuator rod). Curve h1 shows the extension of the second actuator rod 9b from a mid-stroke position. Curve θ shows the corresponding pitch angle of the fin relative to the horizontal plane in degrees. To produce out-of-phase pitch and heave motions, the actuators operate with a phase difference. Changing this phase difference allows adjustment of the maximum pitch angle of fin 3 during heave motion. As can be seen from the graph, the second actuator rod 9b moves slightly ahead of the second actuator rod 9a. It can be seen that the pitch angle of the fin is highest when the first actuator rod 9a and the second actuator rod 9b are in the middle of the stroke and move in the same direction (such as at t=0 during the downstroke and at t=3 during the upstroke). When the first and second actuators are in the end positions, such as at the top or bottom of the stroke, such as at t_1,5 and t=4,5.

[0083] Figure 6 A propulsion unit 1 according to one or more third exemplary embodiments is disclosed, wherein a body 2 is configured to be rotatably arranged to the vessel 100. The propulsion unit 1 disclosed herein is similar to that shown in Figures 2a to 2b. Figure 2D , Figure 3 and Figure 4 The disclosed propulsion unit 1. The body 2 includes a rudder stock 11 for rotatably arranging the body 2 to the keel 101 of the vessel 100. The rudder stock is arranged on the top side of the body 2, such as the side facing the bottom of the vessel 100 when the body 2 is mounted to the vessel 100. The body 2 can thus be configured to rotate about the rudder stock 11 and serve as a rudder 6. The rudder stock 11 may be hollow to accommodate one or more actuators 4a, 4b and / or a first actuating rod 9a and / or a second actuating rod 9b. One or more actuators 4a, 4b and / or a first actuating rod 9a and / or a second actuating rod 9b may be arranged inside the rudder stock 11 such that they can move vertically within the rudder stock 11. The rudder stock 11 may include bearings (such as swivel bearings) for rotatably arranging the rudder stock to the vessel 100, such as to the keel 101 of the vessel 100. In some embodiments, the rudder stock 11 may form the bearing race, such as the inner race of the bearing.

[0084] Figure 7A vessel 100, comprising a propulsion unit 1 for propelling a vessel 100, is disclosed according to one or more second exemplary embodiments disclosed herein. The vessel 100 includes a keel 101. The body 2 of the propulsion unit 1 may be disposed to the bottom of the vessel 100, such as to the keel 101 of the vessel 100. Fins 3a, 3b are configured to pitch and heave relative to the bottom of the vessel 100 (such as relative to the keel 101 of the vessel 100). When the fins 3, 3a, 3b pitch and heave, thrust is generated to propel the vessel 100. Figure 7 In the exemplary embodiment shown, the propulsion unit 1 includes two actuators for generating heave and pitch movements of the fins 3, 3a, and 3b. Therefore, the motion pattern of the fins 3 can be precisely controlled to match the loads on the hull and the fins 3 within the boundary layer of the hull. The body 2 of this document is fixedly arranged to the vessel 100 (such as a keel 101 arranged to the vessel 100) and can thus constitute the stern fin of the vessel 100. The propulsion unit also includes a rudder attached to the trailing edge of the body 2. However, in one or more embodiments, the vessel 100 may include the propulsion unit according to one or more of the first and third exemplary embodiments disclosed herein.

[0085] Figure 8 A perspective view of the interior of an exemplary vessel 100 including an exemplary propulsion unit 1 according to the present disclosure is shown. A main body 2 is fixedly mounted to the vessel, and a first actuator 4a and a second actuator 4b are arranged inside the vessel 100. Figure 8The propulsion unit 1 shown includes a sealing device according to one or more example embodiments herein for preventing water from entering the vessel. To generate heave and pitch movements of the fins 3, 3a by the first actuator 4a and the second actuator 4b, the hull and body include openings for receiving the first actuator 4a and the second actuator 4b and / or the first actuator rod 9a and the second actuator rod 9b. The openings are open to 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 protruding from the body and entering the vessel 100. The first actuator rod 9a and / or the second actuator rod 9b and / or the first actuator 4a and / or the second actuator 4b may be arranged within one or more hollow tubes 12; 12a, 12b. The one or more hollow tubes 12; 12a, 12b may be steel pipes welded to the hull of the vessel 100. One or more hollow tubes 12; 12a, 12b may include a first end (such as a distal end) arranged to project into the hull of the vessel 100 and a proximal end arranged in the body 2 of the vessel 100. The first end (such as a distal end) of one or more hollow tubes 12; 12a, 12b may be configured to extend above the waterline of the vessel 100. To prevent water from entering the hull of the vessel 100 through openings, one or more hollow tubes 12; 12a, 12b may each include a seal 20 arranged 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. By providing one or more hollow tubes 12; 12a, 12b protruding into the hull of the vessel 100 on the main body 2, and arranging seals 20 at the distal ends of one or more hollow tubes 12; 12a, 12b above the waterline of the vessel 100, less complex and cheaper seals can be used.

[0086] Figure 9An example propulsion unit 1 according to the currently disclosed embodiment is shown. The example propulsion unit 1 includes two actuators 4, such as a first actuator 4a and a second actuator 4b. One of the two actuators 4 (such as the second actuator 4b) is constrained in its movement such that it can only be displaced (e.g., extended or retracted) in the vertical direction of the vessel (e.g., along the vertical axis). The example propulsion unit 1 includes one or more support surfaces 21 for constraining the movement of the second actuator 4b. The one or more support surfaces may be roller supports and / or sliding bearings. The one or more support surfaces 21 may be fixedly arranged to the hull of the vessel or to the body of the propulsion unit 1. The one or more support surfaces 21 may be configured to prevent the second actuator 4b from pivoting relative to the hull of the vessel. 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 in the vertical direction, and therefore can only perform heave movements. However, the fin 3 can still pivot about the pivot point 5b to allow changes in the pitch of the fin 3. The movement 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, oscillations in the forward / rear direction of the ship can be prevented when the fin 3 is heaving and / or pitching. The first actuator 4a can be unconstrained, allowing it to pivot relative to the ship's hull when it extends and / or retracts. In one or more example propulsion units 1, the two actuators 4a; 4b can be arranged at an angle to each other, such that the extension directions of the two actuators 4a; 4b are not parallel. For example, the first actuator 4a can be arranged at an angle to the vertical axis of the ship. The first pivot point 5a and the second pivot point 5b can be fixedly arranged (e.g., non-slidingly arranged) in the fin 3. In other words, the fin 3 can pivot about the first pivot point 5a and the second pivot point 5b. However, the first pivot point 5a and / or the second pivot point 5b can be non-slidingly arranged relative to the fin 3. In one or more example propulsion units, the first pivot point 5a and the second pivot point 5b can be pin joints. By fixing the first pivot point and the second pivot point in the fin 3, the stability and / or controllability of the fin 3 can be improved, allowing for more precise control of the pitch of the fin 3. Furthermore, by fixing the first pivot point 5a and the second pivot point 5b to the fin 3, friction induced in the propulsion system can be reduced, as there is no sliding movement in one or more connections between the actuators 4a, 4b and the fin 3. Reducing the number of moving parts in the underwater arrangement of the propulsion unit 1 further reduces the risk of corrosion and potential jamming of moving parts, as well as potential system failure. Therefore, the performance of the propulsion unit can be improved.

[0087] Figure 10 An example propulsion unit 1 based on the currently disclosed example is shown. Figure 10The example propulsion unit 1 shown includes 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 can be connected to the fins via corresponding pivot points (such as a first pivot point 5a, a second pivot point 5b, and a third pivot point 5c). Figure 10 In the example propulsion unit 1 disclosed herein, one of the three actuators 4 (such as the second actuator 4b) is configured to displace (e.g., extend or retract) in the vertical direction of the vessel (e.g., along the vertical axis). One of the three actuators 4 (such as the second actuator 4b) may be restricted in the lateral and / or longitudinal directions such that one of the three actuators cannot displace (e.g., extend or retract) in the lateral and / or longitudinal directions of the vessel (e.g., along the lateral and / or longitudinal axes). The configuration herein to displace only in the vertical direction means that the second actuator does not move in the forward and / or rearward directions of the vessel when the actuator extends and / or retracts. The restricted displacement of the second actuator 4b in the vertical direction only can be achieved by controlling the extension and / or retraction of each of the actuators 4a, 4b, 4c. By providing a propulsion unit 1 with a third actuator, the movement of the fins can be precisely controlled without the need for a support surface to prevent movement of the fins in the forward and / or rearward directions. By controlling the movement of the fins without using a support surface, 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 underwater reduces the number of moving parts in the underwater propulsion unit. Reducing the number of moving parts in the underwater propulsion unit also reduces the risk of corrosion and potential jamming of moving parts, as well as potential system failures. Therefore, the performance of the propulsion unit can be improved.

[0088] Because the movement of the second actuator 4b is constrained, the pivot point 5b connecting the second actuator 4b to the fin 3 can only be displaced in the vertical direction, and therefore can only perform heave movements. The fin 3 is configured to pivot about the pivot point 5b to allow changes in the pitch of the fin 3. By constraining the movement of one of the three actuators (such as by limiting the movement of the second actuator 4b), the movement of the fin 3 can be precisely controlled. For example, oscillations in the forward / rear direction of the ship can be prevented when the fin 3 performs heave and / or pitch movements. The first actuator 4a and / or the third actuator 4c can be unconstrained, such that they can pivot relative to the hull of the ship as the first actuator 4a and / or the third actuator 4c extend and / or retract. In one or more example propulsion units 1, the three actuators 4a, 4b, 4c can be arranged at an angle to each other, such that the extension directions of the three actuators 4a, 4b, 4c are not parallel to each other. Actuators 4a, 4b, and 4c (such as plunger-type actuators) can be arranged to the hull of the ship such that the forces acting on actuators 4a, 4b, and 4c do not counteract each other, for example, interact with each other. One or more of actuators 4a, 4b, and 4c can be arranged such that one or more of actuators 4a, 4b, and 4c can absorb forces in the longitudinal direction and in the vertical direction of the ship. The forces acting in the longitudinal direction can be, for example, longitudinal thrust. For example, a first actuator 4a can be arranged at a first angle to the vertical axis of the ship, a second actuator 4b can be arranged at a second angle (such as parallel) to the vertical axis of the ship, and a third actuator can be arranged at a third angle to the vertical axis of the ship. A first pivot point 5a, a second pivot point 5b, and a third pivot point 5c can be fixedly arranged (such as non-slidingly arranged) to fin 3. In other words, fin 3 can pivot about a first pivot point 5a, a second pivot point 5b, and a third pivot point 5c. By arranging two of the actuators (such as the first actuator 4a and the third actuator 4c) at a non-zero angle 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 when the pitch angle of fin 3 changes, as viewed from a horizontal plane (such as a plane perpendicular to the vertical axis of the ship). The first pivot point 5a, the second pivot point 5b, and the third pivot point 5c can be pin joints in one or more example propulsion units. By fixing the first pivot point 5a, the second pivot point 5b, and the third pivot point 5c in fin 3, the stability and / or controllability of fin 3 can be improved, allowing for more precise control of the pitch of fin 3.

[0089] To provide pitch and / or heave motion for fin 3, two or more of actuators 5a, 5b, and 5c can operate in a correlated manner, such that the displacement of actuators 5a, 5b, and 5c is controlled in a correlated manner. For example, to change the pitch of fin 3, the first actuator 5a can extend while the third actuator 5c retracts. This causes fin 3 to pivot about a second pivot point 5b, causing the leading edge 10 of fin 3 to lower and the trailing edge 16 of fin 3 to rise. To raise the leading edge 10 of fin 3 and lower its trailing edge 16, the first actuator 5a can retract while the third actuator 5c extends. To change the heave of fin 3, all actuators can operate in a correlated manner. By simultaneously retracting the first actuator 4a, the second actuator 4b, and the third actuator 4c, fin 3 can be raised, reducing the distance between fin 3 and the ship's hull. By simultaneously extending the first actuator 4a, the second actuator 4b, and the third actuator 4c, the fin 3 can be lowered, increasing the distance between the fin 3 and the ship's hull. By independently controlling the displacements (such as extension rate and / or retraction rate) of the first actuator 4a, the second actuator 4b, and the third actuator 4c, combined pitch and heave motions of the fin 3 can be generated. This allows the heave and / or pitch of the fin 3 of the propulsion unit 1 to be continuously adjusted to an unlimited number of angle-of-attack curves. Therefore, the performance of the propulsion unit 1 can be improved, as the angle of attack of the fin 3 towards the incoming water is a key factor in the performance of the propulsion unit 1. The heave and / or pitch of the fin 3 can be controlled, for example, based on the conditions of the water around the fin (such as the velocity of the incoming water, such as the velocity at which the water encounters the leading edge 10 of the fin 3) to increase the efficiency of the fin 3. The displacement of actuators 5a, 5b, and 5c can be controlled, for example, such that all forces acting on actuators 5a, 5b, and 5c can be absorbed as tension or compressive forces in one or more of actuators 5a, 5b, and 5c. The displacement of actuators 5a, 5b, and 5c can be controlled, for example, such that one of the actuators (such as the second actuator 5b) only undergoes vertical displacement and has no motion component in the forward and / or aft (such as longitudinal) directions of the ship.

[0090] Figure 11 A graph is shown illustrating two different angle-of-attack curves for controlling the motion (such as heave and / or pitch) of fin 3 based on the conditions of the water around fin 3 (such as the inflow or velocity of the water). The graph shows the pitch angle of fin 3 during one reciprocating motion (such as during one stroke of the fin). Figure 11The dashed line shows the optimized angle-of-attack curve for fins operating in open water, such as when simulating a propulsion unit without a ship. The solid line shows the optimized angle-of-attack curve for operation in the wake behind a ship. Instead of the water flow moving along the longitudinal axis of the ship, the ship's hull can cause the water flow vector to tilt upwards along the stern of the ship. This produces a flow field with vertical and rearward components. The boundary layer of the hull can also slow the water flow, making the water flow rate less than the velocity of water flowing freely without the influence of the ship's hull. In determining the optimal angle-of-attack curve for the fins, the angle-of-attack curve shown by the dashed line takes into account the influence of the ship on the water flowing towards fin 3. By adapting (e.g., optimizing) the angle-of-attack curve for the water conditions around the ship, the efficiency of the propulsion unit can be significantly improved.

[0091] It should be noted that Figure 1 to Figure 11 The features mentioned in the embodiments described are not limited to these specific embodiments. Therefore, any features (such as fin size and actuator type or sealing scheme) included and mentioned in one or more of the first example embodiments of Figures 1a to 1b that relate to the fins, one or more actuators, and / or fin seals also apply to those in Figures 2 to 1b. Figure 5 One or more second example implementations described, and / or about Figures 9 to 11 The example implementation described is, and vice versa.

[0092] It should also be noted that, as used herein, a vertical axis is an imaginary line that runs vertically through the vessel and through its center of gravity; a transverse axis or transverse plane is an imaginary line that runs horizontally across the vessel and through its center of gravity; and a longitudinal axis is an imaginary line that runs horizontally through the length of the vessel, through its center of gravity, and parallel to the waterline. Similarly, as used herein, a vertical plane is an imaginary plane that runs vertically through the width of the vessel; a transverse plane or transverse plane is an imaginary plane that runs horizontally across the vessel; and a longitudinal plane is an imaginary plane that runs vertically through the length of the vessel.

[0093] The implementation schemes of the products (propulsion units and vessels) according to this disclosure are set forth in the following clauses:

[0094] Clause 1 A propulsion unit (1) for propelling a ship, said propulsion unit (1) comprising:

[0095] -The main body (2), which is configured to be arranged at the keel of the vessel and includes a pivot point (5a),

[0096] - Fins (3), which are movably arranged relative to the body (2), and

[0097] -Actuator assembly (4) for generating heave motion of the fins (3) relative to the body (2), the actuator assembly (4) comprising at least one actuator (4a, 4b),

[0098] The fin (3) is connected to the pivot point (5a) such that the fin (3) is arranged to pivot about the first pivot point (5a) when the at least one actuator (4a, 4b) produces the heave motion of the fin (3), thereby producing the pitch motion of the fin (3).

[0099] Clause 2, the propulsion unit (1) as described in Clause 1, wherein at least one actuator (4a, 4b) is a linear actuator.

[0100] Clause 3 The propulsion unit (1) according to any one of the preceding clauses, wherein the propulsion unit (1) includes at least one actuating rod (9, 9a, 9b), and the actuator assembly (4) is connected to the fin (3) via the at least one actuating rod (9, 9a, 9b).

[0101] Clause 4 The propulsion unit (1) according to any one of the preceding clauses, wherein the actuator assembly (4) is configured to operate in an oscillating mode to generate oscillating heave and pitch motions of the fins.

[0102] Clause 5 The propulsion unit (1) according to any one of the preceding clauses, wherein the pivot point (5a) is fixedly arranged to the body (2).

[0103] Clause 6 pursuant to Clause 5, the propulsion unit (1) includes a control arm (7), the fin (3) being attached to the pivot point (5a) via the control arm (7).

[0104] Clause 7 The propulsion unit (1) according to any one of Clauses 1 to 4, wherein the actuator assembly (4) includes a first actuator (4a) and a second actuator (4b), wherein the pivot point (5a) is connected to the second actuator (4b) such that the pivot point (5a) is movably arranged relative to the body (2).

[0105] Clause 8 pursuant to Clause 7, the propulsion unit (1) wherein the first actuator (4a) and the second actuator (4b) are capable of operating independently of each other, such that the phase difference between the heave motion and the pitch motion of the fin (3) is variable.

[0106] Clause 9 The propulsion unit (1) according to Clause 7 or 8, wherein the fin (3) includes a first fin portion (3a), a second fin portion (3b), a first link (8a), and a second link (8b), wherein the first fin portion (3a) and the second fin portion (3b) are connected via the first link (8a) and the second link (8b), wherein the first link (8a) and the second link (8b) are arranged in parallel and are at a corresponding first distance and second distance from the leading edge (10) of the first fin portion and the second fin portion (3a, 3b).

[0107] Clause 10 The propulsion unit (1) according to Clause 9, wherein the body (2) includes a first through groove (13a) and a second through groove (13b) for allowing the first link (8a) and the second link (8b) to protrude through the body (3) and be slidably arranged within the first through groove (13a) and the second through groove (13b).

[0108] Clause 11 The propulsion unit (1) as described in Clause 9 or 10, wherein the first link (8a) is connected to the first actuator (4a) and the second link (8b) is connected to the second actuator (4b).

[0109] Clause 12 pursuant to Clause 11, the propulsion unit (1) wherein the first link (8a) and the second link (8b) are respectively connected to the corresponding first actuator (4a) and second actuator (4b) via the first actuator (9a) and the second actuator (9b).

[0110] Clause 13 The propulsion unit (1) as described in Clause 12, wherein the first actuating rod (9a) and the second actuating rod (9b) are arranged inside the body (2).

[0111] Clause 14 The propulsion unit (1) pursuant to any one of Clauses 7 to 13, wherein the actuator assembly (4) includes a third actuator (4c).

[0112] Clause 15 The propulsion unit (1) as described in Clause 14, wherein at least two of the first actuator (4a), the second actuator (4b) and the third actuator (4c) are capable of operating in relation to variably adjust the pitch angle and / or heave of the fin (3).

[0113] Clause 16, when subordinate to any of Clauses 9 to 12, the propulsion unit (1) described in Clause 14 or 15, wherein the fin (3) includes a third link, wherein the first fin portion (3a) and the second fin portion (3b) are connected via the third link, wherein the first link (8a), the second link (8b) and the third link are arranged in parallel and are located at corresponding first distances, second distances and third distances from the leading edges (10) of the first fin portion and the second fin portion (3a, 3b).

[0114] Clause 17 The propulsion unit (1) according to Clause 16, wherein the body (2) includes a third through slot (13c) for allowing the first link (8c) to protrude through the body (3) and be slidably disposed within the third through slot (13c).

[0115] Clause 18 The propulsion unit (1) as described in Clause 16 or 17, wherein the third link (8c) is connected to the third actuator (4c).

[0116] Clause 19 The propulsion unit (1) as described in Clause 18, wherein the third link (8c) is connected to the third actuator (4c) via the third actuator rod (9c).

[0117] Clause 20 The propulsion unit (1) as described in Clause 19, wherein the third actuating rod (9c) is arranged inside the body (2).

[0118] Clause 21 The propulsion unit (1) according to any one of Clauses 7 to 20, wherein at least one of the first actuator (4a) and the second actuator (4b) is configured to shift in the vertical direction.

[0119] Clause 22 The propulsion unit (1) according to Clause 21, wherein at least one of the first actuator (4a) and the second actuator (4b) is constrained in a direction perpendicular to the extending direction of at least one of the first actuator (4a) and the second actuator (4b).

[0120] Clause 23 The propulsion unit (1) according to Clause 21 or 22, wherein at least one of the first actuator (4a) and the second actuator (4b) is constrained in the lateral and / or longitudinal directions.

[0121] Clause 24 The propulsion unit (1) according to any one of the preceding clauses, wherein the propulsion unit includes a rudder (6).

[0122] Clause 25 pursuant to Clause 24, the propulsion unit (1) wherein the body (2) is configured to be fixedly arranged to the keel of the vessel, and wherein the rudder (6) is pivotally arranged to the body (2).

[0123] Clause 26 The propulsion unit (1) according to Clause 24, wherein the body (2) includes a rudder (11) for rotatably arranging the body (2) on the keel of the vessel, wherein one or more actuators (4a, 4b) and / or at least one actuator rod (9, 9a, 9b) are arranged inside the rudder (11), and wherein the body (2) is configured to serve as the rudder (6).

[0124] Clause 27 The propulsion unit (1) according to any one of the preceding clauses, wherein the body (2) includes a hollow tube (12) protruding from the body (2) on the keel-facing side of the body (2), wherein the first actuating rod (9a) and / or the second actuating rod (9b) are arranged within the hollow tube (12), wherein the hollow tube (12) is configured to protrude into the vessel when the body (2) is arranged to the keel of the vessel.

[0125] Clause 28 The propulsion unit (1) according to Clause 27, wherein the hollow tube (12) includes a seal (14) disposed at the distal end of the hollow tube (12) for sealing the first actuating rod (9a) and / or the second actuating rod (9b) relative to the hollow tube (12).

[0126] Clause 29 The propulsion unit (1) as described in Clause 27 or 28, wherein the rudder (11) is hollow and constitutes the hollow tube (12).

[0127] Clause 30 The propulsion unit (1) according to any one of the preceding clauses, wherein the fins (3) have an elliptical planar shape.

[0128] Clause 31 The propulsion unit (1) according to any one of the preceding clauses, wherein the fins (3) include winglets (15).

[0129] Clause 32 A vessel (100) comprising a propulsion unit (1) for propelling the vessel according to any one of Clauses 1 to 31, wherein a body (2) is disposed to the keel (101) of the vessel (100), and wherein the fins are configured to pitch and heave relative to the keel (101) of the vessel (100).

[0130] Clause 33 The vessel (100) as described in Clause 32, wherein the body (2) is fixedly arranged to the keel (101).

[0131] Clause 34 The vessel (100) as described in Clause 32, wherein the body (2) is rotatably arranged on the keel (101).

[0132] The use of the terms "first," "second," "third," and "fourth," "first-level," "second-level," and "third-level," etc., does not imply any particular order, but is included to identify individual elements. Furthermore, the use of the terms "first," "second," "third," and "fourth," "first-level," "second-level," and "third-level," etc., does not indicate any order or importance, but is used to distinguish one element from another. It should be noted that the terms "first," "second," "third," and "fourth," "first-level," "second-level," and "third-level," etc., used here and elsewhere, are for labelling purposes only and are not intended to indicate any particular spatial or temporal order. Moreover, the labeling of a first element does not imply the existence of a second element, and vice versa.

[0133] It should be noted that the word "including" does not necessarily exclude the existence of other elements or steps besides those listed.

[0134] It should be noted that the words "one" or "a kind" preceding an element do not preclude the existence of multiple such elements.

[0135] While features have been shown and described, it should be understood that they are not intended to limit the claimed disclosure, and it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the claimed disclosure. The specification and drawings should be interpreted accordingly in an illustrative rather than limiting sense. The claimed disclosure is intended to cover all alternatives, modifications, and equivalents.

[0136] List of reference numerals

[0137] 1. Propulsion Unit

[0138] 2. Main Body

[0139] 3 fins

[0140] 3a First fin section

[0141] 3b Second fin section

[0142] 4 Actuator Assembly

[0143] 4a actuator, first actuator

[0144] 4b Second Actuator

[0145] 5a Pivot Point, First Pivot Point

[0146] 5b Second pivot point

[0147] 6 rudders

[0148] 7. Control lever

[0149] 8a First Link

[0150] 8b Second Link

[0151] 9 Actuating rod

[0152] 9a First moving rod

[0153] 9b Second Actuating Rod

[0154] 10. Precursor

[0155] 11. Steer stick

[0156] 12 Hollow Tubes

[0157] 13a First Through-Gate

[0158] 13b Second Through-Gate

[0159] 14. Seals

[0160] 15 small wings

[0161] 16. Trailing edge

[0162] 17 Slender grooves

[0163] 18 sales

[0164] 19 Slender grooves

[0165] 20 Seals

[0166] 21 Supporting Surface

[0167] 100 ships

[0168] 101 Dragon Bone

Claims

1. A propulsion unit (1) for propelling a ship, wherein, The propulsion unit (1) includes: - A main body (2), which is independent of the keel of the vessel and is configured to be located at the keel of the vessel and includes a pivot point (5a), wherein the main body provides directional stability to the vessel. - Fins (3), said fins being partially disposed in the body (2) and arranged slidably relative to the body (2), - An actuator assembly (4) for generating heave motion of the fins (3) relative to the body (2), the actuator assembly (4) including at least one actuator, wherein the at least one actuator includes a first actuator (4a) and a second actuator (4b), wherein a pivot point (5a) is connected to the second actuator (4b) such that the pivot point (5a) is movably arranged relative to the body (2); The fin (3) is arranged to pivot about the pivot point (5a) when the at least one actuator generates the heave motion of the fin (3), thereby generating the pitch motion of the fin (3); The fin (3) includes a first fin portion (3a), a second fin portion (3b), a first link (8a), and a second link (8b), wherein the first fin portion (3a) and the second fin portion (3b) located on opposite sides of the body (2) are connected via the first link (8a) and the second link (8b) extending through the body (2) in a transverse direction, wherein the first link (8a) and the second link (8b) are arranged in parallel and are spaced from the leading edges (10) of the first fin portion and the second fin portion (3a, 3b) by a corresponding first distance and a second distance, wherein the pivot point (5a) is located on the second link (8b).

2. The propulsion unit (1) according to claim 1, wherein the first actuator (4a) and the second actuator (4b) are operable independently of each other, such that the phase difference between the heave motion and the pitch motion of the fin (3) is variable.

3. The propulsion unit (1) according to claim 1, wherein the main body (2) includes a first through groove (13a) and a second through groove (13b) for allowing the first connecting rod (8a) and the second connecting rod (8b) to protrude through the main body (2) and be slidably arranged in the first through groove (13a) and the second through groove (13b).

4. The propulsion unit (1) according to claim 3, wherein the first link (8a) is connected to the first actuator (4a) and the second link (8b) is connected to the second actuator (4b).

5. The propulsion unit (1) according to claim 4, wherein the first link (8a) and the second link (8b) are respectively connected to the corresponding first actuator (4a) and second actuator (4b) via the first actuator (9a) and the second actuator (9b).

6. The propulsion unit (1) according to claim 5, wherein the first actuating rod (9a) and the second actuating rod (9b) are arranged inside the main body (2).

7. The propulsion unit (1) according to claim 6, wherein the actuator assembly (4) includes a third actuator (4c).

8. The propulsion unit (1) according to claim 7, wherein at least two of the first actuator (4a), the second actuator (4b) and the third actuator (4c) are capable of operating in relation to variably adjust the pitch motion and / or heave motion of the fin (3).

9. The propulsion unit (1) according to claim 7, wherein the fin (3) includes a third link, wherein the first fin portion (3a) and the second fin portion (3b) are connected via the third link, wherein the first link (8a), the second link (8b) and the third link are arranged in parallel and are spaced from the leading edges (10) of the first fin portion and the second fin portion (3a, 3b) by corresponding first distance, second distance and third distance.

10. The propulsion unit (1) according to claim 9, wherein the body (2) includes a third through slot for allowing the third link to protrude through the body (2) and be slidably disposed within the third through slot.

11. The propulsion unit (1) according to claim 10, wherein the third link is connected to the third actuator (4c).

12. The propulsion unit (1) according to claim 11, wherein the third link is connected to the third actuator (4c) via a third actuation rod.

13. The propulsion unit (1) according to claim 12, wherein the third actuating rod is arranged inside the main body (2).

14. The propulsion unit (1) according to claim 13, wherein at least one of the first actuator (4a) and the second actuator (4b) is configured to shift in the vertical direction.

15. The propulsion unit (1) according to claim 14, wherein at least one of the first actuator (4a) and the second actuator (4b) is constrained in a direction perpendicular to the extending direction of at least one of the first actuator (4a) and the second actuator (4b).

16. The propulsion unit (1) according to claim 14, wherein at least one of the first actuator (4a) and the second actuator (4b) is configured to be constrained in the lateral and / or longitudinal directions.

17. The propulsion unit (1) according to claim 5, wherein the propulsion unit includes a rudder (6).

18. The propulsion unit (1) according to claim 17, wherein the main body (2) is configured to be fixedly arranged to the keel of the vessel, and wherein the rudder (6) is pivotally arranged to the main body (2).

19. The propulsion unit (1) according to claim 17, wherein the body (2) includes a rudder (11) for rotatably arranging the body (2) to the keel of the vessel, wherein one or more of the actuators and / or at least one actuation rod are arranged inside the rudder (11), and wherein the body (2) is configured to serve as the rudder (6).

20. The propulsion unit (1) according to claim 19, wherein the body (2) includes a hollow tube (12) protruding from the body (2) on the keel-facing side of the body (2), wherein the first actuating rod (9a) and / or the second actuating rod (9b) are arranged within the hollow tube (12), wherein the hollow tube (12) is configured to protrude into the vessel when the body (2) is arranged to the keel of the vessel.

21. The propulsion unit (1) according to claim 20, wherein the hollow tube (12) includes a seal (14) disposed at the distal end of the hollow tube (12) for sealing the first actuating rod (9a) and / or the second actuating rod (9b) relative to the hollow tube (12).

22. The propulsion unit (1) according to claim 20, wherein the rudder (11) is hollow and constitutes the hollow tube (12).

23. The propulsion unit (1) according to any one of claims 1-22, wherein the fins (3) have an elliptical planar shape.

24. The propulsion unit (1) according to any one of claims 1-22, wherein the fin (3) includes a winglet (15).

25. A vessel (100) comprising a propulsion unit (1) for propelling the vessel according to any one of claims 1 to 24, wherein the body (2) is disposed to the keel (101) of the vessel (100), and wherein the fins (3) are configured to pitch and heave relative to the keel (101) of the vessel (100).

26. The vessel (100) according to claim 25, wherein the body (2) is fixedly arranged to the keel (101).

27. The vessel (100) according to claim 25, wherein the body (2) is rotatably arranged on the keel (101).

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