MARINE PROPULSION UNIT

Abstract

A marine propulsion unit for a marine vessel has a power source for rotating a pitchable propeller around an axis. The pitchable propeller is connected with a first shaft and a second shaft, an adjustment device comprising a first part being connected with the first shaft, a second part being connected with the second shaft, and a movable part. The movable part is configured to be moved between a first position and a second position so as to turn the first part and/or the second part thereby providing a phase shift between the first shaft and the second shaft for pitching and/or folding the pitchable propeller.

Claims

1. A marine propulsion unit for a marine vessel, comprising a power source for rotating a pitchable propeller around an axis, the pitchable propeller being connected with a first shaft and a second shaft, an adjustment device comprising a first part being connected with the first shaft, a second part being connected with the second shaft, and a movable part, wherein the movable part is configured to be moved between a first position and a second position so as to turn the first part and/or the second part thereby providing a phase shift between the first shaft and the second shaft for pitching and/or folding the pitchable propeller.

2. The marine propulsion unit of claim 1, wherein the first part comprises a first part end being connected with the first shaft and a first projection extending from the first part end in an axial direction, the first projection having a first inner face with a first inner thread and a first outer face.

3. The marine propulsion unit of claim 2, wherein the second part comprises a second part end being connected with the second shaft and a second projection extending from the second part end in the axial direction, the second projection having a second inner face and a second outer face with a second outer thread.

4. The marine propulsion unit of claim 3, wherein the movable part comprises a third part end, a third projection extending from the third part end in the axial direction, the third projection having a third outer face with a third outer thread, and a fourth projection extending from the third part end in the axial direction, the fourth projection being hollow and has a fourth inner face with a fourth inner thread, the fourth projection being arranged around the third projection with a distance between them.

5. The marine propulsion unit of claim 1, wherein the first part, the second part and the movable part are assembled so that the first inner thread interacts with the third outer thread and the second outer thread interacts with the fourth inner thread so that when the movable part is moved in the axial direction the first part and the second part are turned so that a phase shift between the first shaft and the second shaft occur.

6. The marine propulsion unit of claim 1, wherein one or more bearing is/are arranged between the first part and the second part and the movable part, respectively.

7. The marine propulsion unit of claim 2, wherein the treads are formed as helical guides that may interact with each other.

8. The marine propulsion unit of claim 7, wherein the helical guides comprise a helical grooves and helical protrusions or knobs being configured to interact.

9. The marine propulsion unit of claim 1, wherein an actuator is arranged for moving the movable part in the axial direction between the first position and the second position and any intermediate positions there between.

10. The marine propulsion unit of claim 1, further comprising a control unit being operatively connected with the power source, the movable part and/or the actuator.

11. The marine propulsion unit of claim 1, wherein a coupling is arranged between the first shaft, the second shaft and the pitchable propeller for changing a pitch angle of the pitchable propeller when the phase shift between the first shaft and the second shaft occur.

12. The marine propulsion unit of claim 11, wherein the coupling comprises a first gear and a second gear, the first shaft is directly connected to the second gear and the second shaft is directly connected to the first gear.

13. The marine propulsion unit of claim 11, wherein the pitchable propeller has a plurality of propeller blades, each propeller blade being connected to a blade gear.

14. A marine vessel comprising a marine propulsion unit of claim 1.

15. A method for pitching a pitchable propeller of a marine propulsion unit of claim 1, comprising arranging a power source for rotating the pitchable propeller around an axis, the pitchable propeller being connected with a first shaft and a second shaft, arranging an adjustment device comprising a first part being connected with the first shaft, a second part being connected with the second shaft, and a movable part, moving the movable part between a first position and a second position so as to turn the first part and/or the second part thereby providing a phase shift between the first shaft and the second shaft for pitching and/or folding the pitchable propeller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Examples are described in more detail below with reference to the appended drawings.

[0025] FIG. 1 is an exemplary marine propulsion unit according to an example.

[0026] FIGS. 2-3 are another exemplary marine propulsion unit according to an example.

[0027] FIG. 4 is an exemplary adjustment device according to an example.

[0028] FIGS. 5a-5b show the phase shift provided by the adjustment device.

[0029] FIG. 6 is an exemplary first and second shafts connected with a coupling according to an example.

DETAILED DESCRIPTION

[0030] The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

[0031] Existing solutions often lack the ability to simply and effectively control and adjust the pitch angle of a pitchable propeller. This limitation hampers the ability to fine-tune the propulsion system for improved maneuverability and efficiency in a simple manner. For instance, when navigating through rough seas or executing complex maneuvers, the inability to adjust the pitch angle of the propeller can result in reduced control, increased wear on the propulsion components, and higher power consumption.

[0032] Improvements in marine propulsion technology are therefore needed to address these shortcomings. A more advanced approach that allows for precise and independent control of the propeller pitch can enhance the overall performance and reliability of marine vessels. Such advancements would not only improve power or fuel efficiency and reduce environmental impact but also provide better handling and adaptability in diverse maritime conditions and varying states of the marine vessel.

[0033] Therefore, there is a pressing need for an improved marine propulsion unit that offers a simplified and effective means of controlling the pitch of a propeller. Such an advancement would enhance the overall performance, reliability, and efficiency of marine vessels, addressing the shortcomings of existing technologies and meeting the demands of modern maritime operations.

[0034] The present disclosure address these disadvantages by providing a simple yet robust adjustment device enabling the possibility for changing a pitch angle of the pitchable propeller or even in certain circumstances folding it.

[0035] FIG. 1 is an exemplary marine propulsion unit 1 for a marine vessel according to an example. The marine propulsion unit 1 comprises a power source 2 for rotating a pitchable propeller 3 around an axis 4. The pitchable propeller 3 being connected with a first shaft 5 and a second shaft 6.

[0036] The marine propulsion unit 1 further comprises an adjustment device 20 comprising a first part 21 being connected with the first shaft 5, a second part 22 being connected with the second shaft 6, and a movable part 23. The movable part 23 is configured to be moved between a first position and a second position so as to turn the first part 21 and/or the second part 22 thereby providing a phase shift between the first shaft 5 and the second shaft 6 for pitching and/or folding the pitchable propeller 3. The overall performance and efficiency of marine vessels by allowing for more precise and adaptive control of the propeller pitch is thereby enhanced. This improvement addresses the shortcomings of complex and maintenance-prone prior art systems, resulting in reduced operational costs and increased reliability. Additionally, the ability to dynamically adjust the propeller pitch can enhance power and fuel efficiency while reducing emissions, thereby contributing to more environmentally friendly marine operations.

[0037] The pitch angle of a pitchable propeller 3 refers to the angle between the chord line of the propeller blade and the plane of rotation 4. This angle is measured around the pitch axis 9, which is an imaginary line perpendicular to the blade's chord line and extends through the hub 11 of the pitchable propeller 3. Different pitch angles can significantly influence sailing conditions and the performance of the marine vessel. At a low pitch angle, the blades are more aligned with the direction of rotation. This generates less thrust but allows for higher rotational speeds. This setting is typically used for low-speed operations, such as maneuvering in tight spaces or when the vessel is lightly loaded. It can also be beneficial during acceleration from a standstill. At a high pitch angle, the blades are more perpendicular to the direction of rotation 4. This generates more thrust but results in lower rotational speeds. This setting is ideal for high-speed cruising or when the vessel is heavily loaded, as it provides greater propulsion force. However, it can increase the load on the motor and reduce power efficiency if not managed correctly.

[0038] In addition, at variable pitch angles the blades can be adjusted to various angles between the low and high extremes. This allows for optimized performance across different sailing conditions. By dynamically adjusting the pitch angle, the propulsion system can balance the need for speed, thrust, and fuel efficiency. For example, a moderate pitch angle can provide a good compromise between speed and thrust for general cruising. By adjusting the pitch angle, the propulsion unit can tailor the thrust characteristics to match specific operational requirements, improving overall vessel performance, power/fuel efficiency, and maneuverability under diverse sailing conditions. The present disclosure aiming at providing a solution for adjusting the variable pitch angles of the pitchable propeller in a simple manner.

[0039] According to the present disclosure, a phase shift between the first shaft 5 and the second shaft 6 refers to the relative angular displacement or difference in the rotational positions of the two shafts. The phase shift is the relative angular displacement between two rotating shafts 5, 6, measured as the difference in the angular positions of the shafts at any given moment. It is often described in degrees or radians.

[0040] The phase shift between the first shaft 5 and the second shaft 6 is according to the disclosure achieved through the adjustment device 20 that is configured to modify the relative angular positions of the shafts. This adjustment device 20 comprises the first part 21 connected to the first shaft 5, the second part 22 connected to the second shaft 6, and the movable part 23 configured to be moved between different positions.

[0041] When the movable part 23 is actuated, it interacts with the first and second parts 21, 22 in a manner that causes one or both of the shafts 5, 6 to rotate relative to each other. This interaction may be facilitated by actuating the movable part 23 whereby the common adjustment device 20 translates the linear movement of the movable part 23 into a change in the angular positions of the shafts. The resultant phase shift alters the pitch angle of the propeller blades connected to the shafts, optimizing their orientation for different operational conditions.

[0042] This phase shift may be controlled via an actuator 24 that moves the movable part 23 of the adjustment device 20, thereby finely tuning the propeller pitch for optimal performance under varying loads, speeds, and environmental conditions. The ability to induce a phase shift between the first shaft 5 and the second shaft 6 allows for precise and adaptive control of the propeller pitch. This leads to enhanced propulsion efficiency, better fuel or power economy, and improved maneuverability of the marine vessel, addressing the limitations of prior art solutions that lack such dynamic control mechanisms.

[0043] FIGS. 2-3 show another example a marine propulsion unit 1. The power source 2 is connected with the first shaft 5 and second shaft 6 via the adjustment device 20. The first part 21 is connected to the first shaft 5 via a first connection 31, and the second 22 part is connected to the second shaft 6 via a second connection 32. The connection between the parts 21, 22 and the connections 31, 32 are toothed connections. The movable part 23 is in FIG. 2 in the first position. The movable part 23 is connected with the actuator 24 being configured to move the movable part 23. The actuator 24 is arranged for moving the movable part 23 in the axial direction 35 between the first position and the second position and any intermediate positions there between. A technical benefit may include enabling automated and precise control of the movable part 23, which can improve the efficiency and responsiveness of the propulsion unit 1.

[0044] The actuator 24 may be a motor, linear pneumatic or hydraulic cylinder, drive belt, or a similar device being able to move the movable part 23 in the axial direction. A technical benefit may include providing various options for actuator types, allowing for customization based on specific operational requirements and improving the overall reliability of the propulsion unit.

[0045] The propulsion unit 1 may further comprise a control unit 10 being operatively connected with the power source 2, the movable part 23 and/or the actuator 24. A technical benefit may include enabling centralized and automated control of the entire propulsion system, which can enhance operational efficiency and ease of use. The control unit 10 may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The control unit 10 may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the control unit includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device.

[0046] The control unit 10 may be configured to control the movable part 23 and/or the actuator 24 on basis of vessel data received from the marine vessel. A technical benefit may include allowing the control unit 10 to make real-time adjustments based on operational data, which can optimize the performance and efficiency of the propulsion unit. The vessel data may relate to power consumption, modes of operation of the marine vessel, torque of the motor, load of the marine vessel, speed of the marine vessel, or a combination thereof. A technical benefit may include providing a comprehensive set of data inputs to the control unit, which can enable more accurate and effective control of the propulsion system.

[0047] The control unit may also be configured to adjust the pitch angle of the pitchable propeller 3 on basis of the vessel data. A technical benefit may include enabling dynamic and real-time adjustments to the propeller pitch, which can significantly enhance the vessel's performance and fuel efficiency.

[0048] Also, the control unit 10 may be configured to control the movable part 23 and/or the actuator 24 on basis of input data received from an input unit operated by an operator. A technical benefit may include allowing manual override and control of the propulsion system, providing flexibility and adaptability in various operational scenarios. The control unit 10 may be configured to adjust the pitch angle of the pitchable propeller 3 on basis of the input data. A technical benefit may include enabling precise and responsive manual adjustments to the propeller pitch, which can enhance the maneuverability and control of the marine vessel.

[0049] In FIG. 3, the actuator 24 has moved the movable part 23 to the second position. By the movement of the movable part 23 the phase shift occur between the first shaft 5 and the second shaft 6 whereby the pitchable propeller 3 is pitched around the pitch axis 9. The first shaft 5 is concentrically arranged inside the second shaft 6.

[0050] Furthermore, a coupling 14 is arranged between the first shaft 5, the second shaft 6 and the pitchable propeller 3 for changing a pitch angle of the pitchable propeller 3 when the phase shift between the first shaft 5 and the second shaft 6 occur. A technical benefit may include ensuring efficient transmission of mechanical movements to adjust the propeller pitch, which can improve the overall responsiveness of the propulsion system. The coupling will be further disclosed in relation to FIG. 6.

[0051] Moreover, one or more bearing(s) may be arranged between the first part and the second part and the movable part, respectively. A technical benefit may include reducing friction and wear between moving parts, thereby enhancing the longevity and performance of the propulsion unit. The bearing may be a roller bearing, ball screw arrangement, or the like. A technical benefit may include providing various options for bearing types, allowing for customization based on specific operational requirements and improving the overall reliability of the propulsion unit.

[0052] FIG. 4 shows an example of the adjustment device 20 in a not assembled state. In the first row the first part 21, the second part 22 and the movable part 23 are shown from an outside view and the second row the different parts are shown in a cross-sectional view taken along the A-line in the first row.

[0053] The first part 21 comprises a first part end 40 being connected with the first shaft and a first projection 41 extending from the first part 40 in an axial direction, the first projection 41 having a first inner face 42 with a first inner thread 43 and a first outer face 44.

[0054] The second part 22 comprises a second part end 45 being connected with the second shaft and a second projection 46 extending from the second part 45 in the axial direction, the second projection 46 having a second inner face 47 and a second outer face 48 with a second outer thread 49.

[0055] Moreover, the movable part 23 comprises a third part end 50, a third projection 51 extending from the third part end 50 in the axial direction. In the present example, the third projection extends in an opposite direction compared to the first projection and the second projection. The third projection 51 having a third outer face 52 with a third outer thread 53, and a fourth projection 54 extending from the third part end 50 in the axial direction, the fourth projection 54 being hollow and has a fourth inner face 55 with a fourth inner thread 56, the fourth projection 54 being arranged around the third projection 51 with a distance between them. A technical benefit may include providing a compact and efficient design for the movable part, facilitating smoother and more precise adjustments in the propeller pitch. The fourth projection has fourth outer face 57. The actuator may be connected with the movable part 23.

[0056] Furthermore, the first part 21, the second part 22 and the movable part 23 may be assembled so that the first inner thread 43 interacts with the third outer thread 53 and the second outer thread 49 interacts with the fourth inner thread 56 so that when the movable part 23 is moved in the axial direction the first part 21 and the second part 22 are turned so that a phase shift between the first shaft and the second shaft occur. A technical benefit may include enabling precise control of the phase shift between the shafts, which can optimize the propeller pitch adjustment process.

[0057] The threads may be formed as helical guides that may interact with each other. A technical benefit may include facilitating smoother and more efficient movement between the interconnected parts, which can enhance the precision of propeller pitch adjustments. The helical guides may comprise a helical grooves and helical protrusions or knobs being configured to interact. A technical benefit may include improving the mechanical engagement between components, which can lead to more reliable and accurate pitch adjustments.

[0058] Helical guides may be structural elements designed to facilitate smooth and controlled movement of mechanical parts along a helical path. These guides ensure that rotational and linear movements may be converted or synchronized, such as in the adjustment device of the present disclosure. Helical guides may take the form of grooves, protrusions, or threads that follow a helical (spiral) pattern around a cylindrical component.

[0059] The helical angle, also known as the lead angle, is the angle between the helical path and a plane perpendicular to the axis of the cylindrical component and determines the rate at which the guide moves along the axis as it rotates. Another factor is the pitch, which is the distance between corresponding points on adjacent turns of the helical path. This pitch determines how far the guide moves linearly for each complete rotation.

[0060] The thread profile, which is the cross-sectional shape of the helical guide, can be triangular, square, trapezoidal, or custom-shaped, depending on the application requirements for strength, load distribution, and wear resistance. The choice of material for the helical guides are designed so as withstand the operational environment, including factors like corrosion resistance, mechanical strength, and wear characteristics.

[0061] In terms of interaction mechanisms, helical guides are designed to engage with corresponding parts, such as inner or outer threads, grooves, or knobs. This interaction may ensure smooth engagement and disengagement, minimizing friction and wear.

[0062] The technical benefits of helical guides or threads are many. They ensure smooth and precise movement of the mechanical parts, reducing the risk of jamming or excessive wear. The helical design allows for efficient transmission of force, enabling the conversion of rotational movement into linear movement or vice versa.

[0063] In addition, the threads or the helical guides which are not interacting may have different helical angles or thread leads. A technical benefit may include providing greater flexibility in the design and operation of the propulsion unit, allowing for customized pitch adjustment characteristics. Furthermore, the axial forces in the adjustment device may be cancelled due to the different helical angles or thread leads.

[0064] In an example, the first inner thread 43 and the third outer thread 53 may have a first helical angle or a first thread lead, and the second outer thread 49 and the fourth inner thread 56 may have a second helical angle or a second thread lead, wherein the first helical angle or the first thread lead is different from the second helical angle or the second thread lead. A technical benefit may include enabling differential movement between the interconnected parts, which can optimize the propeller pitch adjustment process.

[0065] In FIG. 5a, the adjustment device 20 is shown. The first part 21 has in the example a first flange 70 protruding from the first part 21. The second part 22 has a second flange 71 protruding from the second part 22. The first flange 70 and the second flange 71 are aligned in FIG. 5a. In FIG. 5b, the movable part 23 has been moved in the axial direction 35 whereby the first part 21 is turned left and the second part 22 is turned right so that the first flange 70 and the second flange 71 have been turned away from each other. By this movement of the movable part the phase shift occur, which in the present disclosure is used to change a pitch angle of the pitchable propeller.

[0066] The first shaft 5 and the second shaft 6 are connected with the pitchable propeller 3 in the hub 11. In addition, a coupling 14 is arranged between the first shaft 5, the second shaft 6 and the pitchable propeller 3 for changing a pitch angle of the pitchable propeller 3 when the first rotation speed and/or second rotation speed vary in relation to the other. A technical benefit may include precise control over the pitch angle for optimized propulsion efficiency.

[0067] In FIG. 6, an example of the coupling 14 is shown. The coupling 14 may comprise a first gear 15 and a second gear 16, the first shaft 5 is directly connected to the second gear 16 and the second shaft 6 is directly connected to the first gear 15. A technical benefit may include reliable and efficient transmission of rotational power to adjust the propeller pitch. The pitchable propeller 3 has a plurality of propeller blades 17, each propeller blade 17 being connected to a blade gear 18. A technical benefit may include individual pitch adjustment for each blade to optimize thrust and efficiency. In the example shown in FIG. 6, the pitchable propeller 3 has a first blade and a second blade, the first blade is connected to a first propeller gear and the second blade is connected to a second propeller gear. A technical benefit may include balanced thrust generation and improved propeller efficiency.

[0068] In another example, the pitchable propeller may have a first blade, a second blade and a third blade, the first blade is connected to a first propeller gear, the second blade is connected to a second propeller gear and the third blade is connected to a third propeller gear. A technical benefit may include enhanced thrust control and distribution across multiple blades.

[0069] In yet another example, the pitchable propeller may have a first blade, a second blade, a third blade and a fourth blade, the first blade is connected to a first propeller gear, the second blade is connected to a second propeller gear, the third blade is connected to a third propeller gear and the fourth blade is connected to a fourth propeller gear. A technical benefit may include maximized propulsion efficiency by distributing load across multiple blades.

[0070] Furthermore, the first gear and the second gear may be connected to the propeller gears. A technical benefit may include providing a robust and reliable connection between the gears and the propeller blades, which can enhance the durability and performance of the propulsion unit.

[0071] The power source 2 may be an electric motor or an engine, or a combination thereof. A technical benefit may include providing flexibility in the choice of power sources, allowing for the optimization of the propulsion system based on specific operational requirements and improving the overall efficiency and performance of the marine vessel. The engine may be an internal combustion engine.

[0072] Furthermore, the pitchable propeller 3 may be foldable. A technical benefit may include compact storage and reduced drag when the propeller is not in use. Also, the pitchable propeller 3 is a single propeller.

[0073] The marine propulsion unit 1 according to the disclosure may be used a thruster unit.

[0074] The present disclosure also relates to a marine vessel comprising the marine propulsion unit. The marine vessel may be a power boat or a sailing boat. A technical benefit may include versatility in application across different types of marine vessels.

[0075] The present disclosure also relates to a method for pitching a pitchable propeller 3 of the marine propulsion unit 1, comprising arranging a power source 2 for rotating the pitchable propeller 3 around an axis 4, the pitchable propeller 3 being connected with a first shaft 5 and a second shaft 6, arranging an adjustment device 20 comprising a first part 21 being connected with the first shaft 5, a second part 22 being connected with the second shaft 6, and a movable part 23, moving the movable part 23 between a first position and a second position so as to turn the first part 21 and/or the second part 22 thereby providing a phase shift between the first shaft 5 and the second shaft 6 for pitching and/or folding the pitchable propeller 3.

[0076] Certain aspects and variants of the disclosure are set forth in the following examples numbered consecutive below.

[0077] Example 1: A marine propulsion unit (1) for a marine vessel, comprising a power source (2) for rotating a pitchable propeller (3) around an axis (4), the pitchable propeller (3) being connected with a first shaft (5) and a second shaft (6), an adjustment device (20) comprising a first part (21) being connected with the first shaft (5), a second part (22) being connected with the second shaft (6), and a movable part (23), wherein the movable part (23) is configured to be moved between a first position and a second position so as to turn the first part (21) and/or the second part (22) thereby providing a phase shift between the first shaft (5) and the second shaft (6) for pitching and/or folding the pitchable propeller (3).

[0078] Example 2: The marine propulsion unit (1) of Example 1, wherein the first part (21) comprises a first part end (40) being connected with the first shaft (5) and a first projection (41) extending from the first part end in an axial direction (35), the first projection (41) having a first inner face (42) with a first inner thread (43) and a first outer face (44).

[0079] Example 3: The marine propulsion unit (1) of Example 2, wherein the second part (22) comprises a second part end (45) being connected with the second shaft (6) and a second projection (46) extending from the second part end in the axial direction, the second projection (46) having a second inner face (47) and a second outer face (48) with a second outer thread (49).

[0080] Example 4: The marine propulsion unit (1) of Example 3, wherein the movable part (23) comprises a third part end (50), a third projection (51) extending from the third part end (50) in the axial direction, the third projection (51) having a third outer face (52) with a third outer thread (53), and a fourth projection (54) extending from the third part end (50) in the axial direction, the fourth projection (54) being hollow and has a fourth inner face (55) with a fourth inner thread (56), the fourth projection (54) being arranged around the third projection (51) with a distance between them.

[0081] Example 5: The marine propulsion unit (1) of any of the Examples 1-4, wherein the first part (21), the second part (22) and the movable part (23) are assembled so that the first inner thread (43) interacts with the third outer thread (53) and the second outer thread (49) interacts with the fourth inner thread (56) so that when the movable part (23) is moved in the axial direction the first part (21) and the second part (22) are turned so that a phase shift between the first shaft (5) and the second shaft (6) occur.

[0082] Example 6: The marine propulsion unit (1) of any of the Examples 1-5, wherein one or more bearing is/are arranged between the first part (21) and the second part (22) and the movable part (23), respectively.

[0083] Example 7: The marine propulsion unit (1) of Example 6, wherein the bearing is a roller bearing, ball screw arrangement, or the like.

[0084] Example 8: The marine propulsion unit (1) of any of the Examples 2-7, wherein the threads are formed as helical guides that may interact with each other.

[0085] Example 9: The marine propulsion unit (1) of Example 8, wherein the helical guides comprise helical grooves and helical protrusions or knobs being configured to interact.

[0086] Example 10: The marine propulsion unit (1) of any of the Examples 2-9, wherein the threads or the helical guides which are not interacting have different helical angles or thread leads.

[0087] Example 11: The marine propulsion unit (1) of any of the Examples 2-10, wherein the first inner thread (43) and the third outer thread (53) have a first helical angle or a first thread lead, and the second outer thread (49) and the fourth inner thread (56) have a second helical angle or a second thread lead, wherein the first helical angle or the first thread lead is different from the second helical angle or the second thread lead.

[0088] Example 12: The marine propulsion unit (1) of any of the Examples 1-11, wherein an actuator (24) is arranged for moving the movable part (23) in the axial direction (35) between the first position and the second position and any intermediate positions there between.

[0089] Example 13: The marine propulsion unit (1) of Example 12, wherein the actuator (24) is a motor, linear pneumatic or hydraulic cylinder, drive belt, or similar devices being able to move the movable part in the axial direction.

[0090] Example 14: The marine propulsion unit (1) of any of the Examples 1-13, further comprising a control unit (10) being operatively connected with the power source (2), the movable part (23) and/or the actuator (24).

[0091] Example 15: The marine propulsion unit (1) of Example 14, wherein the control unit (10) is configured to control the movable part (23) and/or the actuator (24) on basis of vessel data received from the marine vessel.

[0092] Example 16: The marine propulsion unit (1) of Example 15, wherein the vessel data relates to power consumption, modes of operation of the marine vessel, torque of the power source, load of the marine vessel, speed of the marine vessel, or a combination thereof.

[0093] Example 17: The marine propulsion unit (1) of Example 15 and/or 16, wherein the control unit (10) is configured to adjust the pitch angle of the pitchable propeller (3) on basis of the vessel data.

[0094] Example 18: The marine propulsion unit (1) of any of the Examples 14-17, wherein the control unit (10) is configured to control the movable part (23) and/or the actuator (24) on basis of input data received from an input unit operated by an operator.

[0095] Example 19: The marine propulsion unit (1) of Example 18, wherein the control unit (10) is configured to adjust the pitch angle of the pitchable propeller (3) on basis of the input data.

[0096] Example 20: The marine propulsion unit (1) of any of the Examples 1-19, wherein a coupling (14) is arranged between the first shaft (5), the second shaft (6) and the pitchable propeller (3) for changing a pitch angle of the pitchable propeller (3) when the phase shift between the first shaft (5) and the second shaft (6) occur.

[0097] Example 21: The marine propulsion unit (1) of Example 20, wherein the coupling (14) comprises a first gear (15) and a second gear (16), the first shaft (5) is directly connected to the second gear (6) and the second shaft (6) is directly connected to the first gear (15).

[0098] Example 22: The marine propulsion unit (1) of Example 20 and/or 21, wherein the pitchable propeller (3) has a plurality of propeller blades (17), each propeller blade (17) being connected to a blade gear (18).

[0099] Example 23: The marine propulsion unit (1) of any of the Examples 20-22, wherein the pitchable propeller (3) has a first blade (17) and a second blade (17), the first blade is connected to a first propeller gear (18) and the second blade is connected to a second propeller gear (18).

[0100] Example 24: The marine propulsion unit (1) of any of the Examples 20-22, wherein the pitchable propeller (3) has a first blade, a second blade and a third blade, the first blade is connected to a first propeller gear, the second blade is connected to a second propeller gear and the third blade is connected to a third propeller gear.

[0101] Example 25: The marine propulsion unit (1) of any of the Examples 20-22, wherein the pitchable propeller (3) has a first blade, a second blade, a third blade and a fourth blade, the first blade is connected to a first propeller gear, the second blade is connected to a second propeller gear, the third blade is connected to a third propeller gear and the fourth blade is connected to a fourth propeller gear.

[0102] Example 26: The marine propulsion unit (1) of any of the Examples 23-25, wherein the first gear (15) and the second gear (16) are connected to the propeller gears (18).

[0103] Example 27: The marine propulsion unit (1) of any of the Examples 1-26, wherein the pitchable propeller (3) is foldable.

[0104] Example 28: The marine propulsion unit (1) of any of the Examples 1-27, wherein the power source is an electric motor or an engine, or a combination thereof.

[0105] Example 29: A marine vessel comprising a marine propulsion unit (1) of any of the Examples 1-28.

[0106] Example 30: The marine vessel of Example 29, wherein the marine vessel is a power boat or a sailing boat.

[0107] Example 31: A method for pitching a pitchable propeller (3) of a marine propulsion unit (1) of any of the Examples 1-28, comprising arranging a power source (2) for rotating the pitchable propeller (3) around an axis (4), the pitchable propeller (3) being connected with a first shaft (5) and a second shaft (6), arranging an adjustment device (20) comprising a first part (21) being connected with the first shaft (5), a second part (22) being connected with the second shaft (6), and a movable part (23), moving the movable part (23) between a first position and a second position so as to turn the first part (21) and/or the second part (22) thereby providing a phase shift between the first shaft (5) and the second shaft (6) for pitching and/or folding the pitchable propeller (3).

[0108] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms a, an, and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms comprises, comprising, includes, and/or including when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof.

[0109] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0110] Relative terms such as below or above or upper or lower or horizontal or vertical may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being connected or coupled to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being directly connected or directly coupled to another element, there are no intervening elements present.

[0111] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0112] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.