device

Abstract

Device (100) for roll stabilization of a watercraft (208) when underway, at anchor or at zero speed and / or for influencing the course of the watercraft (208), having a fin-carrying shaft (110) on which a guide fin (112) is arranged, wherein the fin-carrying shaft (110) can be driven by means of an electromechanical drive unit (120) to change an actual angle of attack (α) of the guide fin (112) in the water (220), and the drive unit (120) is arranged on the hull (204) by means of a foundation (200), characterized in that the electromechanical drive unit (120) is formed with a synchronous motor (126) which drives the fin-carrying shaft (110) by means of a step-down eccentric gear (130), wherein a rotor shaft (136) of the synchronous motor (126) is designed at least in sections as a hollow shaft (150),in which a coupling (138) for the rotationally fixed connection of the rotor shaft (136) to an input shaft (140) of the eccentric gear (130) is integrated.,

Description

The invention relates to a device for roll stabilization of a watercraft in travel, in front of the anchor or at zero speed and / or for influencing the heading of the watercraft, having a fin-carrying shaft on which a guide fin is arranged, wherein the fin-carrying shaft can be driven by means of an electromechanical drive unit for changing an actual angle of attack of the guide fin in the water, and the drive unit is arranged on the fuselage by means of a foundation.Fin stabilizers for passenger ships, larger yachts, swimming ponts and the like are known from the prior art in a wide range of variations. In this case, generally square fin shapes are used. In the case of the square fin types, the aim is to optimize the hydrodynamically effective fin surface for roll stabilization in front of the anchor or at zero speed of the ship to arrange the fin shaft as close as possible to the front fin edge.EP 2 172 394 B9 discloses an automatic antiroll stabilization system of a watercraft. The previously known system for stabilizing rolling movements of a watercraft in front of the anchor comprises, inter alia, a stabilizing fin which can rotate about an axis and which is fastened transversely to a longitudinal extent of a hull of the watercraft. The stabilizer fin has a hydrodynamic profile which, in operation, is subject to relative movement with respect to the hull by the water flow to produce a hydrodynamic lifting force. Furthermore, the system has an actuator arrangement which is designed to cause the stabilizing fin to rotate about said axis, wherein the actuator arrangement can be regulated by a regulating system as a function of a roll signal of the watercraft. The regulating system has for this purpose sensor means for generating a roll signal. The regulating system is coupled to an encoder for regulating the angular position of the stabilizing fin. The control system further comprises a microprocessor control unit adapted to process the roll signal provided by the sensor means. A control unit is used to control the electric motor. The actuator assembly includes an electric motor connected to the stabilizer fin through a planetary gear reduction gear, an input shaft of the reduction gear is mounted to an output shaft of the electric motor, and an output shaft of the reduction gear is fixed relative to the shaft supporting the stabilizer fin, the encoder being coupled to the electric motor.EP 2 452 870 A1 shows a device for roll stabilization, which has a synchronous motor and a reduced gear. US 2019 / 0 202 535 A1 likewise shows a device for roll stabilization having an engine and a transmission. General means for transmitting motor power are disclosed in DE 17 81 389 A.It is an object of the invention to specify a device for roll stabilization and / or influencing the course of a watercraft with a reduced installation space requirement and reduced operating noises with optimum controllability.The object mentioned at the beginning is achieved in that the electromechanical drive unit is formed with a synchronous motor which drives the fin-carrying shaft by means of a reducing eccentric gear. Due to the electromechanical drive unit, a spatially compact, cost-effective and quiet device for roll stabilization of a watercraft can be realized with a high degree of efficiency. The device does not require complex piping in comparison with produced electro-hydraulic drives, so that reduced installation and maintenance expenditure results. The device can be operated with small amounts of oil and no transverse forces are produced during the generation of torque. In addition, the electromechanical drive device can be controlled electronically in an excellent manner. A foundation of the device connected to the hull requires a lower manufacturing accuracy, wherein in particular no locating bolts are necessary any longer. Water cooling is generally required instead of air cooling. Due to the water cooling of the synchronous motor, an even lower noise level and a more compact design are achieved compared to air cooling.The eccentric gear preferably has two toothed disks arranged offset circumferentially with respect to one another by preferably 180°. As a result, optimum runout properties are obtained with simultaneously minimized noise emission and high torque transmission capacity. In addition, by rotating the toothed disks slightly circumferentially with respect to one another, a virtually complete freedom from play of the eccentric gear can be achieved.A rotor shaft of the synchronous motor is designed at least in sections as a hollow shaft in which a clutch is integrated. This results in an extremely space-saving construction. The coupling also makes possible a problem-free assembly of the device and integration into the hull of the watercraft and simplifies maintenance.Preferably, a locking device is assigned to the rotor shaft of the synchronous motor. As a result, the device can be held mechanically in a predeterminable position, for example when not in use or in a rest state.In the case of a further advantageous embodiment, the synchronous motor is controlled by means of power electronics which are controlled by a control and / or regulating device. This allows comprehensive speed and torque control of the synchronous motor, for example in a four-quadrant operation. Preferably, for example, in a four-quadrant operation. Preferably, the synchronous motor is designed as a permanently excited synchronous machine or as a brushless direct current motor ("brushless DC motor") in order to ensure optimum controllability.In the case of a favorable technical development, the synchronous motor has at least one motor generator which comprises a rotor position sensor for determining a rotor position angle and a rotational speed sensor for determining a number of revolutions of the rotor shaft. As a result, the control of the synchronous motor can be further optimized.An actual angle of attack of the fin-carrying shaft can preferably be directly detected by means of a rotation angle sensor assigned to the latter, wherein the rotation angle sensor is designed to detect at least one full revolution of the fin-carrying shaft. As a result, the angle of attack of the fin-carrying shaft with respect to the incoming water can be detected directly with high accuracy and independently of the rotor position of the synchronous motor. Any circumferential offset or a slight rotation between the rotor shaft of the synchronous motor and the fin-carrying shaft can thus be seen.In a development, the rotor position sensor and / or the angle of rotation sensor are preferably each designed as absolute sensors. In comparison with incremental rotor position sensors and incremental rotational angle sensors, this makes it unnecessary to calibrate the sensors to a defined position, for example after a power failure or after a longer operating period. Furthermore, an accumulation of possible measurement inaccuracies is avoided.Preferably, a target angle of attack of the guide fin can be calculated by means of the control and / or regulating device on the basis of the rotor position angle. This makes it possible to detect the position of the guide fin independently of the rotation angle sensor, knowing the reduction ratio of the eccentric gear.Preferably, in the case of an excessively large deviation between the calculated setpoint angle of attack and the actual angle of attack of the guide fin measured by means of the angle-of-rotation sensor, an action, in particular a warning signal, a recalibration or the like, can be triggered with the aid of the control and / or regulating device. This allows the accuracy of the position control of the guide fin to be further optimized and maintained for long service lives.In the case of a technically advantageous embodiment, the rotor shaft of the synchronous motor, an input shaft of the eccentric gear, an output shaft of the eccentric gear and the fin-bearing shaft run substantially flush with one another. This results in an optimum mechanical efficiency with at the same time optimum runout properties.In a technical development of the device, it is provided that the device is arranged on the hull of the watercraft in such a way that it is possible to influence the heading of the watercraft in the manner of a rudder system. This provides additional functionality of the device. For example, at least one device can be arranged in the region of a stern of a watercraft, wherein the fin-carrying shaft with the guide fin is oriented in the manner of a rudder or a rudder system substantially perpendicular to the longitudinal axis of the fuselage and at the same time in the direction of gravitational acceleration or in the direction of the bottom of the water. In the case of an insert as a fin stabilizer, on the other hand, the device or the guide fin is placed on the hull of the watercraft substantially parallel to the water surface or at a slight angle to the latter. When used as a fin stabilizer, at least two devices are arranged in pairs and symmetrically to one another with respect to the longitudinal axis of the hull of the watercraft or on a starboard side and a port side of the hull of the watercraft. A rudder installation can, on the other hand, be realized with at least one device. Even in the case of an application of the device as a rudder or as a rudder system for influencing the heading of the watercraft, a certain stabilizing effect with respect to rolling movements of the hull of the watercraft in the water can be achieved.A preferred exemplary embodiment of the invention is explained in more detail below with reference to schematic figures. They show FIG. 1 is a block diagram of an exemplary apparatus constructed as a fin stabilizer of a ship, FIG. 2 shows a perspective view of the fin stabilizer of FIG. 1 obliquely from above, FIG. 3 is a partial longitudinal section of the fin stabilizer of FIG. 2, and FIG. 4 is an enlarged perspective view of an electromechanical drive unit of the fin stabilizer.FIG. 1 shows a block diagram of a device, which is exemplarily designed as a fin stabilizer of a ship. A device 100 for roll stabilization of a watercraft not shown here in travel, in front of the anchor or at zero speed by the water and / or for influencing the course of a watercraft is designed here merely as a fin stabilizer 102 by way of example. In addition, it is possible to place the device 100 on a hull of a watercraft in such a way that it is also possible to influence the heading of the watercraft and the device thus assumes the function of a conventional rudder system. This constellation is not shown in the figures.The device 100 or the fin stabilizer 102 comprises, among other things, a pivotable fin-carrying shaft 110 to which a guide fin 112 or a stabilizing fin for the preferred damping of rolling movements of the watercraft is fastened. The fin-carrying shaft 110 is oriented substantially parallel to a longitudinal axis, likewise not illustrated here, of a hull of the watercraft preferably designed as a ship, wherein the guide fin 112 runs substantially parallel to a water surface (cf. FIG. 2 ; reference numeral 222) in a rest state or inactive state of the fin stabilizer 102. For changing an actual angle of attack α of the guide fin 112, the fin-carrying shaft 110 is correspondingly pivotable by means of an electromechanical drive unit 120.The electromechanical drive unit 120 comprises, among other things, a synchronous motor 126 which rotationally drives the fin-bearing shaft 110 by means of a highly step-down eccentric drive 130. The eccentric gear 130 preferably has two toothed disks 132, 134 which are offset from one another circumferentially by 180°, as a result of which a wide range of play is ensured. The detailed structural design of the eccentric gear 130 operating with a conventional involute toothing is sufficiently familiar to a person skilled in the art of electromechanical drive technology, so that at this point, for the sake of brevity and brevity of description, a detailed explanation of the eccentric gear 130 can be dispensed with. The synchronous motor 126 furthermore has a rotor shaft 136 which is connected in a rotationally fixed manner to an input shaft 140 of the eccentric gear 130 by means of a clutch 138 which cannot be released during operation. By means of a slowly rotating output shaft 142, the eccentric gear 130 drives the fin-carrying shaft 110 with the guide fin 112 so that its actual angle of attack α can be pivoted in a range from 0° to 360° inclusive. The rotor shaft 136 is also assigned a fixing device 146, by means of which the rotor shaft 136 can be temporarily locked, so that, for example when the fin stabilizer 102 is inactive, the guide fin 112 can be fixed or held in a suitable pivot position, which opposes the surrounding water with the smallest possible flow resistance. The rotor shaft 136 of the synchronous motor 126 is preferably designed at least in sections as a hollow shaft 150 in which the clutch 138 is integrated in a space-saving manner. The hollow shaft 150 surrounds the rotor shaft 136 of the synchronous motor 126 coaxially for this purpose, at least in sections. As a result, there is a significant reduction in the axial installation space requirement of the electromechanical drive unit 120. The rotor shaft 136 of the synchronous motor 126, the input shaft 140 of the eccentric gear 130, the output shaft 142 of the eccentric gear 130 and the fin-bearing shaft 110 are aligned substantially with one another, which results in a high energy efficiency combined with a low installation space requirement.The synchronous motor 126 is controlled by power electronics 160 which are fed from the on-board power supply 162 of the watercraft or of the ship. The on-board power supply 162 is embodied here merely by way of example as a three-phase three-phase power supply system with a neutral conductor. Any protective conductor is not shown. The power electronics 160 are comprehensively controlled or actuated by a powerful digital-electronic control and / or regulating device 166. By means of a position sensor 170, for example, the spatial position and the movements or the rotation rates of the watercraft or of the ship in all three spatial directions can be detected completely. Thus, all roll, pitch and yaw movements of the hull of the ship can be measured. For reasons of simplification, the position sensor 170 can be designed as a roll sensor 172, so that at least roll movements of the hull of the watercraft can be detected by the control and / or regulating device 160. The synchronous motor 126 further has a motor generator 176 coupled to the rotor shaft 136, which comprises at least one rotor position sensor 178 and at least one rotational speed sensor 180. With the aid of the rotor position sensor 178, a rotor position angle φ of the synchronous motor 126 can be determined, so that stator or rotor windings of the synchronous motor 126 can be controlled or energized in a correspondingly time-shifted manner. In addition, the rotational speed sensor 180 allows at least a detection of a number n of revolutions performed by the rotor shaft 136. Furthermore, the current actual angle of attack α of the fin-carrying shaft 110 and thus of the guide fin 112 in the water can be detected with high accuracy by the control and / or regulating device 166 by means of a rotation angle sensor 186 directly, that is to say independently of the rotor position of the synchronous motor 126. The rotational angle sensor 186 on the fin-carrying shaft 110 is preferably designed to detect at least one full revolution of the fin-carrying shaft 110. As a result, the current actual angle of attack α of the fin-carrying shaft 110 with respect to the incoming water can be detected directly by the control and / or regulating device 166 with high accuracy and independently of the rotor position of the synchronous motor. Any circumferential offset or a slight rotation between the rotor shaft 136 of the synchronous motor 126 and the fin-carrying shaft 110 can be detected and compensated by a suitable control of the synchronous motor 126 by means of the power electronics 160 controlled by the control and / or regulating device 166, resulting in optimum roll stabilization of the ship.Preferably, both the rotor position sensor 178 and the rotational angle sensor 186 are each designed as so-called absolute sensors with high precision, so that, among other things, recalibration due to accumulating measurement inaccuracies or after a power failure is unnecessary.The control and / or regulating device 166 is furthermore designed to determine, on the basis of the measured rotor position angle φ, a desired angle of attack β of the guide fin 112 to be respectively preset for optimum roll stabilization of the ship, so that the fin-carrying shaft 110 of the guide fin 112 can be rotated accordingly by means of the synchronous motor 126 controlled by the power electronics 160 via the eccentric gearing 100 connected between them. This control process is preferably carried out while simultaneously taking into account the measured values supplied by the position sensor 170 relating to the spatial position of the ship in the water. The control and / or regulating device 166 is furthermore designed to additionally trigger an action 192, for example in the form of a warning signal, a recalibration of the fin stabilizer 102 or the like, by means of the control and / or regulating device 166 in the event of an excessively large deviation between the calculated setpoint angle of attack β and the actual angle of attack α of the fin-carrying shaft 110 measured by means of the angle of rotation sensor 186.The control and / or regulating device 166 is furthermore provided to damp at least periodic rolling movements and, in the ideal case, also all pitching and yawing movements of the ship in the water on the basis of the measurement signals or measurement values supplied by the sensors by means of suitable actuation of the synchronous motor 126 with the aid of the power electronics 160 as effectively as possible. For this purpose, corresponding control algorithms are implemented within the preferably digital-electronic control and / or regulating device.FIG. 2 illustrates a perspective view of the fin stabilizer of FIG. 1 from obliquely above. The fin stabilizer 102 is fastened on the inside to a fuselage skin 202 of a fuselage 204 of a ship 206 by means of a foundation 200. The ship 206 is only exemplified here as an example of any watercraft 208 with a hull in which the inventive fin stabilizer 102 can be used. The fin-carrying shaft 110 passing through the fuselage skin 202 is fastened to the fin guide 112. A longitudinal central axis 210 of the fin-carrying shaft 110 extends substantially perpendicular to a longitudinal axis 216 of the hull 204 of the ship 206. By means of the electromechanical drive unit 120, the actual angle of attack α of the fin-carrying shaft 110 and thus of the guide fin 112 can be pivoted in relation to the surrounding water 220 in a range of preferably 0° to 360° or between ±180° including the respective interval limits. In the position of the guide fin 112 illustrated in FIG. 2, this extends here, merely by way of example, substantially parallel and below a water surface 222 which is merely indicated in the drawing, that is to say the actual angle of attack α of the guide fin 112 is set here, by way of example, to an actual angle of attack α of approximately 0°.An installation angle γ between the longitudinal central axis 210 of the fin-carrying shaft 110 and the horizontal plane running parallel to the xy-plane of the coordinate system 224 can in principle lie between 0° and 90°. At an installation angle γ of 90°, the longitudinal central axis 210 of the fin-carrying shaft 110 of the guide fin 112 of the fin stabilizer 102 runs perpendicular to the horizontal plane and thus parallel to the orientation of the gravitational acceleration g, wherein the fuselage skin 202 runs in the region of a floor of the ship 206 or of the watercraft 208.If the fin stabilizer 102 is arranged with an installation angle γ of approximately 90°, for example in a aft ship region (stern) and there usually behind the propeller of the ship 206 or of the watercraft 208, the apparatus 100 can additionally act as a rudder system for influencing the course of the ship 206. If the longitudinal central axis 210 extends at an installation angle γ of approximately 0°, that is to say approximately parallel to the horizontal plane or parallel to the xy plane 224 (water surface 222) and therefore also perpendicular to the direction of gravitational acceleration g, then a rudder effect of the fin stabilizer 102 is ruled out. Generally, the installation angle γ of fin stabilizers that cannot be pivoted into the hull 204 of the ship 206 or the watercraft 208 is at a value of approximately 45°.A rectangular coordinate system 224 illustrates the spatial location of all components relative to each other. The longitudinal axis 216 of the hull 204 of the ship 206 runs approximately parallel to the x-axis and the longitudinal central axis 210 of the fin-carrying shaft 110 is oriented substantially parallel to the y-axis or transversely to the longitudinal axis 216 of the hull 204, while the z-axis of the coordinate system 224 is directed parallel to the gravitational acceleration g or to the direction of action of the gravity approximately orthogonally to the water surface 222. The rolling movements of the hull 204 of the ship 206 to be damped primarily by means of the device 100 or the fin stabilizer 102 take place about the x-axis of the coordinate system 224, while pitching movements take place about the y-axis and yawing movements take place about the z-axis.The electromechanical drive unit 120 again comprises, inter alia, the synchronous motor 126 with the eccentric gearing 130 connected downstream thereof for realizing a high mechanical reduction ratio.FIG. 3 shows a partial longitudinal section of the fin stabilizer of FIG. 2, and the fin stabilizer 102 is firmly connected to the fuselage skin 202 of the fuselage 204 of the ship 206 or of a watercraft 208 by means of the foundation 200. The fin-bearing shaft 110 is guided sealingly through the fuselage skin 202 of the ship 206 and is rotatable about its longitudinal central axis 210 by means of the electromechanical drive unit 120. The guide fin 112 connected to the fin-carrying shaft 110 is not shown in the illustration of FIG. 3. The electromechanical drive unit 120 of the fin stabilizer 102 according to the invention again comprises the synchronous motor 126, the rotor shaft 136 of which, preferably designed as a hollow shaft 150, is connected to the eccentric gear 130 in a rotationally fixed manner by means of the clutch 138. The eccentric gear 130 is in turn coupled rotationally fixedly to the fin-carrying shaft 110.As a partial aspect of the invention, the coupling 138 is arranged at least in sections coaxially within the hollow shaft 150, resulting in a considerable reduction in the required axial installation space of the fin stabilizer 102 along the longitudinal central axis 210. The mechanical clutch 138 is not intended for momentary opening or release. Rather, the coupling 138 simplifies, among other things, the assembly and any possibly required dismantling of the fin stabilizer 102 for repair purposes, maintenance purposes or the like. Furthermore, it can be seen from FIG. 3 that the rotor shaft 136 of the synchronous motor 126, the clutch 138, the eccentric gearing 130 and the fin-carrying shaft 110 are aligned with one another along the longitudinal central axis 210, resulting in a high energy efficiency of the fin stabilizer 102.FIG. 4 shows an enlarged perspective view of an electromechanical drive unit of the fin stabilizer. The fin stabilizer 102 is fastened on the inside to the fuselage skin 202 of the fuselage 204 of the ship 206 by means of the foundation 200. The fin-bearing shaft 110 which can be rotated about its longitudinal central axis 210 by means of the electromechanical drive unit 120 is guided through the fuselage skin 202 in a watertight manner. The electromechanical drive unit 120 comprises the synchronous motor 126, the clutch 138 and the eccentric gear 130 with the fin-carrying shaft 110 and the guide fin 112 fastened thereto. As a purely optical exemplary embodiment of the rotational angle sensor 186, the synchronous motor 126 has a pointer-like, mechanical indicator element 230 in order to visually visualize the current actual angle of attack α of the fin-carrying shaft 110 of the guide fin 112 in the interior of the hull 204 of the ship 206 for a viewer. The indicator element 230 is for this purpose mechanically coupled in a suitable manner to the fin-carrying shaft 110. The fin 112 has a streamline cross-sectional profile 232 with a leading edge 234 and a trailing edge 236 for the surrounding water 220.The fin stabilizer 102 for roll stabilization of a ship, which is described here only by way of example as an example of a device according to the invention, requires a reduced installation space requirement, causes only minimal operating noises and has an optimum controllability for optimum damping of undesired roll movements about the longitudinal axis of the ship 206.The invention relates to a device (100) for roll stabilization of a watercraft (208) during travel, in front of the anchor or at zero speed and / or for influencing the course of the watercraft (208), having a fin-carrying shaft (110) on which a guide fin (112) is arranged, wherein the fin-carrying shaft (110) can be driven by means of an electromechanical drive unit (120) to change an actual angle of attack (α) of the guide fin (112) in the water (220), and the drive unit (120) is arranged on the fuselage (204) by means of a foundation (200). According to the invention, it is provided that the electromechanical drive unit (120) is formed with a synchronous motor (126), which drives the fin-carrying shaft (110) by means of a reducing eccentric gear (130). As a result, the device ( 100) has a considerably reduced installation space requirement, causes only low operating noises and can additionally be regulated electronically in an optimum manner.List of reference characters100 Device 102 fin stabilizer 110 fin-supporting shaft 112 guide fin 120 drive unit (angle of attack) 126 synchronous motor 130 eccentric gear 132 toothed disk 134 toothed disk 136 rotor shaft (synchronous motor) 138 clutch 140 input shaft 142 output shaft 146 fixing device 150 hollow shaft 160 power electronics 162 on-board power supply 166 control and / or regulating device 170 position sensor 172 roll sensor 176 motor generator 178 rotor position sensor 180 rotational speed sensor 186 rotational angle sensor 192 action 200 foundation 202 fuselage skin 204 fuselage 206 ship 208 watercraft 210 longitudinal central axis (fin-supporting shaft) 216 longitudinal axis (fuselage) 220 water 222 water surface 224 coordinate system 230 display element 232 cross-sectional profile 234 leading edge 236 trailing edge g gravitational acceleration (gravity) α actual angle of attack (stabilizing fin) β target angle of attack (Stabilizing fin) γ Installation angle φ Rotor position angle n Number of revolutions

Claims

Device (100) for roll stabilisation of a watercraft (208) during travel, in front of the anchor or at zero speed and / or for influencing the course of the watercraft (208), having a fin-carrying shaft (110) on which a guide fin (112) is arranged, wherein the fin-carrying shaft (110) can be driven by means of an electromechanical drive unit (120) to change an actual angle of attack (α) of the guide fin (112) in the water (220), and the drive unit (120) is arranged by means of a foundation (200) on the fuselage (204), characterized in that the electromechanical drive unit (120) is formed with a synchronous motor (126) which drives the fin-carrying shaft (110) by means of a reducing eccentric mechanism (130), wherein a rotor shaft (136) of the synchronous motor (126) is formed at least in sections as a hollow shaft (150), in which a clutch (138) for rotationally fixedly connecting the rotor shaft (136) to an input shaft (140) of the eccentric gearing (130) is integrated.Device (100) according to claim 1, characterised in that the eccentric gear (130) has two toothed discs (132, 134) arranged offset circumferentially with respect to one another by preferably 180°.Device (100) according to either of Patent Claims 1 and 2, characterized in that a locking device (146) is assigned to the rotor shaft (136) of the synchronous motor (126).Device (100) according to one of Patent Claims 1 to 3, characterized in that the synchronous motor (126) is actuated by means of power electronics (160) which are controlled by a control and / or regulating device (166).Device (100) according to Patent Claim 4, characterized in that the synchronous motor (126) has at least one motor generator (176), which comprises a rotor position sensor (178) for determining a rotor position angle (φ) and a rotational speed sensor (180) for determining a number n of revolutions of the rotor shaft (136).Device (100) according to claim 4 or 5, characterised in that an actual angle of attack (α) of the fin-carrying shaft (110) can be directly detected by means of a rotation angle sensor (186) assigned to it, wherein the rotation angle sensor (186) is designed for detecting at least one full revolution of the fin-carrying shaft (110).Device (100) according to claim 4, 5 or 6, characterised in that the rotor position sensor (178) and / or the angle of rotation sensor (186) are preferably each designed as absolute sensors.Device (100) according to one of Patent Claims 4 to 7, characterized in that a setpoint angle of attack (β) of the guide fin (112) can be calculated by means of the control and / or regulating device (166) on the basis of the rotor position angle (φ).Device (100) according to one of Patent Claims 4 to 8, characterized in that, in the event of an excessively large deviation between the calculated setpoint angle of attack (β) and the actual angle of attack (α) of the guide fin (112) measured by means of the angle-of-rotation sensor (186), an action (192), in particular a warning signal, a recalibration or the like, can be triggered with the aid of the control and / or regulating device (166).Device (100) according to one of the preceding patent claims, characterized in that the rotor shaft (136) of the synchronous motor (126), an input shaft (140) of the eccentric gearing (130), an output shaft (142) of the eccentric gearing (130) and the fin-carrying shaft (110) run substantially flush with one another.Device (100) according to one of the preceding patent claims, characterized in that the device (100) is arranged on the hull (204) of the watercraft (208) in such a way that it is possible to influence the heading of the watercraft (208) in the manner of a rudder installation.

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