Method and a steering arrangement for turning a propulsion unit of a vessel

A steering arrangement for turning a propulsion unit of a vessel comprising:

• a gearwheel being connected to the propulsion unit,
• at least one steering electric motor being operatively connected to the gearwheel,
• a drive for controlling the steering electric motor,
• a force transmission arrangement comprising a clutch being arranged between the gearwheel and the steering electric motor, wherein the at least one steering electric motor is arranged to rotate the gearwheel and thereby also the propulsion unit via the force transmission arrangement,
• a first measuring unit for monitoring rotational motion of the steering electric motor,
• a second measuring unit for monitoring rotational motion of the force transmission arrangement after the clutch,
• wherein the output signal of the first measuring unit and the output signal of the second measuring unit are monitored to detect a difference in the output signals indicating slipping of the clutch, the steering electric motor being controlled to at least reduce the difference in the output signals when the difference in the output signals exceeds a predetermined threshold, and
• wherein the reduction of the difference in the output signals of the two measuring units is realized by setting the rotation speed of the steering electric motor to be substantially the same as the rotation speed of the force transmission arrangement after the clutch.

A method for controlling a steering arrangement for turning a propulsion unit of a vessel, the steering arrangement comprising:

• a gearwheel being connected to the propulsion unit,
• at least one steering electric motor being operatively connected to the gearwheel,
• a drive for controlling the steering electric motor,
• a force transmission arrangement comprising a clutch being arranged between the gearwheel and the steering electric motor,
• a first measuring unit for monitoring rotational motion of the steering electric motor,
• a second measuring unit for monitoring rotational motion of the force transmission arrangement after the clutch,
• the method comprising:
• rotating the gearwheel and thereby also the propulsion unit via the force transmission arrangement with the at least one steering electric motor,
• monitoring the output signals of the two measuring units for detecting a difference between the two output signals indicating slipping of the clutch,
• controlling the steering electric motor to at least reduce said difference in the output signals of the two measuring units when the difference in the output signals of the two measuring units exceeds a predetermined threshold, wherein said controlling includes setting a rotation speed of the steering electric motor to be substantially the same as a rotation speed of the force transmission arrangement after the clutch when the difference in the output signals of the two measuring units exceeds the predetermined threshold.