Arrangement and method for turning a propulsion unit

A propeller drive arrangement for moving and steering a vessel traveling in water, which arrangement comprises:

• an azimuthing propulsion unit (6), which comprises a pod (1) positionable outside said vessel below sea level, a first electric motor (2) positioned inside said pod, for rotating a propeller (5) connected to said pod, and a shaft means (8) connected to said pod for supporting said pod in a rotatable manner from a hull of said vessel (9),
• operating means for turning said azimuthing propulsion unit (6) in relation to said hull of said vessel (9) for steering said vessel in accordance with a steering command originating from a vessel's steering control device (38),
• characterized in that said operating means comprises a second electric motor (20) for turning said azimuthing propulsion unit (6) via a mechanical power transmission equipment (40) connected to said second electric motor, the arrangement further comprising
• a power supply unit (30) for supplying electric power to said second electric motor (20),
• a control unit (34) for controlling the operation of said second electric motor by controlling said power supply unit (30),
• a sensor means (16) functionally connected (18) to said control unit (34) for detecting the rotational position of said azimuthing propulsion unit (6),
• said control unit (34) being, arranged for processing both a steering command information originating from said steering control device (38) and rotational position information originating from said sensor means (16) and to control the operation of the second electric motor (2) on the basis of said processing.