Marine battery driven motor

A motor device for providing propulsion of a floating vessel comprising:

• an electrical motor,
• a propeller arranged inside a propeller house,
• a hollow rotatable or non-rotatable mid-section arm, and
• a battery and controlling unit,
• wherein the rotatable or non-rotatable mid-section arm comprises:
• a peripheral end coupled to the propeller house and a near end coupled to the battery and controlling unit,
• a controlling logic for motor control is provided and arranged inside the rotatable or non-rotatable mid-section arm and electrically connected to the battery and controlling unit on one side and to the motor device on the other side,
• wherein the controlling logic further comprises a heat conductive substrate, which is arranged to contact the inner surface of the rotatable or non-rotatable mid-section arm in a portion of the inner circumference of the rotatable or non-rotatable mid-section arm, and
• wherein the controlling logic and a heat conductive substrate are mounted inside the rotatable or non-rotatable mid-section arm in a portion which will be below the water surface when the motor is in an operative mode propelling the floating vessel in order to use ambient water outside the said portion of the rotatable or non-rotatable mid-section arm as a heat sink for the heat generated in the controlling logic.