A rudder rotation command assembly for a floating navigation craft comprising a hull and a directional rudder rotatably mounted with respect to a structure integral with said hull about a rudder rotation axis, wherein said rudder rotation command assembly comprises: - a rotary electric motor comprising a stator and a rotor configured to rotate with respect to said stator about a rotor axis; - a supporting structure comprising a motor fixing portion configured to fix said stator to said supporting structure, and a hull fixing opposite portion adapted to fix said supporting structure with respect to said structure integral with said hull; - a rudder connecting device arranged to receive a rotary motion from said rotor and fixable to said directional rudder, so as to correlate the rotation of said rotor with respect to said stator with the rotation of said directional rudder with respect to said supporting structure, wherein: - said rotor axis is arranged coaxially with said rudder rotation axis; - said rudder rotation command assembly comprises a speed reduction gear coaxial with said rotary electric motor and with said rudder connecting device, connected to and interposed between said rotor and said rudder connecting device; characterized in that: - said rudder connecting device comprises a connecting flange connected indirectly to said rotor by means of said speed reduction gear, and a connecting body fixable to said rudder, said connecting flange and said connecting body being rotatable about the rudder rotation axis, and comprising a plug-in coupling configured to constrain/release in rotation said connecting body to/from said connecting flange, selectively, between a constrained position and a released position, - said connecting body has an engagement seat to removably engage a lever bar which can be manually actuated by an operator to manually rotate said connecting body in said released position. - a rotary electric motor comprising a stator and a rotor configured to rotate with respect to said stator about a rotor axis; - a supporting structure comprising a motor fixing portion configured to fix said stator to said supporting structure, and a hull fixing opposite portion adapted to fix said supporting structure with respect to said structure integral with said hull; - a rudder connecting device arranged to receive a rotary motion from said rotor and fixable to said directional rudder, so as to correlate the rotation of said rotor with respect to said stator with the rotation of said directional rudder with respect to said supporting structure, wherein: - said rotor axis is arranged coaxially with said rudder rotation axis; - said rudder rotation command assembly comprises a speed reduction gear coaxial with said rotary electric motor and with said rudder connecting device, connected to and interposed between said rotor and said rudder connecting device; - said rudder connecting device comprises a connecting flange connected indirectly to said rotor by means of said speed reduction gear, and a connecting body fixable to said rudder, said connecting flange and said connecting body being rotatable about the rudder rotation axis, and comprising a plug-in coupling configured to constrain/release in rotation said connecting body to/from said connecting flange, selectively, between a constrained position and a released position, - said connecting body has an engagement seat to removably engage a lever bar which can be manually actuated by an operator to manually rotate said connecting body in said released position.