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 (U), 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 (R); - 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 (R) is arranged coaxially with said rudder rotation axis (U); - 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 (U), 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 (R); - 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 (R) is arranged coaxially with said rudder rotation axis (U); - 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 (U), 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. <EOS>