The inventive arrangement of motorized floating mobile systems (7; 107; 207) for moving mooring booms (4A to 4E) for boats B in inner harbors (P), to translationally move the booms (4A to 4E) perpendicular thereto, to provide maneuvering space for the boats (B), is arranged between at least two adjacent booms (4; 4A to 4E), whereas the other spaces between booms are closed for maneuvering. Each system comprises: means for positioning the booms transverse to the translation direction; means (9, 10) disposed on the two ends of each system for attaching the front portion of adjacent systems together or to an attaching means arranged on the end of a pier or a fixed boom; means for translationally guiding parallel to a pier or a main pontoon, with respect to a fixed point of a pile or dolphin (8); and means for translationally moving the booms in a synchronous manner.