A system for mounting a head frame to a spreader includes a sheave assembly connecting the head frame to a crane so as to permit the lowering of the head frame, mutually cooperating engagement devices for coupling the head frame and the spreader, an actuator arranged to connect mutually engageable transmission connectors on the head frame and spreader, and a registration device for registering the coupling of the head frame and the spreader. The registration device is arranged to prevent engagement of the transmission connector until the head frame and spreader are coupled.