in this manner the opening 172 accommodates for more minute deviations in the alignment between the lock box groove 164 and the capture bar in other words the opening 172 allows the capture bar 174 to move forward or backward proximal to distal within a predefined range to precisely align with and be received by a corresponding groove 164 of the lock box 162 in order to reposition the tail hook assembly 160 between an engaged position and a disengaged position where the capture bar 174 is not received by at least one of the grooves 164 of the lock box 162 a hydraulic cylinder 176 is concurrently mounted to the tail hook assembly 160 and the frame 102 corresponding hydraulic lines are run along at least one of the frame rails 120 122 and along the gooseneck 130 to terminate in hydraulic connectors proximate the forward end of the gooseneck these hydraulic connectors are adapted to engage corresponding hydraulic connectors of a tow vehicle or an on board pump 178 powered electrically from an on board power supply 179 e g a generator a battery etc or an electric cable from the tow vehicle to provide a hydraulic source of power to the hydraulic cylinder 176 in order to selectively reposition the tail hook assembly 160 between an engaged position and a disengaged position the tail hook assembly is repositioned from the disengaged position to the engaged position when the device is repositioned underneath a.