This is my first job with the finished boat trailer dolley. Owner pulling his boat down the highway when a car shot our from a side street and hit the boat trailer in front of the axle assembly on the right side knocking the axles loose and shiftin the boat on the trailer. Tip of tongue to lower unit of motor was 36"7". The dolley is hooked to the trailer coupler with the axle setting back up under the boat and trailer. The frame of the trailer sets on a sliding tiedown on each side. A chain is ran from the tiedown on one side over the trailer frame to a tiedown on the other side and secured with a rachet binder. A come-a-long is attached to each side of the dolley and over to the opposite side of the trailer. These are used to center the axle for straight pulling. On a side impact the trailer will be bowed and the dolley will have to set further to one side than the other to make it pull straight. As the pictures show, the axle had to be approx 6" further to the left of center. Fork the rear cross member of the trailer, secure and its ready to tow. Works great!