With the increase of dock width, gantry and semi gantry cranes have developed in parallel, and commonly use pitch boom and horizontal amplitude system for gantry single arm 50t cranes. The development of gantry cranes in ports has made it easier for multiple cranes to work in parallel on the same ship. The commonly used gantry crane is a revolving gantry crane with a rotating part connected to the column body, or a rolling bearing type supporting and rotating device with a large bearing connected to the door seat to reduce the tail diameter of the rotating part. The gantry structure has also been adopted to reduce the coverage surface of the dock (the projection of the main body of the gantry on the ground). In the process of development, gantry cranes have gradually been promoted and applied to shipyards and hydropower construction sites with operating conditions similar to ports.