Ship lifts of first step and third step in Goupitan are the largest wire rope hoist vertical ship lifts with chamber entering water built in the world at present. This paper investigates the mechanical characteristics in the processes of chamber getting in and out water by prototype observation, and verifies some innovation designs of the ship lift. The results indicate that the ship lift runs smoothly and stably when the chamber gets in and out of water with design speed. The parameters, such as wind speed of the overflow holes, hydraulic load on the chamber, chamber stress and deformation, rolling drum torque and stress, stably change within the expected and safety range. Good results are achieved in the design of the blow holes and the wedge shape of bottom plate of the chamber. Within the design operation speed, the getting in and out of water speeds of the chamber have little impact on the mechanical characteristics of the ship lift, and there is still some room to optimize the chamber running speed.