This article constructs two robust controllers using sliding mode control (SMC) techniques. The ship-crane system is operated in the complicated condition in which the disturbances due to viscoelasticity of seawater and the flexibility of handling cable are fully taken into account. With two actuators composed of trolley-moving force and container-hoisting torque, the controllers 

We construct two controllers for floating container cranes based on the combination of feedback linearization, sliding mode, and proportional-derivative controls. The disturbances composed of viscoelasticity of sea water, elasticity of suspended wire rope, and sea-excited motions of ship are fully considered. The controllers simultaneously conduct four duties: tracking the trolley to reference, lifting the container to desired cable length, reducing the axial container oscillation and container swing.