DP Systems for Track Control of Dredging Vessels

The problems of implementing special control functionality for trailing suction dredgers in dynamic positioning (DP) systems are considered, focusing mainly on the dredging track control modes. The motion controller is proposed which provides the trajectory steering with the draghead under restrictions, imposed by the dredging process and equipment (sufficiently large velocities, drift angle limitations etc.) Algorithms of drag head position measurements and drag pulling force estimation are discussed. The results of sea trials of a DP system operating on real large hopper trailing suction dredger are presented.