This paper is devoted to increasing the automation level of docking operations through the development of a mobile application for a decision support system capable of determining the optimal option for loading ballast into floating dock compartments when setting up and launching ships. The proposed decision support system and the mobile application allow implementing effective ballasting of the floating dock before docking the ship based on mathematical calculations of the impact of the ship on the floating dock and the ballasting rules. To test the developed system, the paper presents the functioning of the mobile application for a case of calculation of the docking up process of a 4,100-ton ship. In particular, the load forces of this ship are calculated with a graphical display of the distribution of the influence of 20 sections of the ship on 6 pontoons of the floating dock. As a result, this decision support system with the implemented mobile application has the characteristics of a convenient interface and is easy to operate. It can provide the dockmaster data and suggestions for decision-making, and during its operation, it is actively replenished with a database of the docked up ships.