An overview of the NavSim application on ship manoeuvring research as well as in commecial projects is presented in the paper. It describes the principes adopted in the development of the numerical manoeuvring s8imulation model. The standard Graphical User Interface Tools provide and efficient mean to control a ship the way it can be controlled from the bridge. The manoeuvring scenario includes simulation of the environmental loads and allows using topographical data that are read from the electronic chart. The mathematical model built in Simulink is briefly discussed to complete the definition of NavSim. | 