In this paper we are interested in numerical modeling of ‘dynamic’ phenomenon of squat by finite elements analysis. It proposes a set of modular numerical tools; therefore, interchangeable. This model enables the study of the interaction between a two-dimensional potential flow in highly restricted waterways on irregular shaped bottom with stationary free surface in taking into account the dynamic response of a ship. The proposed model has been used to validate a stability model based on the extension of the one-dimensional theory of Schijf to the dynamic effects by pointing out stable and unstable squat positions for a ship. It is also shown that for two cases of depth change in shallow water (‘step’), unstable position may be reached.