In this paper, damaged stability of a Vietnamese wooden fishing boat is analyzed by a set of Theory in Register and by using the Autoship program. The purpose of this study is to optimize the distance between bulkheads to ensure the safety of the ship and also improve the economic efficiency. The authors use the Autoship program to simulate the 3D model of the ship and its positions in cases of its water flooded one or more compartments. In this study, we mostly use the Added Weight Method to define the position, the change of draft, the change of trim, the heeling and the change of stability of the ship.