This article focuses on fuzzy set theory as intelligent tools for navigator's decision-making to improve the safety of marine vessels in collision situations. A lot of progress has been made, especially in the field of artificial intelligence. The paper goal is to develop a decision support system based on artificial intelligence to determine a ship's trajectory in a collision situation. In this present work ship trajectory optimization in collision situations is presented as multistage decision-making in a fuzzy environment. The navigator's subjective assessment in making a decision are taken under consideration in the process model and it shows the modified membership function of constraints.