One of the most significant phases for automation of communication processes in shipping is building a knowl- edge base for inference processes. Communication processes include: exchange of information, perception of communication and interaction between navigators. Computing with words has been used to represent infer- ence processes covering imprecise concepts that are characteristic of natural languages. Elements of classical predicate calculus were adopted as a basic form of writing inference rules. Methods for constructing a knowl- edge base were chosen. The knowledge base architecture was proposed. This article also presents examples of inference rules in a knowledge base for automatic communication in shipping.