The correct analysis and assessment of navigational situation, taking into account the existing Collision Regulations, provides a basis for making the right decisions on a seagoing vessel. Such basis is important for ensuring the safety of navigation in different, often complex, situations. The interpretation of the relevant rules is therefore of key importance. They contain generalizations arising from a multitude of possible scenarios at sea. The consequence of this is imprecision hindering interpretation of the rules. This is of particular concern in the implementation of those rules in navigational information systems and decision support systems. This paper provides a preliminary analysis, based on practical examples, of the applicability of fuzzy logic as a tool for the algorithm-based interpretation of International Regulations for Prevention of Collisions at Sea (COLREGs). The COLREGs general concept shall be presented with an indication of the imprecision of rules in selected areas. For this purpose, the current methods of legal interpretation shall be presented and applied. This will allow to classify the COLREGs into two groups: crisp and imprecise. The real collision case shall be presented and discussed. The conducted preliminary considerations will help determine initially whether the incorporation of the principles of fuzzy logic in the law may facilitate interpretation of legal provisions by setting acceptable boundaries of such interpretation, and thus also the implementation of provisions in the navigational decision support systems
