Abstract
The paper introduces a visualization method that enables the navigator to estimate an encounter situation and choose collision avoidance manoeuvre, if necessary. It is based on the Collision Threat Parameters Area method and offers new features: fuzzy sectors of forbidden speed and course values, the possibility to use any given ship domain and a new formula of collision risk assessment. All these elements result in a method, which enables the navigator to differentiate between varying levels of risk and to point out the direct threats. The method is fast enough to be applied in the real-time decision support system.