How must a vessel determine the risk of collision?

A vessel must determine the risk of collision by using all available means appropriate to the conditions, which encompasses a variety of factors and tools. This includes visual observation, radar, AIS (Automatic Identification System), and sound signals, among other navigational aids and techniques. The use of multiple methods allows for a comprehensive understanding of the surrounding maritime environment, accounting for visibility, traffic density, weather conditions, and vessel maneuverability.

This approach emphasizes the importance of situational awareness and the need to assess risks dynamically. By relying solely on a single method—like radar—or ignoring other vessels, a navigator could miss critical information that may lead to a collision. Similarly, making assumptions based on partial information, such as believing signals indicate safe passage without further verification, can lead to dangerous misunderstandings. The principle of using all available means aligns with the COLREGs, which advocate for proactive measures in collision avoidance.