When operating radar, what is essential for assessing risk of collision?

In the context of operating radar to assess the risk of collision, systematic observation and long-range scanning are crucial practices. Utilizing radar effectively allows a navigator to detect other vessels over significant distances, thereby providing valuable information about their positions, courses, and speed relative to the own vessel. This early detection is critical for making timely decisions to avoid potential collisions.

Long-range scanning enables operators to identify the presence of other ships even before they become a threat, facilitating proactive measures. Systematic observation means that the operator continually monitors radar displays for any changes in target positions and movement, ensuring that all navigational aspects are accounted for in real-time. This ongoing vigilance is essential for maintaining safety at sea, as conditions can change rapidly.

The other options do not provide an effective method for collision assessment. Relying solely on visual navigation may overlook vessels that are out of sight or not detectable due to weather conditions, while disregarding small vessels can lead to dangerous situations since they may also alter courses unexpectedly. Adhering strictly to the radar's limitations is important for accuracy but does not replace the need for continual scanning and observation to properly assess risk.