How does radar contribute to collision avoidance?

Radar significantly contributes to collision avoidance primarily by detecting and tracking other vessels and obstacles in the vicinity. This technology emits radio waves that reflect off objects, allowing it to identify their position, speed, and direction. This information is crucial for mariners as it enhances situational awareness, enabling them to make informed navigational decisions.

By utilizing radar, navigators can see beyond visual range and can detect vessels and obstacles even in adverse weather conditions such as fog or rain. The ability to continuously track moving objects helps in assessing their trajectories, thus providing the necessary data for timely and effective maneuvers to prevent collisions.

The other options, while relevant to navigation and safety in their own right, do not directly relate to the core function of radar regarding collision avoidance. Visual aids may help provide context but do not offer the real-time tracking capability that radar does. Similarly, predicting weather changes and measuring distance to harbors are important navigational tasks but are outside the primary role of radar in collision avoidance.