What is the main purpose of identifying "in-sight" of another vessel?

Identifying another vessel as "in-sight" primarily serves to prevent collisions. This concept is crucial in navigation and collision avoidance, especially when vessels are operating close to one another. When a vessel is able to see another, it can effectively assess its movements and intentions, allowing for timely maneuvers to avoid potential accidents.

Understanding the positions and courses of nearby vessels enables the captain and crew to make informed decisions regarding navigation, such as adjusting speed or changing course, to maintain a safe distance. This practice aligns with the fundamental principles of safe seamanship and is a key component of the "Rules of the Road," which dictate how vessels should conduct themselves in order to avoid accidents on the water. While visibility aids in other aspects such as signaling and regulatory compliance, the primary focus when identifying a vessel as "in-sight" is the proactive prevention of collisions.