A risk of collision exists if the compass bearing to an approaching vessel does not what?

A risk of collision exists if the compass bearing to an approaching vessel does not change appreciably. This principle is based on the understanding of navigation and vessel movement. When two vessels are approaching each other, the relative motion between them can be assessed by observing the compass bearing.

If the bearing remains constant, it indicates that the two vessels are on a collision course. Conversely, if the bearing changes appreciably, it suggests that the approaching vessel is either altering its course or speed relative to your vessel, thereby reducing the risk of collision. Therefore, noticing a significant change in the bearing is crucial for preventing an accident at sea. Understanding this concept is key for safe navigation and the effective operation of a vessel.