Which indication may suggest that a risk of collision exists?

The indication that a risk of collision exists is illustrated effectively by an approaching vessel with no change in bearing. When a vessel is on a constant bearing towards another vessel, it indicates that the two vessels are on a collision course. This situation signifies that the angle of approach is not changing, which effectively means one vessel is approaching the other, leading to an increased risk of collision if no evasive action is taken.

In contrast, if a vessel is stationary, it does not pose an immediate risk of collision on its own, as there is no movement involved. Meanwhile, a vessel that is far off in the distance may not present a collision risk either, especially if it is moving away or at a safe distance. An appreciating change in compass bearing implies that the two vessels are altering their positions relative to each other in a way that may prevent a collision, as they are not maintaining a constant course toward one another. Overall, the key factor in assessing collision risk lies in the movement and relative position of vessels, where a constant bearing signifies an imminent approach that demands attention and action.