In which situation would risk of collision exist?

The situation where the risk of collision exists is when a vessel is on your starboard quarter, with the range decreasing and the bearing remaining constant. This indicates that the other vessel is moving toward you rather than away, and because the bearing is constant, it suggests that the two vessels are on a potential collision course. The continued decrease in range indicates that they are getting closer, heightening the risk of collision.

In collision avoidance, vessels need to be aware of their surroundings and the movements of other vessels. A constant bearing coupled with a decreasing range signifies that the other vessel is likely on a trajectory that could intersect yours unless there is an intervention, such as altering your own course or speed. Maintaining awareness of such situations is crucial for safe navigation and preventing accidents at sea.