What must two power-driven vessels do when they are on reciprocal courses and risk of collision exists?

When two power-driven vessels are on reciprocal courses and there is a risk of collision, they must change course to starboard. This is consistent with the International Regulations for Preventing Collisions at Sea (COLREGs), specifically Rule 14. The rule states that when two vessels are approaching each other on nearly reciprocal courses, each shall alter their course to starboard. This maneuver ensures that both vessels pass on the port side of each other, reducing the risk of collision.

In this situation, simply signaling or reducing speed does not address the underlying issue of collision risk. Maintaining their courses would continue to endanger both vessels, as they would remain on a collision course. Changing course to starboard is a proactive measure that directly addresses the navigation principles needed to avoid collision in this scenario.