What action must a vessel intending to overtake another vessel take?

A vessel intending to overtake another vessel must sound a signal to indicate its intention. This action is important as it serves to communicate with the vessel being overtaken, ensuring awareness and promoting safety on the water. According to the International Regulations for Preventing Collisions at Sea (COLREGs), when a vessel approaches another from behind, it is not only courteous but also a necessary procedural step to provide notice of the maneuver. This practice helps prevent misunderstandings, allowing the overtaken vessel to maintain its course or take appropriate actions.

The other responses do not align with the protocols established to ensure safe navigation and good seamanship. Passing without warning can lead to confusion and potential collisions, while overtake only if the other vessel is not maneuvering overlooks the fact that maneuvers may be necessary during the overtaking process. Lastly, changing course to starboard before overtaking may not always be appropriate, as the maneuver depends on the specific situation and the positions of the vessels involved.