In a narrow channel, a signal of intent which must be answered by the other vessel is sounded by a vessel __________.

In the context of navigating through narrow channels, vessels have specific rules to ensure safe passage. When a vessel is overtaking another vessel in a narrow channel, it is required to sound a signal of intent to inform the other vessel of its maneuver. This is crucial for maintaining safety and avoiding collisions in confined spaces where visibility and maneuverability can be limited.

The signal is a way of communicating the vessel's intent to pass, and the other vessel must respond to this signal, indicating recognition and understanding of the action about to occur. This communication is essential to allow the vessel being overtaken to take appropriate actions, such as adjusting its speed or course.

In contrast, vessels passing ahead or at anchor do not have the same signaling requirements as overtaking vessels. The vessel being overtaken also has specific rules regarding its response, but it is the overtaking vessel that initiates the signal of intent. Therefore, understanding the implications of these maneuvers in narrow channels is vital for navigational safety and compliance with the Rules of the Road.