What signal indicates disagreement to being overtaken in a narrow channel?

The signal indicating disagreement to being overtaken in a narrow channel is five or more short rapid blasts. This sound signal is used by vessels to communicate their intentions and concerns, particularly in situations where navigating space is limited, such as narrow channels.

When a vessel feels it is unsafe to be overtaken due to the potential risks involved, it conveys its disagreement using this specific sound signal. The urgency and frequency of the five or more short blasts effectively convey the message that the vessel does not consent to being overtaken at that time.

Understanding this signal is crucial for ensuring safe navigation among vessels when navigating tight spaces, as it allows for effective communication and helps to prevent collisions. The other signals do not convey the same meaning in this context; for example, one prolonged blast generally indicates the intention to pass or maneuver, which contrasts with the intent expressed by five or more short blasts.