What sound signal is used by a vessel restricted in maneuverability?

A vessel restricted in maneuverability is signaled to other vessels using one long blast followed by two short blasts. This sound signal is important for ensuring safe navigation by clearly communicating the vessel's limitations due to its operational constraints, which may include issues like being anchored or engaged in underwater work.

The sound signal helps to alert nearby vessels to take proper precautions while navigating in close proximity, allowing them to maintain a safe distance or adjust their course if necessary. This type of communication is essential for avoiding collisions and ensuring overall maritime safety.

In the context of COLREGs, sound signals are vital for vessel communication, particularly in conditions of reduced visibility or busy waters where visual signals may not be as effective. Each specified sound signal carries specific meaning, and using the appropriate signal helps to maintain safety on the waterways.