What sound signalling equipment is typically used on an 18-meter vessel?

On an 18-meter vessel, the use of a whistle is appropriate for sound signaling. A whistle is essential for communication between vessels, especially in situations where visibility may be reduced or when maneuvering in close quarters. According to the COLREGs, vessels of this size are required to use a whistle to signal their intentions, warn other vessels, and navigate safely in various conditions.

The whistle produces a clear sound that can be heard over significant distances, making it effective for maritime communication. It is specifically designed to indicate a vessel's presence and actions, which is crucial for safety on the water.

In contrast, other sound signaling devices like a gong, bell, or horn may have specific applications on different sizes of vessels or in particular situations but do not fulfill the general requirements for sound signaling on an 18-meter vessel as effectively as a whistle does.