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

The use of a whistle as the sound signaling equipment on an 18-meter vessel is appropriate due to its effectiveness in marine communication and the requirements set forth by the international regulations. Whistles produce a clear sound that can travel significant distances over water, making them ideal for signaling in various conditions, especially in foggy or low-visibility situations.

According to the COLREGs, vessels that are less than 12 meters in length are generally required to carry a sound signaling device such as a bell or a whistle. Vessels between 12 and 20 meters, which include 18-meter vessels, are required to have a whistle, ensuring they have an adequate means to signal their presence to other vessels.

The whistle's effectiveness relies on its ability to produce distinct sound signals that can be universally understood by mariners, thereby enhancing safety and communication at sea. Understanding these regulations helps ensure compliance and maintain safe navigation practices.