What size vessel is required to carry a whistle or horn?

The requirement for carrying a whistle or horn depends on the size of the vessel and the regulatory jurisdiction. Generally, vessels 12 meters (39.4 feet) or longer are required to carry a whistle or horn for signaling purposes. However, smaller vessels may also need to have sound-signaling devices depending on local regulations or specific circumstances, such as operating in busy waterways. It's essential for operators to familiarize themselves with the regulations applicable to their specific area and vessel size.