What should be carried regarding a horn or whistle on a Public Vessel?

• A. A horn capable of producing a 4 to 6 second blast
• B. Only a whistle
• C. Any sound device
• D. No horn required

Answer: (A)

The key idea here is that vessels must have a sound signaling device capable of producing a prolonged blast. A horn or whistle that can emit a 4 to 6 second blast provides a clear, sustained signal that other mariners can hear and recognize, which is essential for communication and safety on the water, especially in crowded or low-visibility conditions. A short or intermittent sound from a whistle isn’t guaranteed to meet standard signaling expectations, and not every sound device can reliably deliver a long, audible blast. So having a horn or whistle that can produce a 4–6 second blast ensures you can meet the regulatory requirement and effectively signal your presence or intentions. The other options either don’t guarantee a long enough signal, are too vague, or incorrectly suggest no horn is needed.