Which signal indicates a vessel anchored in fog?

• A. One short blast, a prolonged blast, and a short blast
• B. One prolonged blast and two short blasts
• C. One short blast
• D. Two short blasts followed by a long blast

Answer: (A)

In fog, sound signals tell nearby vessels what your vessel is doing so they can steer clear. An anchored vessel uses a pattern that clearly marks that status to others.

The sequence of a short blast, a prolonged blast, and a short blast is designed to stand out in reduced visibility and communicate “I am anchored here.” The first short blast grabs attention, the middle prolonged blast signals that the vessel is not underway (anchored), and the final short blast reinforces the message, helping nearby vessels recognize the situation even if visibility is poor. This combination is distinct from signals used for vessels that are moving or have other maneuvering restrictions, making it the best cue that the vessel is anchored in fog.