BOTH INTERNATIONAL & INLAND What does the continuous sounding of a fog whistle by a vessel indicate?

Correct Answer: Option C — A vessel is in distress

Annex IV, paragraph 1(l) defines the continuous sounding of any fog-signaling apparatus as a distress signal. This is a clear, unambiguous indication that a vessel is in serious trouble and requires immediate aid, distinguishing it from standard navigational signals used for routine operations or position keeping in fog.