INTERNATIONAL ONLY. In a foggy situation, the signal of one prolonged blast followed by two short blasts could indicate a vessel

• A. Not under command
• B. A vessel making way
• C. A vessel at anchor
• D. A vessel in distress

Answer: (A)

In foggy conditions, ships use specific sound signals to convey their status so others can take appropriate action. One prolonged blast followed by two short blasts is the international signal for a vessel that cannot maneuver—not under command. That means the vessel is unable to comply with the collision avoidance rules due to an exceptional constraint (like engine or steering failure) and must rely on other ships to take early, significant action to avoid it. The other statuses—being underway and able to maneuver, being at anchor, or being in distress—have different sound patterns, so this particular signal clearly points to a vessel not under command.