Which signal does a power-driven vessel sound when making way in fog?

• A. One prolonged blast every two minutes
• B. One prolonged blast every minute
• C. Two prolonged blasts every two minutes
• D. Three short blasts every minute

Answer: (A)

In fog, a power-driven vessel that is moving (making way) signals with a single prolonged blast at intervals not exceeding two minutes. This tells other vessels that you are underway and progressing, so they can anticipate your movements and adjust course if needed. The cadence is deliberately simple and relatively infrequent to ensure the sound carries clearly through limited visibility.

The other patterns don’t match this situation: a more frequent signal would imply a different status; two prolonged blasts indicate another category of vessel, and three short blasts is not the prescribed signal for a power-driven vessel making way in fog.