In heavy fog, when you hear the fog signal of a vessel ahead, what action should you take?

• A. Stop immediately
• B. Hold course and speed
• C. Slow to bare steerageway and navigate with caution
• D. Increase speed to pass quickly

Answer: (C)

In heavy fog, hearing the fog signal from a vessel ahead means you must take proactive action to reduce the risk of collision. The best course is to slow down to bare steerageway and proceed with caution. By reducing speed to the minimum at which you still have control, you improve your ability to observe the other vessel, assess its course and speed, and maneuver if necessary. This aligns with the rules requiring a safe speed and early, prudent action to avoid collisions in reduced visibility. Stopping immediately can create new hazards or be impractical; maintaining speed does not reduce risk, and speeding up to pass quickly in fog increases the chance of a collision. Stay alert, use all available navigation aids, and be prepared to alter course or stop if the situation changes.