What action should you take when operating a boat if you hear the fog signal but cant see the other boat?

If you hear a fog signal from another boat but cannot see it, you should reduce your speed and maintain a proper lookout. Use radar and other navigation aids to help determine the other vessel's position. Be prepared to take evasive action if necessary, and sound your own fog signal to alert others to your presence. Always stay vigilant and ready to respond to any potential hazards.