Back in the days when I was first learning to sail, I went out with a class to do spinnaker sets and douses... we went out in clear weather, but while we were out, a fog formed on the bay and channel opening. As we finished and headed in, the instructor suggested starting the motor and heading into the fog, I countered with sailing slow and listening... it proved to be the right choice, as we heard and then suddenly saw a power boat appear in front of us... they apparently had at least GPS (or perhaps no common sense) and were motoring somewhat fast for the harbor entrance.

Had we not heard them, we might have collided. I'd have to say we learned more than spin sets that day.

Going through the fog, the sounds of the big horn on the lighthouse and wail of the little horn on the point became very obvious at the entrance to the bay... real reminders of true sailing.