Fog Horn

As a ship navigates through the foggy waters of coast, a foghorn is sounded to warn them of the rocks and coral reefs. The wind blows the fog right in front of the ships path. A foghorn or fog signal or fog bell is a device that uses sound to warn vehicles of hazards or boats of the presence of other vehicles in foggy conditions. The term is most often used in relation to marine transport. When visual navigation aids such as lighthouses are obscured, foghorns provide an audible warning of rocks, shoals, headlands, or other dangers to shipping.