Fog Signals: Past, Present, and Future

Before the advent of reliable fog signals, mariners navigating in poor visibility relied solely on their own bells and careful dead reckoning. The losses of life and cargo from fog-related collisions were staggering.

Early lighthouse fog signals included cannon fire, large bells struck by clockwork mechanisms, and steam-powered sirens. Each had its drawbacks — cannon powder was expensive, bells could not be heard over crashing surf, and steam sirens required constant stoking.