The History of Fog Signals by Wayne Wheeler
Beeeohhhhh, the mournful sound of the fog signal hooting and echoing across a bay shrouded in gray. It seems as though that sound must have always been part of the bayscape. But, in fact, fog (correctly termed, sound) signals are relative newcomers to the field of navigational aids, and the most popular of them, the diaphone and diaphragms, are of the 20th century.
Since the mighty Pharos of Alexandria, Egypt (circa 280 B.C.) mariners have had, after a fashion, a light to guide them into port or clear of dangerous reefs. Although the light signal from the lighthouse tower left much to be desired until the 18th century, there was some sort of light to guide the seafarer. But light, no matter how powerful, cannot penetrate fog and other conditions of reduced visibility.
Fog Bells by Thomas Tag
What do church steeples and fog signals have in common? Well in many cases, a strange “Rube Goldberg” looking machine filled with gears, cables, fan-blades and a giant sledge hammer. We are talking about the tower clockwork in the case of a church and a fog-bell striker in the case of a fog signal.
Many types of fog signals were invented, including cannons, bells, whistles, sirens, steam trumpets, reed horns, etc. This story will concentrate on the uses of bells and bell strikers as aids to navigation.