Flagstaff Hill Maritime Museum and Village
Instrument - Foghorn, Late 19th century
... English Rotary Norwegian Pattern nautical foghorn within... Northey None English Rotary Norwegian Pattern nautical foghorn ...
A foghorn is a device that uses sound to warn of navigational hazards like rocky coastlines, or boats of the presence of other vessels, in foggy conditions. The term is most often used with marine transport. When visual navigation aids such as lighthouses are obscured, foghorns provide an audible warning of rocky outcrops, shoals, headlands, or other dangers to shipping. An early form of fog signal was to use a bell, gong, explosive signal or firing a cannon to alert shipping. From the early 20th century an improved device called the diaphone was used in place of these other devices, The diaphone horn was based directly on the organ stop of the same name invented by Robert Hope-Jones, creator of the Wurlitzer organ. Hope-Jones' design was based on a piston that was closed only at its bottom end and had slots, perpendicular to its axis, cut through its sides, the slotted piston moved within a similarly slotted cylinder. Outside of the cylinder was a reservoir of high-pressure air. Initially, this air would be admitted behind the piston, pushing it forward. When the slots of the piston aligned with those of the cylinder, air passed into the piston, making a sound and pushing the piston back to its starting position, whence the cycle would be repeated.
This method of producing a low audible sound was further developed as a fog signal by John Northey of Toronto and these diaphones were powered by compressed air produced by an electric motor or other mechanical means that admitted extremely powerful low-frequency notes. The example in the Flagstaff collection is an early cased and portable diaphone used on pleasure or sailing craft. By manually turning the crank handle air is produced and fed into valves that direct air across vibrating metal reeds to produce the required sound. in foggy weather, fog horns are used to pinpoint a vessels position and to indicate how the vessel is sailing in foggy conditions. One blast, when sailing on starboard tack and two blasts, when sailing on a port tack and three dots, when with wind is behind the vessel.
Since the automation of lighthouses became common in the 1960s and 1970s, most older foghorn marine installations have been removed to avoid the need to run the complex machinery associated with them, and have been replaced with an electrically powered diaphragm or compressed air horns. The example in the collection is significant as it was used in the early 19th century for sailing vessels was important but these portable crank fog horns have also been superseded by modern electric varieties. Therefore the item has a historical connection with sailing and maritime pursuits from our past.English Rotary Norwegian Pattern nautical foghorn within a boxed pine varnished case with exposed corner dovetailing, original leather carrying strap, brass side crank, and original copper trumped horn. Card accessory with Directions for Use in both English and French.Noneflagstaff hill, warrnambool, shipwrecked coast, flagstaff hill maritime museum, maritime museum, shipwreck coast, flagstaff hill maritime village, great ocean road, foghorn, maritime technology, maritime communication, marine warning signal, portable foghorn, bellows foghorn, crank handle, robert hope-jones, john northey
Flagstaff Hill Maritime Museum and Village
Flagstaff Hill Maritime Museum and Village