In navigation operation since centuries, the foghorn has been used as a navigational aid that helps vessels and its crew to identify potential colliding threats in exceedingly foggy weather.
These threats could be incoming vessels from the opposite direction, rocks, shallows and even indiscernible rocky formations jutting above the water.
The fog horn can be regarded as a very excellent complement to lighthouses. Considering that in really hazy weather, signalling from lighthouses could be missed, fog horns were developed which would resonate audibly rather than pinpoint visually.
Foghorn Developments: Past and Present
In the past (at least a couple of centuries ago) foghorns used to be manually operated and mounted on lighthouses. Basically, huge bells that would resonate at times of need, during misty weather conditions, a person had to periodically ring the bell to indicate the unfavourable weather. Apart from bells, even cannon guns were utilised as were whistles blown.
To overcome the aspect of manually ringing the ship horn, various innovators in the 1800s came up then contemporised versions of the air horn. The Foulis air horn developed by Robert Foulis in the mid-19th century was developed on the lines of the low tones of the piano. The Foulis air horn was the first ship sign that utilised steam power to automatically flag audible resonance to the vessels.
The Daboll trumpet named for its inventor, Caledon Leeds Daboll is yet another landmark development to the navigational aid technology. Apart from these two innovators, several other technological pioneers tried to provide a highly reliable and suitable ship sign which could last for years together.
In this context, the development of the diaphone can be regarded to be extremely valuable. A diaphone is a device that emits two sounds – one indicating the fog signal and the second indicating the end of the emitting of the horn’s sound.
The introduction of computer technological systems added another dimension to the concept of foghorns. Through a computer-operated sensory system, a laser ray is sent and if a reflection of the ray is conspicuous, then the computer is commanded to emit the required ship horn. Since the whole process is computer-controlled, there is no margin for any errors of any sort.
The requirement and need for foghorns has become quite redundant on account various technological advancements. Yet still certain vessels and boats are equipped with the fog horn so as to help them guide in case of any weather emergency. This makes come alive, a singular maritime tradition of centuries past.