Digest>Archives> September 2009

Collecting Nautical Antiques

Fog Signals

By Jim Claflin


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Because of an unusual recent find we wanted to take this opportunity to talk about coastal fog signals this month. Shown is an incredibly rare pair of Leslies Tyfon or Supertyfon fog signal trumpet horns long ago discarded from Point Judith Lighthouse.

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The Tyfon and Supertyfon were early 20th century improvements to steam and compressed air fog signal apparatus. Employing a metal diaphragm vibrated by air pressure, it was more compact and efficient than its predecessors. These beautiful trumpets are made of a machined brass mounting head with a large copper bell or horn. This horn measures 19" long with a 13 ¾" bell. These two horns can be seen protruding from the fog signal building shown in this 1938 photo.

Coastal fog signals were practically unknown in this country until the middle of the nineteenth century, with the exception of a few isolated bells and guns. Probably the first fog signal device used in the United States was at Boston Light in 1719. This was a cannon which was fired to answer signals from ships in thick weather.

During this period bells were also used occasionally as fog signaling devices, but they were usually small and rung by hand. As their value, especially in inside waters and harbors became recognized, larger bells were developed. Bells were initially hand-rung. Weight-driven striking machinery was developed by the 1870s. Soon apparatus governed by clockwork was devised for ringing a regular code or characteristic. By the 1900s many bells were in use, ranging from small hand bells to those up to 4,000 lbs. in weight.

The trumpet was the next improvement. The first unit was installed experimentally in 1851. The original device consisted of a steel reed enclosed in a box to which was attached a large trumpet. The apparatus was sounded by means of compressed air produced by suitable machinery, powered by a horse. Although the sound was more penetrating than that of a bell, the expense and inconvenience of the maintenance of a horse prevented its extended use. A modification was made, using a hot-air engine as the motive power and trumpets so equipped were established at a number of stations along the coast.

Steam whistles were investigated first in 1855 and an installation of a 5 inch whistle was made at Beavertail Light Station, R.I. in 1857. This was the most powerful apparatus devised up to that time, and in point of volume and carrying power of the sound, it was considered a most efficient aid. The steam fog whistle was the same instrument ordinarily used on steamboats and locomotives. Steam fog signals were from 6 to 18 inches in diameter and operated by steam under pressure of from 50 to 100 lbs. An automatic weight or engine-driven arrangement turned on and shut off the steam by opening and closing valves at predetermined intervals.

Experiments with sirens were first made in 1867, and the first service installation was at Sandy Hook Beacon in 1868. Originally this instrument consisted of a large cast iron trumpet to the mouthpiece of which was attached a chamber containing a slotted disk or plate revolving upon a fixed disk or seat, also slotted. The revolving slotted disk and the slotted valve were both operated by a small steam engine with steam at about 70 lbs. pressure to produce the notes.

About 1900 the diaphone was developed - essentially an oscillating siren driven by an oscillating air motor. The first unit installed in the United States was at Buffalo Breakwater North End Light in 1914. It operated well on 30 lbs. of air.

Changes in equipment kept pace with the development of steam power plants and, in the twentieth century, with the developments of internal combustion engines. The developments resulted in the use of whistles, horn, siren and other more modern fog signaling devices.

By the 1950s, the types of fog signals found in use in this country included the so-called 6 inch siren, diaphone type and diaphragm horns, with a few reed horns still in service, all these units being operated by compressed air.

Today an occasional electric air oscillator type or other electric fog signal can be heard moaning through the fog. Activation of such signals is completely automated: a laser or photo beam is aimed out to sea, and if the beam reflects back to the source, the foghorn is activated. However, most fog signals have years ago been discontinued, modern navigational aids rendering these large, long-range foghorns unnecessary.

For more information on fog signals, a great source is Lost Sounds by Alan Renton. (Scotland. 2001. 209 p. Soft wraps. $24.95.) The book visits a number of lighthouses at different times over the last 130 years to reveal the philanthropic, scientific and romantic story of the fog signal - how it came about, how the machinery worked and, for the mariner and the keeper, how their lives were affected.

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This story appeared in the September 2009 edition of Lighthouse Digest Magazine. The print edition contains more stories than our internet edition, and each story generally contains more photographs - often many more - in the print edition. For subscription information about the print edition, click here.

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