Lightships and Lighthouses

by Frederick Arthur Ambrose Talbot

CHAPTER XXII
FLOATING LIGHTHOUSES

Hand in hand with the development of the unattended light for service on land positions has proceeded the adaptation of the floating light. This may be described briefly as an enlarged edition of the lighted buoy, which is such a conspicuous feature of our harbours and estuaries. Yet it is more than a buoy. It can fulfil all the purposes of a light-vessel, both as regards the emission of a ray of light or a distinctive sound, so that both audible and visual warning are given simultaneously. These lights likewise are automatic in their action, and, when set going, require no further attention for some time. Nine months or more are often permitted to pass without human hands touching them, and they have solved some very abstruse problems in connection with coast lighting.

For instance, there is probably no such lonely stretch of coastline as that of British Columbia and Alaska. There is only one large port north of Vancouver—Prince Rupert—and this rising hive of maritime activity is 550 miles distant. The coast is as wild as that of Norway, which, indeed, it resembles very closely, bristling as it does with fjords and islands, with rugged cliffs rising abruptly from the water to a height of several hundred feet. Navigation at night is extremely hazardous, as the path leads by devious ways through deep channels intersecting the outer barriers of islands, where fogs hang low and thickly. The captain has to pick his way carefully, determining his course by timing the period between the blast of his siren and its echo, as it is thrown from headland to headland. As the passenger traffic developed, the masters of the vessels entrusted with so many human lives felt the increased responsibility keenly, and agitated for more adequate protection. The erection of lighthouses, even of the most economical type, would have entailed huge expenditure by both the United States and Canadian Governments, while the question of maintenance would have bristled with searching problems.

Accordingly, it was decided to adopt the floating automatic system, which had proved eminently satisfactory in other parts of the world. In this manner a highly successful and inexpensive solution of the difficulty was found. These buoys have been installed at all the most treacherous points leading to sounds and canals, as the lochs are called, and have been found in every way equal to the simplest type of attended lighthouse. The southern coast of Nova Scotia has been protected in a similar manner, a chain of automatic lights, spaced ten miles apart, having been completed, so that this wild, rugged shore is patrolled very efficiently at the present moment. Other countries have not been dilatory in adopting the same methods. Consequently, to-day the automatic floating lighthouse is one of the handiest, most efficient and reliable devices for assisting navigation that the lighthouse engineer has at his command.

The lights assume different forms, this factor being influenced by position, specific duty, and local conditions. Similarly, the character of the illuminant employed also varies, acetylene, compressed oil-gas, petroleum, and electricity, being utilized, according to circumstances. On the whole, however, acetylene gas appears to be the most favoured illuminating medium, inasmuch as the preparation of the carbide of calcium has undergone such marked improvement.

When Mr. Thomas L. Willson discovered the cheap process for the manufacture of carbide of calcium upon a commercial scale, and the new industry became placed upon a firm footing, it was only natural that the inventor should realize the possibilities of applying the new illuminant to the assistance of navigation. Acetylene gas gives a brilliant clear light of intense whiteness, which is capable of penetrating a great distance. Accordingly, he set to work to devise a buoy lighted by this gas, and able to carry sufficient storage of calcium carbide to burn for weeks or months without attention. When he had completed the first apparatus of this character, he handed it over to the Marine Department of the Canadian Government for submission to any test that they might consider expedient, in order to ascertain the limits of its application. The buoy was set in position and watched carefully. Periodically it was examined to ascertain whether overhauling and cleaning were necessary, as well as the behaviour of the light under all conditions of weather. Captains of vessels passing the beacon were requested to pronounce their opinions upon the quality of the light, and their remarks concerning its range, facility with which it might be picked up, reliability, and so forth, were carefully marshalled and digested by the authorities. Precisely what the officials thought of the invention is reflected most convincingly by the fact that to-day over 300 lights working upon this principle are stationed in Canadian waters, both upon the storm-bound ocean coasts and upon the wind-swept shores of the Great Lakes and waterways.

Fig. 16.—Sectional Elevation of the Willson Automatic Floating Light. (See [next page].)

The Willson buoys are absolutely automatic in their operation. All the impurities in the gas are removed by passing it through a special purifier, so that the burner cannot become clogged or the light impoverished. A charge of 1,300 to 1,500 pounds of carbide is carried within the apparatus, and the gas is generated under low pressure. The lantern is fitted with a Fresnel lens, so that the light is condensed into an intensely powerful and penetrating horizontal beam. One prominent feature is that the candle-power of acetylene gas is seven times as high as that of compressed oil-gas, while the reservoir of a given size will contain this equivalent of more light. The candle-power of these floating lights obviously varies, the largest size being capable of emitting a beam of 1,000 candle-power, this flame being the maximum that the lens will stand without breaking.