THE KNOCK-OUT BLOW TO THE U-BOATS

Dominion, Volume 12, Issue 281, 23 August 1919, Page 7

THE KNOCK-OUT BLOW TO THE U-BOATS

STORY OF A WAR-TIME SECRET THE SUBMARINE DETECTOR . iN'aval experts slate with conviction that if tho conflict had continued through another summer, tho mibmarino would literally havo been driven from tho ocean.' The "Journal of Elt&tricity" (San Francisco, .Tune 1) describes tho operation of the wonderful electric, "list- . piling device" which was perhaps tho most important of- America's efforts toward the- termination of the submarine menace. This device, kept secret, ot course, during the. war, was tho composite work of-several largo electrical const.ructing'firnis, assisted'and advised bv many eminent: scientists, engineers, . and research men, under the auspices of the National Research Council. From . these sources grew finally the American ; submarine detector—a development of the . old principles of sound-wave transmission in water in an altogether new ana ' 'startlinK manner. • pch'eme at Work. ] "The apparatus 'was first designed to 1 liauc overhead from naval, craft, amid- 1 ship below the- water-line, and it depended for its direction-getting qualities on the peculiar and heretofore little un- ' derstood faculty of the human ear to de- . tect the. direction of sound by the'shifting of that sound from one ear to the other. To overconio the obstacle of interference of' sounds made by the listening.ship's own motors another device was j developed which could be trailed off" tho stern a hundred or so feet away, where i the' engine noises of the ship wero out I of range, and the sound .was' then brought i in to tho operator in the ship's hold. A 1 third adaptation of the listening prin- ] ciplo was.an instrument which protrud- f cd through'the hull and was a station- i ary part of the vessel's equipment. < While demonstrating the device to the British Admiralty the engineers were | asked to study the question of fitting submarine detection units to aeroplanes, | balloons, and dirigibles. After some experimentation, followed by more practi- ■ cal tests, and conferences with the Lanca- , shire group of scientists at. Harwich, apparatus was developed which met, these needs,'- and many aircraft were equipped 1 with sound-detectors which rendered it i possible for them to follow the course of e the enemy'after they had 6een her submerge. a valuable -faculty .whiclr such I oraft did not possess until the introduo- •' tfc-ii of the American detector. <

"Whon the devices had proved -themselves eminently satisfactory after _ exhaustive experimentation here, the Navy Department organised a special service party-lindcr. Captain R. H. Leigh, of the Ibireau of-Steam Engineering,;to demonstrate tho detectors to the British Admiralty. Shortly after the arrival of this party abroad, the American submarine detectors- were universally adopted by all the Allied navies. ( "Under ideal conditions, with extraneous 'noises reduced to a minimum or entirely eliminated, the device was effective at a rauge of fifteen to twenty-five miles, and iiuder average circumstances at (v- range of between three and eight miles. Trained operators could clearly distinguish between the sounds made by approaching surface craft and underwater vessels (submarines). Within five miles the engino characteristics of different vessels were clearly marked, even to tho point of identifying by name certain unseen vessels after they had been observed previously for more than one time. The direction of sound could usually be computed within a very few degrees of its actual location, ami a good, judgment of the distance could generally be made. If. was found practical to tell when a submarine changed from her oil engines .