EDISON AND THE WAR

Evening Star, Issue 20959, 25 November 1931, Page 12

EDISON AND THE WAR

COMBATTING THE " U " BOATS The part played by the late Mr T. A. Edison in combatting the submarine menace during the Great War is not generally known. It was explained some years ago by a writer in an American journal. When submarine activity began to play havoc with shipping, the problem of detecting the location of submarines by sound was considered one of the foremost problems of the day. Mr Edison gave this problem a large part of his attention, and in 1917 had reached a fair degree of success in detecting sounds of torpedoes as far as s,oooyds distant. . Mr Edison became convinced that if ho could instal on a ship a deyico that should be arranged so that it would always be from 10ft to 20ft ahead of the bow of the vessel, and if_ this device should carry a vibrating diaphragm, it would not have to contend with the noises of the ship itself. The device succeeded, and boats moving nearly a mile away could be readily heard while the vessel was going full speed. A submarine bell five and a-half miles away could also be heard by the operator whiles big storm was in progress. With this device there would be no difficulty whatever in hearing a torpedo more than 4,oooyds away, and this is far beyond the effective distance at which a torpedo can be launched from a submarine.

It was also decided by Mr Edison to provide cargo boats with a means of turning the ship very quickly to a right-angle course on hearing the launching of a torpedo by his listening devh . His plan included the use of four sea anchors each about Oft in diameter at the mouth, and each attached to a 4iu rope. The plan was to fasten the ends or these ropes securely in the bow of the ship and to have the sea anchors placed at the end of the ropes midway of the ship. [f the observer at the listening device reported a torpedo launched by a submarine at a distance, the signal was given and the four sea anchors were to bo immediately released and thrown overboard, and the helm thrown hard over, bringing the ship almost to a standstill, rapidly turning her at right angles to her original course. In a test a loaded vessel 325 ft in length was turned 90deg from her course in 2min XOsec with an advance of only 200 ft. One of the problems placed before Mr Edison was to provide a searchlight to be used under water by submarines. After making a great number of experiments he found that the green line of barium in the arc (light) penetrated sa. water farther than any other he had observed. His last experiments were with a 60ft tube filled with sea water, at the end of which sufficient light was transmitted to read print. Dux-ing the height of enemy submarine activity, Mr Edison also devised a typo of projectile which would enter the water direct without ricochet, and would continue its course without deflection and making a penetrative hit. A simple light device for use by look-out men in watching for periscopes in bright sunlight was suggested by Mr Edison. It consisted of a tapering metallic box, open at both ends, fitted with a light-excluding eyepiece, and having diaphragms placed at intervals along its inside length. _ The device was painted a dead black inside and out, and its construction was very cheap. With it objects could be discerned in the full light of day that were otherwise invisible.