OVERCOMING FOG

Gisborne Times, Volume XXV, Issue 2028, 13 March 1907, Page 4

OVERCOMING FOG

A most important invention to safeguard mariners is finding its way to favor. This is tho method ol subninriuo signalling patented by an American, by which the sound ol a boll on a buoy near the shore, or on a vessel, aro communicated to an approaching vessel. Suppose a vessel fitted with the apparatus is approaching a const where there is a patent buoy,'in a fog. The apparatus oil tho vessel consists of a microphone in a tank of special solution, attached to tlio inside of tho ship below the wator-line. A wiro extends from the micropliono to the wheel-house, and ends in a telephone receiver. There arc two sots of apparatus, ono on each side of tho vessel, and tho navi-gator-tells by tho indicator from which sot the sound is coming. As tho ship approaches the buoy tho notes of tho boll aro transmitted through tlie sea to tho microphones, and tho navigator, listening above, can tell by the difference in the volume of sound from tho instruments whotlior the danger is on the port or tho starboard side. If the sound from the instruments is the same, tho danger is straight ahead. A boll rung in a tank of water in the lorepeak of a ship will transmit notes to the ships in the neighborhood. The notes of a submerged bell have been detected sixteen miles away. The Admiralty experimented with the invention last year with most satisfactory results. It was clearly demonstrated that at a distance of five miles tho submarine boll could bo heard, and its distance located with certainty. This is a distance beyond the certain range of any aerial sound signals in uso by liglit-vcssels in fog. Tho officers who conducted the trials reported that if liglit-vcssols round the coast were fitted witli submarine bells, it would bo possible for ships fitted with receiving apparatus to navigate in fog with almost as great certainty as in clear weather. “The fog signals at present in uso in lightships in Great Britain,” tlioy say, “cannot bo depended on to bo heard in all conditions, oven at ono or two miles distance; and a vessel failing to make the fog signal may bo in a safe course, and in her estimated position, yet sho must stop, or anchor, or alter her course out, because she is uncertain.” Even when a vessol has not tho apparatus, a man can hear tho boll by going below to tho water-lino, and applying his ear to the side of the vessel. Tho usefulness of tho invention to navigators on the Now Zealand coast is obvious.