DIVING APPLIANCES.

Otago Daily Times, Issue 20789, 7 August 1929, Page 12

DIVING APPLIANCES.

ESCAPE -FROM SUBMARINES. HEROIC EXPERIMENTERS. (From Ocr Own Correspondent.) LONDON, June 20, Successful tests have been made this week by the Admiralty with an apparatus designed for • enabling the crew trapped in a damaged submarine to rise to the surface. The experiments were carried out in the very deep waters of Loch Long, Dumbartonshire. Another invention has materially increased the depth at which it is possible for a diver to work in flexible diving dress. The greatest depth to which naval divers had hitherto descended is believed to be 204 feet. With the new apparatus they have reached a depth of 300 feet in Loch Long, and it is claimed that a new world’s record has thus been established. Both appliances were submitted to the Admiralty by Siebe, Gorman, and Co., Ltd,, and they have been tested in Loch Long by volunteer and men from Devonport and Portsmouth on board the naval diving ship Tedmouth. The apparatus for the use of submarine crews weighs only four to five pounds. It is strapped on the man’s chest, and has a flexible tube,with a mouthpiece through which he breathes. The air exhaled into the apparatus is regenerated by the absorption of the carbon dioxide, and- the restoration to it of . the requisite amount of oxygen. .It was severely;; tested on men sunk in a chamber to a depth of 21 fathoms. Wearing ' the apparatus, thfey^quitted the chamber at this depth, and in each instance reached the surface safely in a minute and a-quarter. The device which has so greatly iuci eased the depth ,to which divers in flexible dress can he lowered ,is the outcome of experiments carried out over a period of years by Mr R. H, Davis, the head of the firm, and Professor Leonard Hill, the physiologist. Mr. Davis explained in an interview that a diver equipped with the ordinary apparatus is subjected to pressure which varies with the depth, 1 At the greatest depth which has been .attained in Loch Long the pressure is, 1331 b to the square inch. The monotony and prolonged exposure to winds and tides during this Ion" decompression ” period try the diver severely, for it may last for an hour or more. With the idea of shortening the penod a submersible decompression chamber has. been invented. The diver enters it under water, and' this device, m conjunction with apparatus ■ which supplies him with oxygen in the chamber, has reduced the former time of. decompression to one-third, and also enabied him to . descend to much greater depths than heretofore. , \ DECOMPRESSION CHAMBER. 1 The new decompression chamber is a sted cylinder, about six feet six inches nigh and three feet six inches in dinmeter. It is lowered into the water to the depth at which the decompression stage must begin, as soon as the diver is ready to ascend. An attendant is lowered inside the chamber, and through a door in the bottom he lowers a ladder by which the 'diver climbs; in. The attendant disconnects the diver’s impedimenta, closes the door, and the chamber can then be raised and taken inboard, the diver remaining inside to decompress in comfort; A seat is provided for him in the chamber, aa well as such comforts as hot drink in a thermos flask, in addition to the oxygen apparatus. : The oxygen acts rather like. a vacuum, extracting the nitrogen from the diver’s body- A diver wearing flexible diving dress can, it ■is claimed, work with almost the same ,facility as one on. land, whereas metal, diving armours, though they enable a man to descend, to greater depths, have yet to prove their utility in strong tideways. TRIBUTE TQ THE PERS TNNEIii 7 Mr Davis added that he would like to pay a tribute to the officers and men '■ of fhe Navy who have carried out these tests; ' ' . “ They have done magnificently,” he said, “ Tdke the case of the submarine apparatus. Where,could you find "a finer example of cool courage than their descent into the black depths, many fathoms down, in water, at a temperature of 50 degrees, on a nasty day, with a one and three-quarter-knot tide running?. Remember, too, that i they had to get down to that depth add then escape to the whereas men trapped in' a submarine, have only to get out and come to the surface. In- other words, they had to do the double jouney, and bn both journeys they were relying on a little apparatus weighing only a very few poundsl No praise could be too great for them. They Have proved to their comrades of the service that everything is being done for their safety in case of emergency, and that,in an accident every man will stand, an excellent chance of saving hjmself. The-- same tale can be told of the men who tested the submersible decompression apparatus.”