DIVING APPLIANCES

Hokitika Guardian, 12 August 1929, Page 7

DIVING APPLIANCES

ESCAPE FROM SUBMARINES HEROIC EXPERIMENTS. 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 Watters of Loch Long, Dunbartonshire. 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 Loch Long, and it is claimed that a new world’s record has thus been established.

Both appliances were submitted to Admiralty by Siebe, Gorman, and Co., Ltd., and they have been tested in Loch Long by volunteer officers and men from Devonport and Portsmouth on board the naval diving ship Tedmouth. The apparatus for the use of submarine crews weights only four to five pounds., It is strapped on the man’s chest, and has a flexible tube with 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, they 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 increased the depth to which divers in flexible dress can be lowered is the out come of experiments carried out over a period of years by Mr H. R. Davis, the head of the firm, and Professor Leonard Hill, the physiologist. Mr Davis explained in an interview that a diver equipped ith the ordinary apparatus is subjected to pressure which varies with the depth. 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 long “ decompression ” period try the diver severely, for it may last for an hour or more. With the idea of shortening the period a submersible decompression chamber his been invented. The diver enters it under water, and this device, inc'onjunction with apparatus which supplies him with oxygen in the chamber, has reduced the former time Of decompression to one-third and also enabled him to descend to much greater depths than heretofore.

DECOMPRESSION CHAMBER. The new decompression chamber is a steel cylinder, about six feet six in diameter. It as 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, as 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 TO THE PERSONEL. Mr Davis added that he would like to pay a tribute to the officers and men of the Navy who have carried out these tests.

“They have done magnificently,” he said. “Take the case of the submarine escape appartus. 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 they had to get out and come to the surface. In other Wirds, they had to do the double journey, and on both journeys they were relying on a little apparatus weighing only a very few pounds. 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 himself. The same tale can be told of the men who test ed the submersible decompression apparatus.”