Norwich bulletin., 1916-07-10
REGENT IMPROVEMENTS
 IN DEEP SEA DIVING.
Recovery of Millions of Treasure and
 Many Ships Made Possible.

Many Ships Made Possible.
 Must all the millions of dollars that
 now lie at the bottom of the sea in | the form of ships and their sunken l treasure be forever lost to the world? Most of the vessels that have been sunk whether by accident or in the 1 course of the present war, lie in com | paratiVely shallow waters, many of | them at a depth of less than 300 feet i and the problem of their recovery | does not seem entirely Hopeless in the 1 light of recent improvements in deep | sea diving and the feats accomplish | ed by the expert divers of the U, S. | Navy. The matter is the subject of an ! article in the current number of the l Bulletin of the Pan American Union, | Washington, D. C. In discussing the 1 organization of companies in the Uni l ted States whose purpose is the recoV- ! cry of some of the wealth now lying in | the oceans depth, the writer states: Certain it is s2at the project of ] recovering Sunken ships, or the most | valuable of the treasures that have l gone down with them, is more feasible now then it was only four or five years ago. Such great improvements in diving aDparat have recent, beer made that 1t is TOW possible for a diver to CpCTGt tn" limitC .iTle even at the great dept of 300 feet below the surface These improve | | able experiments in deep-sea diving conducted under the auspices of the | Bureau Of Construction and Repair Of ] the Navy Department of the United i States in 1914. Prior 10 tEis time the | greatest depth reached by divers was | 2l0 feet two English officers having | &2cUmD!1 that feat during a series i Of tests carried on by the British l Admiralty in 1907. For the benefit of those who do not appreciate the diff tyf h 1N1-oy 1 be stated that at a depth of 10 feet l below the surface the pressure is 4l33 pounds per square inch of surface of the body submerged. I1sis pressure increases approximately, and at a depth or lyp feet 1t has increased to 43.2 pOunds and at a depth of 300 feet to 129g pounds.
 F'NOtNIh hstanding this tremendous pressure, the expert divers of the |. $. Navy have succeeded in not only
 reaching a depth of 3G0 to 3G5 feet, but in remaining at that depth for from to 20 minutes at 9 time making examinations and observations in re- gard to e sunken vessel that made it's subsequent salvage possible. This work was done iu connection with the raising of the T.. S. submarine F-4 1 which il will be remembered. plunged ] to iIle 5OEtOn of the sea just off the h1rbOr Ct Honolulu Cl March 9, 1915 i Not only did the divers establish a ] | upon that occasion, but the subsequent i raising and recovery of the I7-4 is the l only instance ill history where Q sunk | en vessel was recovered from a depth | of geo feet"
 | The writer thereuDon gives a brief | sketch of the history of diving as a l useful art from the time of Aristotle 1 down to the present, and after des- | crlblng modern diving outfit and ex- l blaming in some detail the matter of ! I.,iT, r l pressures, viz, tile pressure of the air | inside the helmet and suit and the ex- ! terlnal pressure of the water, continues as follows:
 ''The necessity of having the air 1 pressure within the diving dress cOnl-
 pensate the external water pressure, | thus subjecting the diver to pressure ! directly prOpOrtiOned to the depth to l which he descends, is the dangerous i element in deep-sea diving. At a ! depth, for instance, of 100 feet, a diver l must be subjected to a pressure of l atmospheres, or 60 pounds per square i inth, in order to compensate the ex- | ternaI water pressure. Exposure to | such pressure is apt to be followed by | dangerous physiological effects. conn | monly known as 'caison disease" the | symptoms of which include pains in l the muscles and joints, comonly called 1 bends" deafness, embarrassed breath- l ing, vomiting, fainting, etc, sometimes 1 VS uILiIS III OedLn. They do not ap- | pear while the pressure is being raised i nor so long as it is continued but only ] after it has been removed; and the | view now accepted is that they are 1 due to the rapid effervescence of the l gases which are absorbed in the body | fluids during exposure to pressure. I Experiment las proved that when the i pressure is suddenly relieved the gas | is liberated in bubbles within the ] body, and that these do the harm. Set i free in the spinal cord, for instance. 1 they may cause partial paralysis, or in | the heart lead to stoppage of the cir l cuIation. It naS been found, however | that if the pressure is relieved grad 1 uaIIy the bubbles are not formed. be- 1 cause the gas comes out of solution l slowly and is got rid of by the heart l and lungs. To prevent these effects 1 the withdrawal of the air pressure-in | other words, the deconpression - | should be slow. Hence the divers as- ] cent must be regulated accordingly | and the deeper he has been the slow | CT ana longer must be the periods for | decompression. 1t was particularly in | regard to this matter of decornpression | that the experiments of the U. s. Navy | Department in 1914 led to improved l methods enabling the divers to des- | cend to 300 feet below the surface | Being able to safely observe and di- l rect the work of rescue at suctl l depth, and with modern lifting apa- l ratus, who can say that the recovery l Of ancient treasures of sunken Span | 1sh galleons, of hundreds of more re- cent Wrecks of merchant vessels, and ] finally of many of the magnificent war vessels that have been sent to the bot