Inventions of the Great War

by A. Russell Bond

But these difficulties are not insuperable. There is no reason why a steel manikin cannot be constructed with a man inside to direct its movements.

THE SALVOR'S SUBMARINE

Other schemes have been devised to relieve the diver of abnormally high air-pressure. One plan is to construct a large spherical working-chamber strong enough to withstand any hydraulic pressure that might be encountered. This working-chamber is equipped with heavy glass ports through which the workers can observe their surroundings in the light of an electric search-light controlled from within the chamber. The sphere is to be lowered to the wreck from a barge, with which it will be in telephonic communication and from which it will be supplied with electric current to operate various electrically driven mechanisms. By means of electromagnets this sphere may be made fast to the steel hull of the vessel and thereupon an electric drill is operated to bore a hole in the ship and insert the hook of a hoisting-chain. This done, the sphere would be moved to another position, as directed by telephone and another chain made fast. The hoisting-chains are secured to sunken pontoons and after enough of the chains have been attached to the wreck the pontoons are pumped out and the wreck is raised.

It is a pity that ship-builders have not had the forethought to provide substantial shackles at frequent intervals firmly secured to the framing. A sunken vessel is really a very difficult object to make fast to and the Patent Office has recorded many very fantastic schemes for getting hold of a ship's hull without the use of divers. One man proposes the use of a gigantic pair of ice-tongs; and there have been no end of suggestions that lifting-magnets be employed, but no one who has any idea of how large and how heavy such magnets must be would give these suggestions any serious consideration.

But, after all, the chief obstacle to salvage in the open sea is the danger of storms; months of preparation and thousands of dollars' worth of equipment may be wiped out in a moment.

FIGHTING THE WAVES WITH AIR

However, there has been another recent development which may have a very important bearing on this problem of deep-sea salvage work. It has often been observed that a submerged reef, twenty or thirty feet below the surface, may act as a breakwater to stop the storming waves. An inventor who studied this phenomenon arrived at the theory that the reefs set up eddies in the water which break up the rhythm of the waves and convert them into a smother of foam just above the reef. Thereupon he conceived the idea of performing the same work by means of compressed air. He laid a pipe on the sea bottom, forty or fifty feet below the surface, and pumped air through it. Just as he had expected, the line of air bubbles produced exactly the same effect as the submerged reef. They set up a vertical current of water which broke up the waves as soon as they struck this barrier of air.

The "pneumatic breakwater," as it is called, has been tried out on an exposed part of the California coast, to protect a long pier used by an oil company. It has proved so satisfactory that the same company has now constructed a second breakwater about another pier near by. There is no reason why a breakwater of this sort should not be made about a wreck to protect the workers from storms. Where the water is very deep, it would not be necessary to lay the compressed-air pipe on the bottom, but it could be carried by buoys at a convenient depth.

Summing up the situation, then, there are two serious bars to the successful salvage of ships sunk in the open sea—the wild fury of the waves on the surface; and the silent, remorseless pressure of the deep. The former is the more to be feared; and if the waves really can be calmed, considerably more than half the problem is solved. As for the pressure of the sea, it can be overcome, as we have seen, either by the use of special submarine mechanisms, or of man-operated manikins or even of unarmored divers. We have reached a very interesting stage in the science of salvage, with the promise of important developments. Fifty fathoms no longer seems a hopeless depth.

Even in times of peace the sea exacts a dreadful toll of lives and property. Before the war the annual loss by shipwreck around the British Isles alone was estimated at forty-five million dollars. But the war, although it was frightfully destructive to shipping, may in the long run save more vessels than it sank; for it has given us sound-detectors which should remove the danger of collisions in foggy weather, and the wireless compass, which should keep ships from running off the course and on the rocks. And now, if salvage engineering develops as it should, the sea will be made to give up not only much of the wealth it swallowed during the war, but also many of the rich cargoes of gold and silver it has been hoarding since the days of the Spanish galleon.