APPARATUS FOR RAISING SUNKEN SHIPS AND TREASURE

The Romance of Modern Mechanism by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book here. CHAPTER XV

APPARATUS FOR RAISING SUNKEN SHIPS AND TREASURE

It is somewhat curious that, while the sciences connected with the building of ships have progressed with giant strides, little attention has been paid to the art of raising vessels which have found watery graves in comparatively shallow depths. The total shipping losses of a single year make terrible reading, since they represent the extinction of many brave sailors and the disappearance of huge masses of the world's wealth. A life lost is lost for ever, but cargoes can be recovered if not sunk in water deeper than 180 feet. Yet with all our modern machinery the percentage of vessels raised from even shallow depths is small.

There are practically only two methods of raising a foundered ship: first, to caulk up all leaks and pump her dry; and secondly, to pass cables under her, and lift her bodily by the aid of pontoons, or "camels."

The second method is that more generally used, especially in the estuaries of big rivers where there is a considerable tide. The pontoons, having a united displacement greater than that of the vessel to be raised, are brought over her at low tide. Divers pass under her bottom huge steel cables, which are attached to the "camels." As the tide flows the pontoons sink until they have displaced a weight of water equal to that of the vessel, and then they begin to raise her, and can be towed into shallower water, to repeat the process if necessary next tide. As soon as the deck is above water the vessel may be pumped empty, when all leaks have been stopped.

In water where there is no tide the natural lift must be replaced by artificial power. Under such circumstances the salvage firms use lighters provided with powerful winches, each able to lift up to 800 tons on huge steel cables nearly a foot in diameter. The winches can be moved across a lighter, the cables falling perpendicularly, through transverse wells almost dividing the lighter into separate lengths, so as to get a direct pull. If the wreck has only half the displacement of the lighters, the cables can be passed over rollers on the inner edges of the pontoons, the weight of the raising vessel being counteracted by water let into compartments in the outer side of the pontoons.

There are ten great salvage companies in the British Isles and Europe. The best equipped of these is the Neptune Company, of Stockholm, which has raised 1,500 vessels, worth over £5,000,000 sterling even in their damaged condition, among them the ill-fated submarine "A1." Yet this total represents but a small part of the wealth that has gone to the bottom within a short distance of our coasts.

Turning from the salvage of wrecks to the salvage of precious metal and bulky objects that are known to strew the sea-floor in many places, we must notice the Hydroscope, the invention of Cavaliere Pino, an Italian.

In 1702 there sank in Vigo Bay, on the north-west coast of Spain, twenty-five galleons laden with treasure from America, as the result of an attack by English and Dutch men-of-war. Gold representing £28,000,000 was on those vessels. Down it went to the bottom, and there it is still.

So rich a prize has naturally not failed to attract daring spirits, among whom was Giuseppe Pino. This inventor has produced many devices, the most notable among them the hydroscope, which may best be described as a huge telescope for peering into the depths of the sea. A large circular tank floats on the top of the water. From the centre of its bottom hangs a series of tubes fitting one into the other, so that the whole series can be shortened or lengthened at will. Through the tubes a man can descend to the chamber at their lower extremity, in the sides of which are twelve lenses specially made by Saint Gobain, of Paris, which act as submarine telescopes.

Pino's hydroscope has been at work for some time in Vigo Bay, its operations closely watched by a Spanish war vessel, which will exact 20 per cent. of all treasure recovered. While the hydroscope acts as an eye, the lifting of an object is accomplished by attaching to it large canvas bags furnished with air-tight internal rubber bladders. These have air pumped into them till its pressure overcomes that of the water outside, and the bag then rises like a cork, carrying its load with it. An "elevator"—nine sacks fixed to one frame—will raise twenty-five to thirty tons.

So far Cavaliere Pino has salvaged old Spanish guns, cannon-balls, and pieces of valuable old wood; and presently he may alight on the specie which is the main object of his search.

Another Spanish wreck, the Florida, which was a unit of the Spanish Armada, and sank in Tobermory Bay, the Isle of Mull, has many times been attacked by divers. The last attempt made to recover the treasure which that ill-fated vessel was reputed to bear is that of the steam lighter Sealight, which employed a very powerful sand pump to suck up any objects which it might encounter on the sea-bottom. Many interesting relics have been raised by the pumps and attendant divers—coins, bones, jewels, timbers, cannon, muskets, pistols, swords, and a compass, which is so constructed that pressure on the top causes the legs to spread. One of the cannon, fifty-four inches long, has a separate powder chamber, the shot and wad still in the gun, and traces of powder in the chamber. It is curious that what we usually consider so modern an invention as the breech-loading cannon should be found side by side with stone balls. The heavier objects were, of course, raised by divers. In this quest also the treasure deposit has not yet been tapped.

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