Inventions of the Great War

by A. Russell Bond

The majority of wrecks, however, are found in the open sea, where it would have been foolish to attempt any salvage-operations because of the menace of submarine attack. On at least one occasion a salvage vessel, while attempting to raise the victims of a submarine, fell, itself, a prey to a Hun torpedo. Now that this menace has been removed, such vessels as lie in comparatively shallow water, and in positions not subject to sudden tempests, can be raised by the ordinary methods; or if it is impracticable to raise them, much of their cargo can be reclaimed. However, most of the torpedoed ships lie at such depths that their salvage would ordinarily be despaired of.

IN THE DEPTHS OF THE SEA

It will be interesting to look into conditions that exist in deep water. Somehow the notion has gone forth that a ship will not surely sink to the very bottom of the deep sea, but on reaching a certain level will find the water so dense that even solid iron will float, as if in a sea of mercury, and that here the ship will be maintained in suspension, to be carried hither and yon by every chance current. Indeed, it makes a rather fantastic picture to think of these lost ships drifting in endless procession, far down beneath the cold green waves, and destined to roam forever like doomed spirits in a circle of Dante's Inferno.

But the laws of physics shatter any such illusion and bid us paint a very different picture. Liquids are almost incompressible. The difference in density between the water at the surface of the sea and that at a depth of a mile is almost insignificant. As a matter of fact, at that depth the water would support only about half a pound more per cubic foot than at the surface. The pressure, however, would be enormous. Take the Titanic, for instance, which lies on the bed of the ocean in water two miles deep. It must endure a pressure of about two long tons on every square inch of its surface. Long before the vessel reached the bottom her hull must have been crushed in. Every stick of wood, every compressible part of her structure and of her cargo, must have been staved in or flattened. As a ship sinks it is not the water but the ship that grows progressively denser. The Titanic must have actually gained in weight as she went down, and so she must have gathered speed as she sank.

We may be certain, therefore, that every victim of Germany's ruthless U-boats that sank in deep water lies prone upon the floor of the sea. It matters not how or where it was sunk, whether it was staggered by the unexpected blow of the torpedo and then plunged headlong into the depths of the sea, or whether it lingered, mortally wounded, on the surface, quietly settling down until the waves closed over it. Theoretically, of course, a perfect balance might be reached which would keep a submerged vessel in suspension, but practically such a condition is next to impossible. Once a ship has started down, she will keep on until she reaches the very bottom, whether it be ten fathoms or ten hundred.

A SUBMARINE GRAVEYARD

Instead of the line of wandering specters, then, we must conjure up a different picture, equally weird—an under-world shrouded in darkness; for little light penetrates the deep sea. Here in the cold blackness, on the bed of the ocean, the wrecks of vessels that once sailed proudly overhead lie still and deathly silent—some keeled over on their sides, some turned turtle, and most of them probably on even keel. Here and there may be one with its nose buried deep in the mud; and in the shallower waters we may come across one pinned down by the stern, but with its head buoyed by a pocket of air, straining upward and swaying slightly with every gentle movement of the sea, as if still alive.

This submarine graveyard offers wonderful opportunities for the engineer, because the raising of wrecked vessels is really a branch of engineering. It is a very special branch, to be sure, and one that has not begun to receive the highly concentrated study that have such other branches as tunneling, bridge-construction, etc. Nevertheless it is engineering, and it has been said of the engineer that his abilities are limited only by the funds at his disposal. Now he has a chance to show what he can do, for there are hundreds of vessels to be salved where before there was but one. The vast number of wrecks in deep water will make it pay to do the work on a larger and grander scale than has been possible heretofore. Special apparatus that could not be built economically for a single wreck may be constructed with profit if a number of vessels demanding similar treatment are to be salved.

The principal fields of German activities were the Mediterranean Sea and the waters surrounding the British Isles. Although the submarine zone covered some very deep water, where the sounding-lead runs down two miles without touching bottom, obviously more havoc could be wrought near ports where vessels were obliged to follow a prescribed course, and so most of the U-boat victims were stricken when almost in sight of land. In fact, as was pointed out in a previous chapter, it was not until efficient patrol measures made it uncomfortable for the submarines that they pushed out into the open ocean to pursue their nefarious work. The Lusitania went down only eight miles from Old Head of Kinsale, in fifty fathoms of water.

If we draw a line from Fastnet Rock to the Scilly Islands and from there to the westernmost extremity of France, we enclose an area in which the German submarines were particularly active. The soundings here run up to about sixty fathoms in some places, but the prevailing depth is less than fifty fathoms. In the North Sea, too, except for a comparatively narrow lane along the Norwegian coast—which, by the way, marked the safety lane of the German blockade zone—the chart shows fifty fathoms or under. If our salvors could reach down as far as that, most of the submarine victims could be reclaimed. But fifty fathoms means 300 feet, which is a formidable depth for salvage work. Only one vessel has ever been brought up from such a depth and that was a small craft, one of our submarines, the F-4, which sank off the coast of Hawaii four years ago.