Ocean's Story; or, Triumphs of Thirty Centuries / Maritime Adventures, Achievements, Explorations, Discoveries and Inventions; and of the Rise and Progress of Ship-Building and Ocean Navigation, from the Ark to the Iron Steamships

by Frank B. Goodrich

The abutments of the bridge over the East River, which is to connect New York and Brooklyn by a suspension bridge, with a span high enough to not interfere with the navigation of the river, were built with a somewhat similar device. The towers upon each side of the river had to be so high that a very deep foundation, going down to the original rock, had to be laid, and the workmen engaged in building it worked in a submarine apartment, supplied with air forced down by a steam engine.

The submarine hydrostat, as it is called, is one of the most ingenious and recent applications of the diving-bell principle. Thirty men may work in it at once, for a number of hours, without any inconvenience; while beside this it enables them at will, to float or sink.

Externally, as will be seen from the upper structure in the cut, the machine is a rectangular box, surmounted with another smaller one, entirely closed except at the bottom. The interior of the hydrostat consists of three principal compartments; the lower figure in the cut represents these in section. The lower one, or hold, is open below, and communicates by a shaft with the upper compartment. Between the upper and lower compartments is a third, communicating with the others only by stop-cocks. The upper compartment is called the between decks, and the middle one the orlop deck. All round the hold and the orlop deck runs an air-tight gallery connected with the other compartments only by stop-cocks. The lower part of this gallery contains the ballast, while its upper part is filled with air or water, according as it is desired to float or sink.

PAYERNE'S SUBMARINE HYDROSTAT.

When the hydrostat floats, the hold and a portion of the shaft are filled with water; while the orlop deck, its gallery and the between decks are full of air. The workmen are in the between decks, where are lifting and forcing pumps. When it is desired to sink the hydrostat, the door of the shaft and the hatch of the between decks are closed water and air-tight. The pump is then worked so as to draw water from the outside and fill the orlop deck and its gallery. At the same time the force-pump is used to force air into the hold through a pipe connecting the hold and the orlop deck, and furnished with a stop-cock. As the orlop deck, with its gallery, fills with water the machine gets heavier and sinks, while the hold becomes at the same time filled with air. Though the air thus forced into the hold would tend to float the hydrostat, this tendency is counterbalanced by the filling of the orlop deck with water. When the hold is filled with air, the workmen in the between decks open the shaft and descend to the bottom. A sufficient number remain in the between decks to haul up and dispose of the material excavated, and to attend to the pumps which maintain the supply of air for those in the hold. When they want to rise again, the men ascend from the hold by the shaft to the between decks, closing the shaft again. The air is then let from the hold to the orlop deck and gallery; the hold fills with water, while the orlop deck and gallery become filled with air, and the hydrostat rises to the surface; the men open the hatch of the between decks and obtain free communication with the outer world again.

The dimensions of the hydrostat are as follows: The hold is square, the sides measuring each 26 feet, and being 6 feet 6 inches high. The orlop deck is of the same size. The between decks have the same depth, but are only 16 feet in the sides. The base of the hold therefore covers 676 square feet. This ingenious machine has been already used with the most perfect success in performing various work, such as cleaning out and deepening harbors; searching for lost treasure; removing obstructions in channels, and so on.

One of the most important and interesting pieces of submarine engineering ever done in this country was that undertaken for removing the rocky obstructions in Hell Gate, at the entrance, through Long Island Sound, of New York harbor. The first attempt to remove these was by drilling and blasting, as in an ordinary quarry. This work was, however, quite slow, since the current is there so rapid that operations could be carried on only a few minutes each day at the turns of the tides. The next plan was proposed by a French engineer, M. Maillefert, who had used it with great success in the harbor of Nassau. This plan was entirely new, and had the great merit of being surprisingly cheap compared with those then in use. It dispensed with the costly and difficult process of drilling, but exploded the charges on the surface of the rocks to be removed, while they were covered with the greatest depth of water. Gunpowder burnt in the open air explodes without anything but a harmless flash. The pressure of the atmosphere is not enough to restrain the dispersion of the gases suddenly generated. Under water, though, it is different; its pressure confines the gases and makes them act with destructive effect on all sides. For a couple of years operations were carried on by M. Maillefert with considerable success. But he was hampered by want of means, the money that was spent being raised by private subscriptions; and though the channel was greatly improved, operations were suspended. It was found, too, that this method was of great service in breaking off isolated pinnacles of jagged rock, but when the bed was reached, and the rock reduced to a large, smooth, flat surface, progress in the work became slow, doubtful and costly. This process, however, of exploding charges of gunpowder, under water, by means of an electric battery is very valuable in certain situations.

In 1868 Congress appropriated $85,000 for the needs of Hell Gate, and bids for the work were opened to the public. The contract was awarded to Mr. S. F. Shelbourne, of New York, who proposed to do the work by drilling and blasting, the machinery to be placed on the bottom and worked by a steam pump placed on a vessel above. The rock was to be drilled by mushroom drill, as it was called, a diamond drill worked by a small turbine wheel, driven by steam. This drill was tried on the Frying Pan, one of the worst rocks obstructing the channel, but was found to be too delicate and uncertain of continuous action under the trying requirements of the rough work at Hell Gate. A striking drill was then tried, and a machine was built and put in position, but the very day it was to commence to work it was run against by one of the craft so constantly crowding through Hell Gate, and destroyed. Mr. Shelbourne then retired from any further attempt, and the Government has undertaken it, and placed the management of the operations in the hands of General Newton.