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

PENNSYLVANIA AND OHIO ON THE STOCKS.

The American ship-builder, however, early saw that the model of his craft, which was to be propelled by steam, should differ from that of a ship depending upon its sails alone, and governed himself accordingly. He made her sharp, for speed, and ended her prow straight up and down, as he built the steamboats for river navigation. The consequence was that she rode dry through waves which would pour tons of salt water upon the deck of an English model. George Steers, of New York, a genius in naval architecture, and whose early death was deeply regretted, was the person who did the most to bring into use the present form used in the best models for ocean steamers. One of his first steamers, the Adriatic, built for the Collins line, excited great attention in Liverpool, when she first appeared there. The London Times spoke of her in leading articles, calling upon the English ship-builders to contrast her with ships of their own construction. It spoke of how she glided up the Mersey, making hardly a ripple from her bows, so evenly and quietly she parted the water, while an English steamer of her size so disturbed the stream as to bring up the mud from the bottom. The Times was also specially struck with the ease with which she was handled, turning almost in her length, while for an English steamer turning was an operation requiring so much more space, and making so much more disturbance in the water. From that time to this the English have followed the American models in the construction and equipment of their steamers, and their example has been imitated by most other nations.

The latest specimens of American ship building are shown in the cut representing the Pennsylvania and Ohio on the stocks. These vessels are the pioneers of the new line between Philadelphia and Liverpool.

Nor is this the only change which naval architecture has undergone. The material for ship-building, especially for sea going steamers, has in modern times come to be chiefly iron. Livingstone, in his book of travels in Africa, tells how, when he was putting together on the banks of one of the rivers there the pieces of a small iron steamer which had been sent out to him from England, the natives gathered round, and inspecting the work going on, jeered at him for thinking that a boat built of such a material would float. Their whole experience with iron was that it would sink. When, however, the steamer was completed and launched, they could hardly express their astonishment at finding that she floated.

Though every school-boy, from his text-books on natural philosophy, can explain the reasons why a ship built of iron will float, yet our ancestors would have considered, a proposition to construct a ship from this material very much as the native Africans did. Even in the construction of wooden ships, iron enters now much more than it did formerly. The knees, or bent oak beams, by which the form of the ship was made, have become so scarce and dear that they are now frequently made of iron. It takes so long for an oak tree to grow, and the demand was so great for limbs of such a natural bend as could be used for ship-building, that even before the use of iron for such portions of a ship, the process was in frequent use of bending the beams, or knees, by steaming then and then subjecting them to great pressure.

Iron as a material for ships has some very great and material advantages. It is on the whole lighter, so that an iron ship weighs less, absolutely, than a wooden one of the same size. Then as the knees and other timbers take up less space when made of iron, than when made of wood, and as the thickness of the sides is much less, more space is secured in an iron ship than in a wooden one for carrying the cargo. Besides this, a vessel built of iron can be divided into water-tight compartments, so that an accidental leak will damage only that portion of the cargo contained in that compartment in which it occurs.

This method of construction is also another factor of safety in case of accident by collision or in any other way. One compartment may be injured so as to fill with water, while the others, being uninjured, their buoyancy will still keep the ship afloat. An objection, however, to the use of compartments lies in the fact that, as they must be riveted to the sides, the rows of holes for the rivets necessarily weaken the strength of the sides, so that a ship with compartments, which touches on a rock or other obstacle, at one end, is more apt to break apart than one without compartments, as the sides, unsupported by the buoyancy of the water, have the less strength to support her weight in the length. Still, all things considered, iron has come so much in favor for the construction of large ships, that it is in much more general use for that purpose than wood.

In the construction of an iron ship, the naval architect draws his plans, and sends his construction drawings to the iron rolling mill, where each plate is made of the exact curve and dimensions. The holes for the rivets are punched by machinery, and the plates are then ready to be put together. The hull of the vessel is made of iron bars riveted together, and the plates are riveted to the iron upright ribs, each plate overlapping the preceding. The ribs are placed from ten to eighteen inches apart, and the whole structure is of iron. The simplicity of the construction of an iron ship is such, that when the plates are ready, it can be put together with wonderful rapidity.