A History of the Growth of the Steam-Engine

by Robert Henry Thurston

Fig. 144.—The Modern Steamship.

The [modern steamship] is as wonderful an illustration of ingenuity and skill in all interior arrangements as in size, power, and speed. The size of sea-going steamers has become so great that it is unsafe to intrust the raising of the anchor or the steering of the vessel to manual power and skill; and these operations, as well as the loading and unloading of the vessel, are now the work of the same great motor—steam.

The now common form of auxiliary engine for controlling the helm is one of the inventions of the American engineer F. E. Sickels, who devised the “Sickels cut-off,” and was first invented about 1850. It was exhibited at London at the International Exhibition of 1851. It consists[98] principally of two cylinders working at right angles upon a shaft geared into a large wheel fastened by a friction-plate lined with wood, and set by a screw to any desired pressure on the steering-apparatus. The wheel turned by the steersman is connected with the valve-gear of the cylinders, so that the steam, or other motor, will move the rudder precisely as the helmsman moves the wheel adjusting the steam-valves. This wheel thus becomes the steering-wheel. The apparatus is usually so arranged that it may be connected or disconnected in an instant, and hand-steering adopted if the smoothness of the sea and the low speed of the vessel make it desirable or convenient. This method was first adopted in the United States on the steamship Augusta.

The same inventor and others have contrived “steam-windlasses,” some of which are in general use on large vessels. The machinery of these vessels is also often fitted with a steam “reversing-gear,” by means of which the engines are as easily manœuvred as are those of the smallest vessels, to which hand-gear is always fitted. In one of these little auxiliary engines, as devised by the author, a small handle being adjusted to a marked position, as to the point marked “stop” on an index-plate, the auxiliary engine at once starts, throws the valve-gear into the proper position—as, if a link-motion, into “middle-gear”—thus stopping the large engines, and then it itself stops. Setting the handle so that its pointer shall point to “ahead,” the little engine starts again, sets the link in position to go ahead, thus starting the large engines, and again stops itself. If set at “back,” the same series of operations occurs, leaving the main engines backing and the little “reversing engine” stopped. A number of forms of reversing engine are in use, each adapted to some one type of engine.

The hull of the transatlantic steamer is now always of iron, and is divided into a number of “compartments,” each of which is water-tight and separated from the adjacent compartments by iron “bulkheads,” in which are fitted doors which, when closed, are also water-tight. In some cases these doors close automatically when the water rises in the vessel, thus confining it to the leaking portion.

Thus we have already seen a change in transoceanic lines from steamers like the Great Western (1837), 212 feet in length, of 351∕2 feet beam, and 23 feet depth, driven by engines of 450 horse-power, and requiring 15 days to cross the Atlantic, to steamships over 550 feet long, 55 feet beam, and 55 feet deep, with engines of 10,000 horse-power, crossing the Atlantic in 7 days; iron substituted for wood in construction, the cost of fuel reduced one-half, and the speed raised from 8 to 18 knots and over. In the earlier days of steamships they were given a proportion of length to breadth of from 5 to 6 to 1; in forty years the proportion increased until 11 to 1 was reached.

The whole naval establishment of every country has been greatly modified by the recent changes in methods of attack and defense; but the several classes of ships which still form the naval marine are all as dependent upon their steam-machinery as ever.

H. B. M. Iron-Clad Captain.	H. B. M. Iron-Clad Thunderer.	U. S. Iron-Clad Dictator.	U. S. Iron-Clad Monitor.
H. B. M. Iron-Clad Giatton.		French Iron-Clad Dunderberg.

Fig. 145.—Modern Iron-Clads.