An experimental iron barge was made in 1787 by J. Wilkinson the ironmaster.
As early as 1809 it was proposed by Richard Trevithick and Robert Dickenson that ships should be built of iron, but the proposal was received with derision. The Vulcan, built in 1818 at Faskine near Glasgow, is, so far as is known, the first iron vessel constructed for commercial purposes, and so well was she built that as recently as 1875 she was engaged in transporting coal on the Forth and Clyde Canal, and looked little the worse for wear. Her builder was one Thomas Wilson.
The first iron steamer, however, was the Aaron Manby, built in 1821 at the Horseley Iron Works near Birmingham, to the order of Captain Napier, afterwards Admiral Sir Charles Napier, and Mr. Manby. She was put together at Rotherhithe, and in May 1822 at Parliament Stairs took on board a distinguished party of naval officers and engineers, whom she conveyed for a trip of several hours up and down the river between Blackfriars and Battersea. A contemporary newspaper described her as “the most complete specimen of workmanship in the iron way that has ever been witnessed.” This little vessel was 106 feet long and 17 feet broad, and carried a 30-horse-power engine. Her wheels were of the type known as Oldham’s revolving bars. Her only sea voyage was to France under the command of Captain Napier. Upon arrival she was employed on the Seine or Loire. Another iron vessel intended for navigation on the Seine was shortly afterwards made in this country, and the parts sent to France to be put together.
Little appears to have been attempted in this country for some years in the way of iron shipbuilding, although in Ireland three or four small iron sailers or steamers were constructed for inland navigation purposes. But in 1828 John Laird of Birkenhead had his attention directed to iron shipbuilding, and completed his first iron vessel there the following year. Other builders followed where he showed the way, and in less than three years there were shipbuilders on the Thames, Clyde, and east coast of Scotland who were launching iron vessels, the great majority of which were sailing ships. The famous yards on the Cheshire side of the Mersey remained for some time the headquarters of the new industry. The first iron vessels for the United States—not the first iron-plated vessels, and this is a distinction which should be noted—were launched there, and so immediate was the recognition of the advantages of iron ships over wooden ones that by 1835 there had been built at Laird’s the first iron vessels for use on the rivers Euphrates, Indus, Nile, Vistula, and Don. They were small compared with the wooden vessels afloat.
The Garry Owen, built in 1834 by MacGregor, Laird and Co. of iron, was only 125 feet in length, 21 feet 6 inches beam, with two engines totalling 90 horse-power. There were no Lloyd’s rules as to scantlings for iron steamers in those days, and builders put in as much material as they thought necessary for the strength of the vessel, which usually meant a liberal allowance. The Garry Owen was not much to look at, but she was very strongly built, a circumstance which had a great deal to do with the development of iron steam-ship building. She nearly came to grief on her first voyage, for she was overtaken by a violent storm, which drove her and several other vessels ashore. These others were of wood. Some of them were soon pounded to pieces by the heavy seas, and those that escaped total loss were badly damaged; but the Garry Owen, though bumped and dented somewhat, was able to get afloat again little the worse and return under her own steam.
If a steamer strongly built of iron could survive a storm and stranding which ended the careers of several wooden ships of larger dimensions, it was admitted that there was no valid reason why other iron vessels should not prove equally safe, especially if they were larger. It was considered that iron steamers might find useful employment in short voyages, and several were built.
One of the chief of these vessels was the Rainbow, launched in 1837 for the London and coastal trade. She was 185 feet long by 25 feet beam, and of 600 tons, with engines of 180 horse-power.
The use of iron in construction was not the only factor in the tremendous change which was coming in shipbuilding. A new form of propulsion was necessary, and it was found in the screw propeller.
Before considering this, however, the development in the construction of paddle-wheels and of the engines designed for paddle-boats may be noticed.
The ordinary paddle-wheel had the floats fixed upon the radial arms, but it was soon found that an improvement could be made by causing the floats to assume a position vertical, or nearly so, at the moment of contact with the surface of the water, and to retain that position until the float had left the water. To effect this the floats are not bolted to the arms but pivoted, and are retained in the required position by means of levers operated by an eccentric pin. By this means a much greater propulsive force was exerted. The old style of paddle-wheel with fixed floats is now very seldom employed. These wheels are now only to be found in vessels in which the expense of construction has to be cut down to a minimum, or in a certain type of steamer plying in shallow rivers, where the wheel is rather large, and the dip of the float slight; but here again economy of construction may count for more with the proprietor of the boat than the increased speed he could obtain with the more expensive feathering wheels. Many of the modern wheeled vessels have floats of steel, but in the great majority of cases wood is employed, elm being largely used for this purpose. The floats are usually about four times as long as they are broad. Various forms are used, some being left square at the corners, others are rounded, others again have the outer edge elliptical in shape, and the experiment has also been tried with a fair measure of success of inclining the floats to the axis of the wheel, instead of having them parallel to it. The advantages claimed for this last method are that the stream of water formed by the rotatory motion of the paddles is driven slightly away from the sides of the vessel, instead of in a direction parallel with her length. Wheels of this type, however, lose much of their effectiveness when the engines are reversed. Radial wheels are sometimes made with the floats adjusted so that they enter the water almost perpendicularly, but they are much more oblique under this arrangement when leaving the water.