This vessel, finished in 1818, and called the Vulcan, was the pioneer of all iron boats. For at least sixty years it remained in active service. Indeed, for aught that is known to the contrary, this first iron boat may be still in use in some capacity.
One of the most surprising and interesting things to shipbuilders about the Vulcan, and the boats that were constructed after her, was the fact that they were actually lighter in proportion to their carrying capacity than ships of corresponding size built of wood. In wooden cargo ships the weight of the hull and fittings varies from 35 to 45 per cent. of the total displacement, while iron vessels vary from 25 to 30 per cent. This was a vital point in favor of the iron vessel, and one that appealed directly to practical builders. But the public at large looked askance at the new vessels. To "sink like a stone" was proverbial; and everyone knows that iron sinks quite as readily as stone.
But very soon a convincing demonstration of the strength of iron vessels brought them into favor. A great storm, sweeping along the coast of Great Britain in 1835, drove many vessels on shore, among them an iron steamboat just making her maiden voyage. The wooden vessels without exception were wrecked, most of them destroyed, but the iron vessel, although subjected to the same conditions, escaped without injury, thanks to the material and method of her construction.
From that time the position of the iron steamship was assured. And whereas sea voyagers had formerly looked askance at iron passenger boats they now began to distrust those built of wood. By the middle of the century, iron shipbuilding was at its height, and in the decade immediately following, the Great Eastern was finished—possibly the largest and most remarkable structure ever built of iron, on land or sea. In recent years larger ships have been constructed, but these ships are made of steel.
The Great Eastern marked an epoch in shipbuilding. In size she was a generation ahead of her time, but the innovations in the method of her construction gave the cue to modern revolutionary shipbuilding methods. Sir George C. V. Holmes gives the following account of the great ship:
"She was originally intended by the famous engineer, Mr. I. K. Brunel, to trade between England and the East. She was designed to make the voyage to Australia without calling anywhere en route to coal, a feat which, in the then state of steam-engine economy, no other vessel could accomplish. It was supposed that this advantage, coupled with the high speed expected from her great length, would secure for her the command of the enormous cargoes which would be necessary to fill her. Mr. Brunel communicated his idea that such a vessel should be constructed for the trade to the East to the famous engineer and shipbuilder, the late Mr. John Scott Russell, F.R.S., and he further persuaded his clients, the directors of the Eastern Steam Navigation Company, of the soundness of his views, for they resolved that the projected vessel should be built for their company, and entrusted the contract for its execution to the firm of John Scott Russell & Co., of Millwall.
"Mr. Scott Russell and Mr. Brunel were, between them, entitled to the credit of the design, which, on account of the exceptional size of the ship, presented special difficulties, and involved a total departure from ordinary practice.
"Mr. Scott Russell had systematically, in his own previous practice, constructed iron ships with cellular bottoms, but the cells had only five sides, the uppermost side on the inside being uncovered. Over a large portion, however, of the bottom of the Great Eastern the cells were completed by the addition of an inner bottom, which added greatly both to the strength and to the safety of the ship. It was also Mr. Brunel's idea that the great ship should be propelled by both paddles and screw. Mr. Scott Russell was responsible for the lines and dimensions, and also for the longitudinal system of framing, with its numerous complete and partial transverse and longitudinal bulkheads.
"The following are some of the principal dimensions and other data of the Great Eastern:
| Length between perpendiculars | 680 | feet |
| Length on upper deck | 692 | " |
| Extreme breadth of hull | 83 | " |
| Width over paddle-box | 120 | " |
| Depth from upper deck to keel | 58 | " |
| Draught of water (laden) | 30 | " |
| Weight of iron used in construction | 10,000 | tons |
| Number of plates used in construction | 30,000 | |
| Number of rivets used in construction | 3,000,000 | |
| Tonnage, gross | 18,914 | tons |
| Nominal power of paddle engine | 1,000 | H. P. |
| Nominal power of screw engines | 1,600 | " |