The screw was three-bladed, 15 feet 6 inches diameter, and 19 feet pitch. There were six boilers, and her bunkers held 700 tons, and other accommodation enabled her to stow 510 tons more. To lessen the vibration experienced from the screw and machinery, eight new wrought-iron beams were placed transversely through the vessel, locking her sides together. The bases on which the machinery rested were made stronger, and she was further strengthened by massive iron entablature beams to the engines, buttressed by a framing of teak wood, each piece being 20 inches wide and 3 feet deep, running on either side of the engines transversely and diagonally to the sides of the ship. This solid timber extended 17 feet 6 inches on each side of the engine. The whole of this framing was bolted together and to the sides of the ship by wrought-iron bolts. The new arrangement of the boilers gave her a lessened coal consumption. Little more need be said about this steamer. She made one voyage afterwards to New York and back, and being then acquired by Messrs. Antony Gibbs and Sons was placed in the Australian trade at the time of the gold fever, and continued a regular voyage between England and Australia for many years. She was afterwards patched up afresh and had her engines removed, but was then such a failure that though she got as far as the Falkland Islands, leaking badly, she was abandoned to the underwriters, and is now ingloriously ending her days as a coal hulk. CHAPTER IX DEVELOPMENT OF IRON SHIPBUILDING After the launching of the _Great Britain_ in 1845, steam-ship building was carried on with great activity, though the change from wood to iron and from paddles to the screw was gradual. Many wooden vessels, both steamers and sailers, continued to be built, as the prejudice against iron for ship construction died slowly. The screw propellers were at first simply auxiliary to sail. This was due to three causes: mistrust of the propeller, the cost of continually running it, and the difficulty of carrying sufficient coal. Describing the gradual evolution of the steam-ship in its early days, Mr. John Ward, a director in Messrs. Denny’s famous firm, in his Presidential Address to the Institution of Engineers and Shipbuilders in Scotland, in 1907, said: “The necessities of the screw propeller after its general adoption demanded a much greater increase of engine revolution than constructors in the early days, or for some years after, deemed it prudent to adopt. Thus a great variety of design, including beam, steeple, oscillating, and other forms of machines were used, all with gearing between the engine and the propeller. But a few direct-acting engines appeared very early, and gradually, as engineers gained confidence, the latter type became universal, and assumed the form of the inverted cylinder in the so-called steam-hammer engine which was the universal type for mercantile purposes until the end of the century.