The first ocean-going screw steam-ship of her class to which the modern double or twin-screw system was applied was the iron vessel Far East, which was launched from Dudgeon’s yard, Millwall, towards the close of 1863. She was intended for the China tea trade of the owners of the Lightning and Thunder. The Far East was 227 feet between perpendiculars and 210 feet on the keel; 34 feet beam, 22 feet moulded depth, and 20 feet 6 inches depth of hold; her depth at load water-line was 17 feet, her displacement 2200 tons, and her builder’s measurement tonnage 1258 tons. On her upper deck she had a capacious poop and forecastle, and there were deck-house and cabins amidships. Her engines were of 150 nominal horse-power, driving a two-bladed lifting screw under each quarter. The engines had annular combined cylinders, the diameter of the high-pressure cylinder being 24 inches and of the expansive cylinder 50 inches, with a piston stroke of 24 inches. The screws were 8 feet 2 inches in diameter, with a pitch of 16 feet. Each of the two boilers had six furnaces with 109 square feet of firebar surface, and a tube surface of 1883 feet. The shafting of the screws projected through a wrought-iron tube of great strength bolted to a false iron bulkhead clear of the ship’s frame. The tube at its outer end was connected with a wrought-iron slide, which guided the screw to the well when being lifted, or to the shafting when being lowered. The screws were raised by a worm and barrel apparatus. The lower and top masts were of iron bolted together through flanges, and the topgallant masts fitted closely into the topmast heads, so that the masts from deck to button looked like immense slender poles. There were no tops, but light iron cross-trees spread the rigging, and preventive top and topgallant backstays were carried far aft of the lower rigging. Her funnel was placed well abaft the main-mast. She was given a full rig on all three masts, and in addition carried fore and main try-sails.
No sooner was she afloat than the double-screw steamer Pallas was sent into the water from the adjoining slipway; this being the first time on record that two iron twin-screw vessels were launched from the same yard on the same day.
In January 1865 the double twin-screw steam-ship, Louisa Ann Fanny, was launched, and as it was thought she might possibly be acquired by the Confederates, the bunkers were so arranged as to afford ample protection for her engines from hostile shot. Her machinery consisted of horizontal direct-acting engines with cylinders of 40 inches diameter, and 22¹⁄₂ inch stroke, driving two three-bladed screws of 9 feet 3 inches diameter and a pitch of 17 feet 3 inches, the distance from centre to centre of the screws being 10 feet 10 inches. She attained, when loaded, a speed estimated at 15³⁄₄ miles an hour after allowing for the tide.
Want of space has prevented the relation of further details of the steam-ship history of the period, though a few from the long list of steam-ship companies of other countries may be mentioned. The Messageries Maritimes de France grew out of a company formed to carry inland mails. In 1851 they contracted to carry some of the oversea mails, and extending their operations as the years went on are now the largest steam-ship company in France. The next largest French company is the Compagnie Générale Transatlantique, which was formed in 1862 and is also a mail carrier. To this company belong the largest steamers ever constructed in France. The Hamburg-America Company of Germany launched its first steamer, the Borussia, in 1855 for the Atlantic service, and the Norddeutscher Lloyd followed in 1856 with the Bremen. These boats were, however, built in Great Britain, as all large German steam-ships were until comparatively modern times. The Austrian Lloyd Steam Navigation Company, which belongs to Trieste, was founded as far back as 1836 for the Mediterranean service.
This chapter may be fitly brought to a conclusion with a reference to the Great Eastern—the wonder and the failure of her age in popular estimation. To the general public she appeared as an extraordinarily large ship which was a complete failure as a commercial undertaking. To a few she was the embodiment of all that skill and scientific genius had conceived in construction up to that time. She was the great illustration of the longitudinal system of construction invented by Scott Russell, and of the use of longitudinal and transverse bulkheads.
Scott Russell’s invention of the longitudinal frame was due to his perception of the fact that as vessels increased in size the longitudinal strain would become greater, especially when they were carrying heavy machinery amidships or nearly so. In the vessels of the size then constructed the longitudinal strain experienced by small iron ships was comparatively small. One method adopted to strengthen hulls longitudinally was to give them a number of floor-plates, forming a strong continuous keelson. Other keelsons were also constructed to run fore and aft near the bilges; a bilge stringer was added, while on the outside, bilge keels were sometimes fixed. Russell introduced the system in 1835, but the registration societies did not look with approval on the innovation and nothing came of it at the time.
As ships were made larger, however, the nature of the stresses they had to bear became better understood, and precautions had to be taken to prevent the hogging and sagging to which they are subjected by the motion of the sea, besides the lateral and other stresses. In 1835-6 Mr. Russell built three small iron vessels, one of which had a longitudinal middle-line bulkhead and four transverse bulkheads connected by longitudinal stringers and without transverse frames. The other two had no longitudinal bulkheads but were fitted with a greater number of transverse partitions and stringers. He applied the latter method in 1850 to a small iron screw boat on the Humber, and in her some deep web plates were fastened by angle irons to the shell-plating and were also stiffened with angle irons along the inner edge. The inventor described this arrangement as being ordinary transverse bulkheads with the whole of the centre portion removed. The same year he built an iron paddle-steamer, 145 feet in length by 15 feet beam, and 7 feet 6 inches depth, on the longitudinal principle. Notwithstanding its extraordinary length in proportion to its beam and depth the vessel was a perfect success. One notable vessel constructed on this principle was the Rhenus, 197 feet over all, by 25 feet extreme breadth, and 9 feet depth, and drawing only 3 feet of water. These vessels, which were almost experimental in character, were followed by several others of a more highly developed type, such as the Baron Osy, a fine and fast paddle-steamer launched in 1855 for the London and Antwerp service. She was strengthened with the partial or open bulkheads of the type already described, which acted as frames, and had broad top stringers under the deck. This vessel had an oscillating condensing engine with two cylinders, and her paddles gave her a speed above that of other vessels on the route. The success achieved by her, both in regard to constructional strength and seaworthiness, had not a little to do with the designing of the Great Eastern. Before this, however, in 1852, Scott Russell designed with Brunel, who was consulting engineer to the Australian Royal Mail Steam Navigation Company, two steamers, the Victoria and Adelaide, on the wave-line principle, but they were not on his longitudinal system though including some of its features. In these vessels he introduced for the first time fore and aft bulkheads amidships combined with a part iron deck. They had an important influence on the adoption of the longitudinal system, as the constructional strength of the vessels was provided for by the addition of a flat keelson extending almost to the bilges and connected at either side with a longitudinal bulkhead which formed the coal bunkers and rose as high as the main deck, the hull thereby being transformed into a powerful box-girder. The experience derived from these vessels caused them to be the forerunners of the Great Eastern, and like her they were a financial failure. They could not carry enough fuel for the voyage, and this and other considerations led Brunel to design the great ship in an attempt to solve the difficulties to which these vessels had directed attention. He estimated that the vessel would be able to attain a speed of 15 knots at a less coal consumption per ton than any steamer in existence. The Eastern Navigation Company was formed in 1851 and decided on the construction of a steamer in accordance with his views. It was proposed to run a line of big steamers to the East, via the Cape of Good Hope, and as the vessels were referred to as Leviathans the name Leviathan was chosen for the first (and, as it happened, the last) vessel the company ever owned. This was the Great Eastern. The lines of the vessel were designed by Russell, who also built the hull. The details of the ship’s construction were settled by Russell and Brunel; the longitudinal system was adopted, together with the bulkhead system, to which Russell attached such importance.
The Great Eastern was built with an inner skin from the keel to the water-line, thus being a double-hulled vessel. The inner and outer skins were of the same thickness of iron plates, the bottom plates being one inch thick and the other plates three-quarters of an inch. The space between the two hulls was 34 to 36 inches, and this was estimated to hold 2500 tons of water-ballast if required. The transverse iron bulkheads divided the ship into a number of compartments, each sixty feet long, and in order to add to the strength of the ship and increase her safety in case of collision, there was no opening in these bulkheads lower than the level of the second deck. For 350 feet of her length the vessel had two longitudinal bulkheads 36 feet apart, beside which there was a second intermediate bulkhead up to the main deck, forming a coal bunker. Five of her six masts were of iron and hollow, and the sixth of wood.
Model of the “Great Eastern.”