Screw steamer

“ The first steamer constructed of iron was the Aaron Manby, a small paddle-wheel vessel about 50 feet long, built at Horsley, England, in 1821; and the first screw steamer of any importance was the Archimedes, an iron vessel of 237 tons, built in England in 1839. The Great Britain, built at Bristol, England, in 1843, was the first screw, as well as the first iron steamer to cross the Atlantic, but it was not until 1850, when the Inman liner City of Glasgow began to run regularly between Liverpool and Philadelphia, that iron screw steamers took a recognized place upon the ocean. ”

“ The application of the screw-propeller to steam-ships has given to them a great superiority, because they are not liable to any accident to paddle-wheels, exposed as such must be to collision with the floating ice. It is recorded that, on one occasion, a screw-steamer, near Upernavik, on the coast of Greenland, actually charged an iceberg, and drove right through it, as a railway-engine might crash through a fence or hurdle. ”

“ The race of water from the wheels past the ship being at a high velocity, and raised above the normal level, causes a resistance to the ship beyond that due to her passage through the water, as in the case of a screw ship. On the other hand, the paddle boat is more readily got into motion and her speed more rapidly arrested than is the case with the screw steamer; and it is claimed for the paddle-wheel—although the foundation for such a claim is rather nebulous—that when the engines are working at full speed the ship is prevented from the excessive rolling observable with a screw vessel. ”

“ A steamer whose screw or paddles are revolving and driving the hull through the water will not, amidst the heaviest sea, give you the same sensation you get from a vessel tumbling about on a strong, fine-weather swell, not a breath of air to steady her or give her way. The steamer in a measure escapes the worst of the seas by sliding out of them; her bows are lifting clear of the washing coil whilst her lee sponsons are buried, and she half jumps the intervening hollow as her paddles{114} thrust her from the summit of the surge. ”

“ Therefore, while admitting the importance and necessity of providing for special service a small class of fast, full-power steamers, it is submitted that the auxiliary screw-steamer is the description of ship to which the largest and best consideration should be devoted; for to the nation possessing the most efficient fleet of such vessels must belong the dominion of the sea. ”

“ F. P. Smith, an English farmer. Ericsson patented a peculiar form of screw-propeller, and designed a steamer 40 feet in length, of 8 feet beam, and drawing 3 feet of water. The screw was double, two shafts being placed the one within the other, revolving in opposite directions, and carrying the one a right-hand and the other a left-hand screw. These screws were 51∕4 feet in diameter. On her trial-trip this little steamer attained a speed of 10 miles an hour. Its power as a “tug” was found to be very satisfactory ”

“ The economy is not the result of the application of the power by the screw, as compared with the side-wheel, but of the sail alone; and this economy is more or less, just as canvas is employed more or less in the propulsion. The screw is the better form of steamer for using sail; and the low speed at which propellers generally run, is a means of making that sail more effective. We have already seen, in the section on the cost of steam, that it generally requires twice the original quantity of fuel to increase the speed from eight to ten knots per hour in either style of steamer. ”

“ When a steamer is in a rough sea, especially if she is lightly laden, the screw is frequently out of water for several seconds at a time. Relieved from the resistance of the water, the screw whirls with the rapidity of lightning and gives the stern of the ship a very lively shaking. ”

“ The propeller proved itself efficient to an unexpected degree in both smooth and rough water.
The attention of the admiralty was now invited to the new invention, to which at the outset the sentiment of the engineering world was almost universally opposed. The admiralty considered it to be desirable that experiments should be made with a larger vessel before recommending the adoption of the screw in the navy. Accordingly a small company was formed, and the construction of a new screw steamer, the Archimedes, resolved upon. ”

“ These three steamers are built of steel, and each carries four masts. They are all driven by triple-expansion engines, and the last-named vessel is a twin-screw steamer. The respective measurements are as follows:—
America, 5,158 tons gross, built and engined by Gourlay Brothers & Co., Dundee, in 1891, is 435 feet long, 46 feet 3 inches broad, and 25 feet 2 inches deep, with engines of 516 nominal horse-power. ”

“ But the achievements of screw steamers are not always satisfactory at first, and time has shown some curious instances where what appeared at first sight a little thing prevented great results. To-day we know somewhat of the screw propeller, but it is very difficult, if not impossible, for the cleverest and most experienced engineer to define his knowledge or to classify his facts so as to deduce any rules from them that shall enable him to lay down fixed laws for the practical guidance of others. ”

“ The bossing out of the stern, as in the Teutonic and Majestic, permits the screws to work without any exterior overhanging bracket, as in other screw steamers. The central boss of the propeller is made of steel; the three blades, weighing eight tons each, are of manganese bronze. A new feature in the machinery is what is called an “emergency governor,” which, in case of the shaft breaking, or the screw racing from any other cause beyond a certain speed, is designed to act automatically on the reversing gear and stop the engines. These gigantic engines are started and reversed by steam. ”

“ The Admiralty thereupon ordered the 'Rattler' to be built on the same lines as the paddle-wheel steamer 'Alecto,' with screw engines of the same nominal horse power by Messrs Maudslay, and very soon several more men-of-war were ordered to be fitted with screws. An early example of a successful screw vessel was the Royal yacht 'Fairy,' built of iron in 1845, and engined by Messrs Penn. She had oscillating cylinders driving a cogged wheel geared into a pinion on the screw shaft, so that the screw made five revolutions for every one of the engines. ”

“ The next year the Novelty was built for the owners of the Archimedes by Mr. Wimshurst at Blackwall, to demonstrate still further the seagoing merits of a screw-propelled vessel. Her two-bladed screw was placed as near the sternpost as possible, and one of its features was that it had only a quarter of a turn to the blade. Her boilers worked at a steam pressure of sixty pounds above that of the atmosphere, the highest then attempted, and up to then regarded as impossible for a steamer. ”

“ Recognising that very considerable numbers of passengers are willing to sacrifice speed to comfort and safety, the managers of the White Star Line determined to make an innovation by building a twin-screw cargo steamer of exceptional size and power, fitted with accommodation for a limited number of saloon and third-class passengers. The new steamer which was called the Cymric, commenced work in the Liverpool and New York trade in 1898. Her tonnage is 13,096 tons gross. Her passenger accommodation in both classes is excellent, and she has proved a very attractive ship. ”

“ However, after the construction of the Great Britain had been commenced, the steamer Archimedes, fitted with Smith’s screw propeller, arrived at Bristol during her tour of the ports and demonstrated once and for all that the screw propeller could be used in seagoing vessels, and that, provided engines of sufficient power were installed, the screw propeller was more suitable for large hulls built to make ocean voyages than the best paddle-wheels then designed. ”

“ Enough has been written to indicate in some detail the progress made in steam-ship construction. Wood was the material chiefly used until near the middle of the nineteenth century. Iron then began to take its place and the screw-propeller to supersede the paddle-wheel. Some iron screw steamers have already been mentioned, but this was inevitable, as no hard and fast line can be drawn across the history of invention and commercial [192] enterprise, to separate iron from wood and screw from paddle. ”

“ The Inman and International liners City of New York and City of Paris, steel twin-screw steamers, were launched in 1888 and 1889. These two steamers marked one of those epochs of complete transformation in type of vessel necessitated by the public demands and rendered possible by the advance of engineering science. [93] They had considerable beam and their subdivision into water-tight compartments was more thorough than in any vessel hitherto built. Another innovation in their construction was the arrangement of fore and aft bulkheads in addition to the transverse bulkheads. ”

“ These facts are indisputable; how can we account for them but upon the theory that iron screw steamers are the cheapest and best for the traffic?... We exhort our shipping merchants to examine the question candidly for themselves, ... for we assure them that 'the Philistines are upon them!' We have not a single new Atlantic steamship on the stocks, from one end of the country to the other, while in Great Britain there are 16,000 tons of new iron screw steamers building for the American trade. ”

“ The twin-screw Rennes, built in 1866, was sent to the Thames to be overhauled, and her engines were compounded by Messrs. J. and W. Dudgeon, the result being a great increase in speed and a reduction of somewhere about 45 per cent. in coal consumption. Two new screw steamers, [109] the Newhaven and Dieppe, were built for the company by La Société des Forges et Chantiers at Havre, but owing to structural imperfections, a considerable amount of trouble was experienced before they could be made to meet the requirements of Lloyd’s and the Board of Trade. At their best they were very slow. ”

“ Three years ago we directed attention to the great [287] increase of foreign screw steamers, and showed clearly how they were rapidly taking away the trade that had been formerly carried by American ships.... Our merchants did not heed this injunction, and, as a consequence, their rivals have grown stronger, while they have become weaker. To-day nearly all the mail and passenger, besides a great deal of the goods, traffic, is carried by foreign ships, the great majority of which are iron screw steamers. ”

“ He did not attach much importance to the particular form of the blade either in single or twin screws, as he believed so long as the disk area, the surface, and pitch were properly adjusted to the speed of the vessel, and to enable the engines to use, at the maximum speed, just the full quantity of steam that the boilers can make, we have got pretty nearly as far as we can get. To fix these dimensions of the propeller accurately at the present time, and without further knowledge of the action of the screw on the water, was, he thought, impossible. All the rules and formulæ are empirical. ”

“ J. Stevens, of the United States, put to sea with a steam-boat propelled by a screw, turned first by a rotatory engine, and then by Watt’s reciprocating engine; and, as this small craft steamed from Hoboken to New York, she has by some writers been considered the first sea-going screw of which there is any certain account. Richard Trevethick, in 1815, patented “a worm or screw revolving in a cylinder at the head, sides, or stern of a vessel,” as also a “stuffing-box, inclosing a ring of water.” ”

“ The shaft must be guided vertically and horizontally in bearings at certain intervals to prevent it from breaking, and where it issues from the vessel, the leverage of the screw against the water causes it to tremble and vibrate enormously, just where the vessel is weakest; and in wooden vessels converted to screw propulsion the difficulty and cost of repairs are very great. It is found that metal linings for the screw shaft are quite inefficient, and surfaces of wood are required. If any lever movement obtains in the screw shaft, the destruction of the bearings is very rapid. ”

“ He is endeavoring to feel his way to using the steam in one cylinder only, and so far the results have been encouraging, and he is now fitting a 2,200-ton vessel on that system. He is also endeavoring to do without a crank shaft, the forward end of the screw shaft carrying an ordinary crank with overhung pin. This experiment also promises satisfactorily. In his opinion the great improvement of the immediate future is to increase the steam production of our boilers. A ton weight of a locomotive boiler produces as much steam as six tons of an ordinary steamboat boiler. ”

“ Paddle, it was suggested that the screw-propeller might probably be used as an auxiliary power, for occasional use during calms and contrary winds; the vessel to be a sailing-vessel under ordinary circumstances; but to have a marine engine and a screw for exigencies at times when the ship would be brought to a stand-still or even driven backwards. About seven years ago, an American packet-ship, the Massachusetts, a complete sailing-vessel in other respects, was provided with a screw and a steam-engine powerful enough to keep the ship moving when winds and tides were adverse ”