SYMINGTON'S IMPROVED FIXED PADDLE-WHEEL, FOR OCEAN STEAMERS. NEXT to the incrustation of the boilers, no part of the machinery of the Steam Vessel more requires alteration, or has exercised more ingenuity, than the paddle-wheel. It is surprising how many patents have been taken out, to protect what no one would be inclined to appropriate―improvements in the paddle-wheel, that exist only in the imagination of their authors. No object, perhaps, can boast a greater number of devotees; the patent list literally swarms with them. Professors of learned Universities, professors of unlearned Universities,* professors of all denominations, professors of everything, and professors of nothing, have equally contended for immortality, in a paddle-wheel. Some were made on strict mathematical principles, to solve some great problem in geometry and physics, with curves and angles "founded on data that could not err:" these were anything but a wheel of fortune, for, when tried, they pertinaciously stood still, or else run away from the engine. Others were made on no principle at all, giving full scope to imagination, which revelled ad libitum; and truly none but professed inventors could possibly invent anything so singular as some *The "Verulam," to wit. of them. If invention be a characteristic of genius, these gentlemen can boast, certainly, of a very large share of the divine gift. The most ingenious attempts at complication it is possible to conceive-annular rings-wheels within wheels -adjusting balances and tumbling bobs-eccentrics and revolving peculiarities, presenting friction enough to wear themselves out in no time, are the masterpieces of this class of inventors. After all, for river navigation, where the line of flotation is always the same, there is, perhaps, none better than the common paddle-wheel; inasmuch as it can be nicely adjusted to enter and leave the water with the least possible loss of power, or strain to the machinery. But it is far different at sea, where the rolling and pitching of the vessel plunges the wheel on one side axle-deep, whilst the other is performing its rotations more in air than water. The following evidence of C. Williams, Esq., extracted from the Report, in 1822, before made use of, will best describe, in the language of experience, the serious disadvantages of the common paddle at sea:— "In what manner do the wheels operate to produce obstructions in the way of the proper speed and the power of the vessels-The violent action of the paddles, in a heavy sea, striking the water, shakes and strains both the vessel and machinery, and produces what Captain Percy, of the 'Hero,' has very well described, as having a tendency to drive the top and bottom asunder; the result of this severe action is, that the engine loses its speed, and scarcely performs one-half or one-fourth of what it should do." Mr. Symington's first paddle-wheel had moveable parts, and though the friction was reduced to a mere nothing, as will be seen by reference to the drawing of his horizontal windmill, which is the motion of the paddle-wheel reversed, too much objection existed to moveable paddles, to persevere in its introduction; he therefore adopted the principle of the angle, but abandoned the motion. The wheel now offered to notice, has lately undergone some alterations from practice, and may be seen at work in two tugs, "The William Symington," of 35-horse power, and the "Dragon," of 80-horse power. It has decided advantages over the common wheel, in preventing concussion, and acting more efficiently when deeply immersed, owing to the peculiar angle at which it enters and leaves the water. It is nearly as cheap in its first cost as the common wheel, equally strong, not so liable to be injured at sea, and certainly cheaper to keep in repair. The following extract from a letter from the intelligent engineer of the "Dragon,” to the Directors of the Company to which she belongs, will sufficiently prove its advantages for sea-going steamers. What has served so long the rough usage of a tug of 80-horse power, will answer any purpose: "I have now had to do with the Symington Paddle-wheels about twelve months, and during that time we have been several times round the Foreland, in very rough weather. We have been over to Holland, to Dunkirk, and in constant work towing, yet we have only had to get three new floats to replace those we had lost: and when the floats are joined as above, the wheel will be so firmly united together that none of the bolts will be liable to work loose; for the easy edgeways entrance of this paddle into the water does not strain the wheel, nor shake the vessel, as the common float-boards do, by their striking the water with their whole surface flat ways. "You will remember that our vessel gained much credit with the parties concerned, by towing a ship out from among the ice, when none of the tugs having the common floats would venture to her assistance; and, should such a case occur again, I am convinced, from their easy action in a heavy sea, that we should be able to show the decided superiority of the Symington Paddle-wheel over the common ones. "I am confident that for ease of action, shown by the absence of that disagreeable vibration so much complained of, and the small expense of trouble or money, we may challenge comparison with any paddle-wheel in existence; and, 11th Nov. 1839. "I am your obedient servant, "CHARLES MONTGOMERY, "Engineer of the Dragon."" |