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The two pieces of work which perhaps will be most permanently linked with the name of Ericsson are the screw-propeller as a means of marine propulsion, and the "Monitor" as a type of warship. In addition to these, however, his life-work was rich in results which bore direct relation to many other improvements in the broad field of marine engineering and naval architecture.
He lived to see the paddle-wheel grow in importance and estimation as a means of propulsion only in turn to be supplanted by the screw-propeller, which gradually increased in engineering favor from the days of its obscure infancy until it became the only means employed for the propulsion of ships navigating the high seas, while it had become a most serious rival to the paddle-wheel even for the purposes of interior and shallow-water navigation, long a field considered as peculiarly suited to the paddle-wheel and to the engines adapted to its operation.
Thus, in 1837, the "Francis B. Ogden" was built for the special purpose of testing the power of the screw-propeller, and was operated on the Thames for the benefit of the British Admiralty and many others. Shortly after this, and largely through the influence of Capt.
Here is his own description of it: "To the lead was attached, upon the principle of the screw-propeller, a small piece of clock-work for registering the number of revolutions made by the little screw during the descent; and it having been ascertained by experiment in shoal water that the apparatus, in descending, would cause the propeller to make one revolution for every fathom of perpendicular descent, hands provided with the power of self-registering were attached to a dial, and the instrument was complete.
"You are discharged for inefficiency," he said. "You are reporting a side-wheeler for a screw-propeller." "There is no signal in the code for such modern inventions," I retorted. "I suppose the fog of your practical realism is too obscuring for you to see that clipper just coming in," I continued, as a full-rigged ship spread its filled sails against the glowing sky of the late afternoon.
Having drained it he spat out the last mouthful, and along with it a lively creature like a small shrimp, with something like a screw-propeller under its tail! Enjoying our tea under the shade of the mimosa, we rested for an hour, and then, saddling our steeds and slinging on rifles and cartridge-pouches, we mounted, and sallied forth upon the plain.
When once a clear understanding had been obtained there was no difficulty in designing suitable propellers, with proper diameter, pitch, and area of blade, to meet the requirements of the flyer. High efficiency in a screw-propeller is not dependent upon any particular or peculiar shape; and there is no such thing as a "best" screw.
Ericsson's contributions to the art of naval warfare are embodied in the "Princeton," the "Monitor" and its class, and the "Destroyer." In the "Princeton" the material used was wood, and in the "Monitor" and "Destroyer" iron, following simply the developments of the age. In the three the means of propulsion was by screw-propeller.
F. P. Smith, a farmer of Hendon, in England, took out a patent for his screw-propeller, and exhibited some experiments with it attached to a model boat, and in the following autumn built a boat of six tons' burden, of ten horse-power, and fitted with a wooden screw. This vessel was kept running upon the Thames for nearly a year, and her performance was so satisfactory, that Mr.
In the work of introducing his propellers good progress was made, especially in boats built for use on the Great Lakes, so that by 1844, when the U.S.S. "Princeton" went into commission, there were in use some twenty-five vessels with the screw-propeller as a means of propulsion.
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