His experiments in screw propulsion commenced in 1801, and were continued until some time in the year 1806. The engines that he tried in 1802, 1803, and 1804, were all non-condensing; and the boilers were all multi-tubular, in which steam of a high pressure was maintained. His propeller was the short four-bladed screw propeller now in use.
The following description of this boat is given by Colonel Stevens in a letter to the Medical and Philosophical Journal of New York, January 1812:
"To avoid the mischievous effects, necessarily resulting from the alternating stroke of the engine of the ordinary construction, I turned my attention to the construction of steam engines on the rotary principle. And the first steamboat put in motion on the waters of the Hudson, was one constructed on this principle. I trust, then, I shall be pardoned, should I enter into a more minute description of this little curiosity than may at this time appear necessary. For simplicity, lightness, and compactness, the engine far exceeded any I have yet seen. A cylinder of brass, about 8 inches in diameter, and 4 inches long, was placed horizontally
![]() | on the bottom of the boat: and by the alternate pressure of the steam on two sliding wings, an axis passing through its center was made to revolve. On one end of this axis, which passed through the stern of the boat, wings, like those on the arms of a windmill, were fixed, adjusted to the most advantageous angle for operating on the water. |
Fig. 5 Shorter's Plan of Alternate Paddle Propulsion.*
Fig. 6 Shorter's Plan of Screw Propulsion.* *Traced from his Patent Specification No. 274. A. D. 1800. |
This constituted the whole of the machinery. Working with the elasticity of the steam merely, no condenser, no air pump was necessary; and as there were no valves, no apparatus was required for opening and shutting them. This simple little steam engine was, in the summer of 1802, placed on board a flat-bottomed boat I had built for the purpose. This boat was 25 feet long, and about 5 or 6 feet wide. She was occasionally kept going until the cold weather stopped us. When the engine was in the best order, her velocity was about 4 miles an hour. I found it, how-ever, impracticable, on so contracted a scale, to preserve due tightness in the packing of the wings in the cylinder for any length of time. This defect determined me to resort again to the reciprocating engine."
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