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Steamboat Days | |||||
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CHAPTER 2
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 Colonel John Stevens |
Stevens' boiler carried a working pressure of over fifty pounds to the square inch, when usual pressures were from four to seven pounds. It was a "sectional" type boiler, and exceedingly well planned. The engine was direct-acting, high-pressure, condensing type, 10 inches diameter of cylinder and 24 inches piston stroke. It drove a four-bladed screw propeller, and considering that pitch and slip of wheels had not then been measured in exact terms, its form was excellent.
The first Stevens steamboat performed so well that a second was immediately laid down, using the same engine, but employing a boiler of larger capacity, while the drive was through gearing to twin screws, the twin-screw propulsion being another of those instances of Stevens' use of a device brought forward long afterward as new.
These first two Stevens boats were so successful that Colonel John and his sons built Phoenix, which had its first trial in 1807, but too late to anticipate Fulton. This steamboat was driven by paddle-wheels, and was shut out of New York State waters by the monopoly granted Fulton and Livingston. It was placed on the run between Hoboken and New Brunswick, and afterward on the Delaware River.
 The Phoenix |
From this time forward the Stevens--father, sons and nephews---continued to construct steamboats, and when the New York State monopoly granted to Fulton had been swept aside the Stevens built the most successful steamboats operating on the Hudson River. In the twenty years succeeding the time of Fulton and Colonel John Stevens, changes and improvements followed until a recognized- type of American river boat and its steam-engine were developed, principally by Robert L. Stevens, son of Colonel John Stevens.
Robert L. Stevens not only succeeded to the development of boilers and engines, but, as a naval architect, he arrived at a knowledge of the laws governing the variation of resistance at excessive speeds, and he determined and introduced into his practice those forms of least resistance and those graceful water lines which later came to distinguish naval architecture. He introduced the "hollow water line" in Phoenix and here anticipated the famous Baltimore clippers, and the invention of the "wave line" form of vessels. He adopted the feathering paddle-wheel and the outboard, or sponson guards, now universally used in river steamboats.
He designed Philadelphia in 1813 and introduced a number of new devices; and he was one of the first to use anthracite coal, then a new and almost unmanageable fuel. He fitted the boiler of Passaic to burn coal in 1818, and following that year its use became general. It was Robert L. Stevens, too, who designed the "skeleton beam," a characteristic feature of American river boat engines, and he placed the first example of this light, strong construction on the steamboat Hoboken, built in 1822. He built Trenton, extraordinarily powerful and fast for the times, and when it had been out two seasons, placed the two boilers on the outboard guards, a fashion that continued for many years.
Trenton made steamboat history when Stevens adopted the plan of making paddle-wheel floats in two parts, placing one above the other, and securing the upper half to the forward and the lower half to the after side of the arm, obtaining a smoother action of wheel, without loss by oblique pressure.
In 1827 Stevens designed North America, built that year--hull by William Capes, New York, 218 feet length, 30 feet beam and 8 feet draught, with two beam engines of 44 inches cylinder diameter and 8 feet stroke. This was one of Stevens' largest and most successful boats, and ran between New York and Albany, making 16 miles' speed.
Anticipating difficulty in keeping the long, light, shallow hull in shape when irregularly laden, and when steaming at the high speed expected to be obtained when pushed to the limit, Stevens adopted the expedient of stiffening the hull by means of a simple form truss. This proved satisfactory and the "hog frame," as it has since been inelegantly but universally called, came to be, and continued a feature of American river steamboats of larger size for half a century.
It was in North America, too, that Stevens introduced artificial blast for forcing fires, and next he adopted spring bearings under the paddle shaft of New Philadelphia, built in 1828; and he fitted the steam-cylinder with the "double poppet valve," since universally used on steam-engines. In 1840 he first used metallic packing rings on Trenton, and in 1841, in association with a nephew, Francis B. Stevens, he invented the familiar "Stevens cut-off," a device for securing the expansion of steam in the steam-cylinder. In this form of valve gear, the steam- and exhaust-valves are independently worked by separate eccentrics, the latter being set in the usual manner, opening and closing the exhaust passages just before the crank passes its center. The steam-eccentric is so placed that the steam-valve is opened as usual, but closed when about one-half the stroke has been made. The result is accomplished by giving the eccentric a greater throw than is required by the motion of the valve and permitting it to move through a portion of its path without moving the valve.
The inventions of the Stevens family and the devices they adopted made standard practice in steamboat building. Transportation in America was advanced, and the development of the country quickened because of their genius. The Stevens forces were marshaled for constructive work. They were pioneers and builders, and for them America has great respect and pride in the number and importance of their achievements. Their memory will continue to be honored through the Stevens Institute of Technology, Hoboken, set down in their old estate, which they founded; and, while it stands, Stevens Castle high above the busy Hudson River will remind us of their purposeful lives devoted to the development of water and rail transportation in America.
Stevens Institute of Technology The Stevens Family Legacy
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