Rigged Model (USNM 160306) 

 is a reconstruction of the twin- 

 screw steamboat, or launch, tried 

 out by Stevens in 1804 in New 

 York Harbor. The original boat 

 used the engine and boiler 

 ( 1 8 1 1 yg) in the Watercraft Collec- 

 tion. {Snnlhwnian photo r^nro.) 



STEX'ENS' MULTITUBULAR BOILER, and STEAM 



ENGINE, 1804 

 Full-Sized Machinery, usnm 181179 



The machinery consists of the original boiler and en- 

 gine employed in a twin-screw steamboat designed 

 by Colonel John Stevens and built at Hoboken, 

 New Jersey, in 1803-04. The boat was tested in 

 in New York Harbor in May 1 804, when a speed 

 of 4 miles per hour was obtained. 



The boiler is of the multitubular design patented 

 by Stevens in 1791 and 1803, having 28 copper tubes 

 each Iji inches in diameter and 18 inches long. The 

 boiler has a small rectangular chest, 14 tubes project 

 from each of two sides of it. The grate is at one end 

 of the projecting tubes; the heat passes around these, 

 under the chest, and then around the tubes at the 

 opposite end and to the smokestack. The Stevens 

 boiler was designed for higher pressure than the 

 Watts boilers used in England, and his boilers were 

 the forerunners of the American high-pressure boilers 

 used later on American locomotives and steamboats. 



The engine is a single-cylinder, high-pressure type, 

 having a cylinder 4li inches in diameter and a stroke 

 of 9 inches, noncondensing and fast turning. The 

 engine and propeller shafts are in one unit. 



The difficulties that discouraged Stevens from fol- 

 lowing up the tests of 1804 with a larger boat can 

 be understood bv inspection of the engine and 

 boiler. Both are crudely built. There were at that 

 time neither tools nor skilled workmen in the L^nitcd 

 States that would enable him to produce machinery 

 and boilers well enough made to withstand high- 

 pressure steam and to produce the speed of engine 

 revolution desirable in Stevens' plan of using twin- 

 screw propulsion. 



In 1844 the boiler and engine were repaired, only 

 defects in workmanship being corrected and these 

 were identified by being painted yellow. Many of 

 these defects were in soldered pipe joints. Some 



worn parts were duplicated and replaced. A test 

 was then made, on the Hudson in October 1844, 

 of the machinery installed in a new hull, and a speed 

 of 8 miles per hour was obtained. 



The exhibit was preserved in the Stevens Institute 

 I'rom 1844 until it was exhiliited in the World's 

 Oolumbian Exposition in 1892, after which it was 

 transferred to the Smithsonian Institution and placed 

 in the Watercraft Collection. 



STEVENS' SCREW PROPELLER, 1804-05 

 Full-Sized Copy, usnm 180397 



This full-sized copy of an experimental screw pro- 

 peller designed by John Stevens complies with a 

 description written by Stevens to Dr. Robert Hare of 

 Philadelphia, Pennsylvania, dated November 16, 

 1805. The wheel has blades separately attached to 

 the hub by a bar or shank fitting into a hole in the 

 hub. The pitch could be adjusted by turning the 

 blade on its shank and the wheel could be tried with 

 two or four blades. 



Stevens had made numerous trials of the screw 

 propeller, using manually operated cranks to turn 

 the propellers, before attempting his steam engine 

 trials of 1804. Stevens' letter to Dr. Hare shows he 

 knew the value of pitch in propeller design as well 

 as the desirability of curved faces on the blades as 

 opposed to flat surfaces. Stevens tests apparently 

 included a long screw but before his twin-screw 

 tests of 1804, he had concluded that this modern- 

 style short screw was the better. 



Purchased. 



STEVENS' TWIN-SCREW STEAMBOAT, 1804 

 Rigged Model, usnm 160306 



This is a model representing a twin-screw steamboat 

 designed by Colonel John Stevens and built at 

 Hoboken, New Jersey, in 1803-04. The steamboat 

 was tried in the spring of 1804 in New York Harbor 



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