"It is well known that the hulls of vessels almost invariably become bowed" after a period of use, James Rees wrote in his patent application. "Particularly is this the case with vessels having shallow hulls and great proportionate breadth of beam, such as are employed upon the Mississippi river and its tributaries. Hence, any mechanism secured to the hull of such vessel, and dependent upon nice adjustment for its operation, is liable to be displaced and rendered useless, or endanger the safety of the vessel." To "obviate these defects and overcome these difficulties," Rees developed his series of shafts and gears, which he felt would not be thrown out of position by a sagging hull.
James Rees's patent application matches this model in most respects. His documentation shows one additional geared shaft and a steam engine, both omitted from the model; otherwise, the essential details are the same. The model demonstrates an arrangement for transferring power from a steam engine to a capstan in order to raise anchors, hoist cargo, or tow the vessel. The piston of an engine engages the gearing via a cranked shaft, transmitting power to the capstan through the turning gears. To double the tractive power, the pin in the top of the capstan can be removed, disengaging the capstan from the motion of the center shaft. The (now-missing) pinion would be put in place on deck, and the motion of the third shaft would drive the capstan.
The Welsh-born Pittsburgh steam-engine builder James Rees (1821-89) probably invented this capstan, although his eponymous eldest son could also be the inventor. James Rees was an active owner and builder of river steamers, and his firm supplied engines for many vessels on the Mississippi, Ohio, and Missouri river systems. He and his wife, also a Welsh immigrant, had five sons and five daughters. He is credited with helping to popularize the use of stern wheels on the western rivers.
James Rees, Capstan, U.S. patent no. 150,790, May 12, 1874.
1880 United States Census, NARA film no. T9-1094, 434D.
Dictionary of American Biography (New York, 1930), vol. XV, 464-65.
The Directory of Pittsburgh and Allegheny for 1875-76.
Frederick Way, Jr., Way's Packet Directory 1848-1983 (Athens, Oh., 1983), 539 et al.