In a recent article in this journal we presented an analysis of productivity change of steamboats on western rivers, 1815–60. Although the steamboat dominated river commerce during this period, other transportation technologies had been and were available. Prior to the steamboat era, keelboats and flatboats were the primary means by which the agricultural surpluses of the trans-Appalachian regions reached outside markets (especially through New Orleans). Although flatboating persisted, keelboating was quickly eclipsed with the introduction of the steamboat. This contrast is explained in part by the differential impact of the steamboat on upstream and downstream rates. Successful keelboat operations depended primarily on upstream revenues, and it was on the upstream rates that the steamboat had its most dramatic effects. One study indicates that by the early 1820's, keelboat revenues on the Mississippi had fallen below or very near to average variable costs, and keelboating was maintained only on shallower waters off the main trunk routes. Alternatively, flatboating not only survived but even expanded in the face of the stiff competition generated by the newer technology. For instance, in 1816, the year before the first successful steamboat navigation of the western rivers, 1287 flatboats arrived in New Orleans. By the commercial year 1846–47, the number of arrivals had increased to a peak of 2792. This persistence of flatboating occurred despite the fact that flatboats underwent no changes in their physical characteristics. Neither were there any apparent technical advances in their handling or navigation.