 In addition to increased capacity, "Discovery II" also proved mechanically reliable, embarking on over 5,000 trips without a single mechanical delay.By the mid-1980s, however, a growing tourism industry meant that "Discovery II", like "Discovery I" before it, was becoming too small for the Riverboat Discovery's needs.The increased number of passengers straining "Discovery II" 's capacity precipitated the design and construction of the third Riverboat Discovery sternwheeler, "Discovery III", in 1986-1987.