Robert Fulton
The first successful trial run of a steamboat had been made several years earlier in the United States by inventor John Fitch, on the Delaware River on August 22, 1787. Attendees included delegates from the Constitutional Convention, who were observing while taking a break from their summer-long sessions at Independence Hall. The steamboat was propelled by a bank of oars on either side of the boat. The following year Fitch launched a boat powered by a steam engine driving several stern-mounted oars. These oars paddled in a manner similar to the motion of a swimming duck's feet. With this boat he carried up to thirty passengers for hire on numerous round-trip voyages on the Delaware River between Philadelphia and Burlington, New Jersey.
Steamboats of the Colorado River
From 1853, ranches were developed nearby up river to supply the fort with beef and barley. That same year gold was found up river. By 1854, copper mines were developed along the river 40 miles above Fort Yuma. The ore provided George A. Johnson & Co. with their first commercial cargo to take to the estuary anchorage. Old Mexican mines where reopened in the interior of the Gadsden Purchase that increased the traffic bringing in machinery and shipping out ore. By 1855, the volume of cargo necessitated putting another boat on the river. By December 1855, Johnson had John G. North build and bring in sections a new steamboat from San Francisco to the Delta estuary. There North assembled and launched the 120 foot long, 80 hp, wood hulled "Colorado". It was capable of carrying 70 tons of cargo while drawing only 2 feet of water and was the first stern-wheeler on the river.
Once the backlog of cargo was relieved by the "Colorado", Johnson looked for ways to keep his boats from being idle. He knew that Brigham Young wanted to establish a route to the Mormon settlements in Utah from the sea up the Colorado River and that merchant interests had been interested in establishing trade with the Mormons by the river route since 1852 when the "Uncle Sam" came to the river. Additionally there was the claim that the river was navigable by steamboat as far as the Virgin River by the fur trapper Antoine Leroux who had successfully rafted down the Colorado from the Virgin River in 1837. In 1856, George A. Johnson was instrumental in getting the support for Congressional funding a military expedition up the river. With those funds Johnson expected to provide the transportation for the expedition but was angry and disappointed when the commander of the expedition Lt. Joseph Christmas Ives rejected his offer of one of his steamboats claiming its cost was too high. Ives, a topographic engineer, used the money to build his own steamboat, the small, iron hulled, sternwheeler "Explorer" in Philadelphia, test it, disassemble and ship it to the Colorado estuary. There at Robinson's Landing, Ives spent a month assembling his steamboat, launching it on December 30, 1857. Johnson had lent Ives one of his men David C. Robinson as a pilot for the expedition, which set off for Fort Yuma the next day.