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.
James Watt junior
Watt later gave some technical assistance to Robert Fulton, providing in 1807 for Fulton the engine for "North River Steamboat", which was the first steamboat to run on the Hudson River. Becoming more seriously interested in marine engines, he bought in 1817 the "Caledonia" of 102 tons, fitted her out with new engines, and went in her to Holland and up the River Rhine to Coblenz, the first steamship to leave an English port. On his return he made major improvements in marine steam engines.