John Fitch was an American inventor who pioneered the construction of steamboats in the United States and developed the first marine screw propeller. He carried out the first successful trial of a 45-foot steamboat on the Delaware River on 22 August 1787, in the presence of members of the Constitutional Convention. Later he built a larger vessel that carried passengers and freight between Philadelphia and Burlington, New Jersey. He was granted a US States patent for a steamboat in 1791, but it was only two decades after this that Robert Fulton was able to make steamboats profitable.