Steamboat
Similar boats were made in 1785 by John Fitch in Philadelphia and William Symington in Dumfries, Scotland. Fitch successfully trialled his boat in 1787, and in 1788, he began operating a regular commercial service along the Delaware River between Philadelphia and Burlington, New Jersey, carrying as many as 30 passengers. This boat could typically make and travelled more than during its short length of service. The Fitch steamboat was not a commercial success, as this travel route was adequately covered by relatively good wagon roads. The following year, a second boat made excursions, and in 1790, a third boat ran a series of trials on the Delaware River before patent disputes dissuaded Fitch from continuing.
French battleship Napoléon
The United Kingdom already had a few coastal units with screw/steam propulsion in the 1840s, called "blockships", which were conversions of small traditional battleships into floating batteries with a jury rig, with a medium engine for speeds of to . The Royal Navy had also commissioned a number of steam sloops, being the first screw-propelled warship to be launched anywhere in the world in 1843. Both nations had also developed steam frigates, the French launched in 1845, and the British a year later. However, "Napoléon" was the first regular steam battleship to be launched.
In 1847, Britain had designed a screw/steam battleship named , but the project much delayed and she did not enter service until 1854. Her sister ship, was ordered in 1849 and commissioned in January 1853. Another sailing battleship, was converted to steam on the stocks and launched in March 1851; she beat "Agamemnon" into service in November 1852. Britain’s reluctance to commit to the steam battleship apparently stemmed from her commitment to long-distance, worldwide operation, for which, at that time, sail was still the most reliable mode of propulsion.