In 1798, inventor Robert Fulton demonstrates a primitive submarine, the Nautilus, modelled on Thomas Bushnell's Revolutionary War-era creation, the Turtle. Fulton's vessel carries sail for surface propulsion and is driven by a hand-cranked screw propeller while submerged. It carries a primitive explosive device called a 'torpedo' as its only armament.

Improved versions will be developed over the next several years, and in the War of 1812, Fulton's submersibles will prove valuable in confrontations between the American navy and its British counterpart on the Mississippi River and the Great Lakes. It will not be un til the 1840s, however, that a seagoing version will be practical, and even then, the early models will be incapable of crossing the Atlantic entirely underwater.