Did the first three people to drive it die? ;-)
But seriously, there were other designs around the same time. The French and the Union both were trying something similar.
"The American engineer Robert Fulton built one of the earliest submersible craft in 1800 in France under a grant from Napoleon. A collapsible mast and sail provided surface propulsion, and a hand-turned propeller drove the craft when submerged. A notable feature was the copper sheets over the iron-ribbed hull. Despite some experimental successes in diving and even in sinking ships, Fulton’s Nautilus failed to attract development support from either the French or the British."
... and why is the CSS Hunley noteworthy, and these others not?
Wiki: "Turtle (also called American Turtle) was the world's first submersible with a documented record of use in combat. It was built in 1775 by American David Bushnell as a means of attaching explosive charges to ships in a harbor. Bushnell designed her for use against British Royal Navy vessels occupying North American harbors during the American Revolutionary War. Connecticut Governor Jonathan Trumbull recommended the invention to George Washington; although the commander-in-chief had doubts, he provided funds and support for the development and testing of the machine."
