Why did Fulton abandon his work on submarines?

Answer 1

Though Robert Fulton's submarine Nautilus (designed between 1793-97) was the first practical submarine design (it had a working ballast system and successfully dove to 25 feet), the primary reason he gave up was that it suffered from leaks. Additionally, though it had initially impressed the French during trials, when Napoleon wanted to see it, he found that Fulton had dismantled the Nautilus and destroyed many of its key components. Napoleon thought Fulton was a charlatan, and the French Navy had no use for what they believed then to be a suicidal machine.

The British, wanting to keep control over what appeared to them to be a potentially lethal device, brought Fulton to Britain to continue his work. However, with Nelson's victory over the French fleet at the Battle of Trafalgar, the French threat was eliminated, and Fulton was ignored until he finally left to return to America. His papers were left at the U.S. Consul in London, and went undiscovered until 1920. He never again worked on submarine designs.