On 7 September 1776, the experimental American submarine Turtle, under the guidance of army volunteer Sergeant Ezra Lee, was alleged to have attacked HMS Eagle, which was moored off what is today called Liberty Island, but was unable to bore through the hull. When Lee attempted another spot in the hull, he lost the ship, and eventually abandoned the attempt.
British naval historian Richard Compton-Hall stated that the problems of achieving neutral buoyancy would have rendered the vertical propeller useless. The route Turtle would have had to take to attack HMS Eagle was slightly across the tidal stream which would, in all probability, have resulted in Ezra Lee becoming exhausted having only 20 minutes of air. There is no record of the Royal Navy recording an attack.[2] In the face of these and other problems Compton-Hall suggests that the Turtle got nowhere near HMS Eagle and the entire story was fabricated as disinformation and morale-boosting propaganda, and that if Ezra Lee did carry out an attack it was in a covered rowing boat rather than Turtle.[2]