http:// www.history.com/this-day-in-history/worlds-first-submarine-attack
On this day in 1776, during the Revolutionary War, the American submersible craft Turtle attempts to attach a time bomb to the hull of British Admiral Richard Howe’s flagship Eagle in New York Harbor. It was the first use of a submarine in warfare.
September 7 – American Revolution – World's first submarine attack: The American submersible craft Turtle attempts to attach a time bomb to the hull of British Admiral Richard Howe's flagship HMS Eagle, in New York Harbor.
The route the 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 the Turtle.