What was the first submarine used for and what was the event?

The first submarine used for military purposes was built in 1776 by David Bushnell (1742-1824) of the US. His "Turtle" was a one-man, wooden submarine powered by hand-turned propellers. It was used during the American Revolution against British warships. The Turtle would approach enemy ships partially submerged to attach explosives to the ships's hull. The Turtle worked well but the explosives did not.