Check out the Submarine Force Library and Museum, on the Thames River in Groton, Conn., near the huge submarine base and submarine-construction complex there, right across the Thames River from New London, whence you can take a ferry to Long Island and Block Island and get on an Amtrak train, too.
In 1775, at the start of the Revolutionary War, David Bushnell, then a Yale student, was said to have designed and built the world's first submarine used in combat -- a one-man boat that could be used to mine ships with explosives.
He called it Turtle. He developed the ideas of using water as ballast for submerging and raising submarines as well as for the screw propeller, which was used in Turtle.
Bushnell also proved that gunpowder could be exploded under water and made the first time bomb. Thus Turtle was designed to be used to attack ships by attaching a time bomb to their hulls, using a hand-powered drill and ship auger bit to penetrate the hulls.
On Sept. 6, 1776, Turtle, manned by Sergeant Ezra Lee of the Continental Army, was used to attack the British 64-gun ship of the line HMS Eagle, which was moored in New York Harbor. However, Turtle's attack failed.
But Bushnell pressed on.
You can see a replica of Turtle in the museum.
Yankee ingenuity indeed!