Episode Details

When a quiet Georgia doctor and teacher named David Bush died in 1824, his neighbors learned he was really David Bushnell, who had tried to break the British blockade with a submarine. As a Yale student in 1775 he built a clockwork flintlock that could fire gunpowder inside a sealed keg underwater, then designed a way to deliver it unseen. With his brother Ezra Bushnell, carpenter Phineas Pratt, and New Haven clockmaker Isaac Doolittle, he built the Turtle: two oak shells bound with iron bands and coated in tar, about 10 feet long, 6 feet tall, and 3 feet wide. It had a foot valve and brass pump for ballast, hand cranked screws for propulsion, about 30 minutes of air, and dials lit by glowing foxfire fungus.

Winter cold stopped the foxfire glowing in November 1775, and even Benjamin Franklin could not suggest an alternative. George Washington, skeptical, provided funding, but Ezra fell ill, so volunteer Sergeant Ezra Lee had two weeks to learn the controls. On the night of September 7, 1776 Lee spent two hours cranking across New York Harbor to Admiral Richard Howe's flagship HMS Eagle off Governors Island, but his screw would not bite, probably striking an iron plate near the rudder rather than copper sheathing. At dawn, chased by a British boat, he released the 150 pound charge, which exploded in the East River. The Turtle sank with its transport sloop in the Hudson that October, and Bushnell's later floating mines led to the mocking Battle of the Kegs.

• The Turtle was the first submarine with a ballast tank and the first watercraft with a documented propeller.
• British naval historian Richard Compton-Hall has argued the attack may never have happened as described.
• Washington later wrote to Thomas Jefferson that the Turtle was an effort of genius requiring too many things to combine.
• A 2003 Massachusetts College of Art and Design replica was tested at the US Naval Academy.
• In 2007 artist Duke Riley surfaced his homemade sub, the Acorn, near the Queen Mary 2 and was cited for marine mischief.