 In the early 1770s, David Bushnell, a Yale College freshman and Patriot, began experimenting with underwater explosives. By 1775, with tensions on the rise between the Thirteen Colonies and Great Britain, Bushnell had practically perfected these explosives. That year he also began work near Old Saybrook, Connecticut on a small manned submersible craft capable of affixing such a charge to the hull of a ship. The charge would then be detonated by a clockwork mechanism that released a musket firing mechanism, probably a flintlock, adapted for the purpose. According to Dr. Benjamin Gale, a doctor who taught at Yale, the firing mechanism and other mechanical parts of the submarine were manufactured by a New Haven clockmaker named Isaac Doolittle.
