William Day (October 23, 1715 in Springfield, Massachusetts – March 22, 1797 in Sheffield) was a Springfield, Massachusetts (United States), sea captain who acted against America's enemies in both the French and Indian War and the American Revolutionary War. In 1777 he received the first gun salute to an American fighting vessel in a European port.
Little is known of the life of Revolutionary War sea captain William Day, beyond what was learned by those he captured in 1777. The birth and death dates assigned to him for this article are based on a claim he made then: that during the French and Indian War (the long American conflict which spread to Europe as the Seven Years' War) he served as a privateer on behalf of the British and their American colonists against French shipping. The family of William Day (1715-97) still possesses a portrait of him celebrating his triumph against a French convoy in that conflict, strongly implying that he is indeed the 1777 William Day.
In August 1756, Day was hired by George Campbell, a merchant of Liverpool, England, to command a 14-gun privateer brigantine named Brave Blakeney. Sailing into the Atlantic Ocean, he met with another British privateer, the Hawke of Exeter, and they agreed to co-operate. On 6 October, they sighted a small convoy of four French merchant ships off the Spanish coast near Cape Finisterre; these were the Robuste (14 guns), the Juste (22 guns, 10 of which turned out to be fakes), La Gloire (armament uncertain) and Victoire (10 guns). The French ships formed a battle line, but Blakeney got in among them and after a two-hour battle forced the surrender of the Juste. Meanwhile, Hawke's crew boarded and captured the Robuste. When these two ships were secured with prize crews, the British privateers chased the others. La Gloire threw guns and other equipment overboard to gain speed, but was caught by Blakeney; Victoire managed to elude Hawke long enough to escape in the night.