On December 29, 1929, just after 2:00 a.m., the Coast Guard patrol boat C.G. 290 lay in wait by a small group of islands in Naragansett Bay, Rhode Island. The islands provided cover for rumrunners who regularly dashed their shipments of illegal liquor to the mainland during the era of Prohibition. The job of the Coast Guard, to intercept smugglers, was difficult that night due to a thick fog that blanketed the sea. But Boatswain Alexander C. Cornell, the commander of the patrol boat, was one of the most zealous of the so-called “rum-chasers” and took his duty to heart–he would capture them, no matter the cost.

Through the mists, a mechanized growl of engines drew closer. Cornell peered out of the starboard window of the pilothouse. “Here she comes,” he said. His crew got the searchlight ready–as well as C.G. 290’s machine gun.

The violent events that followed would stir anger against the enforcement of Prohibition and eventually contribute to the national ban’s demise.

Out of the fog, a gray shape appeared. The boat was low in profile and equipped with powerful 300-horsepower engines. Cornell knew the vessel in an instant–the Black Duck, a rumrunner that could easily make speeds of over 30 knots and which had evaded capture on numerous occasions. All about its decks were stowed burlap sacks–each of these 383 individual packages carried assorted liquors, a bounty for the upcoming New Year.

The Black Duck would have picked up the booze from a mothership that loitered outside of American territorial waters along with other large vessels in what were called “rum rows.” Since the United States could not enforce Prohibition outside of the country’s territorial waters, the Coast Guard was relegated to catching the craft that darted from the motherships to the various coves and lonely beaches of the American shore.

It was an impossible task, since a great part of the country ignored the validity of the 18th Amendment, especially in New England which was “wet” territory. In fact, the local, young men aboard the Black Duck saw smuggling as a means of making extra money. The pilot of the Black Duck, Charlie Travers, had even served a brief enlistment in the Coast Guard. He was known to be charitable with his ill-gotten earnings.

Cornell testified that they had given a signal to the rumrunner to heave-to, but instead the Black Duck pulled out to sea. Cornell ordered his men to fire a warning shot. “Let them have it,” he ordered. But according to Cornell, the Black Duck suddenly veered its course and headed straight into the fire. Twenty bullets riddled the rumrunner’s pilothouse leaving three of the four men aboard dead, and a fourth man with a wounded hand. The Black Duck then returned to the C.G. 290 looking for help.

The sole survivor of the Black Duck, Charlie Travers, claimed that the C.G. 290 had not flashed any signal to them. Travers contended that he had veered the boat in order to avoid a collision since the C.G. 290 came suddenly out of the fog, and he didn’t immediately recognize the boat as Coast Guard. The Coast Guard, according to Travers, opened fire on them without warning.

There were enough variances between the forensic evidence and Cornell’s story to question the truth of the Coast Guard’s account. For example, when the Black Duck was examined, the bullet holes did not match with Cornell’s account.  The holes seemed to show that the Black Duck may have been speeding away from the fire, not turning into it.  Still, the Coast Guard held an inquiry and exonerated Cornell. But the matter did not end there.

To the public at large, the Black Duck became a symbol of the failures of Prohibition. On January 1, 1930, Cornell received a letter addressed to “Mr. Cornell, the Hun” which warned him not to come ashore since “Death is waiting for you and your crew.” On January 3, a protest meeting was held in Boston, where the chair of the meeting claimed that 1,100 men, women and children had been killed in the so-called “Rum War.” After the meeting, an angry mob attacked a Coast Guard recruiting station. Property of the Coast Guard was vandalized. Then on January 7, a mob of 20 men attacked Cornell’s houseboat while it was moored near New London, Connecticut. Although Cornell himself was not home, his wife and five children huddled in fear as stones shattered the windows of the boat.

There were demands for an impartial investigation into the affair. Public figures questioned the integrity of government and what was considered to be appropriate law enforcement—as well as the hypocrisies of Prohibition. Politician John F. Fitzgerald (grandfather of President John F. Kennedy) pointed out how the illegal cargo aboard the Black Duck would be consumed by “public officials everywhere.” Representative Fiorello LaGuardia, the future mayor of New York, noted how Prohibition “cannot be enforced.” Forgotten, seemingly, was the fact that the Black Duck, was indeed carrying liquor. In fact, Charlie Travers was determined suitably punished by a federal grand jury for having lost his thumb in the attack.

This episode was one among a series of key incidents to shift public opinion and lend momentum to efforts to repeal Prohibition. Four years later, on December 5, 1933, the 21st Amendment to the U.S. Constitution was ratified, repealing the 18th Amendment and bringing an end to the national ban of alcohol in America.

The critic and journalist, H.L. Mencken, wrote at the time, “It is not often that anything to the public good issues out of American politics. This time, they have been forced to be decent for once in their lives.”

Joseph A. Williams is the author of The Sunken Gold: A Story of World War I, Espionage, and the Greatest Treasure Salvage in History. and Seventeen Fathoms Deep: The Saga of the Submarine S-4 Disaster.