On February 28, 1844, President John Tyler cruises the Potomac with 400 others aboard the U.S. Navy’s new steam frigate USS Princeton, not realizing that his life will soon be in danger. In attendance that day were political dignitaries and their guests, which included the wealthy New Yorker David Gardiner and his two daughters. The 54-year-old Tyler, a recent widower, had fallen for Gardiner’s youngest, the lovely 20-year-old Julia, to whom he had proposed marriage. She had not yet responded.

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The Princeton carried a brand new 12-inch, 27,000-pound cannon called the Peacemaker. The gun’s co-designer, John Ericsson, argued with the ship’s captain, who wanted to demonstrate the new weapon, over whether it was safe to discharge because he feared it had not been sufficiently tested. Days before the cruise, Captain Robert Stockton had boasted about the Navy’s new ship and armament, which he had helped design, to congressmen and reporters. He and the crew were eager to show off the cannon’s ferocity, and despite Ericsson’s warnings, Stockton insisted on firing the cannon during the Potomac cruise. The first two successful and ear-splitting volleys sent the crowd into wild applause.

Halfway through the cruise, President Tyler, below deck, proposed a toast to the three great guns: the Princeton, her Commander and the Peacemaker. Then the secretary of war asked for a third firing toward Mount Vernon in honor of George Washington. Stockton may have recalled Ericsson’s concerns or thought it best not to push their luck with the new cannon, because he initially refused the secretary’s request. In the end, though, he bowed to his superior’s wishes and gave the order to fire.

The third round proved deadly. In the worst peacetime disaster of its time, the cannon exploded, killing several aboard, including Julia’s father and two members of Tyler’s cabinet. Tyler was halfway up the ladder to the upper deck when the explosion occurred. Julia Gardiner fainted when she heard of her father’s death and, after the ship docked, Tyler whisked her off to safety in his arms. Julia’s admiration for Tyler deepened into love and they were married later that year.