[Amnorix]

Originally Posted by patteeu

That's amazing.

Yeah, no kidding. I was stunned.

http://en.wikipedia.org/wiki/USS_Princeton_(1843)

A more detailed review, however, suggests that it wasn't eight cabinet members, but rather eight people including two cabinet members, and some other senior members of government.

Peacemaker accident

Contemporary lithograph depicting the explosion


On 28 February, she departed Alexandria, Virginia on a pleasure and trial trip down the Potomac with President John Tyler, his Cabinet and approximately two hundred guests on board. Upon the final firing of Stockton's Peacemaker, the defective gun at last burst, instantly killing Secretary Upshur; Secretary Gilmer; Captain Beverly Kennon, Chief of the Bureau of Construction, Equipment and Repairs; Virgil Maxcy of Maryland, Chargé d'Affaires to Belgium, 1837–42; David Gardiner of New York, the father of Julia Gardiner who later married President Tyler; and the President's valet, a black slave named Armistead. It also injured about 20 people, including Captain Stockton. When Julia Gardiner, who was aboard, found out her father had died in the explosion she fainted into President Tyler's arms. Some believed this is how they had met, but they had actually been introduced prior to the incident.

More detail on what went wrong with the gun:

The “Oregon”, originally named "The Orator", was a 12-inch (300 mm) smooth bore muzzle loader (ML) made out of wrought iron and was capable of firing a 225-pound (100 kg) shot 5 miles (8 km) using a 50-pound charge. It was designed by Ericsson and manufactured in England at the Mersey Iron Works and shipped to the U.S. in 1841. The design was revolutionary in that it used the "built-up construction" of placing red-hot iron hoops around the breech-end of the weapon, which pre-tensioned the gun and greatly increased the charge the breech could withstand.
The "Peacemaker" was another 12-inch muzzle loader made by Hogg and Delamater, New York, New York, under the designs and direction of Capt. Stockton. Attempting to copy the Oregon, but not understanding the importance of Ericsson's hoop construction, Stockton instead heavily reinforced it at the breech by simply making the metal of the gun thicker, ending up with a weight of more than 27,000 pounds (12,000 kg). This produced a gun that had the typical weakness of a wrought iron gun, the breech being unable to withstand the transverse forces of the charge. This meant it was almost certain to burst at some point. Stockton only allowed for a few test charges before putting it aboard the Princeton.
Princeton was sent to Washington, D.C. in late January 1844, arriving 13 February. Washingtonians displayed great interest in the ship and her guns. She made trial trips with passengers on board down the Potomac River on 16, 18, and 20 February, during which the Peacemaker was fired several times.