and the armaments required to support it, said the Navy welcomed politicians "to fire their souls with patriotic ardor for a naval war". Design Machinery Princeton was the first ship with screw propellers powered by an engine mounted below the waterline to protect them from gunfire. Her two vibrating lever engines, designed by Ericsson, were built by Merrick & Towne. They burned hard coal and drove a six-bladed screw. Ericsson also designed the ship's collapsible funnel, an improved range-finder, and recoil systems for the main guns. Guns Twelve carronades were mounted within the ship's iron hull. Ericsson had also designed the ship to mount one long gun. The gun, a smooth bore muzzleloader made of wrought iron, was built by Mersey Iron Works in Liverpool, England. It could fire a , shot using a charge. Its revolutionary design used "built-up construction", 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. Originally named "The Orator" by Ericsson, Stockton renamed it the "Oregon gun." It was shipped to the United States in 1841, where it was tested, reinforced to prevent cracks, and proof-fired more than 150 times. Captain Stockton wanted his ship to carry two long guns, so he designed and directed the construction of "Peacemaker", another muzzleloader, by Hogg and DeLamater of New York City. "Peacemaker" was built with older forging technology, creating a larger gun of more impressive appearance but lower strength. Stockton rushed "Peacemaker" and mounted it without much testing. According to Kilner, "Peacemaker" was "fired only five times before certifying it as accurate and fully proofed." Attempting to copy the "Oregon gun," but not understanding the importance of Ericsson's hoop construction, Stockton instead heavily reinforced it at the breech simply by making the metal of the gun thicker, ending up with a weight of more than , more than half again as heavy as the Oregon gun. This produced a gun with the typical weakness of a wrought iron gun, the breech unable to withstand the transverse forces of the charge. This meant it was almost certain to burst at some point. 1844 Peacemaker accident President Tyler hosted a public reception for Stockton in the White House on February 27, 1844. On February 28, USS Princeton departed Alexandria, Virginia, on a demonstration cruise down the Potomac with Tyler, members of his cabinet, former