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Rodman Gun

History of the Rodman Gun

The 20" Rodman is the largest muzzle-loading gun ever made in the United States. The ability to manufacture a cannon of this size required new technology developed by Thomas Jackson Rodman.

This new casting process grew out of Rodman's interest in gun improvement, developed during his training at the U.S. Army War College at West Point, New York, and following a particularly tragic incident aboard the USS Princeton in 1844 Already received.

Lieutenant Thomas Jackson Rodman was assigned to the Army Ordnance Department at the Allegheny Arsenal in Pittsburgh, Pennsylvania, after finishing seventh in his class at West Point in 1841. In 1844, the USS Princeton was one of the most advanced ships of its timebecoming the first helical steam warship fielded by the U.S.

Navy. She soon installed a 14-foot 6-blade auger powered by a coal-fired boiler. She needed guns that could project power, so in January 1844, the Princeton sailed to New York to receive two of her cannons, named "Peacemaker" and "Oregon."

The Oregon is a 12" (300 mm) smoothbore loaded wrought iron gun that fires a 225 lb (100 kg) bullet at 8 km (5 mi) and is loaded with 50 lb gunpowder. The gun is manufactured by Mersey Steel The factory was built in England and sold to the US Navy in 1841. A new construction method was used, placing hot iron hoops from the forge on the rear of the cast cannon. The procedure should allow more powder to be used to prevent explosions when fired. The second gun - the Peacemaker - was made in the US by Hogg and Dela Matt in New York and was also a 12-inch muzzle loader that rivaled the British-made Oregon in firing and range.

However, the construction process was different, as Peacemaker did not use the extra band for support. During the casting process itself, the metal thickness at the breech end increased.

The weight of the cannon was greatly increased without reducing the shortcomings previously encountered in the manufacture of wrought iron cannons.

The USS Princeton arrives in Washington, D.C., to board a distinguished team to observe the firing of new heavy artillery. She sailed out to sea near the capital, and the demonstrations began with the first test gun, the Peacemaker. The first shot was a success. However, a second shot detonated the cannon, killing several nearby observers, including Secretary of State Abel P. Upshur, Secretary of the Navy Thomas Gilmer and members of several other prominent political parties.

The Navy investigated the incident and reviewed the manufacturing process, concluding that a serious error had occurred in the casting of the weapon. The incident was the talk of the military at the time, and Lieutenant Rodman, stationed at the Allegheny Arsenal, began researching the metallurgical properties of gunmetal used to cast guns.

Rodman was a gifted inventor who now has the ability to experiment at personal expense. As an Army officer assigned to the arsenal, he had a workshop and competent staff to trial and error various theories and processes.

Casting a cannon is a long and difficult process, and for some it's even an art form. Rodman concluded that the process of forming, heating, cooling, and reheating created stresses and strains in the metal, creating critical weaknesses that only became apparent later.

Also in the final stages, the cannon gets bored, and that alone puts more pressure on the metal. Rodman agreed with the Navy's findings that stress fractures were the cause of the Peacemaker's explosion.

The method invented by Rodman is to reduce the temperature flow during the pouring process by continuously flowing water through the hollow pouring tube. Now the metal cools from the inside out, allowing each layer of metal to compress without tension, creating a weapon with fewer mistakes. Rodman reviewed the new program with the War Department, but was initially rejected. However, he applied for and received a U.S. patent application to manufacture his new cannon at the Fort Pitt Foundry.

By 1849, Rodman's cannon using his new process proved to be safer than anything previously made in the United States, and could fire more shells in a row without incident.

Major Rodman is now director of the Armory in Watertown, Massachusetts, overseeing the operations of the Fort Pitt, Pennsylvania, foundry. He knew the 20-inch gun would weigh 100,000 pounds, and heavier than the armory could hold.

New machinery had to be designed and built to support the large six-kiln project. On February 11, 1864, the 20-inch gun was cast in a four-piece mold. The process uses tap water flowing through the barrel. The gun took over a week to build. At the end of the process, the gun was engraved with "No.

1 116,497 lb / Fort Pitt Pa 1864". She was then transferred to Fort Hamilton in New York Harbor, where she still resides today. The second Rodman gun was located across from the Port of New Jersey at Fort Hancock. The third was sold to Peru.

The 20-inch Rodman's cabin itself weighs an impressive 36,000 pounds.

During the American Civil War, the Confederate arsenal also ended local production of replica Rodman guns. However, their quality is not as good as that of the northern factory.