The Cannons Cast Around a River of Water — The History of the Rodman Process

On February 11, 1864, the Fort Pitt Foundry in Pittsburgh poured about 80 tons of molten iron into a single mold in 22 minutes. Down the middle of that mold ran a pipe of cold water. When it cooled, it was the largest cannon in the world: a 20-inch gun weighing about 58 tons, able to throw a 1,080-pound iron ball more than four miles. This is the history of the Rodman process: how an Army captain from Indiana figured out that cooling a gun from the inside would make it far stronger, why his own department refused to let him try for fourteen years, the brutal firing trials that proved him right, the men and furnaces of the Fort Pitt Foundry, what it cost him, and how his idea survives today inside modern cannon barrels and diesel engines. We also show where you can still walk right up to his guns. CHAPTERS 0:00 February 11, 1864: 80 tons in 22 minutes 2:34 Guns that burst: Thomas Jackson Rodman 8:20 How to cast a gun around a river of water 14:36 The 15-inch, Fort Pitt and the 20-inch gun 21:26 The price 26:16 Steel, and the idea that never died 30:20 Where to see a Rodman gun today 33:23 Somebody did this by hand SOURCES Thomas J. Rodman, Reports of Experiments on the Properties of Metals for Cannon, and the Qualities of Cannon Powder (Ordnance Department, 1861) U.S. Patent 5,236, Improvement in Casting Ordnance, Thomas J. Rodman (1847) Cullum's Biographical Register of the Officers and Graduates of the U.S. Military Academy, Thomas J. Rodman J. Leander Bishop, A History of American Manufactures (1868), the Fort Pitt Works Heinz History Center, Rodman's Big Gun Rivers of Steel National Heritage Area, Rodman's Great Guns Pittsburgh Tribune-Review, Fort Pitt Foundry known for monster weapons (2008) Frank Leslie's Illustrated Newspaper, April 9, 1864 Naval History and Heritage Command, Dictionary of American Naval Fighting Ships: USS Princeton National Park Service: the Lincoln Gun at Fort Monroe, the 20-inch Rodman Gun at Fort Hancock, the 15-inch Rodman at Fort Foote, the 15-inch Rodmans at Fort Jefferson, and the Rodman guns of Fort Washington U.S. Army, Rock Island Arsenal history and self-guided tour (Brig. Gen. Thomas J. Rodman, Quarters One, the Rodman Gun) VA News, Army veteran Thomas Jackson Rodman Nature, vol. 128 (1931), review of Macrae, Overstrain of Metals and its Application to the Auto-Frettage Process U.S. Army, Watervliet Arsenal history HistoryNet, The Man Behind the Rodman Gun This video is an independent historical documentary made for educational purposes. It is not affiliated with or endorsed by the U.S. Army, the National Park Service or any museum mentioned. Figures come from the published sources listed above; where sources disagree, we give a range or use the most authoritative one. Archive images are public domain or used under fair use for commentary and education. Some visuals are illustrative reconstructions. If you spot an error, tell us in the comments with your source. Somebody did this by hand. Now you know how. #rodman #CANNON #foundry #pittsburgh #civilwar