Total Overkill: The Civil War Monster Cannon
June 10, 2014
While working with one of the Midwest Genealogy Center’s archival collections, the Titus Family Collection, I came across an interesting bit of history. In the course of my transcription of letters written by Private Square Holt during the Civil War, I came across a reference to a “gun that fired a thousand pound shot.” This description intrigued me, so I decided to look into the gun and to find the history of this “monster” cannon.
To say Union Major Thomas Jackson Rodman liked big guns is an understatement. In an era where 8-inch cannons were the typical heavy weapons, he created a series of “monster” cannons, the largest of which was the 20-inch Rodman gun. He limited his ambitions reluctantly to a “mere” 20-inch gun firing a half-ton shot as “quite big enough.” Anything larger would have required massive machinery just to load it!
This was the largest gun ever attempted at that time, and it took 6 different furnaces and 160,000 pounds of molten iron to cast it. The finished barrel weighed 116,497 pounds, and it was over 20 feet long. It could fire a shell weighing 1080 pounds as far as 5 miles. The carriage for it weighed 36,000 pounds.
The Pittsburgh Gazette reported on July 23, 1864 that "Juveniles, aged from ten to fifteen years, were amusing themselves today in crawling into the bore on their hands and knees. A good sized family including ma and pa, could find shelter in the gun and it would be a capital place to hide in case of a bombardment....”
Rodman's 20-inch cannons were fantastic weapons for their time, but from a practical point of view, their usefulness was extremely limited. Aiming time varied, but it took 2 minutes and 20 seconds just to traverse the gun and carriage 90 degrees. Hitting a fast-moving target would have depended largely on luck. They were never fired in anger.
These large guns still exist. The "No. 1" sits at Fort Hamilton in Brooklyn, New York. The second 20-inch Rodman looks out over New York Harbor from Fort Hancock in New Jersey.
If you are interested in seeing the letter that started it all, as well as the rest of the Titus Family Collection, click through the completely digital archival collection at MGC’s archival collections webpage.
David C. J.
Midwest Genealogy Center