Also known as: Rodman columbiad.
| Type | Heavy iron smoothbore columbiad |
|---|---|
| Process | Hollow casting with a water-cooled core |
| Role | Seacoast and heavy defense |
| Largest | 20-inch bore, firing a shot of over 1,000 pounds |
Strength through casting
The Rodman gun was a heavy smoothbore columbiad whose strength came from the way it was cast. Rather than casting the gun solid and boring it out, Rodman's process cast it around a hollow, water-cooled core so the iron solidified from the inside outward, leaving the bore surface in compression and greatly reducing the internal stresses that caused large guns to burst.
The method produced seacoast columbiads of 8-, 10-, 15-, and even 20-inch bore, the largest being among the biggest cannon ever built. Rodman guns armed the heavy and coastal batteries and could throw shot or shell at both high and low angles.
On this site
Sources & further reading
- CivilWarArtillery.com research archive: cannon identification pages, manuals, and reports.
- United States Army, Ordnance Department. The Ordnance Manual for the Use of the Officers of the United States Army. 2nd ed. Philadelphia: J. B. Lippincott, 1862.