Columbiad

Ten-inch Confederate Columbiad at Fort Donelson National Battlefield

The Columbiad was a large caliber, smoothbore, muzzle loading cannon able to fire heavy projectiles at both high and low trajectories. This feature enabled the columbiad to fire solid shot or shell to long ranges, making it an excellent seacoast defense weapon for its day. Invented by Colonel George Bomford, United States Army, in 1811, columbiads were used by the United States coastal artillery from the War of 1812 until the early years of the 20th Century. Very few columbiads were used outside of the U.S. Army, however.

The first columbiads produced in 1811 possessed a 7.25-inch diameter bore and took a fifty pound projectile. The army did not widely adopt early columbiads due to initial high costs of manufacture. Only after 1844 did an eight-inch model and a ten-inch model see mass production.

The eight-inch columbiad could project a 65 pound shell 4400 yards or 4800 yards for solid shot; the model weighed 9240 pounds. The ten-inch columbiad weighed 15,400 pounds and hefted a 128 pound shell to 4800 yards or solid shot to 5600 yards. These cast iron weapons were typically mounted on seacoast carriages designed to recoil up a slightly inclined set of "rails" or wooden beams. The mounted columbiad could pivot left or right on a traversing rail. In most cases the arc of pivot was less than 180 degrees, but some batteries allowed 360 degree traverse. Because of the weapons' enormous weight, once emplaced, columbiad batteries were not usually relocated.

Just prior to the American Civil War, ordnance officer Thomas Jefferson Rodman developed an improved version of the columbiad, which became known by his name. Specifically the Rodman gun was designed to reduce cracking and other weaknesses found in such large iron castings. The process evolved ensured the iron cooled evenly from the inside out, and resulted in what we might call today a "soda bottle" shaped casting with smooth, tapered exterior. The "Rodman" process also allowed the manufacture of much larger bore columbiads.

Between 1858 and the end of the Civil War, Northern foundries produced eight-inch, ten-inch, fifteen-inch and twenty-inch Rodman style columbiads. The smaller bore columbiads shared similar range factors to the older weapons, but the fifteen-inch models weighed over 25 tons and could fire 400 pound projectiles out to 5000 yards. The monster twenty-inch model weighed over 60 tons but could range to over 5 miles. Very few of the largest types were built, and none were fired in anger during the war.

Confederate States also used columbiads extensively, mostly stocks captured from Federal arsenals at the time of seccession. These acquitted themselves well against early ironclad warships. In addition, the Confederates produced limited quantities of eight-inch and ten-inch columbiads without the Rodman process; these could not withstand sustained use. The Confederates also rifled some columbiads in an effort to improve weapon performance.

After the Civil War, many columbiads remained in place at seacoast fortifications around the U.S. In the late 1870s several were rifled and tested for use against modern steel clad ships, with poor results. Strapped for funding, the post-war Army continued to carry smoothbore columbiads on inventory lists until after the Spanish-American War, when modern breech-loading rifled cannon replaced them. Today many columbiads are on display at several Federal and state parks commemorating the 19th Century seacoast fortifications. Still others "guard" courthouses around the United States.

References: Ripley, Warren. Artillery and Ammunition of the Civil War. The Battery Press, Charleston, S.C., 1984.