Dahlgren Guns "Massive Smoothbores"
John A.B. Dahlgren had already had a distinguishing 24-year career with the U.S. Navy before the secession of the Southern states. He had begun his career as a seaman at the age of 17 in 1826 and served for 16 years before becoming a midshipman in 1842. During a tour of duty at the Washington Navy Yard that began in 1847, Dahlgren established the U.S. Navy's ordnance department and began designing naval guns.
Though Dahlgren designed several classes of guns, he is best known for the massive smoothbore iron canon cast in the distinctive "soda bottle" shape that provided extra-thick walls at the breech of the gun. The revolutionary design allowed for the production of larger, more potent guns that were less likely to explode at the breech when fired.
The first Dahlgren-designed canon was the 9-inch gun produced in 1850; it was followed by an 11-inch version the next year. These smoothbore canon were designed to fire shells against the wooden ships of the era, but they proved to be strong enough also to fire massive 170-pound solid shot, which was more effective against the new ironclad ships of the Civil War.
In 1862 the Navy asked Dahlgren to design 15-inch and 20-inch versions of the guns. The barrel of the 15-inch gun weighed over 20,000 pounds and required a hoist and a two-man crew to load the 400-pound spherical shot. Dahlgren guns were very effective weapons against ships and coastal fortifications and were placed on many of the new federal ironclads; the Monitor used two 11-inch Dahlgrens during its battle with the Merrimack in Hampton Roads, VA.
The Confederacy captured many Dahlgren guns and used them effectively in its own defense. While in command of the blockade off Charleston, SC., Dahlgren had the opportunity to both receive and deliver the effects of his brainchild.
Fascinating Fact: Only one 20-inch Dahlgren gun was produced, but it was never used in the war.
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