Forts Versus Ironclads

Forts Versus Ironclads. . The Confederate response to Union gunboats on the western rivers was to build a series of forts. The better forts were built on higher ground allowing for "plunging fire" upon Union ships. Forts Sevier, Clark, and Terry in Clarksville were located to protect the rivers and two railroad bridges. Fort Sevier's height above the river, however, would have slowed its rate of fire, as the downward angle of the guns would have been too steep. Fort Donelson was heavily armed against the gunboats with 12 guns including 32-pounder smoothbore cannons, a 10-inch Columbiad smoothbore and a 6.5 inch rifled Columbiad, and two 30-pounder Carronades. Fort Henry had 17 heavy guns facing the river. By contrast, Forts Sevier and Clark had a combined total of six heavy guns. These forts also used smaller 6 to 12-pounder cannons for land defense. , Some of the bigger guns were mounted on wooden carriages, called barbettes, which allowed for recoil and reloading. Barbettes swiveled on a central pole called the pintle. Columbiads were mounted on iron carriages strong enough to take the shock of their fire, but sometimes broke while firing, which happened at Forts Henry and Donelson. , Confronting the forts were Union "City Class" ironclad gunboats measuring 175 feet long by 51 feet wide and initially costing $89,600 each. Ironclads carried three 8-inch guns in the bow, with four 43-pounders and six-32 pounders mounted along the casemates - sloped, armored structures framed with wood 18 inches thick and covered by 2.5 inches of iron plate. , Union timberclad gunboats, converted from steamboats, lacked armor but carried heavy guns and were designed to attack other boats and troops close to the rivers.