The Rodman gun is any of a series of American Civil War–era columbiads designed by Union artillery officer Thomas Jackson Rodman[1] (1815–1871). The guns were designed to fire both shot and shell. These heavy guns were intended to be mounted in seacoast fortifications. 8-inch, 10-inch, 13-inch, 15-inch, and 20-inch bore (20, 25, 33, 38, and 51 cm) Rodman guns were produced. Other than size, the guns were all nearly identical in design, with a curving bottle shape, a large flat cascabels, and ratchets or sockets for the elevating mechanism. Rodman guns were true guns that did not have a howitzer-like powder chamber, as did many earlier columbiads. Rodman guns differed from all previous artillery because they were hollow cast, a new technology that Rodman developed that resulted in cast-iron guns that were much stronger than their predecessors.