Rodman gun

The Rodman gun is a family of large smoothbore cast iron cannons designed by American Union artillery officer Thomas Jackson Rodman for United States coastal defense, produced from 1861 into the early 1870s and used through the American Civil War and afterward. Rodman developed a hollow casting method that cooled the guns from the inside out rather than the outside in, producing stronger barrels than earlier casting techniques allowed, and the guns were built in bores from 8 inch up to a rare 20 inch size at foundries including Fort Pitt in Pittsburgh, Cyrus Alger and Company in Boston and West Point Foundry in Cold Spring, New York. More than 140 examples survive today at coastal fortifications around the United States, recognizable by their curving bottle shape and large flat cascabel.