To combat the North’s revolutionary ironclads, the South developed equally revolutionary weapons such as submarines, torpedoes, and land mines. On December 12, 1862, the USS Cairo became the first victim of an electrically-detonated torpedo. Since raised and restored Cairo is now on display in Vicksburg National Military Park: https://www.nps.gov/vick/learn/historyculture/uss-cairo-gunboat.htm.