The torpedoes used by the Confederates were various in form and construction. The most efficient ones were the galvanic and percussion. The percussion or "sensitive" ones exploded by the act of forcible contact. Some of these were made in the form of a double cone, with percussion tubes arranged around the cylinder thus formed, at the point of contact of the bases of the cones.
Benson John Lossing, ed. Harper's Encyclopedia of United States History (vol. 9) (New York, NY: Harper and Brothers, 1912)
Courtesy the private collection of Roy Winkelman