With the Northern fleet blockading the South's ports, the torpedo boat was devised as a counterblockade weapon. In 1863, the first purpose-built torpedo boat was conceived and built near Charleston, South Carolina using private funding. Using an earlier concept of Ross Winans, Dr. Ravenel provided the initial design for the vessel and the construction was completed with the aid of David C. Ebaugh. Named the "David", this cigar-shaped, semi-submersible vessel was fitted with a torpedo at the end of 14-foot iron spar mounted at the bow. The idea was to drive the steam-powered boat at an enemy ship and detonate the torpedo along the hull. On October 5, 1863, the CSS "David" was used to attack the USS "New Ironsides" near Charleston Harbor, causing damage but failing to breach the hull.