obscure. She or other torpedo boats tried more attacks on Union blockaders; reports from different ships claim three such attempts, all unsuccessful, during the remainder of October 1863. On March 6, 1864, David attacked in the North Edisto River. The torpedo boat struck the blockader first on the port quarter, but the torpedo did not explode. Memphis slipped her chain, at the same time firing ineffectively at David with small arms. Putting about, the torpedo boat struck Memphis again, this time a glancing blow on the starboard quarter; once more the torpedo misfired. Since Memphis had now opened up with her heavy guns, David, having lost part of her stack when rammed, retreated up the river out of range. Memphis, undamaged, resumed her blockading station. Davids last confirmed action came on April 18, 1864 when she tried to sink the screw frigate . Alert lookouts on board the blockader sighted David in time to permit the frigate to slip her chain, avoid the attack, and open fire on the torpedo boat. Neither side suffered any damage. The ultimate fate of David is uncertain. Several torpedo boats of this type fell into Union hands when Charleston was captured in February 1865. David may well have been among them. Wrecks discovered On January 20, 1998, underwater archaeologist Dr. E. Lee Spence led a Sea Research Society expedition, funded by philanthropist Stanley M. Fulton, to find the remains of the two Confederate torpedo boats shown in various photos taken shortly after the fall of Charleston. Spence's theory was that the two vessels had been abandoned where they lay and were simply filled over as the city expanded. Spence used still existing houses in the pictures to triangulate where they might be. Using a ground penetrating radar, operated by Claude E. "Pete" Petrone of National Geographic Magazine, the expedition located two radar anomalies consistent with what would be expected of the two wrecks. The anomalies were under present-day Tradd Street, so no excavation was done. A post-war letter written by David C. Ebaugh, who supervised the construction of David, described her as abandoned at what was then the foot of Tradd Street. Other "David"s "David" came to be the generic term for any torpedo boat resembling this David. An unknown number of torpedo boats of the David-type were built for and operated by the CSN. When Federal forces captured Charleston in February 1865, they