Hunley and McClintock moved to Mobile, to begin development of a second submarine, American Diver with the collaboration of two others. Their efforts were supported by the Confederate States Army. Lieutenant William Alexander of the 21st Alabama Infantry Regiment was assigned to oversee the project. The builders experimented with electric and steam propulsion for the new submarine, before falling back on a simple hand-cranked propulsion system. American Diver was ready for harbor trials by January 1863, but she proved too slow to be practical. Nonetheless, it was decided to tow the submarine down the bay to Fort Morgan and attempt an attack on the Union blockade. However, the submarine foundered in the heavy chop caused by foul weather and the currents at the mouth of Mobile Bay and sank. The crew escaped, but the boat was not recovered.
