The German U 1: no war patrols, training flotilla only,
http://uboat.net/wwi/boats/index.html?boat=1
I think, the answer should be: "CSS H.L. Hunley who attacked the USS Housatonic Febr. 1864",
http://en.wikipedia.org/wiki/H.L._Hunley.
On raising and conservation of the Hunley, see here:
http://www.tms.org/pubs/journals/JOM...Byko-0103.html, cit.:
"When all the work is done, the sub will be moved to a permanent home in the ---Charleston Museum---, a tribute to the cutting-edge technology of 1863, uncovered and preserved with the cutting-edge technology of the 21st century."