Scientists Discover New Stealth Feature on H.L. Hunley
http://www.news.navy.mil/search/display.asp?story_id=18815

Conservators of the Civil War submarine H. L. Hunley, working with the Naval Historical Center (NHC), discovered a previously unknown stealth feature called a deadlight while removing the concretion on one of the 10 glass ports, June 15.

(read the rest at the URL, but ya know, those deadlights were very apparent when I saw the Hunley.)