The H.L. Hunley, a Confederate submarine, sealed its place in history on a February night in 1864 when it became the world's first sub to sink an enemy warship in combat. Then its own fate was sealed when it sank mysteriously to the bottom of the ocean off the coast of Charleston, S.C., killing its crew of eight.

There the Hunley rested on its starboard side at a 45-degree angle until it was lifted from the ocean floor at that exact angle in 2000. Late last week, preservationists finished two painstaking days of work that allowed them to rotate the Hunley to its upright position.

Starting Wednesday, conservation specialists at Clemson University's Warren Lasch Conservation Center in Charleston began the process of rotating the 7-ton, 40-foot submarine to expose a side of its hull never before seen in the post-Civil War era....