The Confederate submarine H.L. Hunley sits in a conservation tank at a lab in North Charleston, S.C., after a steel truss that had surrounded it was removed. Four days of events are scheduled for February 2014 to mark the 150th anniversary of the mission in which the hand-cranked submarine became the first sub in history to sink an enemy warship. The Hunley and its eight-man crew never returned from the mission. The wreck was discovered off Charleston in 1995 and raised five years later and brought to the conservation lab.

CHARLESTON, S.C. - Four days of events will be held in February marking the 150th anniversary of the Confederate submarine H.L. Hunley becoming the first sub in history to sink an enemy warship.

The hand-cranked sub and its crew of eight set off a torpedo that sank the Union blockade ship USS Housatonic off South Carolina in February of 1864 as the Confederacy tried to break the Civil War blockade of Charleston.

The Hunley never returned from the mission. The wreck was finally located off the coast in 1995, raised five years later and brought to a lab in North Charleston where it is being conserved. The plan is for the Hunley to eventually be displayed in a museum in North Charleston.

The four days of anniversary events begin on Valentine's Day and continue through Feb. 17, the 150th anniversary of the night the crew set off on its mission from Breach Inlet between Sullivans Island and the Isle of Palms northeast of Charleston.

There will be an honor guard and period re-enactors at the North Charleston lab from Friday, Feb. 14, through Sunday Feb. 16th. That Friday, active and retired military personnel will be able to tour the lab for $6, half the usual admission price.

On Saturday and Sunday, the first 150 visitors will receive a replica of the $20 U.S. gold coin credited with saving the life of the Hunley's commander, Lt. George Dixon, at the Battle of Shiloh in 1862.

Dixon's life was saved when a bullet hit the gold coin in his pocket. He carried the coin, on which he had inscribed "Shiloh April 6, 1862 My life Preserver," in his pocket on the Hunley mission.

There will be a $50-a-ticket reception at the lab on the evening of Saturday, Feb. 15, including a talk by genealogist Linda Abrams, who researched the backgrounds of the men of the Hunley crew.

On Monday, the anniversary of the mission, tickets for lab tours are only $1.50. Re-enactors will gather that evening at Breach Inlet for a memorial service honoring the Hunley crew and the five Union sailors who died when the Housatonic sank.

Why the Hunley sank is still a mystery, although scientists think they are close to solving the riddle.

Last year, scientists announced it appears that the charge that sank the Houstonic was attached to the 16-foot spar at the front of the sub. That means the sub may have been close enough for the crew to be knocked unconscious by the explosion and the crew may have died before awakening.

Historians originally thought the Hunley was farther away from the Housatonic and speculated the crew ran out of air before they could crank the submarine back to shore.