While the United States Navy was constructing its first submarine USS Alligator, the Confederacy was developing their own submarines, driven by loyalty to the Confederate states and the potential financial gains from sinking enemy ships.

The Civil War in America, a conflict between the Union (North) and the Confederates (South), began. This war saw the introduction of new weaponry, including mines, accurate guns, and ironclad ships, marking a shift in combat tactics.

J.F. Carlsen entered the freight ship Grethe of Dragør. The ship landed in Charleston in February 1861, where records in the Danish military archives show that Carlsen deserted the ship. In June 1861, he entered Jefferson Davis (the Confederate privateer brig originally named Putnam) as a mate.

Pioneer, the first submarine financed by Horace Lawson Hunley and built by James McClintock and Baxter Watson, underwent testing in the Mississippi River and Lake Pontchartrain. However, the Union advance towards New Orleans forced the team to abandon the project, and Pioneer was scuttled the following month.

Lieutenant George E. Dixon was wounded in the thigh at the Battle of Shiloh. A $20 gold piece, minted in 1860, with the inscription "Shiloh April 6, 1862, My life Preserver G. E. D." on a sanded-smooth area of the coin's reverse side, stopped the bullet, saving his leg and possibly his life. He had the gold coin engraved and carried it as a lucky charm.

American Diver, the second submarine developed by Hunley, Watson, and McClintock, was ready for harbor trials. However, it proved too slow to be practical and sank in rough waters while being towed to Fort Morgan for an attack on the Union blockade.

Hunley was built at Mobile, Alabama.

Hunley successfully attacked a coal flatboat in Mobile Bay, supervised by Confederate Admiral Franklin Buchanan.

Hunley was shipped by rail to Charleston, South Carolina. Shortly after arriving, the Confederate military seized the submarine from her private builders and owners, turning her over to the Confederate Army.

Hunley sank during a test run, resulting in the death of five crew members.

Hunley failed to surface after a mock attack, resulting in the death of all eight crewmen, including Horace Lawson Hunley himself.

Hunley attacked and sank the USS Housatonic, a United States Navy ship, in Charleston's outer harbor. However, Hunley did not survive the attack and sank, taking all eight members of her third crew with her.

The Civil War in America, a conflict between the Union (North) and the Confederates (South) ended.

Underwater archaeologist E. Lee Spence reportedly discovered Hunley.

The National Park Service submitted the Sea Research Society's (Spence's) location for H. L. Hunley for inclusion on the National Register of Historic Places.

H.L. Hunley's placement on the National Register of Historic Places was officially approved.

Diver Ralph Wilbanks located the wreck while leading a NUMA dive team.

E. Lee Spence donated Hunley to the State of South Carolina.

The in situ underwater archaeological investigation and excavation culminated with the raising of Hunley.

Clive Cussler filed a lawsuit against E. Lee Spence for unfair competition, injurious falsehood, civil conspiracy, and defamation.

Lead researcher Maria Jacobsen found a misshapen $20 gold piece, minted in 1860, with the inscription "Shiloh April 6, 1862, My life Preserver G. E. D." close to Lieutenant Dixon.

The remains of the crew were laid to rest at Magnolia Cemetery, in Charleston.

Spence's lawsuit was dismissed through summary judgment.

Scientists reported they had found that the crew of Hunley had not set her pump to remove water from the crew's compartment, and this might indicate she was not flooded until after they died.

It was announced that conservator Paul Mardikian had found evidence of a copper sleeve at the end of Hunley's spar, indicating the torpedo had been attached directly to the spar, meaning the submarine may have been less than 16 feet (5 m) from Housatonic when the torpedo exploded.

The Duke team's experiments and results were published August 2017 in the peer-reviewed journal PLoS One and eventually became the subject of the book In the Waves: My Quest to Solve the Mystery of a Civil War Submarine.

Researchers reported that the keel blocks, which the crew could release from inside the vessel to allow the sub to surface quickly in an emergency, had never been released.