How did the Confederate submarine H.L. Hunley change naval warfare?

The H.L. Hunley changed naval warfare by becoming the first submarine in history to successfully sink an enemy warship in combat.12

On February 17, 1864, the Confederate submersible attacked and sank the Union sloop Housatonic in Charleston harbor using a spar-mounted torpedo. This event marked a revolutionary moment in naval history, demonstrating the potential of underwater vessels to challenge superior surface fleets.132

While the Hunley itself was lost shortly after the attack—likely due to a shock wave from its own weapon that incapacitated the crew—its success proved that unconventional, small-scale submersible craft could pose a lethal threat to traditional warships. This development was part of a broader shift toward technological innovation during the American Civil War, which also saw the introduction of ironclad warships and increased reliance on steam power and rifled ordnance.132