H. L. Hunley (submarine) - Armament

Armament

Hunley was originally intended to attack by means of a floating explosive charge with a contact fuse (a torpedo in Civil War terminology) towed behind it at the end of a long rope. Hunley would approach an enemy vessel, dive under it, and surface beyond. As it continued to move away from the target, the torpedo would be pulled against the side of the target and explode. However, this plan was discarded as impractical due to the danger of the tow line fouling Hunley's screw or drifting into Hunley herself.

The floating explosive charge was replaced with a spar torpedo, a copper cylinder containing 90 pounds (41 kilograms) of black powder attached to a 22-foot (6.7 m)-long wooden spar, as seen in illustrations of the submarine made at this time. The spar was mounted on Hunley's bow and was designed to be used when the submarine was some 6 feet (1.8 m) or more below the surface. The spar torpedo had a barbed point, and would be stuck in the target vessel's side by ramming. The spar torpedo as originally designed used a mechanical trigger attached to the attacking vessel by a cord, so that as the attacker backed away from her victim, the torpedo would explode. However, archaeologists working on Hunley have discovered evidence, including a spool of copper wire and components of a battery, that it may have been electrically detonated. Following Horace Hunley's death, General Beauregard issued an order that the submarine was no longer to attack her target underwater. In response to this order, an iron pipe was attached to the bow of the submarine and angled downwards so the explosive charge would still be delivered under sufficient depth of water to make it effective. This was the same method developed for the earlier "David" type surface craft so successful against the USS New Ironsides. The Confederate Veteran of 1902 printed a reminiscence authored by an engineer stationed at Battery Marshall who, with another engineer, made adjustments to the iron pipe mechanism before Hunley left on her last mission on the night of February 17, 1864. A drawing of the iron pipe spar, confirming its "David" type configuration, was published in several early histories of submarine warfare.