The Submarine "Pioneer" was given a full test in Lake Pontchartrain in March of 1862. An anchored barge was the target. A spar torpedo was the weapon.
From Infernal Machines by Milton F. Perry
(As the owners watched, she glided slowly toward the barge; Captain Scott took his bearings and submerged. The torpedo struck true and the target vessel was blown "so high that only a few splinters were heard from.")
Soon after New Orleans fell and the Pioneer scuttled in a bayou. The operation was then moved to Mobile were the experience from the building and testing of the "Pioneer" helped with the new effort the "Hunley".