Investigating the Loss of H.L. Hunley

Recent archeological investigations of the civil war submarine H.L. Hunley have changed our understanding of how the vessel conducted its final attack on the U.S.S. Housatonic. Previously, the submarine was thought to have used a standoff charge against its target, but it is now clear that the charge was bolted to the end of a short spar projecting from the submarine. This means that the submarine would have been in close proximity to the weapon when it exploded. A multi-part investigation is being conducted with the goal of determining if this reduced standoff distance could explain the mysterious loss of the vessel in the minutes or hours after the attack. Here, the results of a bottomup naval architectural analysis and numerical simulations of the final attack weapon effects are reported. Together, the results provide new insight to the vessel's stability characteristics, propulsion, and dynamic loading environment during the attack. Additionally, a discussion of possible loss scenarios, informed by both calculation results and inspections of vessel's hull, is presented. While the story of what happened to H.L. Hunley that night remains shrouded in mystery after this work, several important new research questions emerge.