My favorite Charleston Civil War battle and historic site is the H.L. Hunley, the first ever combat submarine to sink an enemy ship. Last month I finally got the chance to see the real thing at Warren Lasch Conservation Center in North Charleston. Tours are offered Saturday and Sunday ($12 adults, $10 seniors and military, free for kids 5 and under).

To this day we still don’t know what caused the Hunley to sink shortly after USS Housatonic went under. Here are the most significant clues, questions, and theories…you decide! (data courtesy of museum exhibits and website and from wikipedia)

Miscalculated attack or equipment malfunction?
The H.L. Hunley was only 75 feet from USS Housatonic, when the Union sloop exploded. The recommended distance was 150 feet. Was this planned or just coincidence?
It is known the crew worked in almost complete darkness, using only one candle to conserve oxygen.

Did they miscalculate the distance to Housatonic? Was something wrong with the torpedo that forced the crew to come dangerously closer?

The Hunley undoubtedly absorbed a powerful shock wave from the blast. This might have opened the sub’s seams and allowed water to enter. A subsequent submersion “would likely have driven the Hunley into the shallow bottom, blocking the ballast intakes and making it impossible to pump the sub back out. Cold and immersion would have killed the crew relatively quickly.”

However, researchers determined the ballast weights and pump were not deployed, and that the crew was in position. Does this mean there was no imminent flooding? Did the crew just passed out?

All crew members were found sitting at their positions
“They were collapsed more or less where they sat” said Maria Jacobsen, Sr. Archaeologist at the H.L. Hunley project.

“You didn’t see the guys trying to move towards the conning towers to exit. Either something happened very fast or they were not able to move.”

What about those pumps and valves?
2008 findings suggest the valve to the bilge pipe was closed, meaning no one was trying to pump water from the crew compartment.

Yet the submarine plumbing includes 2 pumps, a network of pipes and 9 valves, and so far researchers have not been able to determine exactly how each of the valves is set.

To complicate matters further, Hunley’s plumbing was rigged so that, by the twist of a valve, either pump could control the water level in the other tank.

A neat safety net, that makes the understanding of the sub all the more difficult…

The blue light “Mission Accomplished!”
Both Confederate soldiers from the Battery Marshall on Sullivan’s Island and soldiers from USS Housatonic reported seeing a blue signal after the attack, indicating the sub had survived the explosion. As the lantern could only be seen one and a half miles away, Hunley had come fairly close to shore after the attack.

By then the crew would have hand-cranked underwater for several miles, for almost 2 hours, near the limit of the available air supply. Did they die from exhaustion? Did they asphyxiate?

Where is the damage?
The hull was found almost intact. The only noticeable damage was a large hole in the forward hatch and the fact that the viewpoint was missing.

Further, the rudder was found detached from the sub and directly underneath the stern?

Similarly the aft cut-water was discovered away from its proper location.

Did the sub hit something on its way down? If so how come there is no significant damage to the hull?

How did the equipment become detached and why?

H.L. Hunley, a technological marvel way ahead of its time…
It’s telling that it took 50 years for another submarine to match Hunley’s combat success. In fact, today’s so called “fast attack submarines,” still share amazing similarities to the 150 years old design of the H.L. Hunley:

• World’s first navigating joystick! During the excavation of the H.L. Hunley, archaeologists uncovered a vertical steering rod similar to an airplane joystick that could move in two directions from port to starboard. The vertical rod was part of a system of rods and cables used to connect the submarine rudder while neatly placing it out of the crew’s way. The steering mechanism is both “simple and elegant representing a design for efficiency and space.”
• Adjustable diving planes - Two lateral fins were connected by a horizontal rod. By moving a lever inside the Hunley the dive planes could be adjusted, changing the sub’s underwater position and depth.
• Water ballast tanks, equalized for balance
• Movable snorkel tubes for drawing air into the sub while submerged
• A long cigar-shaped hull - Before its discovery off Charleston Harbor, most believed the sub had a basic, even crude design. “The bow almost has a razor-like texture. It slopes back very gradually. It is much more streamlined than I originally thought.” said historian Mark Ragan.

The spar torpedo…an Infernal Machine!
The spar torpedo was designed to be rammed into the hull of an enemy ship. The torpedo was fastened to the end of the spar and fitted with a barb on its end. The crew will ram the spar torpedo into the enemy ship and then back away, causing the torpedo to detach from the spar.

A line from the torpedo to the Hunley would spool out as the sub reversed course. Once the submarine was at a safe distance, the line would detonate the warhead.

E. C. Singer, one of Hunley’s investors, was the nephew of the sewing machine’s inventor.

Not surprisingly a spool of rope, similar to the spools of thread used on a sewing machine, was used in the torpedo’s rigging…

The H.L. Hunley’s discovery revealed the spar was made of iron, was mostly hollow, and measured 17 feet in length, not 22 feet as most believed.

Further, archaeologists found out the spar was mounted with a y-shaped joint at the bottom of the bow, not at the top as originally thought.

The more we learn about the H.L. Hunley, the more incredible its accomplishment is! This is truly the “find of the century”!

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