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Hunley scientists discover series of 10 stealthy deadlights
BY BRIAN HICKS
Of The Charleston Post and Courier Staff
The Hunley was running dark the night she sank the USS Housatonic, perhaps even buttoned up as if braced for an explosion.
Scientists have discovered a series of complex "deadlights" covering the 10 portholes in the Hunley's ceiling. These inch-thick, cast-iron covers, which resemble the cap on an old car's gas tank, likely served to strengthen the hull and keep it watertight around the glass ports -- the sub's most vulnerable part.
The deadlights also muted the glow of light from inside the submarine when she was running just beneath the surface of the water.
"What's so amazing is that they thought so far in advance," said state Sen. Glenn McConnell, chairman of the Hunley Commission. "They thought about light giving away their position, and they thought about what would happen if it leaks. This is just further proof this wasn't something hastily built out of a boiler. It's a machine."
In old diagrams of the sub, the word "deadlight" appears in connection with the ceiling portholes, which acted as skylights and illuminated the sub during the day. Most people thought that was merely a reference to the portholes, not any mechanism beneath them.
The deadlight coverings have been hidden in the concretion covering the submarine. Scientists are just beginning to chip away at the mass of silt, sand and shell that has enveloped the sub like a cocoon for more than a century. In some places, the concretion is harder and thicker than the sub's metal hull.Conservators have cleared the concretion from one of the two deadlights in the first hull plate that scientists removed to gain access to the sub in 2001. The other remains buried under a mass of concretion.
The deadlights kept the Hunley hidden from Housatonic sailors on the night of Feb. 17, 1864. Although one sailor testified he saw a faint glow of light, probably from the forward conning tower, it wasn't enough to give the Union troops much of a target. No survivors recounted seeing light from multiple portholes.
With the sub cruising just 2 feet below the surface, the portholes -- if left uncovered -- would have looked like an airport runway at night, outlining the sub's exact position.
The thickness of the deadlights suggests they had a more serious purpose, as a thin piece of tin could have blocked the light. Wednesday afternoon, senior Hunley conservator Paul Mardikian removed the glass from the unearthed deadlight and found a piece of dome-shaped rubber, perfectly preserved, underneath.
GRACE BEAHM/STAFF
Senior conservator Paul Mardikian watches as Philippe de Vivies chisels away concretion Wednesday from one of the Hunley's hull plates.
Mardikian said the rubber may have buckled or the inside of the deadlight cover could have been shaped to fit into the porthole. That would have made the sub watertight around the glass, which was only 1 centimeter thick and vulnerable to gunshot -- or perhaps the repercussion of an exploding torpedo.
"It was probably meant to plug it," Mardikian said. "It's very funny with the Hunley, how you think it is so simple and when you get into the details you are amazed at how well it was constructed."
IF YOU GO
Tours of the Hunley are available 10 a.m.-5 p.m. Saturdays and noon-5 p.m. Sundays. Tours are not available on weekdays so that the archaeologists can continue their preservation work.
Tickets are $10 plus a service charge and can be purchased by either calling 1-877-448-6539 or on the Internet at www.etix.com. Children under 5 are free. Tickets can be purchased in advance, and walk-up tickets are also available on a first-come, first-served basis.
X-Ray of two deadlights side by side before concretion removal process beings
Edited By TMSmalley on 1118951846
BY BRIAN HICKS
Of The Charleston Post and Courier Staff
The Hunley was running dark the night she sank the USS Housatonic, perhaps even buttoned up as if braced for an explosion.
Scientists have discovered a series of complex "deadlights" covering the 10 portholes in the Hunley's ceiling. These inch-thick, cast-iron covers, which resemble the cap on an old car's gas tank, likely served to strengthen the hull and keep it watertight around the glass ports -- the sub's most vulnerable part.
The deadlights also muted the glow of light from inside the submarine when she was running just beneath the surface of the water.
"What's so amazing is that they thought so far in advance," said state Sen. Glenn McConnell, chairman of the Hunley Commission. "They thought about light giving away their position, and they thought about what would happen if it leaks. This is just further proof this wasn't something hastily built out of a boiler. It's a machine."
In old diagrams of the sub, the word "deadlight" appears in connection with the ceiling portholes, which acted as skylights and illuminated the sub during the day. Most people thought that was merely a reference to the portholes, not any mechanism beneath them.
The deadlight coverings have been hidden in the concretion covering the submarine. Scientists are just beginning to chip away at the mass of silt, sand and shell that has enveloped the sub like a cocoon for more than a century. In some places, the concretion is harder and thicker than the sub's metal hull.Conservators have cleared the concretion from one of the two deadlights in the first hull plate that scientists removed to gain access to the sub in 2001. The other remains buried under a mass of concretion.
The deadlights kept the Hunley hidden from Housatonic sailors on the night of Feb. 17, 1864. Although one sailor testified he saw a faint glow of light, probably from the forward conning tower, it wasn't enough to give the Union troops much of a target. No survivors recounted seeing light from multiple portholes.
With the sub cruising just 2 feet below the surface, the portholes -- if left uncovered -- would have looked like an airport runway at night, outlining the sub's exact position.
The thickness of the deadlights suggests they had a more serious purpose, as a thin piece of tin could have blocked the light. Wednesday afternoon, senior Hunley conservator Paul Mardikian removed the glass from the unearthed deadlight and found a piece of dome-shaped rubber, perfectly preserved, underneath.
GRACE BEAHM/STAFF
Senior conservator Paul Mardikian watches as Philippe de Vivies chisels away concretion Wednesday from one of the Hunley's hull plates.
Mardikian said the rubber may have buckled or the inside of the deadlight cover could have been shaped to fit into the porthole. That would have made the sub watertight around the glass, which was only 1 centimeter thick and vulnerable to gunshot -- or perhaps the repercussion of an exploding torpedo.
"It was probably meant to plug it," Mardikian said. "It's very funny with the Hunley, how you think it is so simple and when you get into the details you are amazed at how well it was constructed."
IF YOU GO
Tours of the Hunley are available 10 a.m.-5 p.m. Saturdays and noon-5 p.m. Sundays. Tours are not available on weekdays so that the archaeologists can continue their preservation work.
Tickets are $10 plus a service charge and can be purchased by either calling 1-877-448-6539 or on the Internet at www.etix.com. Children under 5 are free. Tickets can be purchased in advance, and walk-up tickets are also available on a first-come, first-served basis.
X-Ray of two deadlights side by side before concretion removal process beings
Edited By TMSmalley on 1118951846
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