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Scientist Lends Voice To Titanic "Faulty Rivets" Research
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2012-04-27
A hundred years after the Titanic sank, a new article in Physics World titled "The Perfect Storm" lends credence to research suggesting that "faulty rivets" contributed to the demise of the "unsinkable" steamer.
Of course, the idea that some of Titanic's rivets were subpar is not a "recent discovery or conclusion," Joe Greenslade of the Industrial Fasteners Institute told GlobalFastenerNews.com. "My son wrote his engineering term paper on this subject in 1994," Greenslade stated.
But the science relayed in "The Perfect Storm" seems plausible. Greenslade characterized the Physics World article as "an accurate accounting of the role brittle rivets played in this disaster." "They believe rivets toward the front of the ship snapped on initial impact and then successive rivets snapped like pulling a row of buttons off a shirt as the ship continued its forward momentum," Greenslade told GlobalFastenerNews.com.
A 1998 FIN History article in the Fastener History section of GlobalFastenerNews.com titled "Did Faulty Rivets Sink the Titanic" includes this: "Two wrought-iron rivets salvaged from the R.M.S. Titanic's hull were found to contain high concentrations of slag, indicating that the largest ship of its time 'may have been done in by structural weaknesses in some of its smallest and least glamorous parts: the rivets,' according to the New York Times."
But while the concept isn't new, a whole new generation is hearing about it.
In anticipation of the 100th anniversary of the disaster, media outlets around the world have seized on the Physics World article, summarizing author Dr. Richard Corfield's analysis as blaming "faulty engineering" for the Titanic's demise.
"Second-rate rivets that held the hull together were to blame for sending the legendary ship to the bottom of the Atlantic," the Scotsman reports.
To that end, Corfield examines the work of metallurgists Tim Foecke at the US National Institute of Standards and Technology and Jennifer Hooper McCarty, then at Johns Hopkins University.
"They combined their metallurgical analysis with a methodical sweep through the records of the Harland and Wolff shipyard in Belfast where the Titanic was built," Corfield writes. "Combining physical and historical analysis in this way proved to be a powerful trick."
Their 2008 book, What Really Sank the Titanic - New Forensic Discoveries, helped substantiate the rivet theory after examining 48 popped rivets from the wreck and finding that the wrought iron contained 9% slag - a glass-like substance that adds strength at concentrations of 2% to 3% but weakens metal at higher levels.
Foecke commissioned rivets to the same specifications, installed them in steel plates and bent them in the laboratory. The rivet heads popped off at loads of about 4,000kg (9,000lb). With the right slag content, they should have lasted until a load of about 9,000kg.
"Foecke and McCarty found that the rivets that held the mild-steel plates of the Titanic's hull together were not of uniform composition or quality and had not been inserted in a uniform fashion," Corfield writes.
"Specifically, Foecke and McCarty found that the rivets at the front and rear fifths of the Titanic were made only of "best" quality iron, not "best-best", and had been inserted by hand. The reason for this was that, at the time of the Titanic's construction, the hydraulic presses used to insert the rivets used in the middle three-fifths of the ship could not be operated where the curvature of the hull was too acute (i.e. at bow and stern)."
Foecke and McCarty speculate that the shipbuilders may have used lower quality rivets to save money, even though "the higher concentration of slag meant that the rivets were particularly vulnerable to shearing stresses – precisely the kind of impact they were subjected to that long-ago night in April 1912."
"Lab tests have shown that the heads of such rivets can pop off under extreme pressure, which on the Titanic would have allowed the steel plates on the hull to come apart, exposing her inner chambers to an onslaught of water."
However, Corfield's does not blame the iron rivets solely for the sinking of the 46,000-ton ship. His argument is more nuanced and comprehensive than that oversimplified "faulty engineering" summary.
"It is a mistake to regard the Titanic as somehow primitive," Corfield writes. "She was the most modern ship of her day in a world that relied on its steam trade to maintain communications between Europe and America in the same way that today we rely on aviation. The Titanic incorporated the latest technological innovations of the age to help ensure her safety."
To that end, he gives natural forces their due, noting that "North Atlantic icebergs are calved on the western coast of Greenland, then circulate anti-clockwise through the Labrador Sea before drifting into the North Atlantic off the Newfoundland coast." There they meet the Gulf Stream, where significant temperature and density differences between these two currents cause icebergs to cluster in a "barrier of ice." Human error contributed in the disaster as well, ranging from a higher-than-recommended speed to "an almost cynical lack of lifeboats."
"No one thing sent the Titanic to the bottom of the North Atlantic. Rather, the ship was ensnared by a perfect storm of circumstances that conspired her to doom," Corfield concludes. "Such a chain is familiar to those who study disasters – it is called an 'event cascade.'"
Of course, the idea that some of Titanic's rivets were subpar is not a "recent discovery or conclusion," Joe Greenslade of the Industrial Fasteners Institute told GlobalFastenerNews.com. "My son wrote his engineering term paper on this subject in 1994," Greenslade stated.
But the science relayed in "The Perfect Storm" seems plausible. Greenslade characterized the Physics World article as "an accurate accounting of the role brittle rivets played in this disaster." "They believe rivets toward the front of the ship snapped on initial impact and then successive rivets snapped like pulling a row of buttons off a shirt as the ship continued its forward momentum," Greenslade told GlobalFastenerNews.com.
A 1998 FIN History article in the Fastener History section of GlobalFastenerNews.com titled "Did Faulty Rivets Sink the Titanic" includes this: "Two wrought-iron rivets salvaged from the R.M.S. Titanic's hull were found to contain high concentrations of slag, indicating that the largest ship of its time 'may have been done in by structural weaknesses in some of its smallest and least glamorous parts: the rivets,' according to the New York Times."
But while the concept isn't new, a whole new generation is hearing about it.
In anticipation of the 100th anniversary of the disaster, media outlets around the world have seized on the Physics World article, summarizing author Dr. Richard Corfield's analysis as blaming "faulty engineering" for the Titanic's demise.
"Second-rate rivets that held the hull together were to blame for sending the legendary ship to the bottom of the Atlantic," the Scotsman reports.
To that end, Corfield examines the work of metallurgists Tim Foecke at the US National Institute of Standards and Technology and Jennifer Hooper McCarty, then at Johns Hopkins University.
"They combined their metallurgical analysis with a methodical sweep through the records of the Harland and Wolff shipyard in Belfast where the Titanic was built," Corfield writes. "Combining physical and historical analysis in this way proved to be a powerful trick."
Their 2008 book, What Really Sank the Titanic - New Forensic Discoveries, helped substantiate the rivet theory after examining 48 popped rivets from the wreck and finding that the wrought iron contained 9% slag - a glass-like substance that adds strength at concentrations of 2% to 3% but weakens metal at higher levels.
Foecke commissioned rivets to the same specifications, installed them in steel plates and bent them in the laboratory. The rivet heads popped off at loads of about 4,000kg (9,000lb). With the right slag content, they should have lasted until a load of about 9,000kg.
"Foecke and McCarty found that the rivets that held the mild-steel plates of the Titanic's hull together were not of uniform composition or quality and had not been inserted in a uniform fashion," Corfield writes.
"Specifically, Foecke and McCarty found that the rivets at the front and rear fifths of the Titanic were made only of "best" quality iron, not "best-best", and had been inserted by hand. The reason for this was that, at the time of the Titanic's construction, the hydraulic presses used to insert the rivets used in the middle three-fifths of the ship could not be operated where the curvature of the hull was too acute (i.e. at bow and stern)."
Foecke and McCarty speculate that the shipbuilders may have used lower quality rivets to save money, even though "the higher concentration of slag meant that the rivets were particularly vulnerable to shearing stresses – precisely the kind of impact they were subjected to that long-ago night in April 1912."
"Lab tests have shown that the heads of such rivets can pop off under extreme pressure, which on the Titanic would have allowed the steel plates on the hull to come apart, exposing her inner chambers to an onslaught of water."
However, Corfield's does not blame the iron rivets solely for the sinking of the 46,000-ton ship. His argument is more nuanced and comprehensive than that oversimplified "faulty engineering" summary.
"It is a mistake to regard the Titanic as somehow primitive," Corfield writes. "She was the most modern ship of her day in a world that relied on its steam trade to maintain communications between Europe and America in the same way that today we rely on aviation. The Titanic incorporated the latest technological innovations of the age to help ensure her safety."
To that end, he gives natural forces their due, noting that "North Atlantic icebergs are calved on the western coast of Greenland, then circulate anti-clockwise through the Labrador Sea before drifting into the North Atlantic off the Newfoundland coast." There they meet the Gulf Stream, where significant temperature and density differences between these two currents cause icebergs to cluster in a "barrier of ice." Human error contributed in the disaster as well, ranging from a higher-than-recommended speed to "an almost cynical lack of lifeboats."
"No one thing sent the Titanic to the bottom of the North Atlantic. Rather, the ship was ensnared by a perfect storm of circumstances that conspired her to doom," Corfield concludes. "Such a chain is familiar to those who study disasters – it is called an 'event cascade.'"
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