Tiny flaws that caused a Titanic waste of life

BY MARK HENDERSON

London Times

New evidence suggests that the rescue of 1,500 people would have succeeded but for weak rivets that allowed the hull to 'unzip', Mark Henderson reports

THE most celebrated disaster in maritime history owed as much to substandard rivets as it did to the iceberg, an analysis of the sinking of the Titanic has revealed.

The liner would have survived the collision for long enough for most of, or even all, its passengers to be rescued had it not been put together with weak rivets that caused its hull to unzip on impact with the ice, according to the new research.

Although faulty construction has long been suspected as having contributed to the loss of RMS Titanic on April 15, 1912, the first experiment to mimic what happened to the rivets that held the hull together has shown that they could not have withstood the collision.

This weakness meant that either five or six of the ship’s watertight compartments flooded, causing the ship to sink in slightly more than two hours. With stronger rivets, fewer compartments would have been compromised, and although Titanic would probably still have sunk it would have remained afloat for several hours longer.

As Carpathia arrived to assist Titanic less than two hours after she went down, most of the 1,523 people who died might have been saved. The new evidence has emerged from an experiment by two metallurgists. Tim Foecke, of the US National Institute of Standards and Technology, in Maryland, and Jennifer Hooper McCarty, of Oregon Health and Science University, first developed the rivet theory after examining 48 popped rivets from the wreck. This showed that the wrought iron contained 9 per cent slag a glasslike substance that adds strength at concentrations of 2 to 3 per cent but weakens metal at higher levels.

To test whether this extra slag weakened the rivets, Dr Foecke commissioned Chris Topp, a blacksmith from Carlton Husthwaite, North Yorkshire, to make rivets to the same specifications. These were then used to join 1in steel plates such as those in the hull of the Titanic. When the plates were bent 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.

Dr Foecke said: We don’t know the exact shape of the iceberg so we can’t be sure of the forces involved, but it’s clear that many more rivets would have broken than should have done.

Even a few failures because of flawed metal would have been sufficient to unzip entire seams. As faulty rivets popped, more stress would have been placed on the good ones, causing them to break as well.

As they failed, a domino effect ensued, distributing the increased loads to other rivets until the damaged seams began to open up, Dr Foecke said.

Dr Foecke’s analysis of metal recovered from the wreck has also overturned another popular theory about the sinking: that the ship’s hull ruptured as it was made from brittle steel. Mechanical tests show adequate fracture toughness in the steel at icewater temeratures, fairly close to steels used to build bulk-carrier ships today, he said. The brittle steel theory does not stand up to close scrutiny, and is wrong.

The iceberg did not cause a gash. A series of bouncing impacts popped open rivets along the bow, creating small openings. Dr Foecke said: Witnesses recalled water trickling through the ship’s side, not enough to be considered continuous, but a steady pour on to the deck floors. This is consistent with the notion of seams that steadily bulged open as rivets failed, rather than a gaping hole produced by plate fracture, but it doesn’t explain how so much water filled the ship so quickly.

The findings are included in a National Geographic Channel investigation to be screened next week.