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Failure of Tiny Rivets May Have Sunk 'Unsinkable' Liner

When the remains of the RMS Titanic were discovered more than two miles beneath the surface of the North Atlantic in 1985, the story of the great liner once dubbed "unsinkable" by the press began moving from legend into scientific fact. Numerous research investigations have been piecing together the details of what really occurred on April 14-15, 1912, after Titanic struck an iceberg, broke in half and carried more than 1,500 people to their deaths. Now, the answer to one of the most elusive questions--Why did the 46,000-ton ship sink in less than three hours?--may be contained in a new report from NIST.

The culprit, says NIST metallurgist Timothy Foecke in the report, is very possibly one of Titanic's smallest components--the 3 million wrought iron rivets used to hold the hull sections together.

Foecke performed metallurgical and mechanical analyses on steel and rivet samples recovered from the Titanic's hull. His examinations revealed that the wrought iron in the rivets contained three times today's allowable amount of slag (the glassy residue left behind after the smelting of ore), making it less ductile and more brittle than it should have been. This finding provides strong evidence that Titanic's collision with the iceberg caused the rivet heads to break off, popped the fasteners from their holes and allowed water to rush in between the separated hull plates.

Photographs of Titanic's sister ship, the RMS Olympic, back up the rivet failure theory. Taken after the Olympic collided with another vessel in 1911, the photos clearly show dozens of vacant holes in the hull where rivets once sat. Sonar and other evidence gathered during a 1996 visit to the Titanic also point to seam and rivet failure.

For a single copy of Metallurgy of the RMS Titanic (NISTIR 6118), send a request to Public Inquiries by fax at (301) 926-1630 or by email at inquiries [at] (inquiries[at]nist[dot]gov).

Released February 17, 1998, Updated January 20, 2023