Portland scientist works on Titanic theory

By The Associated Press

Seattle Times

PORTLAND More than 1,500 people died when the Titanic sank in 1912, two hours and 40 minutes after it collided with an iceberg. Why the luxurious ocean liner sank so fast has been the subject of speculation ever since.

But a Portland scientist has done some old-fashioned detective work and laboratory tests to figure out the reason.

One prominent theory blamed the hull's steel plates for being so brittle that they shattered during the collision. But once the sunken ship was found and examined revealing not a single, massive gash in its side but six slits, spread across a wide area some theorists focused on the wrought-iron rivets that held the steel plates together.

Jennifer Hooper McCarty, a licensing associate in the Office of Technology & Research Collaborations at Oregon Health & Science University, was a graduate student at Johns Hopkins University seven years ago. She was looking for a dissertation topic when her thesis supervisor, Tim Foecke, suggested she put the rivet theory to the test. Foecke, of the National Institute of Standards & Technology, was an early theorist about the rivets' role.

She first confirmed earlier tests by Foecke that showed the rivets were made weak by too much slag, a byproduct of the process of making wrought iron. Rivets of purer iron would have remained strong under stress.

She examined every one of the 48 rivets recovered from the 3 million used to build the ship. What she discovered in the lab confirmed speculation. Some rivets she examined showed slag levels as high as 40 percent.

A 2 or 3 percent presence of slag is known to reinforce iron, but even slightly higher concentrations start to turn the metal brittle.

McCarty performed mechanical tests on small pieces that correlated with what she saw under the microscope: The samples broke. In computer simulations, failure followed again.

She pored over historical records, and witness accounts led her to reimagine the collision.

"A lot of survivors didn't even feel it, and some talk about it as a glancing-blow-type thing," she said. "The flooding and the timeline it's not consistent with something that opened a gaping hole. Yes, it sank quickly, but the initial flooding happened with water coming through a seam."

McCarty and Foecke compiled their findings for a National Geographic TV program that aired recently. A blacksmith in England was hired to re-create hull plates and rivets to specifications of the day for testing under strain. When the test was performed, the rivets started popping sooner than they should have. The theory that the Titanic's hull plates opened like a zipper found its strongest evidence yet.