How did the largest ocean liner in the world, designed to resist 72 hours of the worst of catastrophes, go down in less than three? During diving operations carried out since 1996, sonar has shown that there were no ruptures or cracks in the structure of the wreckage. The six openings on the starboard side of the Titanic, caused by the blow of the iceberg, demonstrate that the joints between the plates had become detached.

As it turns out, rivets were found, some that appeared ripped out of the hull because their flat parts were missing. These rivets were given to Dr Timothy Foecke, the chief metallurgist at the National Institute of Standards and Technology’s Metallurgy Division (American governmental organisation located in Gaithersburg, Maryland). He studied their structure and composition using sophisticated analysis techniques: microscopic metallography, gamma spectral analysis, and surface chemical reactions.

The deadly detail

Scoriae are impurities that come from molten minerals. To reinforce cast iron, a small percentage of scoriae is necessary; an excess of scoriae actually makes it weak and brittle.

Normal rivets contain 2% scoriae; the rivets analysed contained an average of 9.3% (19 of 48 rivets analysed had an excess of scoriae, some as much as 17%). Cross sections of the rivets demonstrate that the scoriae are distributed all along the rivet and that the wire (direction of fibres) turns abruptly at a right angle with respect to the rivet shank, creating an area of great weakness.

These results show that the impact of the iceberg did not cause indentations in the starboard side of the ship as it was long thought, but probably caused the breakage of structurally weak rivets. This allowed the disassembly of the hull plates, and, consequently, the entry of water.