The R.M.S. Titanic sideswiped an iceberg at 11:40 p.m. on April 14, 1912. Estimated to be able to stay afloat for 2 days under the worst scenario, the ship sank in less than 3 hours [Gannon, 1995].
Main Cause for Sinking
The iceberg created a 300-foot gash in the Titanic's hull above and below the waterline.
Structural Errors That Accelerated the Sinking
Tests on Titanic's steel showed that the steel had high sulfur content, which increases the brittleness of steel by disrupting the grain structure [Hill, 1996]. This increase in brittleness contributed to the severity of the hull's damage. Titanic's steel showed high levels of oxygen, which leads to an increased ductile-to-brittle transition temperature. For Titanic's steel, that temperature was determined to be 25 to 35 degrees C [Hill, 1996].
The water temperature that night was below freezing. The wrought iron rivets that fastened the hull plates to the Titanic's main structure also failed because of brittle fracture during the collision with the iceberg. Low water temperatures contributed to this failure [Garzke and others, 1994].
Contributing to this failure in the midsection was the design of Titanic's huge spiral staircase. The staircase not only weakened the midsection's structure, but served as a means for water to pass up through the ship.
As it filled with water, the bow submerged, raising the stern out of water. When the stern reached an angle of about 45 degrees, the stresses in the ship's midsection (15 tons per square inch) caused the steel to fail and the bow to rip loose and sink [Gannon, 1995].
The lower section of the Titanic was divided into sixteen major watertight compartments.
Actually, the compartments were watertight only in the horizontal direction--their tops were open.
After the collision, six watertight compartments began filling with water. Soon, water spilled over the tops.