In the first hour, author Brad Matsen(1) discussed his research into how and why Titanic sank so quickly. According to Matsen, the ship did not rise high out of the water before the hull broke as depicted in James Cameron's blockbuster film. Instead, Titanic sat relatively level in the water, Matsen said, then suddenly broke in the middle and was gone within four minutes.
A key piece of supporting evidence was the bending pattern in a fragment of the ship's steel found by noted divers, John Chatterton and Richie Kohler. Matsen believes the builders made compromises in the construction of Titanic that likely caused its demise, and even tried to cover it up to avoid negligence claims by survivors and families of those lost that fateful night.
Ian also spoke briefly with Richie Kohler(2) during the first part of the second hour about his 2005 expedition to Titanic's wreckage.