The bow of the Stockholm was reinforced for ice and made a perfect battering ram. Finally, the Doria was arriving in New York with near-empty fuel tanks, and the Captain had chosen not to ballast the empty tanks with seawater. In addition, their watertight bulkheads were not tall enough, and could be over-topped by a 20 degree list. They were opulent ships, which also contributed to their top-heaviness. Sister ( and replacement ) Leonardo da Vinci later had 3000 tons of iron ballast set into her bilges in an attempt to correct this. The real reason for the sinking was that the Doria and her sisters were deficient in stability, making them far more susceptible to rolling. In fact, the Andrea Doria was not hit that badly by the much smaller Stockholm, and should not have sunk.
