Indeed, nothing about the Titanic's accident, failure, and sinking should have been beyond imagination in prospect.
It was well known that icebergs were likely to be encountered on the North Atlantic sea-lanes, especially in the month of April, when the Titanic sailed. A collision with an iceberg was thus a credible accident scenario. One form such a collision could take was a grazing, in which case the ship's hull could be gashed open, or its rivets sheared off. Either way, water would be let into the bow, reducing its buoyancy. As water continued to flow in and the bow dipped farther down, the bulkheads -- which only went so high, a fatal design flaw -- would be overtopped. The bow would then continue to sink lower, raising the stern. If the stern were raised out of the water, a condition for which the structure was not designed, then the ship could break in two, and its sinking would shortly follow. It certainly was an easy calculation to make to determine that the number of people in distress would far outnumber the capacity of the lifeboats.
This failure scenario, which is now what is believed likely to have happened in fact, should have been the basis for obviating faulty design decisions. However, whether due to ignorance, overconfidence, or rationalization, neither the design of the Titanic nor its operation seems to have been modified or adjusted to ensure that the credible scenario did not play out in actuality.
Everyone involved -- from designers to owners to crew to passengers -- seems to have expected success more than feared failure, perhaps owing to the generally infrequent occurrence of ships hitting icebergs on transatlantic crossings.
But success is a fickle guide, and we should always want to balance our hopes for success with a proper acknowledgment that failures can and do occur. Failures, after all, provide the lessons and wisdom to foresee even beyond the hypothetical wherein a newly proposed design, plan, or policy is likely to go awry. An overreliance on past successes, as was the case with the Costa Concordia, can be a sure blueprint for future failures.
This column has been reprinted from chapter 14 of Henry Petroski's latest book, To Forgive Design: Understanding Failure, published in March by the Belknap Press of Harvard University Press, © 2012 by Henry Petroski, pp. 328-330, with a new introductory paragraph.