The Titanic's sinking was a hundred years ago this month, and not all the commemorations are directly related to James Cameron's movie. For one thing, we can finally get to the bottom of just why anyone ever called Titanic "unsinkable."

Of course, the whole unsinkable thing waqs mostly a bit of marketing hubris, an incredibly unfortunate choice of words that has since achieved rather understandable infamy. And it's not as though ships have become anymore foolproof in the last century, as we recently saw with the Costa Concordia tragedy.

Indeed, whatever Titanic's marketers might have thought, the ship had plenty of key design flaws that helped hasten its demise when it hit the iceberg on April 15, 1912. Scientific American has a great interview with Duke professor Henry Petroski, author of To Forgive Design: Understanding Failure, in which he runs down all the things that made the Titanic so tragically sinkable:

Probably the fact that the bulkheads didn't go higher, so that they weren't truly watertight and didn't actually compartmentalize water between the bulkheads. Other design elements meant to ensure passenger safety weren't adhered to. Although the ship was designed to carry enough lifeboats, it wasn't at the time of the accident, for example. That would be unheard of today. They had radio, which they called wireless back then, for calling other ships, but it was seen more as a novelty at the time, and ships turned them off after hours.

The Titanic also failed to incorporate a crucial safety feature available long before its maiden voyage. In the 1850s there was a British ship called the SS Great Eastern designed by Isambard Kingdom Brunel and built by John Scott Russell that featured a double hull. A double hull is a similar concept to bulkheads. Water comes in but you keep it from overtaking the interior of the hull. Generally speaking, the distance between the hulls is not that great, so the amount of water that gets in won't be that great.

As to why the ship wasn't built with a double hull? Because it would have been too expensive, and because it would only be needed if the ship was ever sinking...and Titanic was unsinkable. It's hard to know where even to start with logic like that. You can check out the rest of the interview here.

Image from the movie.