If its hull sprang a leak at any one spot, doors would automatically shut and contain the water. If no more than two, or in some cases four, compartments flooded, the Titanic would stay afloat.

Unfortunately, by sideswiping an iceberg, the Titanic compromised its hull, perhaps in part due to poor-quality rivets. The long gashes and separation of the plates exposed a fatal five compartments to the sea. Moreover, the internal bulkheads didn't extend all the way up to the deck and therefore weren't as watertight as advertised, allowing water to slosh throughout. The Titanic therefore sank rapidly, before help could arrive.

But that doesn't mean separate compartments within the hull were a bad idea. They remain a shipbuilding standard today.