But the Titanic was designed to stay afloat with four compartments flooded.That extra two compartments gave the Titanic more buoyancy than any other ship.
There’s this moment in James Cameron’s 1997 blockbuster, Titanic, where Kate Winslet’s character Rose notices something about the lifeboats that ends up being important: “It seems that there are not enough for everyone aboard.” To which Victor Garber, who played Titanic’s architect Thomas Andrews, responds in a flawless Irish accent: “I have built a good ship, strong and true. She’s all the lifeboat you need.” Since the viewer already knows how this story ends, this line comes off as either tragic arrogance or some sort of bad joke.
But it’s central to understanding how the Titanic was designed and how it all went wrong. The Titanic actually had more lifeboats than was required by British law. The Merchant Shipping Act of 1894 required that big ships - those weighing over 10,000 tons - have at least 16 lifeboats that could hold 990 people. Ships only got bigger and bigger from there, but the minimum didn’t change. When the Titanic first launched in 1911, the ship weighed over 45,000 tons, but still only needed 16 lifeboats by law. Titanic had 20, which, if filled to maximum capacity, could carry a total of 1,178 people - nowhere near enough to accommodate the approximate 2,240 passengers and crew on board when the ship sank.
But at least from a design perspective, the builders of the Titanic had every reason to believe that they had constructed the safest passenger ship the world had ever seen. “She’s all the lifeboats you need.” This line might be made up for the movie, but it’s how people talked about the Titanic even after it went down.
Let’s unpack what that means. The Titanic was designed to stay afloat even after taking on serious damage. The bottom of the ship was divided into 16 compartments by these partitions called bulkheads. If the ship’s hull was breached, these compartments could be sealed off from each other with the flick of a switch that closed watertight doors connecting them. Once sealed off, the water in the affected compartments would rise to the height of the sea, called the waterline, but prevent the rest of the ship from flooding. The idea was that the giant ocean liner, even after taking on water, would still be the safest place to wait as lifeboats methodically ferried passengers to a rescue ship.
This bulkhead plus lifeboat strategy had worked successfully just a couple of years earlier when a ship accidentally rammed straight into the side of the RMS Republic. Newspaper diagrams from 1909 showed how the Republic was ripped wide open and where it was taking on water. But the crew remained calm and didn’t evacuate the ship right away. Their confidence was due in large part to a brand new piece of technology they had on board: the Marconi Wireless Telegraph system. When the Republic was hit, its telegraph operator tapped out the morse code signal C-Q-D - the distress call that later became SOS - to all nearby ships. A few hours later, a rescue ship arrived and the crew carefully transferred everyone off the Republic in small groups using lifeboats. The Republic eventually sank, but except for 6 people killed in the initial collision, every single person on board was saved.
The Republic was the first shipwreck to make use of a wireless distress signal and its operator was hailed as a hero. This incident seemed to prove that on the busy North Atlantic route, with other ships always nearby, a combination of careful ship design and this miraculous piece of new technology had made disasters at sea a thing of the past. This 1909 news article, The Triumph of Wireless, pretty much sums up the optimism of the time: “The passenger on a well-equipped transatlantic liner is safer than anywhere else in the world.”
Just three years later… Here’s what went wrong. When the Titanic was built, regulations recommended that all passenger ships should be able to remain afloat with any two adjacent compartments flooded. But the Titanic was designed to stay afloat with four compartments flooded. That extra two compartments gave the Titanic more buoyancy than any other ship. I recently spoke with Sam Halpern, an engineer and long-time Titanic researcher, who created a diagram based on data from a 1996 forensic analysis of the Titanic’s design. He showed me how the ship was designed to stay afloat even with up to four adjacent compartments flooded. The key was to keep the ship level so the waterline never reached the top of the bulkheads and flooded over into the other compartments. These scenarios showed the ship was protected from almost any crash imaginable at the time, including rocks, colliding with another ship and even hitting an iceberg.
However, the Titanic didn’t hit the iceberg head on; instead, it scraped along the side of it. Sonar analysis shows the ship was most likely breached in several places, including Boiler Room six. The movie Titanic does a good job of explaining this. As Victor Garber states in the movie, “That’s five compartments. She can stay afloat with the first four compartments breached, but not five. Titanic will flounder. It is a mathematical certainty.” Flooding the first five compartments overwhelmed the design and the ship was too unstable to remain upright.
At 12:15 AM, the Titanic sent out its first wireless distress call, 35 minutes after hitting the iceberg. Desperate messages followed, including “We have struck an iceberg,” “We are sinking fast,” and “Cannot last much longer. Women and children in boats.” However, the nearest ship to the Titanic, SS Californian, never received these messages because its sole wireless operator had turned off the radio for the night and gone to bed.
The Titanic disaster permanently altered the public’s view on the necessity of lifeboats. This can be seen by comparing a photo of RMS Olympic, the Titanic’s near identical twin, in 1911 to a photo of the Olympic in 1912 immediately following the Titanic disaster, which shows double the number of lifeboats along the top deck. The biggest impact of the Titanic disaster had on safety regulations and ship design was the enacting of the International Convention for the Safety of Life at Sea (SOLAS) in 1914, which required wireless telegraph communication to be active 24/7 and increased the lifeboat minimum to account for everyone on board.
Ultimately, the Titanic disaster was less about a fatal flaw in design and more about tragic timing in the early days of wireless communication and a collision scenario too extreme to have been considered possible until it happened. It is also worth noting that the Titanic was never advertised as “unsinkable,” although this 1911 edition of the trade magazine, The Shipbuilder, did describe both the Titanic and the Olympic as “practically unsinkable.”
Thanks for watching! I had a lot of fun making this one. By adapting the 1911 side plan of the Titanic, we can help visualize how the watertight bulkheads were supposed to work. You can help support our work and keep it free by making a gift to Vox at vox.com/support-vox-video. With your support, we’re able to keep telling these stories and answering questions you didn’t know you had.