FALLIBLE SAFETY FEATURE: The Titanic was built with 16 major watertight compartments in its lower section designed to be sealed off in the event of a punctured hull. This sketch depicts the Titanic's bow section bulkheads.
Image: Courtesy of Encyclopedia Titanica
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The claim that the RMS Titanic was "practically unsinkable" may have been more a marketing tactic than a commentary on its engineering, but its prelaunch reputation of being impervious to the perils of the high seas has lingered for the past 100 years.
It is dangerous to cast engineering projects in such absolute terms—of course there had to be some combination of conditions under which the ocean liner would have failed. As elegant and grand as it was, however, the Titanic—like any other ship—was far from unsinkable.
At nearly 275 meters long with a gross weight of about 42,000 metric tons, the Titanic was the largest ship ever built at the time. It featured 16 major watertight compartments in its lower section that could be sealed off in the event of a punctured hull. Yet the luxury liner sank less than three hours after colliding with a massive iceberg in the North Atlantic, despite some estimates that it should have been able to stay afloat for as long as three days after an accident at sea.
The watertight compartments proved to be a fatal design flaw—one that James Cameron illustrated well early in his 1997 film recounting the fateful April night in 1912 when the Titanic sunk, taking about two thirds of her 2,200 passengers into the icy waters with her. The 90-meter gash in the Titanic's hull caused the ship to take on water near its bow, flooding six of the compartments. When enough water had penetrated the hull breach, the ship pitched forward at an angle that caused water from the individual compartments to spill over their bulkheads, inundating the front of the ship and sending the Titanic like a torpedo to the ocean bottom almost four kilometers below. Had the bulkheads been higher, or watertight at the top as well as the bottom, the water rushing into the hull might have been distributed more evenly, giving passengers more time to escape.
Ironically, builders of the Titanic were given a preview of how their ship might react to a hull breach several months before it even left port. On September 20, 1911, Titanic's sister ship, Olympic, was broadsided by the British warship HMS Hawke, which ripped away metal plates and riveted joints, leaving an 11-meter opening in the starboard side of the Olympic's hull. The collision caused the flooding of two of the Olympic's lower compartments, but the ship was able to make it back to port, perhaps contributing to the unsinkability myth.
Engineering and design are an important part of any construction project, but they are part of a larger system that includes the people that will manage and use the project's end product, whether it is an ocean liner, suspension bridge or spacecraft. Scientific American spoke with Henry Petroski, a professor of both civil engineering and history at Duke University and author of To Forgive Design: Understanding Failure, about the folly of believing a design is infallible, the Titanic's fatal flaws, and how even the best-engineered technology fails when a larger system breaks down.
[An edited transcript of the interview follows.]
It has been a century since the Titanic disaster. Will engineers ever be able to build an "unsinkable" ship?
The short answer is no. And anyway, it seems the claim that it was unsinkable didn't come from engineers but rather from advertisements for the Titanic. The ship had a lot of design features—such as the watertight compartments and their bulkheads—that may have led people to believe that it wouldn't sink.
Any design, whether it's for a ship or an airplane, must be done in anticipation of potential failures. In the case of the Titanic, the engineers would have been asking themselves: "What if we have a hole in the hull?" Well, water's going to come in. "How much water?" That depends on how big the hole is, so you have to make those calculations. You can always imagine a bigger hole or some worse condition.
What were the Titanic's greatest design flaws?
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. The debate over double hulls goes on to this day. After the Exxon Valdez oil spill there was a question as to whether all oil tankers should have double hulls.
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36 Comments
Add CommentI hate when people say that something is impossible just because they don't know how to do it. If current designs are sinkable you need to change the design, if the materials is sinkable you need to change the materials. Ship doesn't need to be made of steel, have ballast and be powered by motor... doesn't it??
Reply | Report Abuse | Link to thisIf you can supply me with one thing that we have managed to engineer into complete, utter, certain and eternal impossibility, I'll eat your hat.
Reply | Report Abuse | Link to thisyes it is, just read the "Epic of Gilgamesh" Noah made a square boat to survive the flood and continue humanities farce.
Reply | Report Abuse | Link to thisIn each of the cases mentioned in this article, going cheap on mission-critical components caused the failure. But this is not always the case. Pressurized or boiling water nuclear reactors actually take the more expensive route in terms of design. This is so that the manufacturers can market and sell expensive core component replacements.
Reply | Report Abuse | Link to thisMolten salt reactors would be safer and less expensive. Those designs can generate their own fuel and each be built on a smaller scale. Companies doing so would be more competitive than the ones that presently own the US Congress, so these will never be approved by the present government. The plutocracy has a financial stake in exposing the public to deadly risks and then monetarizing those risks on the taxpayers when failure occurs.
These engineering issues are always the fault of executive management. While I agree that it is impossible to build an unsinkable ship or guarantee the safety of flight, the risks are always mitigated by the force of design requirements and safety regulations. In general, engineers are the puppets of executive management and they are routinely fired for pointing out deficiencies.
Impossibility may be defined by the engineering or the cost, and most often both. A warship is limited more by the former than the latter, for example, as cost is less of an object when you need to keep something fighting. But even the best warships can be overcome by some of the risks they face. A cruise ship will have a financial limit on it based on the money that the cruise line can make from the passengers. If the cost is such that the passengers would have to pay double going amounts across the board, it's not going to get built, no matter how safe it is.
Reply | Report Abuse | Link to thisRisk mitigation is something that these guys know a lot about. They know at what point the costs are greater than the benefits. Double hulls were mentioned in the article, but what about the cases where a double hull has been breached? Do you order triple hulls for everything, or accept that sometimes chance will get the better of you? For oil tankers that might one day visit a hostile area, do you build them like warships, driving the cost far higher because they might one day be near something that could shoot at them? For vessels sailing in icy waters, do you build them all like icebreakers? Again, you get a massive rise in the costs.
Even with these, it's still possible for an icebreaker to be overwhelmed by ice. It's possible for the best-built warships to be sunk by force. And incompetence/negligence can lead to even more disaster possibilities (witness the Costa Concordia). Yes, there is a point at which it's not possible to get any safer.
Executives have always over ridden engineers in monetizing any pursuit for the purpose of pure revenue and profit. Simply said, lies. No one in corporate America likes to hear that word and they almost forbid it. But our America of today is largely built on lies. Trust the engineers, NOT the executives. Probably people will never understand this. That's why executives get away with their big bonuses and commensurate lies.
Reply | Report Abuse | Link to thisBoston Whaler designed an unsinkable boat about 50 years ago. It was a big hit and it still sells like hot cakes. Of course an unsinkable ship can be designed and built. First, one must define what constitutes a ship, what its specifications and requirements are, and how much you're willing to pay for it. As with wooden ships, there was a limit to how large they could be before their keels broke in heavy seas. Likewise, there are limits to how large any ships can be given the economics of transporting people or materials. Passenger ships would likely be easier to make unsinkable than iron ore carriers. Come to think of it, oil tankers may be the easiest to make unsinkable as the density of oil is less than the surrounding water.
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Reply | Report Abuse | Link to thisOf course it's possible but unlikely to be done in such ships because of the trade off costs would be high in lower cargo, payload, profit.
I'm building boats that can't really sink because even filled with water their bouyancy is higher than water/lower weight/sq'. Since my next one is a 32' trimaran with 3 hulls it's going to be very hard to sink.
In fact today many new techology can help ship to reduce the risk of sink,but I think the new idea is useful for future
Reply | Report Abuse | Link to thisIt's easy to build an unsinkable ship. Primitive men had built it. Balsa wood is 0.17x lighter than water. Build a raft made of balsa wood, 30 cm thick, 30 m long and 10 m wide. This 90 m^3 raft will give a bouyant force of 74 tons. As long as your cargo does not exceed 74 tons, the raft will float. You can add side walls, roof and change the hull shape to make it look like a ship.
Reply | Report Abuse | Link to thisWrt the Titantic:
Reply | Report Abuse | Link to this"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."
Things float only by displacing their equivalent weight of water. As the front bulk heads filled up with water the nose of the ship starting to be pulled underwater. The bulk heads, not high enough to begin with, are now effectively reduced in height by the COS of the angle the ship is diving into the water. Admittedly, given the nature of the COS function, this is not by much. Additionally, there is effectively less of the ship displacing water since more and more of the ship filling up with water and the ship is nose down. Thus, once nose down, the Titanic was rapidly on her way to the bottom.
Without any bulkheads at all, the water would have flooded the entire ship, lowering it in the water evenly (assuming lateral stability). Once the ship was lower in the water it displace more water by the design of a wider hull which provide additional buoyancy. This is how all ships float with a heavy load.
Thus, given the nature of the mechanical hull rip, I hypothesize having no bulkheads in the design would have been better (i.e. the ship stay afloat longer) than with them.
Costa Concordia didn't sink, it ran aground.
Reply | Report Abuse | Link to thisNow, is it possible to build a ship nobody can run aground?
but how will your balsa wood raft hold up to an iceberg?
Reply | Report Abuse | Link to thisBalsa wood that is a bit old-fashioned ides with current technology we could do a bit better, but yes it seems unsinkable :0)
Reply | Report Abuse | Link to thisYou made a nice point, a warship is limited by the engineering and the cruse ship by the cost, very true but also very sad. When it comes to killing there is always money available, but when it comes to safety and environmental sustainability things get suddenly too expensive to pull though. To summarise my last comment, there is a difference between saying something is too expensive or we may not have a ready solutions for it and saying its impossible. To me science is in the detail and it is important to be accurate about it and distinguish the difference if there is one.
Reply | Report Abuse | Link to thisLet us stick to facts and reality and not myths .
Reply | Report Abuse | Link to thisI remember about 10-25 years ago, watching a TV show that ALSO put the blame on the steel(?) plates that the ship was made of. The show pointed out that the plates where more brittle then good steel that is somewhat ductile. That the plates cracked and broke instead of bent. I (think?) the manufacturing temperature was too low, or not enough or too much carbon was in the mix. But again too cheap was the story. Something like the nuclear reactors that their pumps where run by electric lines exposed to the elements. Why not put the cores of nuclear reactors below sea level, just open a value and flood the core?
Reply | Report Abuse | Link to thisThis is really discouraging. In the first place, SCIENTIFIC AMERICAN has a long history of technical malpractice regarding TITANIC, starting immediately after the loss. Now they rope Henry Petroski in to pontificate about a subject to which his expertise very plainly does not extend. TITANIC's designers understood that some of the measures Prof. Petroski advocates were dangerous and their insights have been validated more formally by analyses published by a number of naval architects since then. Most recently see William H. Garzke, Jr. and John B. Woodward, _Titanic Ships, Titanic Disasters: An Analysis of the Early Cunard and White Star Superliners_ (Jersey City, New Jersey: Society of Naval Architects and Marine Engineers, 2002).
Reply | Report Abuse | Link to thisJerryd,
Reply | Report Abuse | Link to thisI am intrigued with your unsinkable 32'trimaran. [1] Please tell me about it. [2] Will it be available For Sale? [3] If so, where and when ? Ship Ahoy. Sunne44
reinforced concrete hulls would be strong and cheap.Slip forms are used for oil rigs,so the technology exists.Submerine type hulls are more efficient and could go under the ice.
Reply | Report Abuse | Link to thisDid any of the above actually read the article?
Reply | Report Abuse | Link to thisHuman errors, mistakes, and transgressions can trump all attempts to foresee disaster.
Balsa wood boat? Someone will build a fire.
self replicating nano particles based on DNA/MNA restructuralization. thus creating the U.S.S Cancer. cancer does what in the human body? the body does what to cancer? the answers to all lies within the toroidial curves presence in (ALL) things, one and the same. (WE) are the answer.
Reply | Report Abuse | Link to thisI guess you could be right. Although I'd point out that no wooden hulled sailing vessel has ever sunk. Not one.
Reply | Report Abuse | Link to this@slumberfoot
Reply | Report Abuse | Link to thisCollision with iceberg can destroy the balsa wood boat but it won't sink like the Titanic because it's lighter than water. Even if it breaks into pieces, the pieces will float. There is no indestructible ship but there are unsinkable ships.
@xardox
You can't burn wood submerged in water. You can only burn the wood above the water but it doesn't provide any buoyant force. The submerged hull provides the buoyant force.
@stan
Hulls made of reinforced concrete or steel will sink if damaged because concrete and steel are heavier than water.
concrete doesn't tear like paper
Reply | Report Abuse | Link to thisConcrete has low tensile strength. Not good for hull. All ships were made of wood until the 19th century. Wooden ships were the first to cross the Altantic, the Pacific and around the world. Today I still ride small motorized wooden boats across island beaches. They are faster than big steel ferry ships.
Reply | Report Abuse | Link to thisconcrete can survive a bomb,which is why it is used for bunkers.a concrete sub wouldn't be crushed like a tin can like a steel sub in deep water.
Reply | Report Abuse | Link to this"Is It Possible to Build an Unsinkable Ship?"
Reply | Report Abuse | Link to thisIndeed it is, but don't expect it to carry much :-)
All it needs to do is displace more weight of water than it itself weighs. That was the failure of Titanic; it stopped displacing water, and that was facilitated by having a place for water to go inside the displacement hull.
A solid displacement hull eliminates that possibility completely. I double dog dare you to sink a piece of lightweight hardwood (without, of course, tying something heavy to it).
"Trust the engineers, NOT the executives."
Reply | Report Abuse | Link to thisOh, I do, but engineers do not PAY for ships.
"Balsa wood is 0.17x lighter than water."
Reply | Report Abuse | Link to thisMaking it about 6 times heavier than water ;-)
A failing unsinkable ship does not actually fail. It is simply reclassified as a "single use, single trip, disposable submarine."
Reply | Report Abuse | Link to thisTwinkies. Oh ... wait ...
Reply | Report Abuse | Link to thisObviously the two main point of its problems are exactly what I wrote on the issue years ago.
Reply | Report Abuse | Link to thisOne reader talks about using no bulkheads..omg lol.
Unsinkable...
For a start an iceberg (probably more a problem today- global warming) can rip through any can of beans no matter what its made of, and so can hitting rocks as captains always do.
one reader mentions displacement and hits the mark, though no solution except a solid hull is voiced. No not going to happen.
The double hull is used as ballast areas these days, so i cant even recommend a water contact foam that expands and fills the hull.
The only solution was as voiced, bulkheads actually separate the ship into compartments, as it was supposed to be, and not badly implemented in the titanic and life-boats.
The reason life boats on 3x the number of people is so that people can get off one side of the ship if the other is unavailable. Not being able to leave the ship from one side IS NOT THE PROBLEM. use the other side.
ALL (most) life-rafts on ships will disengage from there fixings on hitting water or at a certain depth. There will be more than enough liferafts in the water if a ship is sinking. If it runs aground...not so much youll have to release them.
Adding to my previous comment, quite a number of ore carriers are never heard of again. And yes you don't know this. Essentially they hit a big wave and go under, and except coming up again they go down.
Reply | Report Abuse | Link to thisMuch of this is related to age of the vessel, however without being in the investigation panel which hides such information from you, Id say the parameters for carrying a safe load are being exceeded.
Insurance after-all covers the costs of losing entire ships...
There's a little shop I got to that has <a href="http://www.merlesgiftshop.com/default.asp?dept_id=36090&PageNumber=1&sort=">model ships for sale</a>, and the owner is almost always doing experiments with this. Probably not the kind of thing you can replicate on your own, but still. I like jerry d's point. It can be done, as long as there aren't corners being cut.
Reply | Report Abuse | Link to thisHardly a convincing argument, as this was a boat which made only one trip. Not sinking and unsinkable are not the same.
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