Name: What Made the Titan Submersible Design Unconventional?
Uploaded: undefined
Duration: undefined

NOVA

Carlisle Companies

Viking

NOVA Science Trust Logo

OceanGate Expeditions’ Titan submersible had taken passengers down to the Titanic wreckage many times before the ill-fated trip that killed all five passengers on board. So, why did it fail?

An international investigation into the fatal submersible implosion is underway.

OceanGate Expeditions’ Titan submersible had taken passengers down to the Titanic wreckage many times before the ill-fated trip that killed all five passengers on board. So, why did it fail?

What Made the Titan Submersible Design Unconventional?

An international investigation into the fatal submersible implosion is underway.

Tech & Engineering

What Made the Titan Submersible Design Unconventional?Published: July 3, 2023Narrator: OceanGate Expeditions’ Titan submersible had taken passengers down to the Titanic wreckage many times before the ill-fated trip that killed all five passengers on-board.So, why did it fail?Even before the disaster, some experts were criticizing the vessel’s unusual design. Notably, the Titan also traveled to much farther depths, with more passengers than most other submersibles.Sal Mercogliano: Most of the submersibles we've seen follow a very similar design. And that's really where Titan was so different and so radical than previous submersibles.David Pogue: The Titan was a radically different design for the minute you see it, it's not metal, it's not silver. It's a big white capsule.Narrator: David Pogue was on a Titan expedition in 2022, reporting for CBS, but he didn’t travel very deep underwater. As the submersible launched, two buoys secured to the launch platform came untied and the company canceled the dive.David Pogue: At the time, I was annoyed. I thought that was absurdly conservative. Who cares about the platform? The sub is fine. Now, I guess I'm grateful.Narrator: The capsule that contained passengers on the Titan – the hull – was a five-inch-thick carbon-fiber cylinder, capped by two titanium half spheres on either end.Commonly, the hull of a submersible is a sphere, because underwater pressure is distributed more evenly on a sphere than a cylinder, and the deeper underwater, the more pressure. On the ocean floor, that pressure is tremendous. At the site of the sunken Titanic, it’s about 6,000 pounds per square inch.David Pogue: That's like a couple of Toyota Corollas on your big toe.Sal Mercogliano: And so that when, when you're at that bottom, any little fracture, any little hole deformity could be really a fatal flaw.Narrator: To understand how pressure affects a cylinder, think of an egg. Hold it in your hand and squeeze it along the longer axis. Try as hard as you can and I bet you can't break it! The long axis is incredibly strong under pressure. But if you put it on a table and press down on it, applying pressure on the side instead of the top or bottom… crack.Now imagine pressure on the egg equally, all around it—that’s what it’s like underwater. And when that tremendous underwater pressure increases and decreases, it can alter the shape of a vessel, over multiple expeditions.Stefano Brizzolara: When you have a kind of oval shape, or an egg shape, now it deforms more along the shorter axis and less along the longer axis. And larger deformation leads to greater failure.Narrator: The hull is commonly built with titanium or steel. But on the Titan, it was made of carbon fiber, which is more lightweight, for roughly the same amount of strength. But there are a lot of unknowns about how it behaves at depth, in the ocean and over time.Stefano Brizzolara: Carbon fiber has been used for pressure vessels, but not to go deep under the ocean.Narrator: The Titan was comprised of three materials: the carbon fiber hull, or pressure vessel, the titanium end caps, and a plexiglass window.Stefano Brizzolara: The more you can avoid actually changing materials, the better.David Pogue: My own opinion is that the carbon fiber was not the problem with the implosion. My opinion is that it was the fact that it was three materials, dissimilar materials, carbon fiber, titanium and plexiglass for the porthole.Narrator: All three materials have different compressive characteristics and behave differently under changes in pressure and temperature. And in the deep ocean, temperatures can hover near freezing.David Pogue: It's possible that over time, a little crack, a little seam, a little space opened up, and if even a drop of water gets in, it's over. The pressure at those depths obliterates the thing in a fraction of a second.Narrator: Internal and external experts expressed concern about the Titan’s safety. OceanGate did not classify the Titan, a common practice for ensuring safety and compliance on submersibles – although it’s not required.Sal Mercogliano: However, we have seen the use of new technologies over time be questioned, whether it's in deep sea submergence space, air, you know, automobile. The difference here is you don't tend to put new types of technology in commercial passenger use. You tend to use it more in research, in experimental nature. You know, we may find out in the future that what OceanGate had developed will be the norm in the future. We don't know yet. We don't know what the failure was. We don't know what caused it.Narrator: Although the Titan was built in the US, it may not be subject to US laws since it was launched from Canada, into international waters.Sal Mercogliano: A year or two after Titan, do we get some sort of international change of regulation or national change of regulation to make submersibles even safer? They are a safe operation. Submersibles around the world since the 1960s have been safe there in operation every day around the world. Most people get on board an airplane, fly 40,000 feet above the air and above the ground. And don't think twice about it. Will we ever get to the point where we go 13,000 feet under the water and not think twice about it? We're just not there yet.

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US & Territories

Colossal explosions shake a remote corner of the Siberian tundra, leaving behind massive craters. In Alaska, a huge lake erupts with bubbles of inflammable gas. Scientists are discovering that these mystifying phenomena add up to a ticking time bomb, as long-frozen permafrost melts and releases vast amounts of methane, a potent greenhouse gas. What are the implications of these dramatic developments in the Arctic? Scientists and local communities alike are struggling to grasp the scale of the methane threat and what it means for our climate future. (Premiered February 2, 2022)

In the Arctic, enormous releases of methane, a potent greenhouse gas, threaten the climate.

Arctic Sinkholes

The top half of Jupiter in blue and green against a night sky

A composite image of Jupiter using images captured by the James Webb Space Telescope. Image Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Judy Schmidt.

Explore the cosmos, delve into ancient history, and follow an extreme rescue with NOVA’s most-watched documentaries released in 2022.

NOVA’s most popular science documentaries of 2022

Four bright orange loops brand off of a dark blue blob

A transmission electron micrograph of HIV-1 virus particles (orange) replicating from the plasma membrane of an infected H9 T cell. Credit: NIAID, Flickr

Scientists have cured a handful of people of HIV by piggybacking on treatments they received for blood cancer. But does that bring a widespread cure any closer?

What Made the Titan Submersible Design Unconventional?

Support Provided By

Explore More

Ultimate Cruise Ship

The Crash That Shut Down the Global Economy, Explained

An Unsinkable Ship?

Transcript

Credits

Support Provided By

Explore More

Ultimate Cruise Ship

The Crash That Shut Down the Global Economy, Explained

An Unsinkable Ship?