- 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.
- Most of the submersibles we've seen follow a very similar design.
That's really where Titan was so different and so radical than previous submersibles.
- The Titan was a radically different design.
From the minute you see it, it's not metal, it's not silver, it's a big white capsule.
- [Marissa] 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.
- 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.
- [Marissa] The capsule that contained passengers on the Titan, the hull, was a five-inch-thick carbon fiber cylinder capped with two titanium half spheres on either end.
Commonly, the hull of a submersible is a sphere because underwater pressure is more evenly distributed 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] That's like a couple of Toyota Corollas on your big toe.
- Any little fracture, any little hull deformity could be really a fatal flaw.
- 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.
(egg cracks) 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.
- When you have kind of oval shape or an egg shape, now it deforms more along the short axis and less the longer axis, and larger deformation leads to greater failure.
- [Marissa] 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.
- Carbon fiber has been used for pressure vessels not to go that deep under the ocean.
- [Marissa] The Titan was comprised of three materials, the carbon-fiber hull or pressure vessel, the titanium end caps, and a plexiglass window.
- The more you can avoid actually changing material, the better.
- 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.
- 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.
- 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 obliterate the thing in a fraction of a second.
- 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.
- However, we have seen the use of new technologies over time be questioned, whether it's in deep sea submergence, space, air, 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 and experimental nature.
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.
- Although the Titan was built in the U.S., it may not be subject to U.S. laws since it was launched from Canada into international waters - 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.
They're in operation every day around the world.
Most people get on board an airplane, fly 40,000 feet 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.
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