Physicist explains why the Titan submersible’s carbon fiber was ineffective

The carbon fiber debris from the Titan submersible.
Debris from the Titan submersible, recovered from the ocean floor near the wreck of the Titanic, is unloaded from the ship Horizon Arctic at the Canadian Coast Guard pier in St. John’s, Newfoundland. Photo by Paul Daly/The Canadian Press via AP

With the debris of the OceanGate Titan submersible now in the possession of authorities, investigators are hard at work piecing together (literally) what caused the vessel to implode in the Atlantic Ocean more than a week ago.

Northeastern Global News spoke to Arun Bansil, university distinguished professor of physics at Northeastern, last week to try to gain a better understanding of what exactly might have happened all those fathoms beneath the surface, where the five Titan crew members died.

One potential explanation has been widely discussed: the vessel’s experimental carbon-fiber hull, which the company turned around in just six weeks, according to one report

We tapped Bansil again to provide a brief overview (and history) of the use of carbon-fiber materials in deep-sea watercraft. The conversation has been edited for brevity and clarity.

There’s been a lot of chatter about the Titan submersible’s carbon-fiber composition. Can you explain why carbon-fiber material might not hold up as well as titanium, aluminum and steel under deep-ocean pressure?

Head shot of Arun Bansil.
Arun Bansil, university distinguished professor of physics, poses for a portrait in the ISEC building. Photo by Matthew Modoono/Northeastern University

For components requiring light weight and high strength, carbon fiber-based composites have been successfully developed for use in aerospace, automotive, sports, medical and consumer industries. 

When it comes to deep-sea applications, however, this is not the case, and steel, titanium and aluminum are used widely for making pressure hulls.

Titan was the first deep-sea vehicle with a hull made mainly from carbon fibers. The ability of carbon fibers to withstand repeated cycles of stress, especially compressive stress, under deep-sea pressures is not well understood, making it difficult to design safe hulls based on carbon fibers.

The degrading effects of water absorption on the epoxy binding the carbon fibers in the composite should also be kept in mind in assessing the failure of Titan. 

When did carbon fiber begin to be seen as a candidate material for these types of watercraft? 

It seems that adventurist Steve Fossett started exploring the use of carbon fibers around 2000 for the hull of a one-person submersible to dive to the bottom of Challenger Deep, which is the deepest point in the Mariana Trench, at about 36,000 feet.

The submersible DeepFlight Challenger that Fossett commissioned has not been tested or deployed. Titan was the first deep-sea submersible with a carbon-fiber hull. 

Why are companies experimenting with these new materials, and are there other alternatives that have shown promise? 

New materials are the backbone on which transformative science and engineering advances are made. Carbon fibers offer many advantages over metals, such as high strength, lightweight and corrosion resistance. 

Titan had made several dives to the Titanic shipwreck, and we should withhold judgment on the primary trigger for its implosion until the ongoing investigations are completed. 

My guess is that researchers will eventually develop carbon-fiber-based materials for deep-sea applications, along with testing protocols for safe operation of the submersibles.  

Tanner Stening is a Northeastern Global News reporter. Email him at Follow him on Twitter @tstening90.