It’s been a year since the Titan submersible disaster claimed the lives of five people, and until now, details have been scarce. That changed when the first public hearings began on September 16, 2024. A joint effort by the U.S. Department of Homeland Security, Coast Guard, and National Transportation Safety Board, the hearings offer fascinating insights from those involved in the submersible’s design, engineering, and operations.
While the hearings are ongoing and many questions remain, I wanted to share my thoughts on the findings thus far—not to present myself as an expert in submersible engineering, but to invite our readers to join me in thinking through this incident. It’s not every day that you get to witness a live investigation like this, so I hope you’ll share your thoughts, poke holes in my theories, and continue the conversation.
At approximately 9 AM on June 16, 2023, the Polar Prince, carrying the Titan submersible, set sail from St. John’s, Newfoundland to dive to the wreck of the RMS Titanic. Two days later, the Polar Prince arrived at the Titanic location and began to prepare for the dive. At approximately 9:18 AM on June 18, the dive began. The crew expected a 12-hour journey down to the Titanic and back, reaching a depth of approximately 3,750 meters. But at a depth of 3,346 meters, the Titan imploded, leading to the loss of all five crew onboard.
The Polar Prince and OceanGate (the manufacturer of the Titan) began an emergency response, contacting the Joint Rescue Coordination Center (JRCC) at 6:27 PM to report the lost submersible. The JRCC directed them to the Rescue Coordination Center in Boston. At 7:10 PM, they reached out to the Canadian Coast Guard, who referred them to the U.S. Coast Guard. The First Coast Guard District then entered distress phase 4 and began the search for the Titan.
After extensive searching, the Pelagic Research Services 6000 remotely operated vehicle (ROV) discovered the aft tail cone and other debris of the Titan on June 22. This discovery provided conclusive evidence of the catastrophic loss of the Titan and the death of all five people aboard.
Since the hearings began, we’ve gleaned enough information to pull together an initial analysis. As always, I’ll start with a Problem Outline. While there are still unanswered questions, the negative impact of the incident is clear. Since the incident, OceanGate has ceased operations, leaving multiple paying customers holding the bag.
Titan Implosion Problem Outline
To begin our analysis, I’ll start with a simple 5-Why Cause Map™ diagram.
Titan Implosion 5-Why Cause Map™
The 5-Why Cause Map diagram is basic, but I want to highlight the last box: pressure chamber broke. When you see “broke” in a Cause Map diagram, that’s a signal to apply the break fundamental relationship, as you’ll see below.
Titan Implosion 6-Why Cause Map™
This is where the investigation starts to get really interesting. Most of what I’ve read online points to the fact that the Titan’s pressure chamber was constructed with a carbon fiber composite and, at these forces, likely buckled in the middle.
I think that’s a logical conclusion, but the evidence presented at the hearings has led me to question it. I’ll share my theories—but first, let’s take a look at how the Titan was constructed.
The Titan’s main cylinder was built from a composite-wrapped carbon fiber pre-impregnated with epoxy. The manufacturer wrapped the carbon fiber multiple times to achieve a five-inch width. This wrapping is performed over a mandrel in a controlled environment to ensure uniform application. The integrity of the carbon fiber is directly dependent on the technical process and procedures of the layup.
After the main cylinder is fabricated, Grade 3 titanium heads are installed at the front and rear of the submersible. These titanium heads are attached to the carbon fiber using an epoxied titanium edge ring. A single O-ring seals the connection between the titanium heads and the edge ring.
Titan Model1
There were multiple issues with the Titan’s construction. The submersible had an acrylic window that wasn’t rated to full-depth design, there were O-Ring design issues, and many other red flags that we will discuss in future blogs. But here, I want to focus on the wreckage and the carbon fiber to titanium ring joint.
When the event occurred in 2023, I watched a lot—and I mean a lot—of videos and technical analyses trying to dissect what went wrong. Most experts indicated the likely failure point was the center of the carbon fiber shell. The best video I found was by Jeff Ostroff2, who conducted a full finite element analysis (FEA) to identify the most likely point of failure. He and others explained that since the center of the cylinder has the most stress, any discontinuity in the carbon fiber would likely cause the implosion.
But on September 18, 2024, the U.S. Coast Guard released footage from the ROV that discovered Titan on the sea floor. As I mentioned earlier, the ROV footage was the first indication that the submersible was a complete loss. The image below was taken at 3:50 PM on June 22, 2023, when the ROV found the tail section fundamentally disconnected from the pressure hull. As you can see, this section looks relatively intact. This makes sense because all the components of this area are designed to take the full external pressure of the depths.
ROV Image of Titan Tail Cone (Provided to Titan Submersible Marine Board of Investigation by Pelagic Research Services, June 2023)
About 40 minutes later in the ROV footage, we see our first indication of the pressure vessel.
ROV Image of Titan Pressure Vessel, Partial View (Provided to Titan Submersible Marine Board of Investigation by Pelagic Research Services, June 2023)
Shortly thereafter, we can see the front titanium hemisphere. It’s difficult to see, but it appears that the acrylic window was blown out by the extreme pressure. This is not unexpected considering the acrylic window was never rated for the full depth (4,000 meters) of the Titan submersible.
ROV Image of the Titan Front Hemisphere (Provided to Titan Submersible Marine Board of Investigation by Pelagic Research Services, June 2023)
About 30 seconds later, the rest of the pressure vessel comes into view.
ROV Image of the Titan Pressure Vessel (Provided to Titan Submersible Marine Board of Investigation by Pelagic Research Services, June 2023)
Okay, time for a disclaimer: The following is based solely on my own engineering judgment. At the time of this writing, the U.S. Coast Guard, the NTSB, and hearing witnesses have not stated any causes or covered any of this material. These are my interpretations of the evidence presented.
I believe the failure occurred at the joint between the front titanium ring and the carbon fiber shell. Based on the debris, we can clearly see:
However, the front titanium end ring appears to be missing. While more videos may reveal its location, I haven’t seen it in any footage so far.
In the final image from the ROV footage, most of the carbon fiber and debris seem to have been pushed into the rear hemisphere, almost compressed into a single area. During an implosion, the shockwave travels from the point of failure toward the area of least resistance, which supports the theory of a front joint failure.
If, on the other hand, there was a failure in the middle of the pressure vessel, I’d expect the two sides of debris to look the same. I’d expect to see the front and rear hemispheres attached to the end rings, and for the carbon fiber to be evenly distributed between where the two hemispheres were found.
The joint between the carbon fiber and the titanium end ring is simple but crucial in design. The carbon fiber on the Titan is wound 5 inches thick, allowing it to withstand external pressure. Since titanium can't be directly attached to carbon fiber, epoxy is used. Epoxy is a proven technology, but the application process is critical—too much or too little can lead to joint failure. Epoxy also weakens over time, and the dive to the Titanic wreckage was Titan’s 88th dive.
Carbon Fiber to Titanium End Ring Joint
After the joint failed, water rushed in. The front would have collapsed and pushed all the extra pressure to the location of the largest cavity, forcing the water to inrush quickly to the back.
Water Inrush From Joint Failure
It’s also reasonable to believe the hull had issues. On the Titan’s 80th dive, a loud bang was heard—but it was dismissed as pressure vessel movement. No non-destructive examination (NDE) was done between dives, so the condition of the carbon fiber was uncertain.
However, in the hearings, we saw an image of a cut-off section of the carbon fiber hull, which reveals multiple delamination and voids. This sample may not represent the entire cylinder, but it raises concerns.
Carbon Fiber Cut Off
I’ve used this theory to build a 19-Why Cause Map diagram. As you’ll see, there are a lot of question marks in the cause boxes. I’ve also added yellow “Info to Get” boxes to indicate where we need to gather evidence to support or disprove possible causes. This is the same process I follow when facilitating an investigation: Document what we know and don’t know and create immediate action items to get evidence for the unknowns.
Titan Implosion 19-Why Cause Map™ With Evidence to be Gathered
click the image to enlarge
As I said before, the analysis above is based solely on my engineering judgment. Evidence is still pouring in, and it’s been fascinating to watch. If you’re watching too, please let me know what you think. Tell me where I’m wrong and share your own thoughts and theories.
Please see my initial draft report here:
Stay tuned for a follow-up when the investigation concludes.
And if you haven’t been following this closely, join me in nerding out. Here are my favorite links to get started:
Stay tuned for a follow-up when the investigation concludes.
1 - Titan Model Source: File:Dimensions Titan.jpg; Logo removed and labels added by ThinkReliability
2 - Jeff Ostroff's Video