Will latest Titan sub find help unravel mystery of what happened on doomed trip to the Titanic that killed 5 when vessel suffered catastrophic failure 12,500ft deep
- The discovery of an intact part of the doomed Titan sub could shed light on the tragedy that killed five people last June
The discovery of a new set of parts belonging to the doomed Titan sub appears to shed some light on what caused the disaster that claimed the lives of five people in June 2023.
According to the US Coast Guard, last week investigators recovered various parts of the vessel, including an intact aft titanium endcap that was covered by a tail cone on the submersible.
Analyst Michael Chillit, who has been conducting his own investigation into the disaster, wrote in a post on X that the emergence of the endcap photo suggested that investigators may now be able to solve the mystery.
‘There was a lot of speculation that it was the observation port that failed, but now a damaged landing frame and a fully intact rear hemisphere suggests to me that failure occurred in the composite near where it was joined to the frame and the aft hemisphere,’ Chillit said.
He also wondered if officials recovered any pieces of the ship’s observation port was recovered. The coast guard has not said in detail what new pieces of the submersible were recovered.
Investigators have recovered various pieces of the craft, including the aft end cap which connected the hull to the rear of the vessel
Shahzada Dawood, 48, one of Pakistan’s richest men, who along with his teenage son Suleman Dawood, 19, (together, left) died on the Titan along with British explorer Hamish Harding (right)
Stockton Rush, the CEO of OceanGate, which launched, Titan, perished on board the submersible last Sunday along with his four passengers, including PH Nargeolet (right)
Tourists Hamish Harding, 58, Shahzada Dawood, 48, and his son Sulaiman Dawood, 19, French Navy pilot Paul-Henry Nargeolet and OceanGate CEO Stockton Rush all perished on board the submersible.
The observation port and the end cap were linked to the hull with titanium. The hull of the vessel was made of carbon fiber, a cheaper alternative more commonly used in aerospace.
Carbon fiber is thought to be as strong as titanium against pulling forces but not pushing ones such as the extreme pressure created by being deep in the Atlantic Ocean.
When it fails, it shatters without warning, compared to titanium which would bend.
A July 2023 New York Times feature also noted how difficult it can be to bond the joints of different materials such as titanium and carbon fiber. The hull was glued to the titanium rings at either end and the end caps were attached.
Forensic metallurgist Tim Foecke told the Times at the time that altering the size of the hull’s geometry
Another theory put forward in the Times feature is that the titanium glue could have been degraded by saltwater.
Additional presumed human remains were carefully recovered from within Titan’s debris and transported for analysis by U.S. medical professionals, the Coast Guard said.
The U.S. Coast Guard announced that they recovered presumed human remains along with parts of the Titan after the debris field was located at a depth of 12,500ft
Its vehicle Odysseus 6K reached the seafloor after days of searching and found debris of the sub around 1,600 feet from the bow of the Titanic
The recent salvage mission conducted under an agreement with the U.S. Navy was a follow-up to initial recovery operations on the ocean floor roughly 1,600 feet away from the Titanic, the Coast Guard said.
The new materials were offloaded at an unnamed port.
Chillit later indicated that he believed the implosion took place in ‘the area where the landing frame, the hull, and the Titanium end-cap were joined.’
The Coast Guard previously said it recovered presumed human remains along with parts of the Titan after the debris field was located at a depth of 12,500 feet.
Investigators believe the Titan imploded as it made its descent into deep North Atlantic waters on June 18.
The multiday search mounted after Titan went silent captured attention around the world. The submersible was attempting to view the British passenger liner that sank in 1912.
The Coast Guard’s Marine Board of Investigation said investigators from the U.S. National Transportation Safety Board and the Transportation Safety Board of Canada joined the salvage expedition, and the Coast Guard is coordinating with international investigative agencies to schedule a joint review of the evidence to determine the next steps for forensic testing.
The Marine Board of Investigation, meanwhile, will continue its analysis and witness interviews ahead of a public hearing on the tragedy, officials said Tuesday.
OceanGate, the operator of the vessel, has since gone out of business. Among those killed in the implosion was Stockton Rush, the submersible’s pilot and CEO of the company.
Previous theories on what happened to the Titan sub that caused it to shatter as it approached the Titanic killing all five on board
The pulled not kept safely theory
The Alvin research sub is transported to dive sites on the deck of a dedicated mothership, which is outfitted with custom winches and a large crane that places it in the ocean.
In contrast, Titan had no dedicated mothership, and to cut costs it was towed out to sea on the fatal dive by a smaller chartered vessel, the Polar Prince.
The Polar Prince, a decommissioned Canadian Coast Guard icebreaker, was smaller and older than the ships OceanGate had used in previous years, in a cost-cutting move by Rush.
Using a tow cable, the ship dragged the Titan across hundreds of miles of open sea on top of the launch platform that was used to submerge and retrieve the sub.
The Alvin research sub is transported to dive sites on the deck of a dedicated mothership, which is outfitted with custom winches and a large crane that places it in the ocean
In a column for Travel Weekly, Arnie Weissman recounted a harrowing tale of a ‘near-disaster for the sub and platform’ during high seas.
‘At the end of the rope that linked the stern of the ship to the platform, we saw that the front of the platform and the sub were under water,’ he wrote.
It was not clear what had happened, but crew members theorized that a fishing buoy spotted in the area may have gotten a line tangled with the platform and dragged it under, filling air tanks with water.
Attempts to lift the platform with a buoy on the tow line were unsuccessful, and Rush had to send divers out to clear water from the platform’s bouncy tanks, a process that took half a day.
The no fishing line was discovered tangled in the platform, leaving the cause of the incident a mystery.
Weissman recalled that, when asked about whether the incident jeopardized the sub, Rush joked: ‘So a sub is under water. Why is that a problem?’
Prioritizing taking more people
Alvin, the famous research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution, has a spherical design.
At the depths of the ocean deep, a sphere is the optimal shape to resist crushing pressures that can reach three tons per square inch, because the pressure is equally distributed across the hull.
The downside to the Alvin is its cramped capacity — the sub is only capable of taking three people to the ocean floor.
Titan’s design was roomier, with space for five people in a pill-shaped sub, which consisted of a carbon-fiber tube capped by titanium hemispheres on each end
Rush, who was charging $250,000 per passenger for his dives to the Titanic wreckage, would have only been able to take two customers per trip with a similar design, assuming an OceanGate pilot went along.
Instead, his Titan design was roomier, with space for five people in a pill-shaped sub, which consisted of a carbon-fiber tube capped by titanium hemispheres on each end.
Tim Foecke, a retired forensic metallurgist, told the Times that the Titan’s change in hull geometry — from a tight sphere to a lengthy tube — may have contributed to the sub’s catastrophic failure.
He noted that the larger a sub is, the stronger and thicker its hull must be in order to withstand the same pressure.
In two subs with the same hull thickness, the larger one would ‘collapse or buckle’ first, he said.
Choosing carbon fiber
One of Rush’s main innovations in the Titan was the use of carbon fiber for much of the hull, which is cheaper and lighter than titanium
One of Rush’s main innovations in the Titan was the use of carbon fiber for much of the hull, which is cheaper and lighter than titanium.
OceanGate promoted the Titan’s carbon fiber construction – with titanium endcaps – as ‘lighter in weight and more efficient to mobilize than other deep diving submersibles’ on its website.
The material reduced Titan’s weight to 21,000 pounds, compared with Alvin’s 45,000 pounds.
But experts say carbon composites are much tougher against pulling forces than they are against crushing forces.
‘I was very surprised’ by the fiber construction of Titan, Foecke told the Times, because compression was the main force that the submersible encountered on its deep sea dives.
Carbon composites also have limited life when subject to excessive loads or poor design which leads to stress concentrations, said Jasper Graham-Jones, an associate professor of mechanical and marine engineering at the University of Plymouth in the United Kingdom.
‘Yes, composites are extremely tough. Yes, composites are extremely long lasting. But we do have issues with composites and the fact that composites fail in slightly different ways than other materials,’ he told the Associated Press.
Furthermore, the Titan’s 5-inch thick hull had been subjected to repeated stress over the course of about two dozen previous dives, Graham-Jones said.
Each trip would put tiny cracks in the structure. ‘This might be small and undetectable to start but would soon become critical and produce rapid and uncontrollable growth,’ he said.
The use of glue
The Titan’s design required attaching its carbon-fiber tube to the titanium endcaps, which was achieved with powerful glue.
But experts say that because different materials change shape at different rates under pressure, maintaining a seal between them can be challenging.
Alfred S. McLaren, a retired Navy submariner and president emeritus of the Explorers Club of New York City, explained that the different materials in the Titan’s hull ‘have different coefficients of expansion and compression, and that works against keeping a watertight bond.’
This image shows a titanum ring being bonded to the Titan’s carbon tube hull. Because different materials change shape at different rates under pressure, maintaining a seal between them can be challenging
In other words, if the carbon fiber tube compressed in a slightly different way than the titanium end caps, it could have compromised the seal between them, particularly after repeated dives.
Experts have also questioned OceanGate’s refusal to seek outside testing and certification for the Titan.
Graham-Jones said it’s standard procedure in engineering to seek outside expertise the ensure that vessels conform to the highest industry standards.
In a 2019 company blog post, OceanGate criticized the third-party certification process as one that is time-consuming and stifles innovation.
‘Bringing an outside entity up to speed on every innovation before it is put into real-world testing is anathema to rapid innovation,’ the post said.
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