The Titan submersible used in the explosion accident that killed five passengers used ultra-light materials and many features that cannot be found in similar submersibles.
The crew compartment of the Deepsea Challenger (left) and Titan (right). Photo: Popular Mechanics
The Titan submersible is made from an unusual material that allows it to descend to sites like the Titanic wreck, which is 12,000 feet (3,810 meters) below the Atlantic Ocean. While submersibles like the US Navy's Alvin (which also explored the Titanic) use a titanium hull, OceanGate's submersible is made from carbon fiber with a titanium lid. The company advertises the Titan as the world's only carbon fiber submersible that can carry five people to depths of 13,000 feet (4,000 meters).
As with aircraft and spacecraft, titanium is used in submarines because it is both extremely light and strong, but it is also extremely expensive and difficult to work with. That is why the US Navy still builds its nuclear submarines from steel, even though the new Virginia-class attack submarines are estimated to have a maximum depth of about 1,500 feet.
The Deepsea Challenger, the famous submersible that carried director and underwater explorer James Cameron to the world’s deepest point, the Challenger Deep, at a depth of nearly 11 kilometers, is made primarily of a special type of glass foam, with the crew compartment consisting of a steel sphere attached to a support. According to the Woods Hole Oceanographic Institution, which operates the Deepsea Challenger, about 70 percent of the vehicle’s volume is made of this foam. The glass foam contains glass spheres embedded in epoxy resin, which provide both buoyancy and structural support.
The carbon fiber construction of the Titan makes it lighter. The Deepsea Challenger weighs about 12 tons and carries one person. The Alvin, with a pilot and two passengers, weighs about 17 tons. The Titan, with a pilot and four passengers, weighs just 10 tons.
There are doubts about whether carbon fiber is suitable for ultra-deep diving, or at least whether the material has been adequately tested for such great depths. At the site of the Titanic, for example, the pressure is as high as 4,200 tons per square meter. Carbon fiber is cheaper than titanium or steel and extremely strong, but it has barely been tested for deep-diving vessels like the Titan.
Unlike the Deepsea Challenger’s spherical design, which distributes pressure evenly, the Titan’s cylindrical shape means some areas are under more pressure than others. At depths of more than 2 miles (3.6 kilometers) below the surface, even a small crack in the hull would cause an immediate decompression.
There have been previous reports of safety concerns about the Titan. David Lochridge, OceanGate’s former director of marine operations, warned the company in 2018 that the ship’s exterior viewing windows were only licensed for depths of 1,300 meters. Lochridge was later fired.
Former passengers also described problems with the ship’s propulsion, navigation, and communications systems, such as controls adapted from game controllers and hatches that cannot be opened from the inside. Most submersibles are certified by international maritime safety organizations. OceanGate, by contrast, said the Titan was so advanced that obtaining certification was too time-consuming.
An Khang (According to Popular Mechanics )
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