The remains of TitanDonald Kramer, an engineer with the National Transportation Safety Board, told the Coast Guard that the innovative carbon fiber hull was found to be separated into three distinct layers. hearing In 2023, the OceanGate submarine was destroyed in a catastrophic explosion.
Kramer would not comment on what caused the hull to separate into multiple layers, but testified that there had been problems with the hull since it was manufactured in 2020.
Using carbon fiber samples saved during construction and dozens of pieces recovered from the seabed, the NTSB provided the most complete picture yet of its experimental properties. TitanThe hull of the ship.
After that TitanOceanGate conducted a deep-sea exploration in 2019 and discovered cracks and delamination in the first hull, so the manufacturer changed to replace it.
The new manufacturer, Electroimpact, used a multi-stage process to wrap and cure the 5-inch-thick hull in five separate layers. Each layer was baked at high temperatures and pressures before being ground flat, an adhesive sheet was added, and another layer was laid on top. The idea behind this multi-stage process was to reduce wrinkles in the final hull, which the company believes was causing test models to fall short of the design depth.
However, Kramer testified that the NTSB found several anomalies in the fresh hull samples. Four of the five layers had wavy patterns, with increasingly deeper wrinkles as each layer passed through. The NTSB also found that some layers had four times more porosity (interstices in the resin material) than was specified in the design. In addition, voids were recorded between the five layers.
“Defects such as voids, surface blisters and porosity can weaken carbon fiber and accelerate hull failure under extreme hydrostatic pressure,” Roy Thomas, a materials expert with the American Bureau of Shipping, told the hearing on Monday.
OceanGate did not create additional test models using the new multi-step process.
The NTSB was able to recover several pieces of the carbon fiber hull from the seabed, one of which was still attached to one of the submarine’s titanium end domes. report The NTSB, published at the same time as Kramer’s testimony, noted that there was little or no full-thickness hull fragmentation. All visible fragments had delaminated in three layers: the innermost of the five layers, the second and third layers, and the fourth and fifth layers. Like peeling an onion, the hull had largely separated from the adhesive that held the layers together.
Fragments of Titan Footage has captured a remote-controlled vehicle sinking into the ocean after the explosion.Photo: Reuters
