Remains TitanThe ‘s innovative carbon fiber hull was found to be separated into three distinct layers, Donald Kramer, an engineer with the National Transportation Safety Board, told the Coast Guard. Hearing In 2023, the Ocean Gate submarine suffers a fatal explosion.
Kramer did not offer an opinion on what caused the hull to delaminate, but testified that there had been multiple issues with the hull since it was first built in 2020.
The NTSB used carbon fiber samples preserved during construction and dozens of pieces recovered from the ocean floor to provide the most complete picture to date of the experimental nature of the craft. TitanHull.
after that TitanAfter a deep-sea dive in 2019, cracks and delamination were found in the original hull, so Ocean Gate replaced it with a new manufacturer.
The new manufacturer, Electroimpact, used a multi-step process to wrap and cure the 5-inch-thick hull in five separate layers. Each layer was baked at high temperature and pressure, then sanded flat, a sheet of adhesive was added, and another layer was built on top. The purpose of this multi-step process was to reduce wrinkling in the final hull, which was thought to be causing test models to not reach the design depth.
But Kramer testified that the NTSB found several anomalies in the new hull samples. Four of the five layers had rippling, and the wrinkling got progressively more severe with each layer. The NTSB also found that some layers had porosity (gaps in the resin material) that was four times greater than specified in the design. It also noted voids between the five layers.
“Defects such as voids, surface blisters and porosity can weaken the carbon fibre and accelerate the failure of the hull under extreme hydrostatic pressure,” Roy Thomas, a materials expert with the American Bureau of Shipping, said at the hearing on Monday.
OceanGate did not create additional test models using its new multi-step process.
The NTSB was able to recover a number of carbon fiber hull fragments from the ocean floor, one of which was still attached to one of the submersible’s titanium end domes. Report In a report issued at the same time as Kramer’s testimony, the NTSB noted that there was little or no full-thickness debris in the hull. All visible debris had peeled off into three shells: the innermost of the five layers, the layer made up of the second and third layers, and the layer made up of the fourth and fifth layers. Like peeling an onion, the hull had peeled off at the glue that held the layers together.
Remains Titan A remotely operated vehicle captures a submersible that exploded on the ocean floor.Photo: Reuters
