I just heard some sort of expert on the radio down under (excuse the Pun). He stated that the reported banging every half hour would only be heard if the capsule was made of steel but with a combination of Carbon Fibre and Titanium you may as well bang your head on a wooden log (his words) also they are starting to discover Carbon Fibre can deteriate and develop stress cracks under water especially going through pressure cycles. Also the main observation window was not designed for such depths, this was highlighted by the safety officer and because of his insistance he was sacked.
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