Titan sub noise heard on board support ship. 2

[LittleInch]

Just watched a new documentary by the BBC and others like Discovery so if you're interested look out for it. Implosion: The titanic sub disaster.

Key new part for me is that they released video of the moment a loud "crump" was actually heard on board the support vessel apparently through the hull with Rushs wife Wendy doing the monitoring of the sub and her saying "what was that?". They then got a message from the sub which must have been somehow delayed saying dropped two weights which confused them. It is pretty chilling to listen to alright. That and the fact that they were thought not to be at the ocean floor implies they were getting some warnings.

This is a clip but there are others.

Not much we didn't already know, but they have noted dive 81 (out of 88) where there was a very large bang heard which they reckon was the point at which the hull was on its last legs after a major internal failure.

The Discovery documentary maker back in 2022 was very unimpressed with the whole thing and persuaded the company to can their documentary as he was convinced it would end in failure and didn't want to be seen to promote the operation.

Looks like it's on Discovery pretty soon. If you're interested, it's pretty good and not that big into the human interest side, but does have input from the wife of the man and his son that died which is quite moving.

How to watch 'Implosion: The Titanic Sub Disaster' - Stream the thought-provoking documentary online

Scientists explore how the Titan submersible implosion was more than just a tragic accident

www.tomsguide.com

 

[XR250]

XR, he hoop strength of the tube is insufficient without the titanium dome. Any failures of the connection between the CF hull and the titanium ring will cause the CF hull to collapse.

Seems odd. So you are saying there is 2-way action going on in the hull despite all the fibers running circumferentially? (I believe)

 

[TugboatEng]

Metals like titanium and aluminum instantly form oxides on their surface in air. Adhesion of epoxy or any paint or adhesive to oxides of metals weakens over time when exposed to moisture.

We know the joint was strong. It survived several dives. If the failure was at the joint, something must have weakened it.

 

[Tomfh]

Seems odd. So you are saying there is 2-way action going on in the hull despite all the fibers running circumferentially? (I believe)

The weave is bidirectional, like shirt fabric, designed to resist both hoop and axial stresses.

That said, the cylinder didn’t rely on the domes for buckling restraint, the domes merely capped the ends and transferred axial load into the hull.

Still, the strain mismatch at the junction, where the hull compressed radially by several millimetres more than the domes, could have introduced significant shear at the interface.

But regardless, the hull was cracking badly well away from the joint, pointing to deeper, more fundamental issues with the cylindrical structure itself.

 

[TugboatEng]

Keep in mind that lawyers might be hiring people to find that the hull was defective so that try can pursue legal actions against Oceangate AND the company that fabricated the CF hull for a bigger pool of money. There is pressure that may be biasing these investigations.

 

[DennisR4]

I think the documentary glossed over the design and development process a little. It made it seem like, after a few early test failures, Stockton Rush jumped straight into a full-size sub. But if you look closely, those early failures appeared to involve failed carbon fibre end caps. Presumably that’s why the final sub used titanium ends.

Rush likely thought the problems were behind him: the cylindrical carbon fibre hull concept had (presumably) passed pressure tests, and the titanium end caps were solid. So in his mind, the design was validated. But he hasn’t counted on the slow progression of microcracks thru the cylindrical hull.

I am surprised more people haven't caught that yet.

 

[RVAmeche]

For a company relying so much on the acoustic monitoring system its really bizarre that Stockton and Co just ignored the results/sounds and kept saying its fine, every sub makes noises....

Like once the data changes significantly after Dive 80 its clear you need to get a new hull or not put people in it. Especially since despite the testing they had no real idea when failure would occur in terms of number of dives or acoustic levels. All they knew was louder = bad and they ignored even that.

 

[LittleInch]

It is where they used experience in metallic submersible and submarines which do shake down and can creak to a completly different material.

Hence wyht eh cyclic testing and monitoring of the noises would have been so useful to actually give them a fingerprint of what was likely to happen and when.

The bang on dive 80 or 81 was so big it went off the chart, but was just ignored. No point in doing it if all you're doing it for is to give a false sense of condition monitoring to the passengers mission "specialists"