Outside Topic OT: Underwater topic

Outside Topic OT: Underwater topic - Printable Version

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RE: OT: Underwater topic - Beeg_Dawg - 06-25-2023

(06-23-2023, 06:44 PM)CowboyIndian Wrote:
(06-22-2023, 09:27 PM)Nan3cy Wrote: I’m absolutely not an engineer, but from what I read, the first and most basic mistake was not getting the carbon-based material tested to see if it would resist the deep-sea pressure. Apparently it didn’t.

My understanding is that the carbon fiber worked for a few dives but over time became "fatigued". That's according to James Cameron, director of "Titanic" and a veteran of many dives in the deep, including the Mariana Trench. Cameron noted that the fact that there were mixed materials (carbon and resin) made it ultimately unsafe.

Didn't catch the name, but a retired Navy submarine specialist noted the same thing. Three key materials used - titanium, carbon filaments and the viewport- all react differently when compressed. His question - Would anyone fly on a plane constructed with untested material and methods of assembly?

Stockton Rush will be synonymous with hubris years from now. He's now famous for all the wrong reasons.

One last thought - if this was a dive anywhere else, this would have made one news cycle. It's about the Titanic more than anything else.

RE: OT: Underwater topic - Goose - 06-25-2023

(06-25-2023, 11:21 AM)Beeg_Dawg Wrote: Three key materials used - titanium, carbon filaments and the viewport- all react differently when compressed.

IMO this was the inherent "fatal flaw" in the design that could not be overcome by engineering. The carbon fiber cylinder may have indeed failed due to water intrusion de-laminating it, but at least in theory that is an effect that could be "engineered out" of the design. The differential compression characteristics of three major parts of the vessel could not. They are inherent characteristics of the materials that can't be changed. Eventually, the junctions of these different materials will fail, one way or another. This may manifest itself as a total failure of one side of the structure, like the viewport shattering, but it would be the differential pressure due to different compression coefficients that would cause it.

RE: OT: Underwater topic - jacket3ree - 06-25-2023

(06-23-2023, 06:38 PM)Hurlburt88 Wrote: I believe carbon fiber composites can also suffer from delamination as the primary fatigue mechanism. Really key to not miss a trick in a design like this.

On a lighter note, classmate of mine for senior mech eng project designed and built a small sub. Prof did not really expect the group would get as far as they did, and the day before they were to test in Lake Lag she nixed it. IIRC, they ended up testing in Lake Tahoe after graduation--successfully. He laughs about it to this day. And for the curious, steel was the key material.

There can't be too many of those guys around. If your classmate's name is Scott, the sub was yellow, had a basketball lodged in the stern cage for buoyancy control, and eventually sat next to the USS Pompanito in the City, I worked with him for a few years in San Jose.

RE: OT: Underwater topic - Hurlburt88 - 06-27-2023

(06-25-2023, 06:46 PM)jacket3ree Wrote:
(06-23-2023, 06:38 PM)Hurlburt88 Wrote: I believe carbon fiber composites can also suffer from delamination as the primary fatigue mechanism. Really key to not miss a trick in a design like this.

On a lighter note, classmate of mine for senior mech eng project designed and built a small sub. Prof did not really expect the group would get as far as they did, and the day before they were to test in Lake Lag she nixed it. IIRC, they ended up testing in Lake Tahoe after graduation--successfully. He laughs about it to this day. And for the curious, steel was the key material.

There can't be too many of those guys around. If your classmate's name is Scott, the sub was yellow, had a basketball lodged in the stern cage for buoyancy control, and eventually sat next to the USS Pompanito in the City, I worked with him for a few years in San Jose.

Good chance same group. My buddy is Tony, and I just can't remember who his partners were--believe he had 2.

RE: OT: Underwater topic - Mick - 07-03-2023

(06-25-2023, 11:21 AM)Beeg_Dawg Wrote:
(06-23-2023, 06:44 PM)CowboyIndian Wrote:
(06-22-2023, 09:27 PM)Nan3cy Wrote: I’m absolutely not an engineer, but from what I read, the first and most basic mistake was not getting the carbon-based material tested to see if it would resist the deep-sea pressure. Apparently it didn’t.

My understanding is that the carbon fiber worked for a few dives but over time became "fatigued". That's according to James Cameron, director of "Titanic" and a veteran of many dives in the deep, including the Mariana Trench. Cameron noted that the fact that there were mixed materials (carbon and resin) made it ultimately unsafe.
Didn't catch the name, but a retired Navy submarine specialist noted the same thing. Three key materials used - titanium, carbon filaments and the viewport- all react differently when compressed. His question - Would anyone fly on a plane constructed with untested material and methods of assembly?

Stockton Rush will be synonymous with hubris years from now. He's now famous for all the wrong reasons.

One last thought - if this was a dive anywhere else, this would have made one news cycle. It's about the Titanic more than anything else.

New Yorker Article from Beeg_Dawg:

The Titan Submersible Implosion Was “an Accident Waiting to Happen” | The New Yorker

RE: OT: Underwater topic - CompSci87 - 07-03-2023

Great article.

It reminds me some of Theranos, but far more egregious. In both cases we have people who took the idea that it's good to break rules in order to innovate way too far. "You're remembered for the rules you break." "Fake it till you make it." But what happens when the rules are there for a very good reason, and you have no chance to make it using your approach, but you forge ahead anyway in a field where you put other people's lives at stake?