Tourist submarine exploring Titanic wreckage disappears in Atlantic Ocean

[aczlan]

Found an article (from Wikipedia) which said that they used passthrough ports in the titanium end bell for wiring to exit the sub, the article: OceanGate CEO Stockton Rush talks Titan sub's design, carbon fiber hull, safety and more in 2022 interviews
Apparently they also looked at doing the end capos from CF:

Another talking about the controller and wiring:

Talking about the CF end caps that they tested:

Talking about what the "mission specialists" did including closing the hatch "they're bolts; you can tell if a bolt is tightened, right"

And a picture of the hinge and one of the lifting rings:

Aaron Z

 

[ProjectTwin]

Also Rush:

 

[Bacho]

Also Rush:

We don’t really have the details to know exactly what that surface is. If that was the carbon layup I don’t think we’d see that seam there.

 

[ProjectTwin]

We don’t really have the details to know exactly what that surface is. If that was the carbon layup I don’t think we’d see that seam there.

Prepreg. You can see it in other photos. It’s clear on the right side of this photo.

 

[M92PV4U]

What's up with the bolt head seating face not being square?

 

[Bacho]

Prepreg. You can see it in other photos. It’s clear on the right side of this photo.

Start 25 seconds in on the video you can see them wind in the carbon over the bare mandrel. I am not convinced that’s the same layup we see on the inside. It’s hard to tell later in the video if that’s a mold release, it’s exposed or the inside of the mandrel left in the tube.

 

[bunk]

What's up with the bolt head seating face not being square?

I bet its counterbored, uses allen head cap screws

 

[aczlan]

I bet its counterbored, uses allen head cap screws

From page 37:

Definitely socket head cap screws, not sure on the counter bored part.

Aaron Z

 

[ProjectTwin]

Start 25 seconds in on the video you can see them wind in the carbon over the bare mandrel. I am not convinced that’s the same layup we see on the inside. It’s hard to tell later in the video if that’s a mold release, it’s exposed or the inside of the mandrel left in the tube.

I’ve seen that. The pictures/video of him in the sub clearly show prepreg

 

[total newb]

Also Rush:

So how do you think he back lit the interior of the body if you are thinking that is the primary cf hull over the titanium spool?

 

[Bacho]

I’ve seen that. The pictures/video of him in the sub clearly show prepreg

How do you identify prepreg as compared to anything else?

I think the weave lines are too straight to be from the filament winder. I think it’s way too coincidental that they would match up like that.

 

[ProjectTwin]

So how do you think he back lit the interior of the body if you are thinking that is the primary cf hull over the titanium spool?

No idea. There’s a lot that I don’t understand with this thing, but you can clearly see prepreg as interior cabin walls.

Lighting was probably from camping world.

 

[ProjectTwin]

How do you identify prepreg as compared to anything else?

I think the weave lines are too straight to be from the filament winder. I think it’s way too coincidental that they would match up like that.

We’ve seen the axial wound carbon video, but there’s a weave pattern there that isn’t what you’d get winding that hull like a bobbin as we saw in the video.

Honestly I don’t think the entire tube construction has been made public.

 

[Bacho]

We’ve seen the axial wound carbon video, but there’s a weave pattern there that isn’t what you’d get winding that hull like a bobbin as we saw in the video.

Honestly I don’t think the entire tube construction has been made public.

So there’s not really any reason to get excited about screws being in that material, Because we don’t know.

 

[ProjectTwin]

So there’s not really any reason to get excited about screws being in that material, Because we don’t know.

But you CAN see that it’s screws into carbon and all he ever talked about was carbon hull. Not carbon over anything.

Dunno.

 

[TrailTamer]

Video from ten years ago.

but the evil 50 years old white man wanking on the cylinder!!!!!!!!!!!!

 

[total newb]

Construction pics and some thoughts.

Dont worry, youll hate this guy also.

 

[redneckengineered]

Here's your answer. "Cylinder inner liner."

 

[fordguy]

So the consensus is, stay the fuxk out of the bottom of the ocean

 

[ProjectTwin]

Here's your answer. "Cylinder inner liner."

Looks like they slid that in after the carbon tube was made and Ti ends glued on. Interesting

 

[total newb]

So it seems to be that the vid we keep seeing of the "titanium" "bobbin" being wrapped in cf is not the actual tube/body construct.

It seems to be just a cf cyl/tube with the secondary insert sleeve as the interior and wire management with the ti end caps.

Nope nope nope, not going for that ride.

Also interesting seeing the alvin construction. I had no idea it was built that way.

 

[aczlan]

So it seems to be that the vid we keep seeing of the "titanium" "bobbin" being wrapped in cf is not the actual tube/body construct.

It seems to be just a cf cyl/tube with the secondary insert sleeve as the interior and wire management with the ti end caps.

Nope nope nope, not going for that ride.

Also interesting seeing the alvin construction. I had no idea it was built that way.

Looks like the bobbin was pulled out, from the video that redneckengineered linked to:

And before the inner liner was installed:

Inner liner installation:

Aaron Z

 

[total newb]

Yeah. Looking at the end of the spindle i see bolt holes which i now relise is the shoulder flange of the bobbin once removed.

 

[CDA 455 II]

 

[CarterKraft]

This article makes it seem like the tube was never up to the task at 3k meters?

Simulation Reveals Exactly How Titan Submersible Imploded

mobile.engineering.com

 

[CarterKraft]

A bulkhead in the center of the tube would seem to have increased the strength by many factors and not compromised the ability to take 5 passengers.

 

[arse_sidewards]

This article makes it seem like the tube was never up to the task at 3k meters?

Simulation Reveals Exactly How Titan Submersible Imploded

mobile.engineering.com

Ronald Wagner (PhD Engineering, Technical University Braunschweig), an expert in the buckling of thin-walled shell structures, took it upon himself to perform A Nonlinear Structural Analysis of the Titan Submersible Shows Implosion and Fracturing, with linear and nonlinear simulations of the Titan submersible, scraping up as much geometry of the vessel as anyone has done, applying loads appropriate to the depth that the vessel traveled and with best guesses as to materials used. He analyzed three modes of failure—the viewport, the adhesive seal between the titanium endcaps and the collapse of the cylindrical hull. Of the three, the analysis of the latter is the most illuminating in the darkness of the tragedy. Using Abaqus, which is well suited to nonlinear finite element analysis (FEA), Wagner is able to show not only how the implosion occurred, as would high-speed photography played back frame by frame, but also explain as no one has been able to do until now, the manner in which the carbon fiber may have shattered.

So basically some textbook engineer did textbook engineer shit but it's newsworthy because "first".

Not saying FEA isn't useful but I'd wager that a lot of those "best guesses" stack up in a way that makes the overall results a lot less reliable than is being portrayed (as is par for the course when engineers engage in these kinds of speculative exercises).

 

[CarterKraft]

So basically some textbook engineer did textbook engineer shit but it's newsworthy because "first".

Not saying FEA isn't useful but I'd wager that a lot of those "best guesses" stack up in a way that makes the overall results a lot less reliable than is being portrayed (as is par for the course when engineers engage in these kinds of speculative exercises).

Well yeah sure but this textbook engineers best guess is a million times better than my armchair quarterback guess no?

 

[aczlan]

Quoatable quote of the day at 1:27 "The carbon fiber is coated with Rhino liner which is sort of what the military uses, it stops water penetration into the carbon fiber at high pressure"

Aaron Z

 

[arse_sidewards]

Well yeah sure but this textbook engineers best guess is a million times better than my armchair quarterback guess no?

Only to the extent that his "best guesses as to materials used" are accurate and his model of how they interact is accurate. Think of it like when the weather throws several different lines on the screen to illustrate where the different models think the hurricane is gonna go. This guy's opinion is one line. It's not actually that much of a practical improvement over a meteorologist who knows where the fronts are and knows how weather works drawing lines on a map.

FEA simulations are good for when you have very well defined situations to model, like a bridge you can go out and measure.

Think about it this way, if you could just plug in "best guesses" for a CF tube into your FEA software and get "splat" as a result then why didn't the builders do that using their known specifications they were planning to build to and change the design? They said they used metal for the domes because they couldn't simulate the CF in high enough detail. That would tend to imply that they were modeling things and running simulations. If the results they were getting were on the edge of "splat" they would have built it different.

Since there's no discussion of simulating wear and tear on the tube or damage from prior dives I think these "best guesses" are more like "we kept running the simulation with less material until it went splat". Remember, the sub didn't go splat the first few dozen times...