Tourist submarine exploring Titanic wreckage disappears in Atlantic Ocean

[arse_sidewards]

"Real time hull monitoring system." Think about that in context with a submarine and try not to laugh. Also I heard that clown Stockton talk about how the porthole would crack under pressure before full failure giving them ample warning to get to the surface. Again, this is a submarine we're talking about. Pretty sure anything that alerts you to catastrophic failure in "real time" is not a good safety measure.

Cranes, questionable bridges, all sorts of shit that can fail catastrophically has deflection sensors (basically fancy load cells) on it so they know when they're flexing it badly before it actually fails. I'm not sure how you'd do that with a pressure vessel that's basically fucked as soon as it starts changing shape but the principal is sound.

I'm not so sure about the porthole.

 

[WLDWUN]

CF is stronger in tension. Sub was in compression.

this is the part that has always had me wondering.

CF is extremely strong in tension, but like a rope not very good in compression.
so how could this have been good to use with the pressure loading from the outside. I would think the resin bonding the fiber would be giving the hull the majority of its strength.

 

[Arps]

Right, but flex is flex. Materials don't care if you're doing it the easy way or the hard way, they just care how much they're deforming.

I aint buying that. Can you explain like im 5?

 

[redneckengineered]

Cranes, questionable bridges, all sorts of shit that can fail catastrophically has deflection sensors (basically fancy load cells) on it so they know when they're flexing it badly before it actually fails. I'm not sure how you'd do that with a pressure vessel that's basically fucked as soon as it starts changing shape but the principal is sound.

I'm not so sure about the porthole.

The principle is not sound when you're 12,000' underwater.

 

[arse_sidewards]

I aint buying that. Can you explain like im 5?

Imagine you're bending an I beam. The material on the edges is flexing a certain amount based on the amount you are bending it and it will ultimately fail based on the amount of distance those edges must flex and the number of cycles. The amount of force it takes to make that flexing happen is dependent on the shape. If you have the beam flanges up/down it'll take a lot of force for a given amount of flex. If the flanges are vertical it will take much less.

 

[ThePanzerFuhrer]

I can't help but wonder if it would have been cheaper to build the tube out of steel but they didn't because they hired a bunch of textbook engineers who like to build shit using "cool modern techniques" like CF, aluminum extrusions and all the other garbage that's all the rage among the engineering circle jerk crowd who would rather showboat than build boring but practical shit.



CF pressure vessels take it just fine.

Obviously not stress in the same directions but still cyclical loading.

Didn’t you read there are only 2 guys in the country that can roll plate good enough to make a sub hull. That wouldn’t be cheap

 

[Provience]

Didn’t you read there are only 2 guys in the country that can roll plate good enough to make a sub hull. That wouldn’t be cheap

If only they had 3d printed an aluminum sub

Well, it probably would have worked better

 

[Ghetto Fab.]

I wouldn't think steel would work that well from a corrosion standpoint. Its great for ships and things, but I would think the corrosion problem would create issues long term if used. I used to work for a place and one of the jobs we did was to make underwater camera mounts so the environmentalists could count the fish where Diablo dumps its cooling water in the ocean. These mounts were made out of 316 stainless and it was amazing how they would corrode in the salt water. They would litterally look like worms were eating paths through them. If I remember right they were also adding zinc weights to help with the galvanic reaction.

At the same place I also worked on a lot of UAV stuff. We made a lot of camera systems for smaller UAVs. All of these used a carbon fiber outer shell. At one point we tried to develop a waterproof version. Something where you could land the plane in a lake and the cameras would still be ok. We weren't going to any great depth, but kept having issues with leaks. Eventually I found out that water was leaking through the carbon fiber shell, in between layers of carbon fiber. Obviously our carbon layup process wasn't the most sophisticated, but it shows an issue with trying to get a homogenous material.

 

[ThePanzerFuhrer]

If only they had 3d printed an aluminum sub

Well, it probably would have worked better

I’m thinking a concrete sub would be better . Concrete excells in a compressive state

 

[redneckengineered]

I wouldn't think steel would work that well from a corrosion standpoint. Its great for ships and things, but I would think the corrosion problem would create issues long term if used. I used to work for a place and one of the jobs we did was to make underwater camera mounts so the environmentalists could count the fish where Diablo dumps its cooling water in the ocean. These mounts were made out of 316 stainless and it was amazing how they would corrode in the salt water. They would litterally look like worms were eating paths through them. If I remember right they were also adding zinc weights to help with the galvanic reaction.

At the same place I also worked on a lot of UAV stuff. We made a lot of camera systems for smaller UAVs. All of these used a carbon fiber outer shell. At one point we tried to develop a waterproof version. Something where you could land the plane in a lake and the cameras would still be ok. We weren't going to any great depth, but kept having issues with leaks. Eventually I found out that water was leaking through the carbon fiber shell, in between layers of carbon fiber. Obviously our carbon layup process wasn't the most sophisticated, but it shows an issue with trying to get a homogenous material.

I will never be able to dig it up because I feel like at this point I've been through a metric shit ton of articles and videos on this whole debacle. But I remember reading where one of the potential sub passengers bailed out on his trip after making a test dive. He wrote an email to Stockton saying he felt like he heard squishing noises in the hull that were abnormal and it seemed like a weakness to him. After reading that I remember an Irate member said that he felt like water would eventually make its way into the CF and create failure points. So maybe there is something to that after all.

 

[CDA 455 II]

I will never be able to dig it up because I feel like at this point I've been through a metric shit ton of articles and videos on this whole debacle. But I remember reading where one of the potential sub passengers bailed out on his trip after making a test dive. He wrote an email to Stockton saying he felt like he heard squishing noises in the hull that were abnormal and it seemed like a weakness to him. After reading that I remember an Irate member said that he felt like water would eventually make its way into the CF and create failure points. So maybe there is something to that after all.

IIRC; the friend who bailed out of the dive also mentioned the sub had old/used scaffolding tubes/pipes.
That sent him red flags.

 

[Hilake2]

I will never be able to dig it up because I feel like at this point I've been through a metric shit ton of articles and videos on this whole debacle. But I remember reading where one of the potential sub passengers bailed out on his trip after making a test dive. He wrote an email to Stockton saying he felt like he heard squishing noises in the hull that were abnormal and it seemed like a weakness to him. After reading that I remember an Irate member said that he felt like water would eventually make its way into the CF and create failure points. So maybe there is something to that after all.

Probably not the same one you’re referencing, but this is an article about Josh Gates, host of 17 or 18 different history/archeology shows my son and I watch on why he bailed on the opportunity.

Discovery Channel host once scrapped plans to take OceanGate sub to Titanic. He explains why

Josh Gates explained his concerns over the Titan submersible that led him to decline a trip to the Titanic wreckage in 2021 for "Expedition: Unknown."

www.today.com

 

[bgaidan]

IIRC; the friend who bailed out of the dive also mentioned the sub had old/used scaffolding tubes/pipes.
That sent him red flags.

As sacrificial ballast. Who gives a fuck?

 

[Void_of_Light]

As sacrificial ballast. Who gives a fuck?

everybody know that only Rogue calibrated bumper plates are certified for use on submarines.

 

[Provience]

As sacrificial ballast. Who gives a fuck?

Anybody paying a quarter mil for a ride

Subs are pricey, why save a grand there, of all places?

 

[plym49.2]

this is the part that has always had me wondering.

CF is extremely strong in tension, but like a rope not very good in compression.
so how could this have been good to use with the pressure loading from the outside. I would think the resin bonding the fiber would be giving the hull the majority of its strength.

Winner winner chicken dinner.

 

[DWT]

That was a reporter that was supposed to go on the dive but bailed and stayed in the ship while they made a dive. It was only a month or so before they fed the fish.

 

[CrustyJeep]

CF pressure vessels take it just fine.

Water at 6000 psi just fine?

 

[CDA 455 II]

As sacrificial ballast. Who gives a fuck?

Obviously; he did.

And he saved his own live caring enough/questioning enough to back out.

 

[CrustyJeep]

CF is stronger in tension. Sub was in compression.

This makes me think they would have been better off omitting the CF and using just the resin. Also not recomended I'm sure, but the CF wasn't really doing shit, and it provided for the possibility of delamination and water ingress.

 

[sdmuleman]

I can't help but wonder if it would have been cheaper to build the tube out of steel but they didn't because they hired a bunch of textbook engineers who like to build shit using "cool modern techniques" like CF, aluminum extrusions and all the other garbage that's all the rage among the engineering circle jerk crowd who would rather showboat than build boring but practical shit.



CF pressure vessels take it just fine.

Obviously not stress in the same directions but still cyclical loading.

From what I've read recently, a steel vessel built to withstand those pressures is not buoyant! Sophisticated floatation is required. The CF hull weighed less and floated, until it didn't!

This. Submarine are unique in that you need to have mass/buoyancy equilibrium. Deeper you need to go, the stronger the hull needs to be, which means thicker/heavier, in turn meaning more weight in structure. To a degree you can balance this out by reducing payload or changing to a stronger shape, but this only goes so far. The traditional way to gain buoyancy is to make the hull bigger, but then stresses increase, in turn requiring more structure. The long and short of this is that you wind up with physical limitations on the size/shape of boats, and to go very deep you are effectively limited to a small spherical hull. Even then steel is limited. Alvin's original pressure hull was steel, and she was limited to ~6500 ft. It was only when a titanium sphere was built that she was able to go down to Titanic's depth.

One way around this is external buoyancy. This is how the bathyscaphes that are the deepest diving manned submersibles worked - they had a large float filled with gasoline to provide enough buoyancy to support a sphere heavy enough for that depth. At these depths this is really only possible with a liquid, which in turns means that leakage of the float is fatal and this is a rather risky approach. Additionally, the vehicle is rather large and awkward.

Using a composite hull actually makes a considerable degree of sense as a stronger material is really the only way to get a reasonably sized submersible to that depth. However, this is a very novel engineering problem for numerous reasons and requires considerable R&D work that obviously was not done.

"Real time hull monitoring system." Think about that in context with a submarine and try not to laugh. Also I heard that clown Stockton talk about how the porthole would crack under pressure before full failure giving them ample warning to get to the surface. Again, this is a submarine we're talking about. Pretty sure anything that alerts you to catastrophic failure in "real time" is not a good safety measure.

Cranes, questionable bridges, all sorts of shit that can fail catastrophically has deflection sensors (basically fancy load cells) on it so they know when they're flexing it badly before it actually fails. I'm not sure how you'd do that with a pressure vessel that's basically fucked as soon as it starts changing shape but the principal is sound.

I'm not so sure about the porthole.

Real time monitoring with strain gauges should be quite doable. You will have some element of elastic deformation which would be measurable and would give an indication of how the hull is behaving. In all likelihood you would be able to see deformation far enough in advance of failure to abort the dive if you know enough about the structural behavior to understand expected and unexpected responses. The key here though is you need a considerable amount of instrumentation in the right spots and detailed understanding of the hull behavior, probably informed by destructive testing.

Additionally, as I understand it, the 'monitoring system' was based on audio sensors and the assumption that hull stress would be correlated with sound somehow. While this might be possible, it seems much more likely to have been someone's innovative idea than something that was actually developed.

I wouldn't think steel would work that well from a corrosion standpoint. Its great for ships and things, but I would think the corrosion problem would create issues long term if used. I used to work for a place and one of the jobs we did was to make underwater camera mounts so the environmentalists could count the fish where Diablo dumps its cooling water in the ocean. These mounts were made out of 316 stainless and it was amazing how they would corrode in the salt water. They would litterally look like worms were eating paths through them. If I remember right they were also adding zinc weights to help with the galvanic reaction.

At the same place I also worked on a lot of UAV stuff. We made a lot of camera systems for smaller UAVs. All of these used a carbon fiber outer shell. At one point we tried to develop a waterproof version. Something where you could land the plane in a lake and the cameras would still be ok. We weren't going to any great depth, but kept having issues with leaks. Eventually I found out that water was leaking through the carbon fiber shell, in between layers of carbon fiber. Obviously our carbon layup process wasn't the most sophisticated, but it shows an issue with trying to get a homogenous material.

Most submarine structures are steel. Stainless is used far less than you'd think. Some use of Inconel/Monel, but mainly plain carbon or low alloy steel. Yes, corrosion is a significant issue, but effective paints, anodes and electric corrosion protection systems help with that.

 

[87manche]

I’m thinking a concrete sub would be better . Concrete excells in a compressive state

Pykrete is my recommendation.

 

[gt1guy]

They had a hull monitoring system that I read about, but with a CF hull it’s useless.

I have no idea how they thought carbon fiber under repeated stresses like they were subjecting it to, would hold up forever.

I had a buddy that designed and produced RC parts. He wanted to make some parts out of Ti even after we discussed how Ti was a bad material for the application (CV shafts).

He produced them anyway. Sent out a lot of replacements as a result.

I was like…”Hey…remember when we talked about Ti being the wrong material for that application?”

His fancy hull monitoring system is what blows my mind. It was obviously a response to being told by all the other folks who build deepwater subs that that CF was the wrong material to be using. He was too smart to listen to the advice, so he built a "system" that never worked. Every dive to bottom, that system should have been telling him that the CF was being degraded. It either didn't work or he ignored what it told him.

I think this guys biggest problem was he is simply incapable on saying "I was wrong".

 

[gt1guy]

I can't help but wonder if it would have been cheaper to build the tube out of steel but they didn't because they hired a bunch of textbook engineers who like to build shit using "cool modern techniques" like CF, aluminum extrusions and all the other garbage that's all the rage among the engineering circle jerk crowd who would rather showboat than build boring but practical shit.



CF pressure vessels take it just fine.

Obviously not stress in the same directions but still cyclical loading.

His building a tube and not a sphere was when the biggest can of worms was opened. The loading on a sphere is equal in all directions, not so on the long span of flat surface of a tube.

Navy subs have interior stiffener rings through out the length of the tube to deal with that issue.

From what I've read recently, a steel vessel built to withstand those pressures is not buoyant! Sophisticated flotation is required. The CF hull weighed less and floated, until it didn't!

That's probably why all the other deep water subs use a titanium. Lighter that steel, so they get a weight advantage out of the gate. There are actually HZ Grade syntactic foams that are rated up to 36000 feet at are used for buoyancy.

If you look at the ROV's that picked up all the pieces, they all had flotation on them.


All the yellow you see on this ROV is flotation. It doesn't crush and the buoyancy doesn't change with depth.

What we'll do when they are working with the divers is add weight to the skids so the ROV is negative, That way if the ROV goes black, it will just sit on bottom. I keep the diver umbilical running over the ROV teather (that yellow cable coming out the top of the ROV) so the diver always has a straight shot back to the bell in an emergency.
In short, I don't give a fuck about that multi million dollar ROV, all I care about is my divers.

Working mid water, everything changes. the ROV will be positive/float and the divers umbilical will always be under the ROV tether.

 

[CrustyJeep]

Navy subs have interior stiffener rings through out the length of the tube to deal with that issue.

They also don't go anywhere near a depth of 12000 feet.

 

[gt1guy]

They also don't go anywhere near a depth of 12000 feet.

Correct, for a very specific reason. Tubes don't work at those depths.


Lets all not forget what PSI truly means. Pounds PER square inch. A hatch that is 30sq/in with 5 psi on one side does not have 5lbs pushing on it. It is seeing 150 pounds of force.

I know most of you already know this, some may not. But it may enlighten a few to the actual forces this sub was under. The term fuck ton is almost a understatement.

 

[DirtRoads]

His building a tube and not a sphere was when the biggest can of worms was opened. The loading on a sphere is equal in all directions, not so on the long span of flat surface of a tube.

Navy subs have interior stiffener rings through out the length of the tube to deal with that issue.




That's probably why all the other deep water subs use a titanium. Lighter that steel, so they get a weight advantage out of the gate. There are actually HZ Grade syntactic foams that are rated up to 36000 feet at are used for buoyancy.

If you look at the ROV's that picked up all the pieces, they all had flotation on them.


All the yellow you see on this ROV is flotation. It doesn't crush and the buoyancy doesn't change with depth.

What we'll do when they are working with the divers is add weight to the skids so the ROV is negative, That way if the ROV goes black, it will just sit on bottom. I keep the diver umbilical running over the ROV teather (that yellow cable coming out the top of the ROV) so the diver always has a straight shot back to the bell in an emergency.
In short, I don't give a fuck about that multi million dollar ROV, all I care about is my divers.

Working mid water, everything changes. the ROV will be positive/float and the divers umbilical will always be under the ROV tether.

You are another fine example of how far this site reaches into every bizarre specialty on earth.

 

[plym49.2]

His fancy hull monitoring system is what blows my mind. It was obviously a response to being told by all the other folks who build deepwater subs that that CF was the wrong material to be using. He was too smart to listen to the advice, so he built a "system" that never worked. Every dive to bottom, that system should have been telling him that the CF was being degraded. It either didn't work or he ignored what it told him.

I think this guys biggest problem was he is simply incapable on saying "I was wrong".

But - but - but it was designed and coded by a kid right out of software college. (See the LinkedIn profile earlier in the thread.)

 

[WLDWUN]

The term fuck ton is almost a understatement.

fuk ton is very much an understatement

assume that cylinder is 48" diameter with a 5" wall
that equates to almost 5000 TONS at depth trying to bring those end domes together through the cylinder.
which means a compressive force of 14,000 psi on the resin...and that is in the stronger direction.

 

[sdmuleman]

His building a tube and not a sphere was when the biggest can of worms was opened. The loading on a sphere is equal in all directions, not so on the long span of flat surface of a tube.

Navy subs have interior stiffener rings through out the length of the tube to deal with that issue.

That's probably why all the other deep water subs use a titanium. Lighter that steel, so they get a weight advantage out of the gate. There are actually HZ Grade syntactic foams that are rated up to 36000 feet at are used for buoyancy.

Yes and no. Big issue with a cylinder is loading of the entire section as a column by the end coverings, and interaction of forces at the junction between cylinder and end closure. If you look at a thin ring of the cylinder in isolation it's the same as a ring of a sphere. The different through is the axial forces. This places the entire cylinder under load like a column, and the structure is consequently susceptible to failure in buckling. The ring frames and deep frames in a navy sub are to mitigate this, not to support directly against water pressure. Designer do take advantage of these to thin the skin, but even if the hull itself was thick enough to handle the water pressure you still need significant internal structure to protect against the entire hull buckling from axial load.

Long and short, there's no inherent reason why a tube type hull cannot work at deep depths. The reason it hasn't been done is that weight would be considerable with practical materials and there's no real reason to need a large hull capable of that depth. USN has built at least 2 boats that were cylindrical steel pressure hulls and went down to at least 3000 ft and some of the soviet boats could go quite deep. A sphere is the most effective shape from a strength/weight perspective, but other options are possible.

Much much does syntactic foam compress at that depth?