Sub goes Missing

[GodIsADeeJay81]

The thing that I feel is wrong is extremmley wealthy people make the news hr by hr for doing a risky pleasure excursion , but the 60 people shot in USA last weekend got next to no news, with no updates on there health and progress.

Americans shooting each other is normal though.
They've had more mass shootings this year than days in the year, so naturally people just become blase about that sort of stuff, distasteful as that may seem

[Spijed]

If nothing else, we've all learned a lot over the last week about some of the terrifying and bizarre physics at play at the bottom of the sea. Best left well alone in my view. I'd spend £250k on going into space though, if I had it like.

I've always wondered how true to the film was the Apollo 13 mission. It seems that could easily have been catastrophic for all concerned, and the space version of what's been on the news in the last few days.

[Rick_Muller]

The thing that I feel is wrong is extremmley wealthy people make the news hr by hr for doing a risky pleasure excursion , but the 60 people shot in USA last weekend got next to no news, with no updates on there health and progress.

Clue is in the name “news” infers it’s something different and “new”. It’s very rare for billionaires to go missing on a sub, yet people get shot and killed all the time, and migrant boats sink all the time too and as such that’s not “news”

[daveisaclaret]

Clue is in the name “news” infers it’s something different and “new”. It’s very rare for billionaires to go missing on a sub, yet people get shot and killed all the time, and migrant boats sink all the time too and as such that’s not “news”

Why is it on the news when the Tories do something awful then

[TomtheClaret]

Does a implosion have the same affect and do same damage as a explosion?

[BennyD]

An explosion is when something expands rapidly into its surroundings. An implosion is when something contracts rapidly into its surroundings. The end result is pretty much the same; anybody in the immediate vicinity will be having issues. Having said that, an implosion will likely be more emphatic, as the space in which the bodies exist disappears into nothing but bubbles.

[fatboy47]

Why is it on the news when the Tories do something awful then

Probably more newsworthy when they don't tbf.

[fatboy47]

Does a implosion have the same affect and do same damage as a explosion?

Ask a horse fiddler.

[GodIsADeeJay81]

Does a implosion have the same affect and do same damage as a explosion?

An implosion crushes, an explosion expands outwards

There’s videos circulating showing an implosion of railway gas canister trailers and it’s quite mental/impressive how it works

[Hapag Lloyd]

Why is it on the news when the Tories do something awful then

I did wonder if one of the usual suspects would manage to turn this thread political

[Lancasterclaret]

Twitter has blown up because the US Navy didn't report instantly on their top secret (technically NATO) submarine devices that there was an explosion underwater around the same time as contact was lost

[NottsClaret]

An explosion is when something expands rapidly into its surroundings. An implosion is when something contracts rapidly into its surroundings. The end result is pretty much the same; anybody in the immediate vicinity will be having issues. Having said that, an implosion will likely be more emphatic, as the space in which the bodies exist disappears into nothing but bubbles.

All very grim but I guess the speed is a blessing. I was reading this morning it would have happened in milliseconds once the structure was breached, faster than the human brain can process anything. Weirdly, it turns it into something like a piston engine, briefly super heating the air inside and turning everything to ash in a flash.

[ClaretDiver]

Just to add something about oxygen, pure oxygen becomes poisonous to the human body if you breathe it at about 4m underwater in a diving environment (ie no sub)

[Vintage Claret]

I've always wondered how true to the film was the Apollo 13 mission. It seems that could easily have been catastrophic for all concerned, and the space version of what's been on the news in the last few days.

I have the Apollo 13 film on DVD and one of the extra features is audio commentary by the mission commander Jim Lovell ( who makes a cameo appearance in the film near the end)

Haven't watched it for a while but I'm sure I recall him commenting that overall the film was broadly accurate in depicting what happened although there was some 'artistic license' used now and again.

[distortiondave]

All very grim but I guess the speed is a blessing. I was reading this morning it would have happened in milliseconds once the structure was breached, faster than the human brain can process anything. Weirdly, it turns it into something like a piston engine, briefly super heating the air inside and turning everything to ash in a flash.

Crikey. I thought they'd be crushed like when you stamp on a can of coke so that there'd be a moment of unimaginable pain but there'd at least be something of them left to recover, but it sounds like they've been vaporised instead.

[Hipper]

Does a implosion have the same affect and do same damage as a explosion?

Cathode Ray Tubes, like old televisions or computer monitors, and florescent light bulbs implode.

[clarets12]

Does a implosion have the same affect and do same damage as a explosion?

No. The damage caused by an implosion is generally localized to the collapsed structure's immediate surroundings.

[CombatClaret]

Unrelated but If anyone wants a long but very interesting read.

https://arstechnica.com/science/2016/02 ... -columbia/

This looks at a section of the report after the 2003 Space Shuttle Columbia disaster which burned up on reentry due to damage to the heat shield sustained on lift off.

It posed the question to NASA, had we realized there was a problem, could we have left the shuttle in orbit and rescued the crew before the air became unbreathable?
It's got a lot of technical info but I think it makes for one of the most amazing rescue stories that never happened;
Tearing up the rule book on how quickly you can prep another shuttle and crew, timing orbits, the moral questions of risking more lives, a shuttle-to-shuttle space walk evacuation.

I found it fascinating and I hope someone one day writes the film.

[Spijed]

Unrelated but If anyone wants a long but very interesting read.

https://arstechnica.com/science/2016/02 ... -columbia/

This looks at a section of the report after the 2003 Space Shuttle Columbia disaster which burned up on reentry due to damage to the heat shield sustained on lift off.

It posed the question to NASA, had we realized there was a problem, could we have left the shuttle in orbit and rescued the crew before the air became unbreathable?
It's got a lot of technical info but I think it makes for one of the most amazing rescue stories that never happened;
Tearing up the rule book on how quickly you can prep another shuttle and crew, timing orbits, the moral questions of risking more lives, a shuttle-to-shuttle space walk evacuation.

I found it fascinating and I hope someone one day writes the film.

Even though it's pure fiction, the film "The Martian" was all about rescuing the astronaut from Mars.

[Raconteur]

Twitter has blown up because the US Navy didn't report instantly on their top secret (technically NATO) submarine devices that there was an explosion underwater around the same time as contact was lost

It is a bit bizarre now. The director James Cameron is saying he knew that the implosion happened on Monday. They are saying it happened just under 2 hours after it set off.


https://www.joe.co.uk/news/james-camero ... y-2-398111

[Lancasterclaret]

It is a bit bizarre now. The director James Cameron is saying he knew that the implosion happened on Monday. They are saying it happened just under 2 hours after it set off.


https://www.joe.co.uk/news/james-camero ... y-2-398111

I know that the anti-submarine net across the north Atlantic is pretty good at detecting submarines (I mean, I haven't read about it since the 1990s) but its clearly top secret about how good it is

Thing is, twitter is full of absolute weapons questioning why the Navy didn't say anything earlier, but as they found the debris quite quickly considering they knew whereabouts to look and couldn't be sure that the explosion/implosion was the Titan

[Lancasterclaret]

https://twitter.com/BrynnTannehill/stat ... 1322346496

This essentially (this guy knows what he is talking about btw)

[fatboy47]

I did wonder if one of the usual suspects would manage to turn this thread political

Never known you complain when one of our friends on the right turns something political.


Strange that.

[atlantalad]

Having worked with different classes of materials and taught materials engineering for a great number of years I must admit I found the design and choice of materials used perplexing. Firstly, the mechanical behaviour and failure of CFRC’s in tension are comprehensively modelled and understood. Hence their extensive use in structures which can undergo tension - aerospace ( i.e. Dreamliner fuselage), autoclaves, etc. Incidentally a Dreamliners fuselage increases in length by about 150mm from ground to 31000 feet owing to pressure differential - but that is an aside.

The very nature of carbon fibres imparts excellent fracture toughness to the composite. Hence their predominant use in structures subjected to tension. Fibre behaviour in compression is less understood. Like most ceramic/glass materials the fibres will fail catastrophically under the action of shear stress - brittle fracture under compressive loads.

Adding to the anomalous use of CFRC in a compressive structure we need to look at the strange shape of the capsule. The ideal shape of the sub, going down to that depth where there are huge compressive stresses should be spherical as there would be a balance of tensile, shear, compressive stresses in the material used. Surprising then that CFRC was used in a lozenger shape design where there would be considerable difference in stress fields between the structural parts and, within their materials (shear stress in particular due to bending). A capsule made from the titanium alloy would have been a much safer option than a structure of two different materials with totally difference responses to slight defects in their macro/ microstructure.

Lastly, failure almost certainly due to fatigue - as has already been alluded to in a previous post I.e. DC 10 fuselage failures. The fact the sub had previously completed 34 successful missions indicates some initial flaw( crack) was growing in size and eventually became too large for the structure to sustain the compressive loads.

[box_of_frogs]

I know that the anti-submarine net across the north Atlantic is pretty good at detecting submarines (I mean, I haven't read about it since the 1990s) but its clearly top secret about how good it is

Thing is, twitter is full of absolute weapons questioning why the Navy didn't say anything earlier, but as they found the debris quite quickly considering they knew whereabouts to look and couldn't be sure that the explosion/implosion was the Titan

I get it, but there is zero remit to tell the press what they did or didn’t heard. Im sure they’ll have told the US Coast Guard and others involved in finding the wreckage. The ‘let’s rescue them’ guff in the media is purely for those that don’t know about the impossibility of doing a rescue at that depth, even if it hadn’t imploded.

Edit - the only good thing here is the seemingly quick deaths they had, assuming the sub wasn’t leaking / in distress prior to implosion.

[Hapag Lloyd]

Never known you complain when one of our friends on the right turns something political.


Strange that.

The only thing strange is you using this particular thread to try score political points.

Shame that.

MOD: Please be aware, political references have been made, and should they continue, the thread will be locked. Please consider this very carefully before stopping what is an interesting discussion in the main.

[Hipper]

Having worked with different classes of materials and taught materials engineering for a great number of years I must admit I found the design and choice of materials used perplexing. Firstly, the mechanical behaviour and failure of CFRC’s in tension are comprehensively modelled and understood. Hence their extensive use in structures which can undergo tension - aerospace ( i.e. Dreamliner fuselage), autoclaves, etc. Incidentally a Dreamliners fuselage increases in length by about 150mm from ground to 31000 feet owing to pressure differential - but that is an aside.

The very nature of carbon fibres imparts excellent fracture toughness to the composite. Hence their predominant use in structures subjected to tension. Fibre behaviour in compression is less understood. Like most ceramic/glass materials the fibres will fail catastrophically under the action of shear stress - brittle fracture under compressive loads.

Adding to the anomalous use of CFRC in a compressive structure we need to look at the strange shape of the capsule. The ideal shape of the sub, going down to that depth where there are huge compressive stresses should be spherical as there would be a balance of tensile, shear, compressive stresses in the material used. Surprising then that CFRC was used in a lozenger shape design where there would be considerable difference in stress fields between the structural parts and, within their materials (shear stress in particular due to bending). A capsule made from the titanium alloy would have been a much safer option than a structure of two different materials with totally difference responses to slight defects in their macro/ microstructure.

Lastly, failure almost certainly due to fatigue - as has already been alluded to in a previous post I.e. DC 10 fuselage failures. The fact the sub had previously completed 34 successful missions indicates some initial flaw( crack) was growing in size and eventually became too large for the structure to sustain the compressive loads.

How easy is it to check for stress issues with CFRC and what experience is there compared to metals?

What would be the reason to choose CFRC as opposed to, say, titanium type designs? Cost? Weight?

The shape was apparently to enable more passengers to be accommodated.

[BennyD]

It was a blatant attempt to make a fortune. A similar thing happened when climbing Everest was turned into a commercial venture, a disaster occurred. Basically, It’s for rich people to see who can p!ss highest up the wall; I’ve been to the top of Everest, well I’ve been down to the Titanic, well I’ve been in low orbit space etc etc. The problem is, that in order to make the most money, you’ve got to cater for the most people for the lowest costs, and I think this will prove to be the case here. Lower production costs of a vessel made to carry more people than perhaps it should. Compromises made for expediency, cheaper materials, and an overall impression of amateurism in a brutally unforgiving environment is a recipe for disaster.

[davideyresleftear]

It was a blatant attempt to make a fortune. A similar thing happened when climbing Everest was turned into a commercial venture, a disaster occurred. Basically, It’s for rich people to see who can p!ss highest up the wall; I’ve been to the top of Everest, well I’ve been down to the Titanic, well I’ve been in low orbit space etc etc. The problem is, that in order to make the most money, you’ve got to cater for the most people for the lowest costs, and I think this will prove to be the case here. Lower production costs of a vessel made to carry more people than perhaps it should. Compromises made for expediency, cheaper materials, and an overall impression of amateurism in a brutally unforgiving environment is a recipe for disaster.

The speculation is that Stockton Rush was trying to make his fortune on the submarines themselves. The trips to the titanic were a sort of proof of concept / advertisement for selling more subs.

He definitely wasn’t making money on the trips themselves because they were burning $1,000,000 in fuel every time they went

[BennyD]

$1m per trip? What the he!! was he fuelling, a fleet of A380s?

[ClaretDiver]

$1m per trip? What the he!! was he fuelling, a fleet of A380s?

Fuel for mothership and sub, permits, wages etc…plus factor in development costs and build costs and I actually think that is on the nose!

However this trip is gonna cost the company a hell of a lot more now!!

[CoolClaret]

He definitely wasn’t making money on the trips themselves because they were burning $1,000,000 in fuel every time they went

Where have you read that? Find that incredibly hard to believe - for one where the hell did they store that amount?

As for the implosion -

Of course they already knew, may have ‘had to be seen to be doing something’ but I think in reality it was the chance to do a highly complex training exercise with real life stressors

I think they did extremely well recovering some debris in the time that they did!

[Spijed]

The more you read about it, the more it sounds like something made on Scrapheap challenge.

[CoolClaret]

The more you read about it, the more it sounds like something made on Scrapheap challenge.

What a program that was!

[davideyresleftear]

Where have you read that? Find that incredibly hard to believe - for one where the hell did they store that amount?

Stockton the CEO said in an interview that passenger fares didn’t even cover the fuel costs. Though how far you believe his word is another question.

It doesn’t just mean the sub, the ship they charter to launch the sub burns through a lot of fuel so I can imagine they do use plenty.

[bfcjg]

https://uk.yahoo.com/news/ross-kemp-tur ... 58095.html
More comments on the safety of the sub.

[CoolClaret]

Stockton the CEO said in an interview that passenger fares didn’t even cover the fuel costs. Though how far you believe his word is another question.

It doesn’t just mean the sub, the ship they charter to launch the sub burns through a lot of fuel so I can imagine they do use plenty.

Ah there we go.

He was a typical Yank businessman that thought he knew better than anyone and made everything he did sound better than it is

Complete ********

[davideyresleftear]

Ah there we go.

He was a typical Yank businessman that thought he knew better than anyone and made everything he did sound better than it is

Complete ********

No arguments there, complete snake oil salesman

[atlantalad]

How easy is it to check for stress issues with CFRC and what experience is there compared to metals?

What would be the reason to choose CFRC as opposed to, say, titanium type designs? Cost? Weight?

The shape was apparently to enable more passengers to be accommodated.

One can use FEA on structural sections to predict stress fields but this relies on the accuracy of the material properties and the modelling used ( i.e. rubbish in rubbish out). FEA would apply equally well to any material so long as there is confidence in the measured material properties and its behaviour under tensile, compressive, shear modes of loading.

CFRC are used in aerospace applications because of their strength/weight ratio. They are very strong when put in tension. Obviously low weigh and high strength is very desirable in aerospace, F1, racing bicycles, etc.

The problem with CFRC is that when they are subjected to bending high "shear" stresses will develop within the cross-section of the structure. Shear stresses will generally be highest at the centre line through a wall section ( thickness). The CFRC structures are manufactured using continuous carbon fibre plies impregnated with resin and these are wound around a mandrel and cured to form the desired outer shape of the structure. Consequently the fibre plies will run parallel to each other - think of stacked fibres criss-crossing each other on stacked layers as the thickness of a structure is built up. The structure will be fine in tension because the strong carbon fibres will carry the load. However the composite will be weak in bending because you'll have a resin rich matrix between the fibres ( an analogy : in a wall section fibre plies are stacked like a deck of playing cards but between each card there is only the resin holding the structure together). When the composite is subjected to bending the resin bonding the fibres will be put under high shear stresses and ultimately at some critical shear stress will delaminate creating a crack in the resin between the fibres layers. The crack will grow in length as the bending ( compressive stresses) increases. So, summary CFRC strong in tension, weak in compression because it is the plastic resin that tries to carry the loads in compression.

Titanium alloy used in aerospace is based on Ti-6Al-4V. The alloy has very small, ( micron size) discrete precipitates in a Ti rich matrix. The precipitates act as "crack stoppers". So, should a crack start in a component made from this alloy it is quickly snuffed out because the precipitates are obstacles to the growth of a crack. Think of it as the crack having to deviate its path to get around the precipitate - it needs more energy to do that. The Ti-6Al-4V alloy has what is called a good fracture toughness ( good at stopping cracks growing).

Simple test for you to see the effect a small crack has on a structure. Get a plain A4 sheet of paper and hold it up in from of you - hand on each of the shorter sides as though you were looking in a mirror. Now, try pulling the paper sheet apart moving your hands apart. Now repeat this but this time just put a small tear, about 10 mm length in the paper on the mid point of one of the long sides. Hold it up so the tear is on the top edge and try pulling the sheet again .

Sorry for the long explanation so late on a Saturday but - sat outside on a beautiful, warm evening drinking a nice Merlot.

[yTib]

Sorry for the long explanation so late on a Saturday but - sat outside on a beautiful, warm evening drinking a nice Merlot.

no apology needed. your username qualifies you to say all sorts of business about the maritime world without any need for credentials.