Steve
Penultimate Amazing
This long fracture does not appear in the picture you posted.
The Sinking of MS Estonia: Case Re-Opened
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This long fracture does not appear in the picture you posted.
Vixen
Penultimate Amazing
The fracture found by the recent Arikas crew found several fractures which they said was 22m long. It was likely a different one from the picture Evertsson's crew took. Arikas has not released any footage as of yet.
Baltic News
Some of the deformations will obviously be due to the ship hitting the seabed, which is partly of moraine clay which is quite hard.
Vixen
Penultimate Amazing
JAIC seem to have decided from day 1, it was like the Herald of Free Enterprise so everything had to fit around this.
It seems entirely highly probable that of course Sweden knew about the hole in the hull but kept quiet, as it did about the ex-Soviet military smuggling on a passenger ferry. I am sure it is all well-intentioned but the public actually are not as dimwitted as it is popularly made out to be.
The JAIC panel itself had many acrimonious disputes but his has all been glossed out to provide a glossy coffee table book that has dissatisfied many. Some will be suffering the anguish of terrible grief, others will be angry 'at the authorities' and others, like Henrik Evertsson are intrigued by the many questions left unanswered.
junkshop
Otto's Favourite
That quote says a deformation 22m long, not a fracture.
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erwinl
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A deformation does not equal a crack, which does not equal a hole.
You spoke of a hole 4 x 22 meters. Where on the ship is that?
Vixen
Penultimate Amazing
That is the picture from Evertsson's documentary. Their equipment is likely pretty basic, compared the the US guy helping out Arikas.
Arikas might be referring to a different location all together, is another possibility.
JayUtah
Penultimate Amazing
I've never seen this "long fracture" referenced in any of the material describing the newly-discovered hole. And I'm unable to find any photographs of it, while I can find many photographs of the hole. Further, the hull plating around the periphery of the hole appears intact (although distorted) in the photographs.
Can you please provide the source you're using to argue the presence of a 22-meter fracture?
JayUtah
Penultimate Amazing
You might be referring to the second hole Evertsson found. He did not include it in the documentary because, according to him, it did not fit the narrative he wanted to tell in the film. He was asked later to account for it, and he assured the public that his experts had said it was a static stress fracture and was not a factor in the collision.
ETA: I see we're talking about a deformation, not a breach. Not the same thing. The problem with the hole is that experts say the flood rate through that hole would not be enough to sink the ship according to any time line proposed. A long crease would, however, be consistent with buckling upon impact with the ocean floor.
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Vixen
Penultimate Amazing
A 'deformation' is a neutral term used by Arikas. It could mean anything from a dent to a fracture. In metallurgy, a metal can be brittle or ductile (has elasticity). I am guessing that any significant deformation caused by a material impact will lead the ship's metal to exhibit a fine line between elasticity and brittleness (breaks).
The simple answer is, we have not yet been told. Just because you can't see a fracture in metal with the naked eye, it doesn't mean it is not there, especially when concealed with thick paint.
Think about a car. You get a dent. You get it fixed ASAP as there is a good chance there is a hairline fracture leaving your vehicle's bodywork prone to rust over the longer term.
Vixen
Penultimate Amazing
The reference is Arikas, as in my link to the Baltic News, above.
erwinl
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Vixen
Penultimate Amazing
Vixen
Penultimate Amazing
The hole is obviously where the two lines cross. If the horizontal line and the vertical line are fractured, as they seem to be, then that makes up the hole, where they meet, and which intuitively tells us the point at which the ship wall is punctured, caused the two fractures up and down as a result. The puncture caused the metal to deform in that manner is my observation.
The 'hole' itself is irregular so it is obvious the word is being used in its vernacular sense and not literally.
junkshop
Otto's Favourite
I can't get your link to work, but I found a report from the Baltic Times, which uses the same wording:
"A deformation of 22 meters in length and four meters in height was registered in the middle part of the vessel on the starboard side...[t]he area of the vessel that has sustained major damages is located next to hard rocks and the deformation matches the geometry thereof, he noted."
It seems to me that the implication here is that the deformation is likely due to the ship landing on these rocks.
"A deformation of 22 meters in length and four meters in height was registered in the middle part of the vessel on the starboard side...[t]he area of the vessel that has sustained major damages is located next to hard rocks and the deformation matches the geometry thereof, he noted."
It seems to me that the implication here is that the deformation is likely due to the ship landing on these rocks.
JayUtah
Penultimate Amazing
Indeed, there's about 25% difference in the kinetic energies of the given sample vessels and speeds.
1,000,000 kg (fishing vessel) at 2.572 m s-1 is 3,308 kJ.
5,000,000 kg (submarine) at 0.977 m s-1 is 2,485 kJ
(Apologies to those who use commas to indicate decimals.)
I'm not sure how accurate the professor expected these estimates to be. He may have just been throwing out ballpark figures off the top of his head. But it's claimed that he excluded the visor (after initially accepting it) because it only had a mass of 55,000 kg. But mass alone doesn't determine kinetic energy. We need to know the velocity at which any projectile is said to strike its target. If we take the professors KE estimates as upper and lower bounds, and split the difference, we get a required velocity of about 10.3 m s-1, or about 20 kts, or about 6 kts faster than MS Estonia was said to be traveling at the time of collision. At the lower bound of 2,485 kJ, the impact velocity would only need to be about 18 kts, or around the speed MS Estonia typically sailed in calmer seas.
The scenario is that the visor detaches and goes by the board, and is thus relatively quickly stopped in its forward motion by the sea. The ship's continued forward motion doesn't have to solely account for total impact velocity. The general belief seems to be that the visor remained afloat for a few seconds, and it would have thus been entrained by such things as wave action. But all that depends on Amdahl's inference of kinetic energy from the appearance of the breach. It's not clear, based on his subsequent comments, that the estimate was narrowly bounded. Nor is it clear that conceivable circumstances rule out damage from the visor. Ruling it out because it "only" weight 55 tons is misleading from an engineering physics standpoint.
Hence why I asked Vixen whether Prof. Amdahl had published his methods and findings. Apparently this was work contracted by the filmmaker. This is common practice. I too have done private science for television programs, and it's not generally work that is otherwise publishable. However in this case it would seem to bear on a forensic investigation of some interest, so there would be more call for publication in the standard literature. In any case, it is likely that the new investigation will produce its own findings using similar methods.
All the workable models of ship collisions start with kinetic energy. But damage to structures must account for the mechanical behavior of the involved structures, because only absorbed kinetic energy determines the yield and shear of ship or stationary structures. This means a knowledge of the geometry of the collision and the structural factors in the objects involved. The Minorsky model was the gold standard for years, assuming a completely inelastic collision and considering only the kinetic energy perpendicular to the receiving ship's axis. After the Sunshine Skyway Bridge accident, it was shown that a more generalized model of collision was needed in order to engineer structures that might have to critically sustain impact from ships.
Beginning in the 1980s, the U.S. Department of Energy began a project to apply finite element analysis methods to structural dynamics. The result was LS-DYNA, a computational kernel that is used in commercial products such as ANSYS, and is an invaluable tool in studying the mechanics of collisions. It works by modeling each structural element in the relevant objects as dozens (or hundreds, or sometimes even thousands) of subelements and resolving the consistutional relationships among adjacent elements as external force is applied. As such, it can model the arbitrary deformation and fracture of materials quite faithfully, when judiciously used. It's a fully-generalized model, so it works for one ship hitting another, one car hitting another, or a rolling pin hitting some unfortunate husband's scalp.
As you note, however, the fidelity of such models is based on quite a number of factors. Model resolution is one of them. The computational requirements for such models are immense, and generally a fully faithful model requires days to run on the world's most powerful supercomputers. I believe the record is still a model of a Nimitz-class aircraft carrier, which required solving a matrix in 1019 unknowns.
One way to make the model computable is to reduce the number of subelements. This means the model can run on affordable computers, but at the cost of degrees of freedom in the model. This results in potential errors such as premature or reluctant yielding of the material, leading to errors in estimates of the kinetic energy required.
Another way to make the model computable is to use lower time resolutions, or to start the simulation with the collision already in progress to some extent. The typical resolution for a high-energy collision (e.g., a highway car accident) is 0.001 second. This can require up to weeks of computing time on very expensive computers. Lowering the time resolution allows the models to run faster, but at the expense of nonlinear critical elements being lost. And starting the model midway through a collision is warranted sometimes when the geometry of an intermediate state can be known, but it does nevertheless introduce simplifying assumptions that may turn out to be wrong.
But fundamentally the downside of a fully generalized solution is that there's no way to prime any of the simulations. The engineer must make reasonable estimates for values such as speed and angle of collision. There is no way to work backward from the final disposition of the materials to the specific cause that resulted in them. Further, in this case the geometry of the alleged impactor is entirely unknown. Any model of it is speculative.
A survey of Prof. Amdahl's prior work reveals that he is indeed an expert in ship collisions, but his prior subjects have been known structures -- either other ships or stationary structures such as bridge piers (cough, Sunshine Skyway, cough). His previous work is valid, of course, because he's working with known objects. But here he's working with unknown objects, and we need to know his assumptions. He gives a higher kinetic energy requirement for a fishing boat, even though a boat has a sharp prow. And a lower estimate for the impact of a bulbous submarine bow, which would ordinarily require greater kinetic energy to cause material to yield. This is why a knife cuts more easily than a baseball bat. Or he may have factored in the strength of a submarine hull -- HY-180 steel or stronger, in the case of U.S. Navy submarines -- and applied it to the elasticity of the collision. We simply don't know unless he shows his work.
The only way to resolve the input conditions for these simulations is to run coarse ones across the entire cross-product range of possible assumed values -- speed, angle of collision, point of collision, water temperature, attitude of the ship, and (most importantly) geometry of the impactor. Those that show promising results -- i.e., those that result in damage that approximates what is observed as the final state in real life -- can be re-run at higher resolution to confirm the results.
But none of that proves that the impact scenario that was simulated is the one that actually caused the damage. The best you can ever say is that the simulated scenario produces results consistent with the observations. It may be one of several possible scenarios, including ones the experimenter didn't think of or control for. Whether that best scenario matches what happened in real life depends entirely on the extent to which the experimenter can validate the variables in his model according to other evidence. The notion that Prof. Amdahl's findings must be spot-on because they are the product of "physics equations" is irresponsible reporting.
Heiwaco!
I see it's already addressed by others, just offering a heads-up that, if anyone would like to, they may search username "Heiwa" here at the forum to see Mr. Bjorkman's body of work specializing in 9/11 trutherism. See especially "The € 1 000 000 Heiwa Challenge."
I'm sad to see that this poor man has any relevance anywhere these days.
JayUtah
Penultimate Amazing
No, it cannot. Deformation has a precise meaning in materials science.
You're obviously not a metallurgist. Ductility is an expression of plasticity, not elasticity. A material displays elastic deformation if it shows strain in response to stress, but then returns to its prior form when the stress is removed. A material undergoes plastic deformation -- including ductility -- when the material retains the strained shape after the stress force is removed. A material yields when it is fractured.
For an "objective" person, you certainly seem to be trying to interpolate your uninformed beliefs on various subjects into this discussion and have them believed without question.
Your uninformed guess is not evidence.
The simple answer is that you have no evidence for your claim.
And epoxy paint is not also brittle at low temperatures? For someone who admits he has no experience in forensic engineering investigation, you seem to be pontificating a lot in order to save face. The photographic evidence shows no fracture. The damage to which you refer is characterized as a deformation, not a fracture. At some point in this discussion will you ever concede that your uninformed claims are not backed up by evidence? Ever?
JayUtah
Penultimate Amazing
Anders Björkman is not a credible authority, for the reasons already given.
JayUtah
Penultimate Amazing
But it's a backward observation. A trained professional can certainly note that the general disposition of the damage is consistent with an impact over a relatively small area. Application of stress will cause different sections of the hull plating to respond in different ways. An elastic response won't be evident in the final form, except possibly in the form of small surface microfractures visible only by microscope. These would not seriously impair the structure performance of the hull plating; such microfractures are commonly incurred in ordinary operation.
A plastic response will be evident in the form of deformations that nevertheless to do not require the material to yield. Most minor ship collisions result only in plastic deformation. And in fact, such behavior is desired because it allows collided ships to retain watertight integrity.
A yield response occurs when materials or welds part. This can occur in hull plating as a shear failure or as a brittle fracture. Temperature affects the ductile-to-brittle transformation point in all metals except for aluminum. Strain rates also dictate yield behavior. That is evident in the final disposition in obviously parted materials.
To say a "puncture" causes "deformation" isn't really a thing. Application of stress results in a combination of the three responses I summarized. One response mode does not cause another. Deformation and parted yields are two possible outcomes of the same initiating cause.
What remains suspicious for me is the lack of paint loss at the impact site and the lack of any paint or coating transfer to the damage site. Impacts almost always result in the loss of paint, especially where scraping or grinding occurs, such as in the proposed submarine impact scenario. What would cause metal to fracture without loss of paint?
The hole seems to occur at or near the joint between two hull plates. This kind of damage is consistent with a collision, of course. But it's also consistent with differential in-plane loading, or "springing" hull plates, as it's sometimes noted commonly. In-plane loading occurs when there is compression trying to push two edges of a material together. It can also occur when there is a moment vector perpendicular to the material plane. At joint edges, the plates can subduct. But buckling is also an extremely common material response of thin sheets to in-plane loading.
This article features a ship whose hull has failed in a way that caused the hull plating to buckle outward in response to in-plane angular loading. Note that the welds have failed at the greatest extent of buckling. https://www.marineinsight.com/naval-architecture/ships-hull-fail-at-midship-region/
Absent any reinforcement, there is no guarantee whether a ship's hull plate will buckle inwards or outwards (or both) in response to such in-plane loading. And if the buckle axis is perpendicular to a seam, and the seam fails, there is no guarantee that the seamed plates will buckle in the same direction. The damage I see at the breach in Estonia's hull is not entirely inconsistent in my opinion with buckling damage. And it explains the lack of coating damage.
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Andy_Ross
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Your own picture shows that the hole is above the waterline!
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