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The Sinking of MS Estonia: Case Re-opened Part II

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Vixen said:
It used the seaworthy certificate as evidence the vessel was seaworthy. Even Captain_Swoop questions whether it was seaworthy.

If a few 'low impact waves' can knock off the bow visor, how can it have been seaworthy?

“Shortly after one o'clock a low wave impact on the visor caused the visor attachments to fail completely. The visor started cutting openings in the weather deck plating and associated structures. Soon the back wall of the visor housing came into contact with the ramp, hitting its upper edge and thus breaking its locks. The ramp fell forwards and remained resting inside the visor. In a few minutes the visor started falling forwards."

JAIC

Note the time, within minutes of Swedish midnight - whoosh! - a low impact wave comes along and the bow visor drops of. As it does.
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Why am I not surprised to discover that’s not what the JAIC report says?

Here’s the actual words:

Shortly after one o'clock a few wave impacts on the visor caused the visor attachments to fail completely...
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Jack by the hedge said:
That's what I see too. Illustrates something about the hazards of quoting secondary sources perhaps.
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Indeed.

But note also that from a metallurgical point of view, it actually could have been the case that the amount of fatigue in one or more critical components of that bottom lock had reached such an advanced state that even a mild stress burden* would have "pushed it over the edge" and caused the lock to fail catastrophically.


* And this of course is the moral behind the "straw that broke the camel's back" aphorism: the camel's back was already so overloaded with fodder that it only took the smallest of additional loads to cause the camel's back to break.
 
Ultrasound is a possibility but then Dye Penetration Testing for micro fractures is the techniques to use I have just been told by a friend who does NDT in the North Sea offshore industry.
 
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Captain_Swoop said:
Ultrasound is a possibility but then Dye Penetration Testing for micro fractures is the techniques to use I have just been told by a friend who does NDT in the North Sea offshore industry.
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Curious, do you know how often they would do that or if it's even a requirement? I work in manufacturing and have seen many catastrophic failures of equipment, so I have a decent understanding of the failure mode. Just wondering if they would only do that type of testing if there was an indicator that something was potentially failing.
 
Captain_Swoop said:
Ultrasound is a possibility but then Dye Penetration Testing for micro fractures is the techniques to use I have just been told by a friend who does NDT in the North Sea offshore industry.
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Yes, that technique is standard across several industries.

ETA: It's not appropriate in all cases, though. Each test method has its strengths and weaknesses. For example, dye-penetration testing requires preparing the surface of components to receive the dye, which usually requires abrading away surface contamination to reveal bare metal. This is obviously not indicated for parts that have narrow strength margins or precise mechanical tolerances or required surface finishes.
 
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Disbelief said:
Curious, do you know how often they would do that or if it's even a requirement? I work in manufacturing and have seen many catastrophic failures of equipment, so I have a decent understanding of the failure mode. Just wondering if they would only do that type of testing if there was an indicator that something was potentially failing.
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I wouldn't think crack testing or ultrasound was a requirement in any routine inspection.

If it was new construction or had structural work done in a refit etc testing of welds etc would be done.
 
Vixen said:
It used the seaworthy certificate as evidence the vessel was seaworthy. Even Captain_Swoop questions whether it was seaworthy.
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This is just the same equivocation you deploy every four or five pages without paying the slightest attention to what anyone else says. Holding certificates of seaworthiness doesn't mean the ship is known to be free of defects. Captain_Swoop has presented the actual nature of the certificates in question. You are evading his request that you reconcile that with your claim.
 
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Captain_Swoop said:
I wouldn't think crack testing or ultrasound was a requirement in any routine inspection.

If it was new construction or had structural work done in a refit etc testing of welds etc would be done.
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I'm sure that new construction would definitely have more stringent requirements, and ultrasound is used for weld verification in many applications. Just didn't know if they would do so on normal inspections, since it's not typical in my industry nor was it on aircraft when I was in the USAF.
 
Vixen said:
Sound effects, old chum.
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Wrong again. The proper annotation, where a screenplay calls out specific music, is "MUSIC:". Occasionally you will see "SOUND:" cues, but it's rare. Sound cues are simply one of the many capitalized elements in the stage direction. Or is this yet another of your homegrown cues that you only share with your particular klatch?
 
It's a little dry, but here's what the JAIC said about the Estonia's safety certification. What you will probably not find is anything saying "it had all these certificates, therefore it must have been seaworthy":
3.6.2 Certificates valid at the time of the accident
International certificates cease to be valid when a ship changes flag. New certificates were therefore issued when the ship became Estonian in January 1993. Two new classification certificates (hull, machinery) were issued by Bureau Veritas in January 1993. The Estonian Maritime Administration had authorised Bureau Veritas in August 1992 to perform the surveys on its behalf and to issue certificates under the 1966 Load Line Convention, the 1974 SOLAS Convention, the 1973 MARPOL Convention and the 1969 Tonnage Convention. The status of the certificates at the time of the accident was as follows.
Passenger Ship Safety Certificate. As a new trim and stability manual was under development, the vessel carried an interim Passenger Ship Safety Certificate, issued on 26 June 1994.
Load Line Certificate. For the same reason the Load Line Certificate was interim, issued on 9 September 1994.
International Oil Pollution Prevention Certificate. A conditional IOPP certificate was issued by Bureau Veritas on 14 January 1993. The validity was conditional on the issuance of a Passenger Ship Safety Certificate.
International Tonnage Certificate. Bureau Veritas issued, on behalf of the Estonian Government, a tonnage certificate under the Tonnage Convention of 1969. The certificate valid at the time of the accident was dated 29 August 1994.
At the request of the owners Bureau Veritas had also issued a Cyprus tonnage certificate, dated 8 June 1993, according to the Cyprus Merchant Shipping Regulations requirements. Bureau Veritas also issued, under the same authority, a Certificate of Survey pursuant to the Republic of Cyprus Merchant Shipping Law of 1963.
The valid certificates at the time of the accident are shown in the Supplement.
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https://web.archive.org/web/2004062...nettomuustutkinta.fi/estonia/chapt03_3.html#3

I don't know where in there Vixen decided the JAIC wanted to persuade us that the ship was seaworthy rather than just report its certification.

Perhaps she read a secondary source's version of the report which doesn't use the original's wording. Again.
 
Disbelief said:
I'm sure that new construction would definitely have more stringent requirements, and ultrasound is used for weld verification in many applications. Just didn't know if they would do so on normal inspections, since it's not typical in my industry nor was it on aircraft when I was in the USAF.
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There are simply too many fittings on a ship for their welds to be routinely tested, and for the components to be routinely checked by any means for metal fatigue. In shipping the most common protection against metal fatigue is to overengineer the component by a large factor. An experienced ear can hear the effect of advanced fracturing using a hammer strike. You take a 3-lb sledge and strike the fitting lightly. Sound parts "ring" while parts compromised by extensive fracturing sound more dull. If someone sufficiently experienced had thought to do that, it might have been instructive. But it was by no means prescribed.

In civilian aircraft, dye-penetration tests (or x-ray or ultrasound) for critical components are called out in the schedules for C and D checks. That would be a difficult check to perform on an articulated hull element because it requires preparing the surface of the component to receive the dye. Ultrasound might actually be a more workable test method if the vessel's mechanism cannot be easily disassembled.

It's important to recall that at this time there were no prescribed design or test procedures for the fittings belonging to articulated bow doors. This is not to say that owners and operators did not realize the importance of keeping those elements in good condition. But there was no industry-wide agreement about what specific activities that entailed.
 
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Jack by the hedge said:
It's a little dry, but here's what the JAIC said about the Estonia's safety certification.
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The involved vehicles' certification history is a standard part of any accident report. It's dry because it's supposed to be.

I don't know where in there Vixen decided the JAIC wanted to persuade us that the ship was seaworthy rather than just report its certification.
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As you say, it could be because she's relying on a secondary source. But it can also be a bias arising from having pre-rejected the JAIC report as politically tainted, coupled with inexperience at digesting accident investigation reports. If you don't often read these reports and don't have a feeling for their boilerplate elements, you could suspect, "Why did they include these if not to convince us that the ship was otherwise sound?"
 
JayUtah said:
There are simply too many fittings on a ship for their welds to be routinely tested, and for the components to be routinely checked by any means for metal fatigue. In shipping the most common protection against metal fatigue is to overengineer the component by a large factor. An experienced ear can hear the effect of advanced fracturing using a hammer strike. You take a 3-lb sledge and strike the fitting lightly. Sound parts "ring" while parts compromised by extensive fracturing sound more dull. If someone sufficiently experienced had thought to do that, it might have been instructive. But it was by no means prescribed.

In civilian aircraft, dye-penetration tests (or x-ray or ultrasound) for critical components are called out in the schedules for C and D checks. That would be a difficult check to perform on an articulated hull element because it requires preparing the surface of the component to receive the dye. Ultrasound might actually be a more workable test method if the vessel's mechanism cannot be easily disassembled.

It's important to recall that at this time there were no prescribed design or test procedures for the fittings belonging to articulated bow doors. This is not to say that owners and operators did not realize the importance of keeping those elements in good condition. But there was no industry-wide agreement about what specific activities that entailed.
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Thank you for the information, it's much of what I was thinking. Since my experience is manufacturing, I didn't want to assume the same for shipping since the stresses are going to much different.

Another part of the problem, is that Vixen appears not to understand the nature of catastrophic failures. She keeps talking about a few strong waves, but totally disregards the years of wear that would lead up to the failure.
 
Jack by the hedge said:
It's a little dry, but here's what the JAIC said about the Estonia's safety certification. What you will probably not find is anything saying "it had all these certificates, therefore it must have been seaworthy":

https://web.archive.org/web/2004062...nettomuustutkinta.fi/estonia/chapt03_3.html#3

I don't know where in there Vixen decided the JAIC wanted to persuade us that the ship was seaworthy rather than just report its certification.

Perhaps she read a secondary source's version of the report which doesn't use the original's wording. Again.
Click to expand...

None of those certificates would involve any detailed inspection of the bow visor.
 
Disbelief said:
Thank you for the information, it's much of what I was thinking. Since my experience is manufacturing, I didn't want to assume the same for shipping since the stresses are going to much different.

Another part of the problem, is that Vixen appears not to understand the nature of catastrophic failures. She keeps talking about a few strong waves, but totally disregards the years of wear that would lead up to the failure.
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Despite that point being strongly and clearly made many times by multiple posters. Deliberate obtuseness is the only plausible explanation.
 
here is a link to Bureau Veritas documents that lay out the requirements for ship classification and testing.

I linked to it once before.
They are concerned with the way the ship is constructed, the materials and techniques used and the standards they have to meet.

Once a ship is built unless any structural changes are made or it needs to be reclassified for a different use then the structure is not tested.
If a ship changes flags (which is not the same as changing ownership) it needs to be recertified in to it's classification under the new flag.
How it was built and the standards it was built to are already known. There will be no NDT testing of fittings and welds, it is a paper exercise as far as construction goes.

https://marine-offshore.bureauveritas.com/nr467-rules-classification-steel-ships

Here is the main page for Rules and Guidelines.

https://marine-offshore.bureauveritas.com/rules-guidelines
 
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