Updates on the Sewol Tragedy


#1

The ferry Sewol has been lifted upright:

https://www.usatoday.com/picture-gallery/news/world/2018/05/10/south-korean-ferry-set-upright-four-years-after-tragedy/34778697/

The Maritime Research Institute Netherlands (MARIN) has reported the results of its study to the Sewol Investigation Commission:
http://english.hani.co.kr/arti/english_edition/e_national/847147.html

An earlier article from the MARIN website shows the models used in the study:

http://www.marin.nl/web/News/News-items/20180302-Nederlands-instituut-MARIN-onderzoekt-Koreaanse-veerbootramp.htm

(In Dutch, but Google Translate does a good job on it).

I think this is worthy of main page news on gCaptain. Perhaps more information can be had from the contact emails in the last link.

My thanks to user ImaginaryNumber on boatdesign.net for pointing out the first two articles.

What a terrible, preventable event.

Earl


#2

Noted and we’ll take a look.

FYI for the lurkers here, we have a anonymous “submit a link” page if you see a story you want
Us to cover but you don’t want to post it publically.

Here’s the link (consider bookmarking it): http://gcaptain.com/share-a-link/


#3

Another real hero, captain Lee Joon Seok, leaving his ship in style in his underwear in the first lifeboat and that 50 minutes after notifying the Coastguard about the incident. Before deserting the ship he had ordered the over 300 passengers, mainly kids, to remain in their cabins and law-abiding as they are they did.

The Marin report focusses on the sinking of the Sewol and not so much on the causes of the sinking. Prosecutors at that time were looking into whether the ferry was safe for operation after a redesign. Modifications included adding an extra deck for extra passenger cabins, raising the passenger capacity by more than 150 people, and increasing the ship’s weight by almost 240 tons, the Korean Register said.

The new loading limit was 895 ton and 2000 ton of ballast was added to keep it stable. However, on the final voyage they had taken on board a staggering load of 3273 ton! What about load lines? What do you expect what will happen if you make a sharp turn?


#4

To answer that question literally it’s the same as wind heel. I’d expect that the ship would heel over and the righting arm to increase until equilibrium was reestablished.

IIRC the captain was a relief captain. How reasonable it is to expect him to assume that the ship is not seaworthy? It’s easy to say he should have checked the stability but had the ship had a bad fire instead everyone would say he should have checked the fire fighting arrangements. Which he probably did not do.


#5

Detained crew members told investigators that the ship was unstable and difficult to steer. Witnesses have said the ferry turned sharply before it began listing. However, it is not clear why the vessel turned and why so sharply. There was plenty of room there. There was a 25 year pilot on board, it could be that he gave the order.

It has also been established that the ferry was being operated despite a request made by the captain on April 1 for repairs to the steering gear. I will try to find the final investigation report to see what caused the vessel to turn, for instance if it had reached a waypoint.

I suppose that on every ship after loading and even while at the end of loading the chief or second officer checks the load line and the drafts. With that kind of overload, more then three times, it must have shown and the captain, relief or not, would have known that it was not safe to depart.
,


#6

In general I think that any “connect the dots” analysis done in hindsight is suspect. What if instead of capsizing the ferry there had been a fire. Likely someone could find dots to connect to show that the captain "should have known’ that it was at risk for fire.

Has anyone checked to see if the firefighting equipment was up to standards? No, because that’s not what they are trying to prove.

In fact if that captain had turned down the job that day likely someone else would get the call. Who ever took that job was destined to be considered to considered a criminal.

With regards to checking the drafts, that may be the practice on deep-sea ships but might not be the case with ferries.


#7

One of Nancy Leveson’s students did a useful analysis of the incident, which contains summaries of the official reports:

http://sunnyday.mit.edu/papers/Kwon-Thesis.pdf

Earl


#8

From the above MIT thesis.

The Captain, Lee Joon-Seok was 69 years old, received the Second Mate License in 1986, had twenty-five years of ferry experiences as the first mate and joined Chonghaejin Marine in 2008. He was the first Captain of the Sewol-Ho. The Captain had been a part-time captain since he retired from the company several months ago. He knew that the first mate had used ballast water as a means to satisfy the load line but could not correct him because the ballast water was the only way to satisfy the load line. He knew the ferry had been overloaded, and the ballast was reduced to satisfy the load line which was the only checkpoint by officers at the KSA. His feedback to Chonghaejin Marine were critically important to the safe operation of the ferry, but after experiencing several frustrations of them not accepting his feedback, he stopped providing feedback.


#9

One moral being “always leave on time, and the hell with the fog”. :sob:


#10

Here is some more material from the thesis. Also the bow and stern doors were not watertight. That fact was known and reported but no action taken. They sinned immensely against all laws of ship stability and the lack of knowledge in that field, with all parties, is incomprehensible.

To get the approval for the departure from the Operation Officer at the KSA who just checked the load line for the approval, he had to adjust ballast water, mostly taking out the water to compensate for the overload. He knew that the ferry would be dangerous due to reduction of the restoring force if ballast was less than that required and due to free surface effects when the tanks were not fully filled. However, everybody including the first mate and the Operation Officer at the KSA thought that the load line was the only critical factor to guarantee the ferry’s safe operation as he testified at the court (08/29/2014).

When the bow and stern doors were closed, the ferry was not watertight due to the bad condition of the rubber packing seals. He reported the issue to the company to fix them several weeks earlier, but no repair was done. He testified at the court (10/08/2014) that he had no means to do more than the report to the company. The inadequate maintenance process allowed the ferry (it was an RORO ship too) to travel with the bow and stern doors not watertight.


#11

Company boss Kim Han-sik repeatedly denied all charges and of being guilty to criminal negligence and pleaded not guilty. He made this statement already before the trial laying the blame entirely on other, lower placed persons: “Executives and employees of our company have committed a grave sin”.

IMG_2714

Kim Han-sik, propped up by helpers, going through the weepie-weepie motions

Kim Han-sik, 71, the chief executive of Chonghaejin Marine Co., was found guilty of involuntary manslaughter and negligence for allowing the ferry to be overloaded with improperly stowed cargo and approving illegal renovations to increase passenger capacity.

The Gwangju District Court delivered a 10-year prison sentence to the head of the company that operated the Sewol ferry, which capsized in April 2014 and killed over 300 passengers, mostly children. During the first and second hearings witnesses on numerous occasions said that they did not remember what had happened. A short memory can be helpful sometimes…

“Kim remodeled the ship and overloaded it with cargo in an effort to overcome the company’s deficits despite being briefed that the ship’s ability to balance itself was compromised,” Judge Yim Jung-yeob said in his ruling.

The CEO was also convicted of embezzling millions of dollars from the ferry company and diverting it to the company owner Yoo Byung-eun’s family for the past four years. In addition to his 10-year jail term, the court imposed a 2 million won fine on Kim.


#12

You posted that before, hopefully this time I get around to reading it.


#13

After the purchase, Chonghaejin Marine made extensive modifications by adding cabins to the third, fourth, and fifth decks to accommodate additional 117 passengers. The modifications led to The increase in weight by 239 tons which increased the VCG with 0,51 m, decreasing the KR’s authorized cargo capacity by half to 987 tons, and increasing the KR’s required 1,703 tons of water to serve as ballast to provide balance, which was four times more than the previous ballast requirement, 370 tons. The modifications were later found to have been based on an illegal redesign of the ship. After the inspections 37 tons of marble were also illegally added to the gallery room at the bridge deck, on a high place, on the back of the ship.

Throughout the previous year of the incident the regular captain had warned the company about the decrease in stability and passenger satisfaction and attributed it to the removal of the side ramp, but the company responded by threatening to fire him; the last warning and threat was on 9 April 2014, seven days before the incident. The captain had also requested a repair for the malfunctioning steering gear on 1 April 2014, which was not done. The on duty helmsman complained later that the rudder at one moment didnot respond. Overloading and improperly secured cargo were seen as the direct causes of the capsizing and sinking of the ship. The MV Sewol was carrying 3,608 tons of cargo, more than three times the limit of 987 tons!

Apart from the load line there were no further tools available such as:

  • Quantitative methods or tools for assessing the total weight of both cargo and vehicles on the ferry.

  • Quantitative methods or tools for assessing ballast water in the ferry.

  • Adequate emergency system: Anti-heeling pumps to return the ferry to its upright position did not work.

  • The only quantitative measurement for assessing the total weight of both cargo and vehicles was the load line.

The third mate Park had previously received instructions from the regular captain that turns over five degrees should be performed with care, as Sewol’s restoring force was low. The expert advisory panel on the police-prosecution joint investigation team later agreed that a turn greater than five degrees made under any conditions would have upset the ferry, concluding that she was in no shape to carry passengers.

The first mate had complained to the associate manager at Logistics team, Kim, Jung-Soo about the ferry’s severe rolling when it was traveling on windy days. The associate manager did not accept the complaints. He had also observed that the regular Captain complained to the associate manager about the overloading, but no corrections were made. Therefore, he simply stopped making the complaints. I suppose that if you had asked them about the GZ curve that they would have looked at you with a bewildered, stupified expression on their faces, how were those people trained? Did they never learn, not even the basics of Ship Stability during their nautical education?

This is a picture of criminal behavior that in the 19th century led to the establishment of the Plimsoll mark. However, it is clear that this means little if you intentionally overload the ship and pump out ballast water until the load line surfaces.

Overseeing the whole incident I think that Chief Executive Kim Han-sik, as overlords generally do, got away very benignly with only 10 years of imprisonment while the captain, not being the regular captain, got a full life sentence. A remarkable difference.


#14

The Sewol sinking keeps intriguing me, probably also because the incident is so bizarre and was totally unnecessary. It beats me how the managers, who bullied the officers with threats of firing them, could sleep well while knowing that not only the crew’s but especially the passengers’ lives were endangered every time they sent a ship to sea.

The capsizing and sinking was due to a sharper then normal turn which caused a heel after which the hardly or not lashed cars started to shift causing a further heel. Flooding started and after two hours the ship sunk. The same could have happened if a strong beam wind was encountered. I did a little exercise to see what the result was of such a beam wind and used for this purpose the USCG wind heel criterion.

A = 30306 ft²
Δ = 11229 ton
h = 30 ft

The problem is what the GM could have been. I suppose that G was close to M and certainly not the minimum IMO required GM of 0.15 m. I gave it a little bit the benefit of the doubt and used a GM of 0.10 m.

To meet the 14° heel of the criterion the ship should have had a minimum GM of 0.59 m! The graph shows that with a GM of 0.10 m the ship is nowhere…

With about 879 tons less of cargo the GM would have been 0.59 m. Nice but then the stability requirements would not have been met due to the wrong ratio of (high) triple cargo load and insufficient ballast.

The Sewol had a very large sail. To illustrate this here is the curve for a ship with only half the sail. For a wind heel of 14° now a GM of 0.2 m is required instead of 0.59 m, quite a difference.


#15

In your post # 8 I see Levenson’s approach using levels of hierarchy approach rather then the chain of events.

I hesitated reading Levenson’s book Engineering a Safer World Systems Thinking Applied to Safety because of the title, seemed a little high-flying for me but it was very readable with good examples.


#16

Not surprising since she was the thesis supervisor.


#17

Beware y’alI, I am throwing another marshmallow at you…:slightly_smiling_face:

With such a rather slow turn and a GM of 0.10 m the ship will heel almost 21°. No wonder they did only dare to change course degree by degree, softly softly. As they said on board: almost no restoring force. Like a balancing act on a taut wire over a deep ravine. With a GM of 0.20 m the situation is already much better, a 11° heel.

A five ship length radius is the usual distance for such tests in which they bring the rudder 35° to either port or starboard. Imagine doing that here… After a for instance port rudder command of 35° the ship will first heel a little to port before the centrifugal force kicks in heeling the ship to starboard.

IMG_2782

These guys don’t care about heeling to starboard with a left turn!

The graphs were made on my iPad with Fooplot. The text in the graphs were added with the Doodle app. BG was calculated with the help of the Ventura’s estimation methods.


#18

I should have been more specific but I intended to point out the horizontal lines in post #8 are divisions between layers of hierarchy.

It’s an over-simplification but the level labeled “Sewol-Ho Operations” are events that might be considered under the control of the captain and crew. The other levels are outside (more or less) of the crew’s control.

This is from Leveson:

Most accident investigation and analysis rests on the use of event-chain models, i.e., the accident causation is described as a chain of failure events and human errors that led up to the actual loss event. Such models are limited in their ability to handle system accidents (arising from dysfunctional interactions among components and not just component failures), software-related accidents, complex human decision-making, and system adaptation or migration toward an accident over time

The gcaptain forum uses (at best) the chain of failure events and human errors. Which method or framing is used can lead to different conclusions as to fault or cause.

Also I intended to point out that Leveson’s book was readable and easy to understand, the summaries are more difficult to understand.


#19

I like the structured approach of the incident which is clearly explained by the diagram. It gives a total overview of the events and how they are connected and interact and finally led up to the climax, the sinking of the ship. There is more to it then human failure and errors only. Leveson’s theory is sound and should be used more often. Must read that book.


#20

There is a thread here: Nancy Leveson Hazard Analysis - but I didn’t make much progress understanding till I read the book.