Disagreement within SIC on MARIN’s analysis
There was a serious disagreement within the SIC on this analysis by MARIN. The “Internal Cause Theory” report of SIC accepted MARIN’s results and interpretation, whereas the “Open-Ended Proposal” report of SIC did not accept MARIN’s conclusion that Sewol’s turning and heeling could be explained by a combination of stability, rudder angle, speed, etc. In particular, the “Open-Ended Proposal” report states that “there are many differences between MARIN and the SIC External Force TF” on how to interpret MARIN test results about the possibility of external force. Eventually, the biggest difference between the two SIC reports is found in Chapter 2, which deals with Sewol’s turning and heeling, and it can be largely attributed to the different interpretations of MARIN test results.
MARIN heard the news that the SIC failed to reach an agreement internally and that SIC produced two versions of its final report at the time of the commission’s closure in early August, 2018. The researchers were curious about public responses in Korea to the final SIC reports and subsequent discussions, as they hoped that their model tests contributed to the investigation of Sewol sinking. They could get some updates from the Korean media with the help of local contacts. The SIC, however, could not even send the final reports to MARIN, as the commission no longer existed by the time the final reports were published after the editing and design process.
The researchers in the Netherlands would not have been able to read it, but the different positions within SIC on MARIN’s analysis and conclusion are visible in the ways in which the two reports refer to the Dutch institute. The “Internal Cause Theory” report states that the SIC selected MARIN as a partner in the Sewol investigation because it “highly appreciated MARIN’s capability and experience in difficult and complex analysis,” whereas the “Open-Ended Proposal” report states that it was because “MARIN had a good capability in model tests and was available, among the three organizations considered, for finishing the tests within the official investigation period.” According to the former, MARIN has its own capacity for data analysis and making a conclusion. In the latter, MARIN is considered a contractor that conducts model tests as requested by its client.
This difference of opinions within SIC about MARIN’s status, however, did not really matter to MARIN. Although the SIC, which had first commissioned the Dutch institute for model tests, ceased its work in August 2018, MARIN did not let go of Sewol. Instead, MARIN started to prepare a scientific publication based on its Sewol model tests since last summer. The product of this work is the other paper that the researchers presented at the RINA conference in March: “Sewol Ferry Capsizing and Flooding.” Henk van den Boom, who had been in charge of the Sewol model test project in 2018, presented the paper himself. The co-authors include Ferrari, who conducted turning and heeling tests, Rinnert van Basten Batenburg, who conducted flooding and sinking tests, and Seo Seung-taek, who participated in the model tests as an investigator at the SIC.
MARIN’s conclusion against external force hypothesis based on model tests
In the paper “Sewol Ferry Capsizing and Sinking,” the MARIN researchers presented their analysis of the external force hypothesis more clearly: “Since no realistic combination of winch force, direction and duration attained the high rate of turn as derived by the External Force Task Force of SIC from the raw AIS heading, the hypothesis of an external force that caused such high values of rate of turn was rejected.” This sentence appears in the conclusion section of the paper. It means that, although they applied forces to the model ship in several different conditions in order to replicate external forces, they could not attain a result in which the ship turned so quickly as to suspect external forces being the culprit behind its capsize. MARIN therefore concluded that it could “reject” the external force hypothesis based on its own analysis of the 2018 model tests.
In fact, a very similar sentence was in the conclusion of the “draft report” that MARIN submitted to the SIC at the end of July 2018, based on the additional model tests requested by the SIC. In the “final report” submitted a week later after receiving some feedback from the SIC, however, the explicit sentence about rejecting the external force hypothesis was not included. Therefore, the SIC’s final report (“Internal Cause Theory”) did not use a clear expression such as “the external force hypothesis was rejected.” This time, the MARIN researchers brought back the sentence from the draft report of 2018 and re-confirmed their interpretation. In the email interview after the RINA conference, the MARIN researchers said that they were “fully confident” about their conclusion of rejecting the hypothesis of external force on Sewol. Their position has not changed from 2018.
MARIN’s explanation of the Sewol sinking related to external force should have been discussed, verified, and concluded within the SIC in the summer of 2018. Without enough time to carefully review all investigation results, however, the SIC found itself in endless debates and was split into two groups supporting “Internal Cause Theory” and “Open-Ended Proposal,” respectively. The SIC’s final report, in its divided form, has not undergone an open process of review and verification by relevant academic societies. The English-language paper that MARIN researchers presented last month opens up a channel through which the international scientific community can have a detailed discussion on the official scientific investigation of the Sewol.