Sacheomwi: "Rapid Turn Before Sewol Ferry Sinking, Low Possibility of 'Rudder Component Malfunction'"

On the afternoon of the 26th, officials from the Special Investigation Commission on Social Disasters announced the results of a demonstration experiment regarding the 'ship solenoid valve seizure,' a key piece of evidence for the 'internal explosion theory,' in front of the Sewol ferry hull raised at Mokpo New Port in Mokpo-si, Jeollanam-do.
[Image source=Yonhap News]

[Asia Economy Reporter Jeong Dong-hoon] The Special Investigation Commission on Social Disasters (SICSD) announced interim experimental results indicating that the previously suspected cause of the Sewol ferry disaster?the sticking (malfunction) of the solenoid valve (electronic valve) in the rudder control device?is unlikely to be related to the accident.

On the 25th, the SICSD presented the results of experiments conducted at the new port in Mokpo, Jeollanam-do, to verify the cause of the Sewol ferry’s sudden list. The commission has been investigating the causes of the sudden turn, the list (the ship leaning to one side), and the rapid flooding to determine the cause of the disaster.

Since the sinking of the Sewol ferry began with a sudden turn to starboard, the commission created a model of the ferry’s steering device and conducted empirical tests to identify the cause of the sudden turn.

Previously, among the six members of the Sewol Hull Investigation Committee, three argued the “internal cause theory,” claiming that the sticking of the solenoid valve caused the rudder to shift to starboard uncontrollably, leading to the sudden starboard turn. The other three members expressed that some aspects could not be explained solely by internal hull factors and did not rule out the possibility of external forces.

The SICSD’s interim investigation results may overturn the “internal cause theory” from the previous hull investigation committee.

The SICSD confirmed design blueprints with Kawasaki Heavy Industries, the manufacturer of the Sewol’s steering device in Japan, and created an identical model to conduct empirical experiments applying various scenarios to verify the rudder’s movement. The experiments were conducted under the assumption that the solenoid valve was stuck.

Following discussions at the full committee meeting, the conclusion was that the first condition had a low probability. All scenarios showed experimental results indicating that the solenoid valve sticking would make it difficult for the Sewol ferry to change its angle before sinking from “full starboard turn to 8 degrees port turn.”

However, some opinions suggested a higher possibility of the first condition being realized. Crew members consistently testified that there was no steering action to change the angle to starboard, and in reproduction experiments, when the solenoid valve stuck during normal steering, the starboard angle change phenomenon was repeatedly reproduced.

The SICSD plans to incorporate these opinions and conduct further investigations into the timing of the solenoid valve sticking in the steering device bound for Incheon, whether the crew intentionally or negligently caused the starboard full turn, and whether any emergency actions were taken, before reaching a final conclusion.