Questions linger 100 days after the Cheonan sinking

Posted on : 2010-07-03 18:48 KST Modified on : 2019-10-19 20:29 KST
Experts say the Lee Myung-bak administration’s rush to meet the local elections deadline left insufficient time to conduct a thorough investigation
 June 29.
June 29.

By Lee Yong-inn

Saturday marked one hundred days since the sinking of the Cheonan on March 26, but the debate over the truth behind the sinking shows no signs of cooling. Despite the official announcement by a joint civilian-military investigation on May 20 stating that the Cheonan sank due to a North Korean torpedo attack, there are still certain aspects of the government and team accounts where the stories have changed or no clear explanation has been given. For this reason, some observers are expressing serious concern that misgivings that began in the “tail” are now wagging the “body,” or the truth about the incident.

The Controversy over “Torpedo No. 1”

The debate has been most heated with regard to the torpedo recovered by a pair trawler on May 15. When announcing its investigation findings on the cause of the sinking on May 20, the investigation team presented this torpedo as conclusive evidence, saying that it was a “CHT-o2D” torpedo manufactured in North Korea. As basis for its claim that this torpedo was responsible for the Cheonan’s sinking, the team cited analysis results on aluminum oxide, an adhesive substance that arises from explosions, the word “No. 1” written in Korean on the torpedo’s propeller, the degree of corrosion on the torpedo and hull, and the correspondence between the torpedo propeller and a North Korean torpedo blueprint.

However, the evidence presented by the team has faced more challenges with each day that passes. To begin, the team explained that the white adhesive substance arose when aluminum powder in the torpedo’s explosive detonated and burned onto the Cheonan’s hull and the torpedo’s propeller. However, Seung-Hun Lee, a physics professor at the University of Virginia in the United States, and Panseok Yang, manager of the Microbeam Laboratory in the Department of Geological Sciences at Canada’s University of Manitoba, conducted their own analyses of the data presented by the team and concluded that the substance was not aluminum oxide resulting from an explosive, but was more likely an ingredient in clay.

Second, the team announced during a June 29 briefing for press groups, including the Journalists Association of Korea and the National Union of Mediaworkers, that its analysis results showed ingredients of “Solvent Blue 5” in the blue oil magic ink used to write “No. 1” on the torpedo’s propeller. However, the solvent line is a commonly used ingredient in ink, and since the team was unable to secure a sample of North Korean ink to compare it with the ingredients in the ink used to write “No. 1,” it is insufficient as evidence.


Third, the degree of corrosion on the torpedo and vessel, which would have been underwater for similar lengths of time, was viewed as an important indicator.

However, the team explained, “Because of significant differences in the corrosion thickness on the torpedo propeller, up to around six times depending on the materials and part, it is difficult to determinate how long the corrosion had been taking place.”

In other words, it was impossible to give a scientific explanation.


Fourth, confidence in the military’s announcement took a hit after the belated discovery that the full-scale Korean torpedo blueprint presented by the team during its announcement did not correspond to the torpedo in question. Also, the team’s announcement suggested that the blueprint was in a catalog produced by North Korea for torpedo sales, but Defense Minister Kim Tae-young and others later changed their story and said that it was on a CD.


Additionally, the team’s announcement and the accounts of Baengnyeong Island sentries differ on the presence of a large water column from a bubble jet torpedo explosion. Besides this, questions have been raised over whether the sonar used to detect submersibles and torpedoes was functioning on the Cheonan, and whether there was really no thermal observation device (TOD) footage from the time of the sinking. 


Why So Many Doubts?

Experts commented that the administration “reaped what it sowed” after trying to solve the puzzle too quickly to meet the timeline of the June 2 local elections.

According to an array of military sources, there was a considerable debate within the Cheong Wa Dae (the presidential office in South Korea or Blue House) and military over the cause of the sinking, with factions developing in support of and against the torpedo explanation. This stemmed from divergent accounts by survivors and eyewitnesses, as well as differing assessments of North Korea’s tactical capabilities. Indeed, the investigation team itself acknowledged at its briefing with three press groups on June 29 that North Korea would be the first to have succeeded at using a bubble jet torpedo in actual fighting.

Military experts also reportedly did not readily accept the possibility of a small-scale submersible typically used for reconnaissance and maneuvering actually being fitted with a heavy torpedo and used to attack. The “torpedo theory” proponents won the day when the “No. 1 torpedo” was salvaged on May 15, and establishing a linkage between the “No. 1 torpedo” and the Cheonan’s sinking became a task of vital importance. Even so, just five days later, the administration made an announcement as though the entire relationship between the torpedo and the Cheonan had been proven.


A military source who asked to remain anonymous said, “If you leave out the time spent moving the torpedo, removing water and dust, and writing a report, the whole examination only lasted about three days.”

“The government has invited distrust by being excessively greedy,” the source added.

Please direct questions or comments to [englishhani@hani.co.kr]