[Cheonan Warship Report2] Eight Questions Needing Answers on the Investigation of the Sunken Naval Corvette Cheonan
- 2010.06.04 (23:28:28)
- 첨부 1
[Cheonan Warship Report2]
Eight Questions Needing Answers on the Investigation of the Sunken Naval Corvette Cheonan
Question 1. Had been really a torpedo-induced water column?
Question 2. No such severe injuries evident of a torpedo explosion found in the bodies of survivors and deceased soldiers
Question 3. Is it true that there is no TOD recordings from the early stage of the Cheonan incident?
Question 4. There are no severe damages evident of an explosion on the severed surface, on the bottom of the ship and in the interior of the hull.
Question 5. Why the military concealed the finding and refloating of the gas turbine room? And why did they omit the investigation of the gas turbine room from investigating?
Question 6. Were the oxidized aluminum substances, not gun powder, evident of an explosion?
Question 7. What is the profile of the YONO class submarine? Is it understandable that the submarine had not been followed for several days by the ROK and the U.S. surveillance?
Question 8. Why couldn't a torpedo launch be detected?
This document summarizes the questions raised by the Center for Peace and Disarmament of People's Solidarity for Perspiratory Democracy (PSPD) on the report released on May 20, 2010 by the joint civilian-military investigation group (JIG) under the Ministry of Defense on the cause of sinking of the naval warship Cheonan.
1. Summary of the Report by the Joint Civilian-Military Investigation Group(JIG)
◯ The Official Results of the JIG (May 20, 2010)
: The PCC Cheonan was believed to have sunken as the ship cut in half due to a strong underwater explosion at the lower left side of the gas turbine room. The site of explosion was approximately 3m left of the gas turbine room at a depth of 6 to 9m. The weapon was confirmed to be a highly explosive CHT-02D torpedo made by North Korea with an explosion warhead of 250kg.
◯ Explosion Due to an Underwater Bubble Jet
● The ship severely deformed toward the top side: The hull and iron sheets were curved inward, the evidence of strong shock waves and bubble detected.
● Detection of a water column
● Partial computer simulation showed the ship cut in half under a similar situation
● Evidence of pressure and bubbles resulted from a torpedo explosion found in the entire hull of the ship
● The found non-crystalline oxidized aluminum substances believed to have come from a high temperature and high pressure explosion.
◯ A Torpedo Attack from a North Korean Submarine
● The torpedo parts discovered by a dredging ship at the site of the explosion on May 15 have the same schematics of a North Korean torpedo on the export brochure published by North Korea. This heavyweight HT-02D torpedo manufactured by North Korea utilizing acoustic/wake homing and passive acoustic tracking methods has 21 inches in diameter and weighs 1.7 tons with a net explosive weight of up to 250kg.
● The hangul "1번" (number 1 in English) handwritten inside of the tail end of the propeller is the same marking found in a North Korean torpedo for military exercise purposes secured by the South Korean military in 2003.
● It was confirmed that a SANGO class (300ton) submarine and a YONO class (130ton) midget submarine left a North Korean base/port in the West Sea two or three days before the attack and returned back to the port two or three days after attacking the Cheonan warship. Among these two, the YONO class was believed to have been responsible for the attack of the Cheonan vessel.
● These North Korean submarines were presumed to have infiltrated and left the South Korean waters via international seas.
● The analysis on the chemicals found adhering to both the torpedo parts and the hull revealed to be oxidized aluminum substances that resulted from a torpedo explosion.
2. Insufficient Evidence Proving a Torpedo Attack
Had been really a torpedo-induced water column?
● The Ministry of Defense stated in its final report that a water column coming from the bubble-jet effect was present. However, it had reported that no water column was detected. The problem is that the changed findings lack convincing power.
● The joint civilian-military investigation group (JIG) claimed that a water column caused by a torpedo was present based on the findings (1) a lookout at the coast of Baengnyeong-do Island reported to have witnessed a 20-30m wide and 100m tall water column, (2) a port-side lookout reported that he felt water drops on his face, and (3) oxidised aluminum substances to have come from a bubble jet were found on the entire hull including the bow and the stern turret.
● The findings, which the water column had left marks on the entire hull including the bow and the stern but only water-drops on the solider's face, are not convincing enough. The survivors including the port-side lookouts testified during the press conference that there was no water column and no smell of gunpowder.
● The Defense Minister when questioned by the National Assembly immediately after the release of the final results stated that the existence of a water column is not important and a simulation on water column will be completed in July.
No such severe injuries evident of a torpedo explosion found in the bodies of survivors and deceased soldiers
● No explosion-related injuries were found in the bodies of the surviving and dead soldiers such as burns, ruptures of internal organs such as the eardrum, and severe fractures, etc.
● No such injuries were found on the bodies of the dead soldiers found very near the site of presumed explosion. And it is not understandable that the final report had no explanation over this important matter.
● The water where the Cheonan incident had occurred is known to be one of the abundant fishing grounds, but the coast guards on the search mission reported no massive death of fish despite the explosion. Although the Ministry of Defense claimed that it was because of fast tides, the water was still at the time of the incident.
Is it true that there is no TOD recordings from the early stage of the Cheonan incident?
● The military had hidden the existence of the TOD (thermal observation device) that recorded the sea scenes from Baengnyeong-do Island including the process of Cheonan sinking and reported finally that no TOD recordings were present at the time when the ship severed into two. However, navy retirees reported that TOD images are recorded automatically and refuted that there would be no blind spots because several TOD devices record the same area at the same time.
● The media including the daily newspaper Hankyoreh reported the testimonies of unanimous witnesses who had seen the TOD images recorded at the time of the ship severing into half. They stated that the Cheonan warship was sailing smoothly and suddenly broke off into half, then the stern sank less than 5 minutes after breaking off and the bow floated about 20 minutes and started to sink after it had suddenly tilted toward the right. They also stated that there had not been a water column.
● National Assembly person Lee Jung-hee of Democratic Labor Party reported the similar findings at the National Assembly during the general discussion session on May 19, 2010.
There are no severe damages evident of an explosion on the severed surface, on the bottom of the ship and in the interior of the hull.
● More than anything else, no evidence indicative of severe damages presumed to have been caused by shock waves of a torpedo explosion has been found on the severed surface. The severed surface partially opened to the public seemed well-preserved compared to other ships damaged by torpedo attacks. Even those ammunitions and goods/articles found from the hull interior were well-organized.
● In the interim reports and the final report on May 20, the military announced that (1) an underwater explosion was highly likely based on the torn shape and (2) the ship sank as the result of a non-contact explosion since there had not been blackened soot coming from an explosion from the interior or exterior of the ship, no evidence of melting from heat and no punctured spots. However, experts refuted that these findings themselves are the specific evidence that the cause was not from a torpedo explosion.
● The Ministry of Defense stating that no punctures form after the breakage from a bubble jet is not convincing enough to explain a proximal explosion.
● Lee Jong-in, CEO of Alpha Underwater Technology Corporation specializing in ship wreckage recovery refuted the findings by the Ministry that breakage from an explosion would smash severed surface in the direction sustaining the explosive force, the severed surface would be damaged up to the point of no recognition, and no electric wires would be left being obliterated.
● He also pointed out that (1) if the torpedo explosion occurred 3m below the bottom of the ship, the ship bottom should show punctures from the explosion and the ship would be full of shattered torpedo pieces, and (2) the severed surface of the Cheonan is characteristic of physical forces rather than an explosion or proximal explosion.
Why the military concealed the finding and refloating of the gas turbine room? And why did they omit the investigation of the gas turbine room from investigating?
● The Ministry of Defense later confirmed the recovery of the gas turbine room, which was missed on the incident, after a civilian testified the recovery on May 18.
● The Ministry asserted that a torpedo with a net explosive power between 200 to 300 kg had exploded approximately 3m left of the bottom center of the gas turbine room. And civilian experts who had considered the possibility of aground or collision pointed out that the gas turbine room would show evidences. Thus, the gas turbine room is the critical evidence that can show the real cause of the Cheonan sinking. Nonetheless, the military tried to hide the recovery and omitted the investigation result at the time of the final report.
● According to the reports by the military, the diesel engine was recovered around mid May, and the gas turbine room was recovered on May 19 and carried to the 2nd Fleet Headquarters on May 20. In other words, investigation on the gas turbine room had not been reflected on the final report.
● Nonetheless, the military reported the final results on May 20, arguing that the findings were sufficient. Coincidentally, campaigns for local elections kicked off on that date. It is suspicious that the military investigation team and the Lee government may have reported the investigation results with undue haste with certain political goals.
● The JIG disclosed some parts of the recovered gas turbine room in pictures after May 31.
Were the oxidized aluminum substances, not gun powder, evident of an explosion?
● According to the media, the military was focusing on finding evidence of gun powder at the time of investigation. The military investigation team reported the finding of little trace of highly explosive substances such as RDX and HMX but did not claim that they are evident of a torpedo attack because they were present in very minute amounts and are used by both the Eastern and Western blocks.
● Instead, the investigation team laid out oxidized aluminum substances as the circumstantial evidence of a torpedo explosion, and reported that these substances were discovered in eight places of the hull and similar substances were found in the North Korean torpedo parts recovered. They reported that these non-crystalline (white powder) oxidized aluminum substances are formed only at high pressure such as a torpedo explosion.
● However, based on the findings that (1) these substances were discovered on the hull composed of aluminum parts but not on other metal parts or the bodies of the crew and (2) a large quantity of oxidized aluminum was present especially on the aluminum screw, doubts have been raised by civilian experts. Some citizens showed pictures of similar oxidized substances from their own motorboat screws, raising doubts that this oxidized substance could just be of oxidized aluminum.
● They also raised the doubt over the minute amount of explosives (RDX, HMX, TNT) detected in the Cheonan warships. The doubt is that the amount of explosives found on the Cheonan is as small as that can be found in other ordinary warships, even though the amount of those explosives is more than that of aluminum in the composition of torpedo explosives.
● Furthermore, a thick layer of aluminum in large quantity covered the torpedo screw discovered but it is beyond common sense that the screw was well-preserved without damage, and it is difficult to understand that the "1번" mark handwritten with a oil pen on the propulsion section of the presented torpedo was well-preserved.
● A National Assembly person, a Democratic Party member, Choi Moon-soon raised a question based on the opinion of Professor Lee Seung-heon, one of the Physics professors at the University of Virginia, which oxidized aluminum discovered in the hull and North Korean torpedo parts was not come from an explosion.
3. Lack of evidence showing the attack was from a North Korean submarine
What is the profile of the YONO class submarine? Is it understandable that the submarine had not been followed for several days by the ROK and the U.S. surveillance?
● The Ministry of Defense is assuming that the attack was from a YONO class submarine. The only ground for assumption is that the South Korean military failed to follow up a SANG-O class submarine and a YONO class submarine along with their mother ship from a North Korean naval base for several days.
● There is no evidence, in other words, there is no specific explanation over how the North Korean YONO class submarine attacked the Cheonan. However, the explanation is just one hypothesis after another.
● The military explained that 300ton or heavier SANG-O class submarines could not be operated at the site of the Cheonan incident because of its big size and they do not have the capability to shoot heavy torpedoes.
● That was why the military presumed that a YONO class submarine was the culprit behind the Cheonan sinking. The YONO class around 120 to 130 ton submarine is smaller than the SANG-O class, in which the existence of this smaller class was reported for the first time through the final report of the investigation. However, doubts are raised because the military is mute about whether this class is capable to launch heavy torpedoes, how long they can stay in underwater, etc.
● However, the YONO class (midget) submarine is another name for the GHARDIR class owned by Iran and it is not known whether North Korea has YONO class submarines. It is confirmed that North Korea had exported YUGO class midget submarines to Iran. YUGO class submarines and P-4 class similar to the YUGO class are not capable or have limited capability to shoot heavy torpedoes.
● The Defence Minister reported on May 22 that the government had known about the existence of the YONO class submarines since 2005. However, he stated on April 2 during the report to the National Assembly that North Korea submarines does not have much underwater navigation capabilities like latest US submarines. He also stated that two submarines were not found at one of three naval bases of North Korea. However, he estimated the possibility low since the naval base is quite far from Bangryung-do. In addition, he repeatedly denied the possibility since the submarines are of low-speed type and they do not have capability of long-lasting submerge.
Why couldn't a torpedo launch be detected?
● Even if the navy could not have followed North Korean submarines with sonar, it lacks convincing power that the they could not detect an approaching torpedo with sonar because it is known that an approaching torpedo is very easy to detect with sonar.
● On this issue, the military had claimed that the Cheonan's sonar system was old so that it had only 70% accuracy in detecting torpedoes in 2Km radius and only around 50% in the 30m shallow water at the scene of the incident.
● It is also doubtful over the fact that the North Korean submarine that had probably been dispatched after the sinking of the Cheonan had escaped without being detected even by the P3C patrol aircraft equipped with advanced radars.
● There are several other questions but PSPD keeps eyes on the process of the accreditation conducted by the National Assembly, then it will raise unanswered issues.