S. Korea: Torpedo Attack Likeliest Cause of Shipwreck

Military authorities believe that a strong external shock was the reason for the sinking of the Navy corvette Cheonan, on March 26, with a torpedo, mine or depth charge the most likely to generate enough impact. The most likely suspect is a torpedo.

Torpedoes and mines attack from under the surface of the ocean, while depth charges are thrown into the water from airplanes or ships to hit submarines. Torpedoes travel between 60 km/h to 70 km/h powered by propellers and can hit targets that are between hundreds of meters to tens of kilometers away. Torpedoes also use sonar detectors to zero in on their targets.

In contrast, mines have no propulsion mechanisms and simply await their targets while floating on the surface of the ocean or submerged. They either collide with unsuspecting ships or are drawn to vessels by the sounds of their propellers or their magnetic fields. This causes floating mines to have a much smaller attack radius than torpedoes.

Depth charges are limited in terms of their targets or methods of attack compared to torpedoes or floating mines. They simply explode due to underwater pressure after sinking into the depths.

If any of the depth charges that were stored at the rear of the Cheonan had exploded, the blast could not have caused the vessel to split in half. And the absence of any suspicious aircraft or vessels near the South Korean Navy corvette at the time of its sinking rules out the possibility of depth charges being used against it.

There are two possibilities regarding a mine. One is an accidental collision and the other is an intended attack. There is no chance that a mine left over from the 1950-53 Korean War had been floating around for 60 years until it hit the Cheonan. And mines laid near Baeknyeong Island around 1975 to prevent a landing by enemy forces have all been deactivated, Defense Minister Kim Tae-young told lawmakers on Friday. It is highly unlikely that a North Korean mine had simply floated south, since that would be completely opposite the direction of the currents in that area, and officials say it would have been far too difficult for North Korea or another enemy to set a floating mine there so that it would eventually make contact with the Cheonan because the corvette sank in an area where it only traveled 15 times before and which is more frequently used by fishing boats.

Even if torpedo fragments are found at the site of the sinking, it would still be very difficult to determine the mode of attack. Two North Korean mini-submarines were unaccounted for during March 24 and 27, but it remains unclear whether this may have any direct link to the Cheonan, government and military officials said.

http://english.yonhapnews.co.kr/national/2010/04/05/31/0301000000AEN20100405008700315F.HTML

Quote: On Monday, Rep. Kim Hak-song, chairman of the parliamentary defense committee, told reporters that the defense minister was referring to two 325-ton "shark-class" submarines, but that it was unclear whether the submarines crossed into South Korean waters. The lawmaker cited a briefing by the Joint Chiefs of Staff.

(2nd LD) Seoul requests Washington's help in probing sunken navy vessel

SEOUL, April 5 (Yonhap) -- South Korea said Monday it has requested help from U.S. experts in probing a naval ship that blasted apart near the tense sea border with North Korea last month, as President Lee Myung-bak called for a thorough and scientific investigation.

The move underscores government efforts to defuse speculation and unfounded allegations surrounding the March 26 sinking of the 1,200-ton corvette Cheonan following a mysterious explosion. One of the 104 crew members has been confirmed dead, while 45 others are still listed as missing. The other 58 were rescued.

In a radio address earlier in the day, President Lee said "accuracy is more important than speed" in determining the cause of the disaster, adding that officials should conduct a thorough investigation of the sunken ship.

"I believe technical support from U.S. experts will be helpful in carrying out an unbiased analysis of the incident," said Gen. Lee Sang-eui, chairman of Seoul's Joint Chiefs of Staff during his meeting with U.S. Forces Korea Commander Gen. Walter Sharp on Monday.

Sharp said Seoul and Washington "will work very closely together to ensure that the current operations are completed."

"The United States will continue to provide technology, equipment and manpower needed to assist the salvage operations," he said.

South Korean officials said earlier in the day Washington has "answered positively" to Seoul's request for help.

Although South Korea has been cautious about presuming what caused the late night explosion 11 days ago, speculation about North Korea's involvement has been flaring largely because the ship sank near the scene of a total of three deadly naval skirmishes between the two Koreas in 1999, 2002 and last year.

North Korea, still technically at war with Seoul as the 1950-53 Korean War ended in a truce, does not recognize the western sea border that was drawn by the United Nations at the end of the war, claiming that it should be redrawn further south.

But Pyongyang has remained silent about the sunken ship.

Seoul's Defense Minister Kim Tae-young last week said a torpedo or floating mines could be possible causes. Kim also told a parliamentary hearing that two North Korean submarines disappeared from South Korean military surveillance March 24-27, though he said the link was "weak."

On Monday, Rep. Kim Hak-song, chairman of the parliamentary defense committee, told reporters that the defense minister was referring to two 325-ton "shark-class" submarines, but that it was unclear whether the submarines crossed into South Korean waters. The lawmaker cited a briefing by the Joint Chiefs of Staff.

The South Korean military has been dogged by allegations of cover-up due in part to its perceived reluctance to disclose information deemed key to finding out what exactly happened on the night of March 26. Fueling those allegations were discrepancies in the time of the explosion, changed several times by officials -- from 9:45 p.m. to 9:22 p.m.

On Monday, the ministry stressed that the latest information is accurate, saying that sailors aboard the Cheonan used the phone as late as 9:20 p.m.

U.S. ships and military divers have been taking part in unsuccessful efforts so far to rescue sailors believed to be trapped in the rear section of the vessel.

During risky underwater operations in the tough Yellow Sea, a South Korean military diver lost consciousness and died.

After finding one body Saturday, the South Korean navy officially called off the rescue operations at the request of families of the missing.

A 2,000-ton sea crane to be used to recover the wreckage arrived Saturday near the scene, and a 3,600-ton crane is on the way.

A total of four giant cranes and three barges will be used to lift the front and rear sections of the sunken corvette from the seabed, according to navy officials.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Two Possible Suspects