Scientists Say Direct Heavy Torpedo Sank Cheonan

A team of scientists believes that the Navy corvette Cheonan sank after being hit by a heavy 206 kg torpedo that ran at a speed of 65 km/h.

Bae Myung-jin, a professor at the Sound Engineering Research Lab of Soongsil University, on Thursday said his team analyzed data about the seismic waves generated at the time of explosion of the Cheonan, which were provided by the Korea Meteorological Administration and the Korea Institute of Geoscience and Mineral Resources. "As a result, we presume that the torpedo ran at the Cheonan at the speed of 65.7 km/h and exploded underwater 2.3 m from the ship with power equivalent to 206 kg of TNT."

He said heavy torpedoes with a payload capacity of 200 kg are usually 7 to 8 m long. The explosive is stored not in the head but in the rear part 1 to 6 m away from the head. Thus even if the head hits the hull, the explosion normally occurs a few meters away from the ship.

"After the initial explosion, it was observed that a series of internal explosions occurred in the stern for about 80 seconds," he said. That suggests the Cheonan was not hit by a bubble jet, as previously assumed, but received a direct blow from a gunpowder explosion.

The team concluded that the ship was probably hit by a Chinese-made 206 kg-class Yu-3 heavy torpedo.