As more evidence surfaces about the sinking of the Navy corvette Cheonan on Friday, speculation is increasingly focusing on a possible attack from one of the North Korean semi-submersibles reportedly operated by crack teams and capable of carrying two torpedoes or mines.

Semi-submersible vessels weigh less than 300 tons and are smaller than submarines. The waters where the Cheonan sank are only 20 m to 30 m deep and difficult for North Korea's mainstay 1,800 ton Romeo class submarines to negotiate. North Korea allegedly uses the semi-submersibles when transporting spies on infiltration missions into South Korea. These flat boats approach coastal waters remaining mostly submerged under water and disappear completely under water as they near the coastline, which makes it extremely difficult to detect them. Defense Minister Kim Tae-young told lawmakers on Monday the semi-submersibles can fire two torpedoes and did not rule out that such a vessel may have attacked the Cheonan.

Kim Hak-song, the head of the National Assembly's Defense Committee, stoked speculation by saying he had heard that North Korean semi-submersibles left their base around that time, but high-ranking military officers said the claim is unfounded.

A North Korean semi-submersible carrying two torpedoes (marked)

South Korea and the U.S. monitor North Korean submarine bases in the West and East seas with American KH-12 reconnaissance satellites, U-2 spy planes and South Korean Kumgang reconnaissance aircraft. If several North Korean submarines disappear at once, South Korea's Navy raises its alert level because submarines, mini-subs and semi-submersibles are capable of delivering the fastest attack against South Korean and U.S. forces.

There is speculation that the Cheonan came so close to Baeknyeong Island in response to intelligence showing that North Korean mini-subs or semi-submersibles had crossed into South Korean waters, but the Defense Ministry denied this as well.

In addition to sharing nuclear technology, North Korea is also believed to be cooperating with Iran in the development of underwater weapons and may have had help from Tehran in developing cutting-edge torpedoes. North Korea's Navy has around 70 mini-subs and a large number of semi-submersibles. Around 20 are believed to be stationed at a naval base near Baeknyeong Island.

go to the home page to the top