[Viewpoint] Dispelling skepticism and suspicionThe submerged stern of the Navy corvette Cheonan broke the sea’s surface for the first time and was towed to shallow waters after being mired in the seabed for more than two weeks.
As a former Navy officer, my heart sank and then brimmed with rage at the devastating sight of the wreckage. The military then fully hoisted the wreckage onto a barge yesterday. The authorities should do their utmost to determine the cause of the explosion as a small comfort to the victims and their families.
On hearing the captain’s testimony that the ship was torn into two after an ear-piercing blast, I suspected the ship must have been sunk by an underwater explosive shock from a torpedo or mine. Otherwise a 1,200-ton warship could not have been so easily halved and sent to the sea’s dark and deadly floor.
My conviction hardened on seeing pictures of the wreckage. The cannons on the rear were undamaged, again discounting a theory that the blast may have come from an explosion inside the ship.
For example, if artillery exploded on deck or inside the hull, there should have been burn traces from fire. But none were found.
The furnace’s destruction suggests the explosion must have occurred from waters below the basement engine room. Unlike other compartments in a warship, the ceiling structure between the lower deck and furnace of the engine room is relatively weak due to boilers and other machinery. So the furnace may have been blown off from the explosive shock.
If a ship is directly hit by an explosive, the blow can create a fire and make holes, but it rarely causes the ship to go down instantly. It took six days for a British Royal Navy ship to sink after it was hit by a guided missile from an Argentine ship during the Falklands War in 1982. A U.S. Navy frigate in the Persian Gulf was struck by a missile fired by an Iraqi warplane in 1987, but did not sink.
But if an explosive is detonated some distance away from the ship, it can create the so-called bubble jet effect, or a pillar of water resulting from the difference of water pressures. The pillar is strong enough to send the ship into the air and then rip it apart. Surviving crew members and guard soldiers on nearby Baengnyeong Island testified that they heard two massive blasts in a row, an indication of a typical underwater explosive.
In 1999, I led my submarine crew in the Rim of the Pacific Exercise. Our target was the 10,000-ton cruiser the U.S.S. Oklahoma City, which was decommissioned in 1979. We had to choose between the strategies of a direct hit on the cruiser or the use of pressure to down it.
We chose the latter and launched a self-contained torpedo that can be triggered when it senses magnetic force. The torpedo exploded beneath the center of the ship where the magnetic force is the strongest, causing just the kind of damage we desired. I remember the explosion from the torpedo propelled the Oklahoma City into the air and tore the ship in two.
The Cheonan was also halved in the middle. Therefore, it is highly likely that a torpedo fired from a submarine or mine destroyed the ship.
It’s hard for a ship cruising on the surface to detect an approaching submarine. Underwater pressure is as hard as rock. A plane can smash into pieces when it falls into an ocean or sea.
Radar cannot always detect submarines deep in murky, high-pressure waters. Sound waves are the only technology to detect vessel movements. But their reach is limited as ocean pressure and temperature differences can hamper sound propagation. During the Falklands War, the British mobilized radar and sonar technology to detect underwater enemy movements from air and sea, but all failed to find their targets.
Stealth is the main feature of a submarine. Under the United Nations maritime law, a naval submarine must rise to the surface and hoist its national flag before entering another country’s territorial waters.
Once the wreckage is fully salvaged and dissected in a comprehensive probe, we will be able to learn the exact cause and means of the attack.
The government and military must not repeat their indecisive and incredible response displayed in the first few days following the accident. We will also need to wait patiently for the investigation results.
The spread of speculation and conspiracy theories on the Internet over the sinking must be reined in. The authorities must also fully disclose the salvage progress and investigation results in order not to exacerbate public distrust.
They should disclose the two parts of the Cheonan so that the people can see the wreckage with their own eyes.
Otherwise, skepticism and suspicions of a cover-up are bound to persist.
*The writer is a maritime researcher at the Korea Institute for Defense Analysis and a former Navy submarine captain. Translation by the JoongAng Daily staff.
by Jung Sung
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