By Lee Tae-hoon
Staff Reporter

As hopes are dimming over the rescue of 46 missing sailors, a host of questions have been raised over the mysterious explosion that caused the 1,200-ton Navy ship Cheonan to break in half Friday night.

The captain, Commander Choi Won-il, said the vessel broke in two five minutes after the blast, as he was assessing the situation.

The Joint Chiefs of Staff (JCS) said 60 percent of the entire ship was underwater 20 minutes after the explosion as water rushed into the body.

In this regard, Minister of National Defense Kim Tae-young said that Choi was probably mistaken as a Thermal Observation Device would have given him the wrong information, indicating that the ship was split in half before sinking.

Questions have also been raised why no new survivors, nor any bodies, have been found since 58 of the ship's 104 crew members were rescued Friday night.

Observers said fierce waves have hampered efforts to find more survivors and most of the missing personnel would have been trapped inside their rapidly sinking vessel, which consists of more than 100 compartments.

They pointed out that the lack of escape drills and the timing of the incident are attributable to the low-survival rate.

``Unless you are in Special Forces, most crewmen participate in an escape drill once or twice a year,'' a Navy officer said on condition of anonymity. ``It also appears that they panicked as the entire ship shook after the explosion, when they were either resting or preparing to go to bed.''

Another lingering question is why a nearby patrol ship fired a warning shot toward the North soon after the tragic sinking.

In this regard, the JSC said one of their ships had fired on a radar contact that turned out to be a flock of birds.

Some military experts, however, point out that the chance of firing warning shots at a flock of birds is unlikely, as the Navy's patrol ships are equipped with sophisticated radar devices.

Meanwhile, military officials were narrowing down the possibility to the vessel's collision with a rock, a torpedo attack from outside forces, including North Korea, or an internal explosion due to the missiles and explosives the ship was carrying.

The Navy plans to salvage the vessel for inspection to determine what caused the incident, a process that may take at least 20 days, officials said.

Experts say if the blast took place within the vessel, the steel of the hull should be bent outward; If a hole was made due to an external force or impact, the steel of the hull should be bent inward.

The ship, first deployed in 1989, was equipped with missiles and torpedoes, according to officials.

leeth@koreatimes.co.kr