Announcing the results of its monthlong probe, a panel of investigators involving military officers and experts concluded that the mooring line was overstretched, though the ropes themselves bore no problems.

The Navy also failed to take enough appropriate measures to prevent such an accident, and it did not give first aid promptly to the wounded, according to the investigators.

"In order to prevent any recurrence, we will strengthen related safety regulations and boost training and education for those in charge of managing the mooring equipment for vessels," the Navy said in a release.

The Navy also plans to reprimand those responsible for the accident, including the captain of the vessel.

At the time of the accident, a welcome ceremony was being held to mark the safe return of the vessel and officers after its six-month anti-pirate mission in waters off Somalia as part of the Cheonghae Unit. (Yonhap)