Fears that the South Korean ferry sinking accident could become one of the country's worst maritime disasters in two decades have been rising as rescue operations are protracted.

The seventh day into search on Tuesday, 302 people have been left dead or missing for long. Though 174 people were rescued shortly after the passenger ship Sewol sank on April 16, there have been no survivors or survival signaling reported since.

A maritime accident tended to turn catastrophic as most passengers face hypothermia resulting in death amid the prolonged or delayed rescue operations.

Divers began entering and searching inside the submerged vessel from Monday, but it led to a surge in death toll. At least 87 people have died, with 215 others still missing. On Monday alone, 28 bodies were retrieved from the ferry.

Hopes were fading among family members of the missing as growing bodies were pulled out of the vessel amid the protracted rescue operations.

For the first five days since the disaster took place, divers had troubles in prying their way into the hull as the site of the accident is famous for the country's second-fastest currents. Chilly and murky waters hampered underwater rescue operations as well.

Five guideline ropes were snaked Monday into cabins and convenience facilities inside the ship, enabling divers to follow along the lines and get there at a much faster than before. It helped with rescue efforts.

Such geographical features and climatic conditions may prolong and curtail the rescue period, but human errors have been the main cause of the delayed rescue and, subsequently, led to the deadliest consequences.

The 6,825-ton Sewol ferry departed around two and a half hours later than scheduled from the country's western port city of Incheon, where other ships delayed their departures due to a heavy fog.

The ship, which was built in Japan in 1994 and had no accidents for 18 years there, was modified by the ship's operator to expand passenger cabins and raise the total capacity including crew by 116 people to 956.

The 476 passengers aboard the ship were nearly half the maximum capacity, but it was offset by an overloaded cargo. The vessel was loaded with 180 cars and trucks and 1,157 tons of freight, far exceeding the reported figure of 150 vehicles and 657 tons of goods respectively.

The ferry, which was en route to the southern resort island of Jeju, capsized and sank in waters off Jindo Island, the notorious area in the country for swift currents. When the ship began tilting heavily to one side, captain was not at the helm and the wheel was handed over to the third mate who conned the ship in the waters for the first time.

The most decisive factor was negligence of duty from some crew members, including the captain who abandoned the vessel and belonged to the first group saved when the ferry tilted so heavily that passengers were unable to move.

If he ordered passengers to leave the ship earlier and help save passengers, the rescued should have been by far higher than now.

The human errors resulting in maritime catastrophes have been seen intermittently in South Korea. The latest case was the " Seohae" ferry sinking accident that claimed 292 lives among 362 passengers.

The passenger ship capsized and sank in the country's southwestern waters in October 1993 as it set sail despite warnings of strong wind. The vessel was loaded with excessive cargo more than doubling the maximum capacity, and passengers on board surpassed the limited number by 141 people. The ship was also modified illegally.

The "Namyoung" ferry sinking accident, the country's worst maritime disaster, killed over 320 people in December 1970. The ship was upturned and submerged in waters for overloaded cargo and passengers. The vessel was on a voyage from Jeju Island to the southern port city of Busan at that time.