Hundreds still missing in South Korea's ferry sinking(2)

Helicopters fly above a sinking South Korean passenger ship in water off the southern coast in South Korea, April 16, 2014.(Xinhua/Newsis)

CAUSE UNCLEAR

It was still unknown why the ferry sank in apparently calm waters. Divers sent down to the wreck are looking to check whether there is a submerged rock and if the ship has a hole in its hull.

There were reports saying the ship have veered off course. However, the Chonghaejin Marine Co Ltd, the registered owner of Sewol, said it did not deviate significantly.

The ferry's original captain who had gone on vacation was replaced by a substitute surnamed Lee, who the company claimed is a veteran with eight years of experience on the Incheon-Jeju Island route.

The ship was not equipped with a voyage data recorder because it was a coastal ferry that sails relatively short distances, according to local media.

Sewol, which travels twice a week between Incheon and Jeju, was built in Japan in 1994 and could carry a maximum of 921 people, 180 vehicles and 152 shipping containers.

No irregularities were found on the ship during a safety check in February.