* Rescue efforts resume on Thursday morning
* About 290 people still missing, many of them teenagers
* Parents blame government, say not enough help and information
Coastguard and navy divers were diving into the waters at the site of the accident, about 20 km (12 miles) off the country's southwestern coast, searching for any sign of the 290 missing people. The vessel capsized on Wednesday during a short journey from the port of Incheon to the holiday island of Jeju.
Grieving parents accused officials of being slow to react and for lack of information.
"I am really angry with the government," said Kwak Hyun-ok, whose daughter who was one of 340 children and teachers from one school on the vessel.
"There is no meaning to life without my daughter," Kwak told Reuters.
Of the 475 passengers and crew on the vessel, nine were listed as dead and 179 had been rescued, according to the South Korean government.
The government said three cranes were being moved to the site of the accident and would arrive on Friday, although efforts were continuing to establish whether there were any survivors on the stricken vessel.
Media reports said submersibles were pumping oxygen into the hull, although the coastguard declined to comment.
There is still no official explanation for the sinking. The ship, built in Japan 20 years ago, was following a well travelled route. Although the wider area has rock hazards and shallow waters, they were not in the immediate vicinity of its usual path.
State broadcaster YTN quoted investigation officials as saying the ship was off its usual course and had been hit by a veering wind which caused containers stacked on deck to shift.
One parent, Park Yung-suk, told Reuters at the port of Jindo where the rescue efforts are centred that she had seen the body of her teenage daughter's teacher brought ashore earlier in the morning.
"If I could teach myself to dive, I would jump in the water and try to find my daughter," she said.
DESPERATE SEARCH FOR ANSWERS
The vessel was listing heavily to one side on Wednesday as passengers wearing life jackets scrambled into the sea and waiting rescue boats.
It sank in roughly two hours and witnesses and local media showed that just one life raft from the ship successfully inflated and launched.
Witnesses told Korean media that the captain of the vessel, who is now being held by police, was one of the first to leave the stricken vessel.
Chonghaejin Marine Co Ltd, based in Incheon, issued a brief statement via local media apologising for the accident but has made no further comment.
As frustration grew, some parents of missing school children hired their own boat on Wednesday night. They appeared to blame the government of President Park Geun-hye and rescue officials for not making a big enough effort.
"Since the government refused to take us to the scene, 11 parents chipped in 61,000 won ($58.79) each to hire a boat and took a reporter and a diver. But there was no rescue operation going on," said one father who declined to give his name.
According to a coastguard official in Jindo, the waters where the ferry capsized have some of the strongest tides off South Korea's coast, meaning divers were prevented from entering the mostly submerged ship for several hours.
The ship has a capacity of about 900 people and an overall length of 146 metres (480 feet). Shipping records show it was built in Japan in 1994. ($1 = 1037.6500 Korean Won)