The South Korean prime minister resigned on Sunday over the government’s handling of the ferry which sunk with more than 300 people on board.
Chung Hong-won said he did not want to be a a “burden on the administration”.
Relatives had criticised the slowness of the recovery operation.
On Saturday four more crew members were arrested, bringing the total to 15. They are accused of negligence and failing to help passengers when the boat went down on April 16.
One of the helmsmen, Oh Yong-seok, made a public apology.
“I am very sorry to the relatives of the victims in that I was not able to do all my duties as one of the crew members,” he said.
Divers have recovered 187 bodies so far and 115 people are still missing, feared dead.
Most of the victims were students from one high school in the town of Ansan, in the south of Seoul.
More than 100 divers are working to rescue those missing. Efforts are being hampered by strong tidal currents and murky water conditions in which divers can barely see in front of them.