The ferry that collided with a barge in thick fog on Friday night, leaving 39 people injured, did see a vessel on its radar but the crew are believed to have underestimated its length.
The barge was said to have been travelling slowly and was being towed by a tugboat when it was in collision with the high-speed First Ferry III north of Cheung Chau.
Little information about the barge had emerged last night. The Marine Department believed it had been loaded with soil for dumping and was being towed by a tugboat from Kellett Anchorage No 2 towards a dumping ground south of Cheung Chau.
New World First Ferry Services, whose ferry was taking dozens of people from Central to Cheung Chau when the accident occurred at about 9.30pm, said the skipper reported seeing a vessel on radar and tried to avoid it.
It is not clear if he slowed down or tried to steer around it.
"Radar can show the presence of an object but cannot indicate its width or length," said the company's spokeswoman.
Three of the injured were initially said to be in serious condition, but by yesterday their condition had improved to stable. A further 16 remained in stable condition; the remainder were discharged from hospital.
One of the passengers said: "It was a big crash. Some passengers were thrown out of their seats."
The captain asked passengers to put on their lifejackets afterwards but managed to bring the ferry into Cheung Chau.
The Marine Department, which was broadcasting alerts about poor visibility throughout Friday night, and the police have launched an investigation.
The collision follows the ferry crash off Lamma on October 1, in which 39 people died.
The New World First Ferry Services spokeswoman said the captain involved in Friday's crash had been with the company since it began in 2000 and had many years' experience in sailing fast ferries from Central to Cheung Chau and Mui Wo.
The collision happened in a narrow channel frequented by many vessels, including high-speed boats to Macau and barges to the mainland, said Captain Tony Yeung Pui-keung, manager of the Vocational Training Council's Maritime Services Training Institute.
"Barges have to make a 90-degree turn north near Shek Kwu Chau," Yeung said. "Then they have to sail between Lantau and Cheung Chau."
He said towlines would not show up on radar and the only thing skippers could do when they had difficulty pinning down objects was to sail at the slowest speed.