Divers working against odds to reach trapped seamen
Decompression risks, poor visibility and strong current make it tough to penetrate upturned hull, officials say
Professional divers and fire service officials cited low visibility in the water and strong currents for difficulties in the rescue operation involving the Ukrainian tug that sank off Tuen Mun.
Stephen Au Siu-kin, of the Professional Association of Diving Instructors, said the water at the scene was murky and visibility low.
'It is difficult to search for survivors in such circumstances,' the diving coach said, adding that strong currents made it even harder.
Divers had, by late last night, been unsuccessful in penetrating the upturned hull of the Neftegaz-67 - which sank 37 metres after colliding with the China-registered Yaohai cargo ship on Saturday night - and reaching anyone who might be alive inside.
Mr Au, who has 15 years' diving experience, said divers could stay only about 20 minutes at that depth.
'It is so dark and murky underwater. Divers could easily be cut by the wreckage and something inside the ship might collapse any time,' he said.
'They cannot dive for too long each time or they will suffer from decompression sickness, which can lead to shock and possibly death.'
Fire Services commanders said any underwater rescue attempt was difficult and dangerous.
Chow Wing-tak, chief fire officer (Hong Kong Island, Islands and Marine Command), agreed that his divers could stay underwater for only 20 minutes because they faced decompression problems.
'The rescue mission is difficult because the water is turbulent and visibility underwater is poor,' Mr Chow said. 'The strong current also pushes our divers away from the wreck.'
Mr Chow said the current had been even stronger than usual on Saturday because it was the middle of the lunar month and a full-moon night.
Director of Fire Services Lo Chun-hung said an attempt was being made to lift the tug and drag it into shallower water so divers could work on it underwater without facing decompression risks.
Fire Services division commander (Marine and Offshore Islands) Wong Chung-shing would not speculate on the chances of finding more survivors.
'When the boat turned upside down, there might have been some air trapped in the cabins,' he said. 'The seamen could rely on the air in the cabins for a while, depending on the number of people and the volume of air.'
Crew members were believed to be in cabins and the engine room at the time of the accident.
Divers had received no response to attempts to communicate with anyone who might be trapped, Mr Wong said.
'We can only send two divers to work underwater each time,' he said. 'If we send too many divers, their breathing tubes might get tangled. That would be very dangerous for them. Also, the water current is too strong and the entry into the boat is too narrow.'
Divers were first deployed about midnight on Saturday. 'We could not locate the boat with information given to us from the marine police as the strong water current had swept it 400 metres from the site where the collision occurred,' Mr Wong explained. 'We had to rely on the Marine Department to help us locate the boat.'
Government Flying Service assistant manager Lo Yiu-wah said helicopters had made four sea searches for survivors but had found nothing.
'Visibility was only about 2 to 4km. It was very poor,' he said.
The search had also been made more difficult because it was at night.
'Two inspections were conducted in the morning, and we could only see some debris floating in the sea.'