Hong Kong rescuers were Tuesday reportedly preparing another attempt to reach 18 Ukrainian sailors believed trapped in their sunken ship, although hopes are slim there is anyone still alive.
A senior fire officer said they had located an entrance near the deck of the tug boat after getting plans showing the layout of the vessel, which sank Saturday night in waters off Hong Kong's international airport, local radio RTHK said.
He said divers would try to gain access when the tide turned later in the day. The officer said poor visibility was hampering efforts to find the crew of the Naftogaz-67, which was stuck upside down on the sea bed at a depth of 37 metres (120 feet).
Marine Department officials have said the crew's only chance of survival would be if they had found an air pocket but admitted they had so far found no signs of life despite repeated dives to the sunken vessel.
Department head Roger Tupper on Monday said medical experts had indicated the missing sailors might survive around 12 hours in an air pocket. Tuesday night would mark 72 hours since the tugboat sank.
Divers carried out numerous sorties and knocked repeatedly on the hull to try to see if there was any sign of life.
"We haven't had any response from within," Tupper said. "We have not been able to ascertain where these 18 missing seafarers are at the moment."
A team of 20 experts, including representatives from the tug's Ukrainian owners, was expected to arrive in Hong Kong Tuesday to assist in the rescue operation, RTHK said.
The tug had 24 Ukrainian crew and one Chinese sailor aboard when it collided with a Chinese cargo ship on Saturday. Six Ukrainians and the Chinese sailor were rescued.
If the sailors do not survive, it would be the worst marine disaster for decades in Hong Kong, one of the world's leading ports and maritime centres.
Tupper said rescuers were struggling with the fact that the boat was overturned, meaning the hatches and deck were embedded in the sea floor -- and that it was extremely cold and dark down at that depth.
The tug was detained in Hong Kong five years ago for an inadequate escape system, local media reported Monday.
Ukraine's ambassador to China, Serhiy Kamyshev, visited the wreck site on Monday to observe rescue operations.
The captain, who was among those rescued, reportedly blamed the Chinese ship for the collision, saying it had refused to give his tug the right of way.
The Naftogaz-67 had reportedly been operating since 2002 for the Swiss company Fortranse Ltd in the South China Sea between China, Singapore, Malaysia and Indonesia. (AFP)
Hong Kong rescuers hope to enter sunken ship