MANILA, Dec 26, 2009 (AFP) - Divers in the Philippines were to attempt to reach the wreck of a sunken passenger boat Saturday while rescuers kept up their search for 23 people still missing after the accident, officials said.
      
The coast guard divers were to use specialist deep-sea equipment to enable them to reach the wreck of the Catalyn B, a flimsy, wooden vessel that sank on Thursday in Manila Bay and now lies in 67 metres (220 feet) of water.
     
While officials said they feared the bodies of the missing may be trapped inside the boat, surveillance aircraft and rescue ships were still combing the waters off the Philippine capital in search of any survivors.

"The rescuers still have not given up hope. That is why it is still a SAR (search and rescue operation)," said a coast guard official, who asked not to be named.
      
Four people were killed when the Catalyn B, which was taking holidaymakers to their home village on a small island off the mouth of Manila Bay, smashed into the far larger Anathalia, a metal-hulled fishing boat, on Thursday.
      
The passenger boat went down within minutes while the Anathalia was impounded by authorities. Forty-six survivors were fished out of the water on Thursday, along with bodies of the four people known to have died.
      
The coast guard had not attempted to reach the Catalyn B previously due to the depth of the wreck but were now able to try using specialist equipment.
      
However officials warned that they would have to assess whether it was safe to enter the sunken vessel and that it may not be easy to determine if there are any bodies trapped inside.
      
Ships and aircraft involved in the rescue effort have widened the scope of their search but had so far only found personal items such as slippers and diapers, another coast guard official said.
      
The cause of the accident was still unknown and there had been no reports of mechanical trouble or bad weather prior to the collision.
      
A formal inquiry is expected to begin within a few days.
      
The Philippines experiences frequent shipping accidents, usually involving poorly-maintained, overloaded ferries, which are the backbone of travel between the archipelago's islands.
      
The world's deadliest peacetime maritime disaster occurred south of Manila in 1987 when a ferry laden with Christmas holidaymakers collided with a small oil tanker, killing more than 4,000 people.