Two people have been confirmed dead and 12 others were rescued after the Rocknes keeled over in the Raune fjord on Monday, plunging some of its crew into the icy waters of the North Sea.

However, 16 people remained missing on Tuesday.

In all, 30 people were on the ship when it capsized. According to Jebsen Management, the crew consisted of 24 Filipinos, three Dutchmen, two Norwegians and one German.

The 12 rescued included eight Filipinos, the three Dutchmen and a Norwegian.

"We have very little chance of finding survivors on board the ship," Ben Wikoeren, a spokesman for the Sola maritime rescue centre in southwestern Norway, said 12 hours after the accident.

"So much time has passed that there is probably not much oxygen inside the hull" of the overturned vessel, where a number of sailors could be trapped, he added.

No sign of life

The Rocknes lies capsized in the
North Sea off Norway

Rescue workers have not found any sign of life inside the vessel since 22:20 GMT when, seven hours after the ship flipped over, three survivors were pulled from the hull where they had been trapped.

After dragging the ship to shallower water, rescuers had drilled a hole in the keel after hearing the three shouting and pounding on the inside.

Another spokesman, Anders Bang-Andersen, said the search for survivors would continue.

"Our philosophy is to continue to search as long as there is a glimmer of hope, and even after that."

With the water temperature in the area hovering around five degrees Celsius, the average person's chances of surviving longer than two hours if immersed in water are slim.

Many of the missing crew members were thought to be trapped inside the hull of the ship, where they could have a better chance of survival.

Body cooling

Twelve sailors have been rescued
but 16 others remain missing

The risk of body cooling, or hypothermia, is acute at these temperatures.

Depending on factors like body weight, the average person can survive for two to three hours in water at a temperature of 10 degrees Celsius, falling to 45 minutes at zero degrees.

Officials said the rescue work was slowed by darkness, underwater currents and the freezing cold, which made the keel of the ship slippery.

The Rocknes is a 166-metre ship carrying a cargo of heavy rocks destined for Emden, in northern Germany, after loading in the Norwegian port of Eikefet.

The ship was built in 2001, and had been used since 2003 to dump rocks offshore to secure underwater oil pipelines by weighing them down.

A large oil spill was spreading around the wreck, witnesses said, as ships dispatched to the scene tried to control the spill.

Henry Bakke, a witness, quoted by Norwegian newswire NTB, said it took only two or three minutes for the boat to flip over.

The cause of the accident was not immediately known.