Rescuers optimistic as they face the unknown

The small team of British rescuers travelling to the Kursk is clinging to the lingering hope that some of the 118 crew of the Russian submarine stranded on the bottom of the Barents Sea will still be alive.

The small team of British rescuers travelling to the Kursk is clinging to the lingering hope that some of the 118 crew of the Russian submarine stranded on the bottom of the Barents Sea will still be alive.

"We have got to be optimistic. There is always a chance," said Commander Alan Hoskins of the rescue team. "We were told yesterday there were signs of life."

Despite this optimism, the three-man crew of the LR5 mini-submarine face a difficult task with potentially fatal risks. Six days since the Kursk was crippled by what is believed to have been at least one explosion, details about the precise conditions they will encounter remain scarce and confused.

The LR5 crew know they face strong currents, poor visibility, the risk that the submarine's air is poisoned, and the danger that its external hatch could open with explosive force due to the likely pressure within the Oscar II-class vessel.

The LR5 has never carried out a "live" rescue mission before. The rescue team is due to arrive at the accident site late this afternoon, after setting sail from Trondheim in Norway at 8.30am yesterday morning on board the Normand Pioneer, a specialised salvage ship.

Despite criticism of the decision to choose a port 36 hours away from the site, Ministry of Defence officials said Murmansk airport was unsuitable for an Antonov aircraft, and that the Normand Pioneer was the most suitable vessel available in the region. It carries its own camera-equipped submersible remote operated vehicle and it has the mechanism needed to lower the LR5 overboard.

Once they arrive over thesubmarine, the LR5 crew will be joined by three Russians - two technical crew and a doctor who specialises in submarine-related illnesses.

Any survivors could be suffering from hypothermia, dehydration, starvation, carbon dioxide poisoning and the bends - the potentially fatal illness caused by sudden changes in atmospheric pressure.

Russian video footage has shown that the damage extends from the Kursk's nose to its coning tower. Despite initial reports suggesting it was listing at 60 degrees or more, the Russian navy has confirmed that the Kursk, lying roughly 108 metres (357ft) below the surface, is listing at only 20 degrees on its starboard side.

For its first trip down, the LR5 is expected to carry air tanks, breathing apparatus for the crew, specialised air-cleaning equipment and medical equipment.

Despite fears that the hatch could only be opened internally, the Russians have released technical drawings which show that the British team should be able to enter the vessel.

"We're confident we can enter the sub without personnel inside," said a Royal Navy source yesterday. "We would be overjoyed if the hatch was opened of its own accord by survivors and they came clambering into the LR5."

The Russians have warned that currents are running at 2.5 knots, which is as great as the LR5's top speed. For optimum operation, the LR5 needs to dock with the submarine in currents of less than one knot.

The three Russians are expected to be first on board the Kursk, but it is unclear whether the hatch can be depressurised. If its pressure is much higher than the normal atmospheric pressure of the LR5, it could blow open suddenly, allowing contaminated air into the rescue compartment.