The Shetland Oil Disaster: Experts puzzled by flooding of fuel tanks ship's fuel tanks

QUESTIONS were being raised last night over how sea water could have flooded the Braer's fuel tanks, disabling the ship's engines and leaving it to the mercy of the wind.

Ulthie Roldan, the senior engineer, said the ship's boiler and generator had failed to fire because of water in the fuel tank. But maritime engineers said it would be almost impossible for a vessel the size of the Braer to be rendered helpless by fuel contaminated by seawater.

Two senior experts said they had never heard of circumstances in which both of a ship's fuel tanks could be rendered useless. Neither engineer would be named, but one said: 'I have been on board vessels when one tank has been flooded, but there are always at least two tanks and I have never heard of two or more being contaminated at the same time. This is very puzzling indeed.'

It is commonplace for some water to enter fuel tanks via the goose-neck air outlets on the decks of all ships. These are pipes that allow air out of fuel tanks when oil is pumped into them. They protrude from the deck and turn 180-degrees so that they point downwards.

The most senior of the two engineers said: 'Some water can get in, but it is usually drained off at the bottom of the tanks. There are also usually extra settling tanks and the generator is usually fed by a different source from the boiler.

'For a tank to be flooded, water would have had to have breached the whole height of the vessel, rolled across the decks and then up into the gooseneck pipe.

'I have never heard of it happening with a vessel the size of the Braer. And it would be most unusual for both tanks to be rendered useless.'

He said the last major incident caused by contaminated fuel was the sinking of the freighter Union Star in December 1981. Eight crew members died after the vessel sent out a distress signal and all eight men of the Penlee lifeboat crew died trying to reach the remaining crew members.

'But the Union Star was much smaller than the Braer,' he said.

The Braer was built by Oshima Shipbuilding in Nagasaki, Japan, in 1975. It is a single-engined vessel with a dead weight of 89,730 tons and is 241.5m (792ft) long. It was registered with the Norwegian classification society Det Norske Veritas in 1985 and has an exceptional record, according to Kris Lunde, DNV spokesman in Oslo.

It had to undergo rigorous, five-year surveys and annual inspections, but DNV inspectors - who are the equivalent of Lloyd's shipping register officials - made no recommendations for improvements.

Mr Lunde said: 'Its last periodic survey was carried out in July 1989 and its last annual inspection was in May of last year. If our inspectors find anything that could improve seaworthiness, they make what is known as a recommendation. We never found cause to make any recommendations. This was a very good ship.'

Norman Hook of Lloyd's Maritime Information Services said the vessel had never been involved in a shipping casualty. Michael Thorp, a director of Oslo-based Skuld Protection and Indemnity insurers, which will pay for the clean-up operation, said it was a 'sound ship managed by a sound and responsible company'.

Mr Thorp said the ship's owners, the Braer Corporation, had insurance with Skuld of up to dollars 500m (pounds 340m), with a further dollars 200m (pounds 136m) elsewhere. 'This is a very prudent company,' he said. 'There is no doubt that we will be paying out because the situation at the moment is that if oil comes from your ship, then you are liable.'

Skuld has sent a team of experts to the scene and Mr Thorp said it had commissioned the services of the International Tanker Owners' Pollution Federation, a research body based in London, financed by the oil industry and headed by Dr Ian White, a marine biologist.