British warship sunk in WWII still leaks oil

Fresh way of separating oil from water

By Michael Boyd, LPS Special Correspondent

The problem of mopping up bunker oil leaking from a sunken British warship has led to a compromise solution between the British Royal Navy (RN) who wish the wreck to remain an undisturbed war grave, and environmentalists worried about the possible effects on local wildlife.

For 60 years the remains of the once mighty HMS Royal Oak have lain untouched, a grave for the 883 men who died when the battleship was sunk in the waters of Scapa Flow near the island of Orkney, off the coast of Scotland. Ever since the night in October 1939, when torpedoes from a German U-Boat ripped into her sides as she was moored, fuel oil has steadily trickled out across the surface of the water. In recent years, the problem has risen as the thousands of tonnes of oil still in the corroding hull threaten a potential environmental disaster.

The oil mopping technique may help prevent an environmental disaster similar to the Amoco Cadiz spillage off the coast of Brittany in 1978, one of the worst instances of oil pollution in history. Photo - "PA" News

As with most problems, it has two sides. The ship is one of the UK's major war graves, honoured annually by the RN and the islanders in a remembrance service when divers hoist a white ensign flag on her stern. But not far offshore, the wreck poses a menace to Scapa Flow's large seal population and several species of rare birds. While respecting the crew's memory, conservationists want the oil removed as quickly and safely as possible. With this dilemma uppermost in their minds, the specialist and experienced engineers from the RN's Environmental Unit at Bath, western England, are conducting a unique operation that they hope will remove the oil without needing to cut open the war grave.

Divers will attach a steel umbrella costing £20,000 to the upturned hull to trap the oil before bringing it to the surface where it will be removed each month. It is estimated that the wreck will be empty by 2014. This novel solution came about when Roger Tollervy, the project's director, realized that it was the natural action of the tide and winds that was already pushing the oil to the surface.

The wreck was first examined by RN divers gathering samples of the leaking oil ready for laboratory analysis. To do this, they rigged a temporary tent over the leak and funnelled the oil droplets into a container. Mr. Tollervy realized that if a structure could be put in place above the hull, the oil would float into it. He asked his engineers to develop a permanent version using natural force rather than pumps, to collect oil that is circulating within the hull. He spent two years on the plan after retrieving the ship's plans from the National Maritime Museum in London, to create a three-dimensional computer model. This allowed the team to assess the structure without entering the hull. Divers later established that oil was escaping through holes created by shrunken rivets.

"The hull is surprisingly strong and is more sound than we expected," he said. "Our extensive structural surveys now judge the hull life to be at least 50 years. Although the superstructure is badly corroded, no oil is stored there. The bunker oil in the main hull is leaking slowly at an average of four litres per hour.

"At the moment, this does not represent an environmental hazard as it is dispersed by the natural action of the ocean. If nothing were done, the oil would seep out for a maximum of another 15 years, assuming a constant flow rate and the maximum amount of oil."

Conservationists, anxious to protect Scapa Flow's seals and rare birds, would prefer a quicker solution. "It's a time-bomb," said Eric Meek, an officer with the Royal Society for the Protection of Birds (RSPB). "The ship is lying less than half a mile offshore and at this time of year, Scapa Flow is an area of major importance for Arctic wintering birds."

Sharing this concern is Bob Moore, director of Orkney Islands Council Harbours, who said: "It's a compromise but hopefully a speedier solution can be arrived at in time." The RN Project team are mindful of these concerns and so, once the canopy has been proven to be satisfactory, it will then considerably accelerate the flow using taps fixed to the rivets. Later, it will also investigate other ways of safely increasing the recovery rate.

In the remote event of any of this oil coming ashore in sufficient quantities to cause shoreline pollution, the RN have back-up and expertise at a huge oil terminal located on the island.

For details, contact Steve Willmot, PR Office, HM Naval Base Clyde, Faslane, Scotland, UK. Tel: +44 1436 674 321, Fax: +44 1436 811 066.