Highlands & Islands

How do you remove an oil rig stuck on a beach?

Image copyright AP

The Transocean Winner oil rig ran aground during a storm on the Isle of Lewis. But how do you remove it? Salvage expert Taggart Smith spoke to the BBC about what might happen next.

Who will be involved in the salvage operation?

Key discussions on strategy will be taking place between the underwriters of the insurance company and the rig owners.

The next step will involve employing a specialist contractor which has experience in sea salvage operations.

Taggart Smith, a salvage expert from maritime engineering company Henry Abram & Sons in Glasgow, said: "They will go out and look at the wreckage and decide what has to be done in order for it to be removed."

He added that the experts would have to factor in minimising the environmental impact and keeping safe those employed to work on the wreck.

What will be the first task of the salvager?

Surveyors, under instruction from a team of engineers, would look to see if there is a puncture in any part of the structure.

The rig has 280 tonnes of diesel oil onboard and Stornoway Coastguard has blocked access to Dalmore beach where the rig is stuck.

Mr Smith said one aim would be to see what potential environmental impact there could be in removing the wreck.

He added: "They will asses if there could be a spillage of oil or other chemicals stored on board the vessel or whether or not the vessel is stable."

Mr Smith said that once the assessment is done it was likely a specialist contractor would be brought in to "strengthen or patch up" the vessel or look to "ballasting or floating" the rig back up.

Once the rig is stable what will happen next?

Put simply, tugs would be brought in to remove the structure. It would be towed to a shipyard for repair or decommissioned.

Mr Smith explained: "I would expect one or two tugs on standby during the process to monitor the wreckage to make sure it doesn't move any further."

How long will the process take, days, months or even years?

At this stage it is very difficult to say what the timescale would be.

For a very straightforward operation you could be looking at days or a few weeks.

For something more complex, it depends what condition the oil rig is in and what the risks of removal could be.

Mr Smith said that in the worst case scenario the operation could last months or even years.

He added: "A good example of that is the Costa Concordia that was grounded off Italy.

"She stayed there for nearly two years before she was removed. But that was because of extensive engineering and construction works that had to take place in order to get her stable and floating and safe to remove."

Could there be a situation where the rig is never removed?

Mr Smith said: "I would expect it would be remove, and the owners would then need to decide whether to scrap it or to repair it.

"The owners and insurers will make that decision based on cost.

"There have been cases where wrecks have been left on a reef - in such circumstances that is down to cost and risk, with perhaps it becoming too risky to remove the wreck or it becoming too expensive to remove the wreck."

How much will it cost?

That is a difficult question to answer, says Mr Smith.

He added: "I would say very expensive, it is really difficult to put a price tag on it.

"Certainly I would expect it would be in the region of millions, by how many millions is impossible to say at this stage."

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