DLO get coveted Blue Peter badge

If you were watching Blue Peter on 3 March 2006 you will have seen Mark Gaskell explaining to Blue Peter presenter Matt Baker, and millions of viewers, how the DLO is helping clean up the environment in the Orkney Islands by removing oil from the Second World War wreck, HMS Royal Oak. Matt was clearly impressed with his experience; he was able to get a rare glimpse of the wreck on the seabed. Mark Gaskell describes how it all came about:

"Christine Lake, our Corporate Business Manager, knows Alex Leger, one of the Blue Peter producers, and when they heard we were doing an operation to remove oil from the wreck in summer 2005, they were keen to come along and film," he said.

"Matt, the presenter, was dressed in full diving kit and lowered in a cage to just below the water line to see the work. Because Matt is a qualified scuba diver anyway, he was really interested in what we were doing and he thoroughly enjoyed the experience. Blue Peter getting involved was good for us as it shows the public the diverse nature of the work we do. There’s now a large Blue Peter badge outside our office to remind us of the experience."

The oil onboard Royal Oak when it sank has been slowly leaking from cracks and holes in the upturned hull ever since. Because of the wreck’s status as a war grave, where diving is normally forbidden, work on the wreck has to be done sensitively and with minimal intrusion. Mark explained how the Salvage and Marine Operations (S&MO) team have been tackling the problem:

"In the early 1990s the oil leakage became worse and we needed to reduce the impact of a catastrophic failure of the hull, and the resulting oil spill. The consequences of a large oil release would be very damaging to the local Orkney environment.

After we experimented with a few different techniques to contain the oil, we decided to remove the problem rather than contain it.

"We chose to use a process called hot-tapping, which involves fitting valves in strategic places on the hull, allowing oil to be extracted from within the wreck without releasing any into the environment. Using divers, a hose is then attached to the valve and the oil is pumped to the surface into a barge."

It all sounds quite straightforward, but there are complications that need to be taken into account. There are a number of explosives still onboard, which are very sensitive, and the team has to be very careful not to disturb these. Also, the exact configuration of the internal tanks is based on research of other ships in her class, as all Royal Oak’s drawings were destroyed many years ago.

The tanks immediately inside the hull contained about 50 per cent of the oil and the hot-tapping process has extracted the majority of this. However there are inner tanks that could hold anything from 900 -1,600 tonnes of oil. In summer 2005, when Blue Peter visited, the S&MO team began to tackle these:

"The inner tank boundary construction is thinner than the outer hull and it had been predicted that this boundary may have wasted over the years, allowing the oil contained within the inner tanks to migrate into the hot-tapped outer tanks," explained Mark.

"This would have meant the majority of the remaining oil could be removed over time using the hot-tap valves. However, our yearly visits to the wreck proved it wasn’t happening.

"We’d removed very little oil, indicating that the tank boundaries were relatively sound, and relying on oil migration alone would be a lengthy and expensive process. Alongside Briggs Marine Contractors Limited, we developed and trialled a cutting tool capable of penetrating the inner tank boundary from the existing hot-taps. This would enable the oil to flow from the inner tanks and be collected from the outer, hot-tapped tanks.

"During 2005 the tool was trialled and one single penetration resulted in over 180 tonnes of previously inaccessible oil being recovered. This was a great boost to the project team and during 2006 we’ll return and try to remove more.

"The wreck is monitored and surveyed regularly to monitor any movement or deterioration. We have to take our time extracting the oil in order to keep any disturbance to a minimum. However, we need to get the oil out sooner rather than later because eventually the wreck will deteriorate and any intervention will become more dangerous.

"Each time we visit Scapa Flow, we learn a little more about the wreck and the process of extracting oil and we often contradict what we thought we knew before. We need to ensure the environmental risk remains as low as possible but we don’t want to weaken the structure."

The team will be carrying on with this work for the foreseeable future, and new technology is emerging all the time which can help them better understand what is happening with the wreck.

Mark continued: "We’re going to do a survey of the wreck in May using a newly developed survey system. This will give us a really clear digital picture of the wreck as it is, showing any cracks that are forming in the structure, and a good idea of how the vessel is lying on the seabed. The wreck is very stable and sturdy considering her age, and the survey will help us reduce any risk; we must always remember it is a war grave."

Alex Leger, who has been one of the Blue Peter producers since the early 1980s, arranged for the Blue Peter team to be at the site.

"The story of HMS Royal Oak is one of enormous importance and access to the site is severely limited'" he said. "Only very lucky television programmes are given access, so Blue Peter jumped at the chance to work with the DLO on the programme.

"The activity of removing oil from the Royal Oak is an interesting and important one because of the environmental issues associated with it, so we were keen to see how the exercise went. It was also important it was done sensitively because it's a war grave. The hot-tapping method is very interesting and the whole exercise looked very efficient.

"We were delighted that the divers allowed Matt to go down in a protective cage to see the work being carried out. It was a fantastic experience for Matt and he enjoyed it immensely. He made good friends with the divers and it was a great pleasure working with such a nice bunch of lads."

Facts about HMS Royal Oak and Scapa Flow

• HMS Royal Oak is 600 feet long and weighs 29,000 tons.
• Scapa Flow, in the Orkney Islands, off the northeast coast of Scotland was the UK’s most northerly naval base. It was believed to be impenetrable.
• Winston Churchill, when announcing the disaster, reluctantly admitted the German U-boat commander Lieutenant Gunther Prien’s operation was “a remarkable exploit of professional skill and daring.” 
• Each year, on the anniversary of the disaster, Royal Navy divers replace the white ensign at Royal Oak’s stern and hold a memorial service. 
• In 1940 it was decided to build permanent barriers to protect Scapa Flow. These became known as the Churchill Barriers and were mostly built over four years by Italian prisoners of war on Orkney.
• Scapa Flow also contains the wrecks of eight scuttled German warships, HMS Hampshire, which was carrying Lord Kitchener when it sank in 1916, HMS Roedean, which sank in 1915, and HMS Vanguard, a warship which sank due to an internal explosion in 1917. All are diveable wrecks apart from HMS Royal Oak and HMS Vanguard where diving is strictly forbidden.