Mission launched to avert potential catastrophe from WW1 British shipwreck

A sunken British warship is a ticking time bomb that will unleash ‘catastrophic damage’ unless action is taken, experts have warned.

The Ministry of Defence is mounting an expedition to the HMS Cassandra, which struck a mine and sank just weeks after the First World War ended.

Today, she lies in the Baltic Sea, slowly leaking oil near the Estonian island of Saaremaa, where she went down with up to 780 tons of fuel, among other pollutants.

Now, a British mission will investigate the wreck, as part of an effort to tackle some 8,500 sunken ships that are threatening ‘catastrophic damage’.

Lydia Woolley, who’s leading the campaign – dubbed Project Tangaroa – described the danger posed by wrecks like the Cassandra.

She said: ‘Potentially polluting wrecks pose a great global threat to coastal communities and marine ecosystems. Left unmanaged, they could result in the destruction of vital fishing grounds and coastal tourism.

‘This would have devastating effects on the marine environment, human health and wellbeing, as well as local and regional economies.’

Marcus Runeson, a Swedish diver who’s been down to the wreck of the Cassandra, said he witnessed oil floating up from the ship.

He said: ‘When we were on top of the wreck site, there were oil droplets coming up to the surface quite rapidly. We could see a new droplet coming up to the surface, maybe every 15 seconds.’

And oil isn’t the only risk. Marcus said the ship was equipped with a number of paravanes – a device that extends outwards from the vessel, intended to snag mines. These contain several hundred kilos of mercury.

‘From oil leakage to mercury, it’s a totally different story in terms of how dangerous it is and the environmental consequences from it,’ he added.

Hoping to spur governments into action, Project Tangaroa has now published The Malta Manifesto.

It warns: ‘We are entering a decade of severely heightened risk of catastrophic damage caused by oil from these wrecks – damage to natural and cultural heritage that cannot be fully remedied. The harm to human wellbeing and the economic cost will also be enormous.’

Leading the expedition will be the Salvage and Maritime Operations (SALMO) team at the Ministry of Defence.

SALMO boss Matt Skelhorn said: ‘With the survey of the Cassandra, we’re already putting into action the proof of concept for the Malta Manifesto. We look forward to sharing the survey outputs in due course, which will inform how we continue to work with the Estonian government to take action to prevent oil leakage if required.

‘Cassandra has the potential to become a blueprint for future international collaboration when it comes to addressing the risks caused by potentially polluting wrecks.’

Mark Spalding, president of The Ocean Foundation, said: ‘We have thousands of environmental time bombs ticking on our ocean floor, with billions in remediation costs and no dedicated funding mechanism.

‘The bureaucratic luxury of slow responses doesn’t match the environmental urgency – we need a Finance Task Force with the authority to act before 2039.’

HMS Cassandra, a C-class cruiser, was lost with 11 of her crew on December 5, 1918. Today, she lies on her starboard side at a depth of roughly 95 metres, with 20 metres of her bow shorn off.

Mr Runeson said she was otherwise preserved in excellent condition, with the advance of rust slowed by her oxygen-free environment.

Yet she would not last indefinitely, he warned. He said: ‘Sooner or later, the Cassandra will rust up totally. Sooner or later, we have to deal with it, definitely.’

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