A REMARKABLE marine operation has taken place off the coast of East Lothian.

The largest construction vessel in the world – Allseas’ Pioneering Spirit – could be seen off the county’s coast for much of the weekend.

The 382 metres long and 124 metres wide vessel transferred its huge cargo of a topside drilling platform onto the 200-metre-long barge the Iron Lady on Saturday.

The following morning, the Pioneering Spirit, which was specifically designed for the single-lift installation and removal of large offshore platforms, separated from the Iron Lady and the cargo barge was towed clear.

The Pioneering Spirit then set off once more for the North Sea.

Pioneering Spirit (right) and Iron Lady could be seen by many on East Lothians coastline over the weekend. ..Picture: Peter Devlin.

Pioneering Spirit (right) and Iron Lady could be seen by many on East Lothian's coastline over the weekend. ..Picture: Peter Devlin.

The operation caught the attention of numerous people along the county coastline, from Prestonpans and Cockenzie and Port Seton along to North Berwick and Dunbar.

Stuart Wallace, chief operating officer at Forth Ports, said: “It was a truly spectacular sight to see this huge vessel offloading its cargo within our deep water on the River Forth.

“Watching the Iron Lady towed safely into the Port of Rosyth by our tugs against the backdrop of all three Forth crossings was a bit special too.

“However, we can expect to see sights like these more and more frequently as oil and gas decommissioning projects from the North Sea and elsewhere gather momentum.

“The Forth Estuary’s deep and sheltered water, alongside the decommissioning facilities on both the River Forth and River Tay, make this an ideal location for operations like this weekend’s.”

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With its cargo safely secured to its deck, the Iron Lady was then towed westwards along the River Forth by Forth Ports’ tugs, the Craigleith, Inchkeith and Fidra in a carefully planned operation to ensure the structure had sufficient clearance to go below the Forth Bridge, Forth Road Bridge and Queensferry Crossing before berthing alongside at the Port of Rosyth. It is scheduled to remain moored at the Port of Rosyth for about six weeks before being towed back east to the Energy Park Fife in Methil, where its cargo will be unloaded for decommissioning.