The November 2018 collision that resulted in the submersion of €500m Norwegian navy frigate Helge Ingstad could have beneficial implications for future salvage operations, as Belgian salvage specialist Scaldis lifted the vessel using a unique Double Duo Lift method.
Scaldis, the Belgian subsidiary of Deme, Jan De Nul Group and Herbosch-Kiere, in cooperation with BOA Offshore, successfully completed the salvage of the Norwegian frigate last Sunday March 3rd.
Scaldis developed a radical lifting method especially for the project by combining its two heavy lift vessels Rambiz and Gulliver.
On November 8th 2018 Helge Ingstad collided with tanker Sola TS in the vicinity of Bergen and sank on the inclined slope of a fjord.
The lifting method combined its two heavy lift vessels: the Rambiz was equipped with two cranes and a total lifting capacity of 3,300 tonnes, while heavy lift vessel Gulliver, also with two cranes, had a total lifting capacity of 4,000 tonnes.
The combined total lifting capacity of 7,300 tonnes made it possible to lift the 133 metre, 5,500-tonne frigate in one piece.
The synchronous functioning of the four cranes allowed the lifting of the wreck and the adjustment of it into a horizontal position in a single operation. To lift the frigate safely and completely out of the water, it was transported to the nearest port while hanging from the crane hooks of the heavy lift vessels. On arrival she was placed on a submersible pontoon. This partially submerged pontoon was subsequently de-ballasted, allowing it to re-emerge above the waterline while supporting the Helge Ingstad at the centre. During this operation, the hoisting cranes stabilized the ship until all sea-fastenings had been secured for later transport.