Antwerp, Belgium-headquartered offshore marine contractor Scaldis used what it called a “double duo lift method” to lift a Norwegian Navy frigate submerged off the coast of Norway. The frigate, called Helge Ingstad, partially sank following a collision with an oil tanker in November 2018.
To lift it, Scaldis, in conjunction with Norwegian offshore services company BOA Offshore, used two of its heavy lift vessels: Rambiz and Gulliver. The Rambiz has two cranes and a total lifting capacity of 3,300 tonnes, while the Gulliver also has two cranes and a total lifting capacity of 4,000 tonnes. According to Scaldis, this enabled the 500 tonne, 133 metre-long frigate to be moved in one piece.
The lifting operation was carried out over six days. According to Scaldis, missiles and fuel had already been removed from the frigate while divers installed 16 hoisting chains under the wreck.
Once the frigate had been lifted into a horizontal position, it was transported by the heavy lift vessels to the nearest port, Hanøytangen, while still suspended from the crane hooks. At Hanøytangen, the frigate was placed on a submersible pontoon which was subsequently de-ballasted, allowing it to re-emerge above the waterline while supporting the Helge Ingstad at its centre, Scaldis explained. During this operation the hoisting cranes stabilised the frigate until all sea-fastenings had been secured for subsequent transport to the Haakonsvern naval base.
Picture credit: © NORSK SJØFORSVARET