The Dutch company Mammoet in cooperation with Smit International is going to salvage the Russian nuclear submarine Kursk that sank last year. Mammoet will carry out the lifting work and Smit International all underwater work. The salvage of the Kursk is being detailed:
1) A special pontoon (The Giant) wwas fitted in Amsterdam with 26 strand jacks, each of which can lift up to 900 tonnes. The pontoon is 140 meters long and 36 meters wide. A section was be cut out to make room for the Kursk's conning tower. The modifications will take about seven weeks to complete. The pontoon left for the Barents Sea when fully modified.
2) Divers removed the seriously damaged bow of the Kursk and cut holes in its hull. They worked at a temperature of between 0 and 6 degrees Celsius. The Russian Navy together with the submarine's designer, Rubin, determined the exact location of the holes based on the design of the submarine's interior. The holes were cut using water jets by means of high-pressure water and abrasives. The Kursk's bow was cut free and left on the seabed so that the rest of the vessel could be lifted as a compact load.
3) When the Kursk was fully prepared, the lifting cables (each made up of a large number of thinner cables) was lowered from the pontoon and anchored in the holes in the Kursk using large steel plugs. The plugs have arms that unfold under the beams and the inner skin to provide a firm anchorage. Each of these attachment points were tested at about twice the necessary force before the submarine was raised.
4) When the weather permited, the submarine was raised to just below the pontoon. The lifting was precisely controlled, centimeter by centimeter. The force on each bundle of cables was set individually to minimize the tension on the Kursk's hull. The strand jacks will each pull bundles of 54 thinner cables (strands) by means of two telescopic cylinders. The impact of the swell of the sea was reduced by heave compensators so that the force exerted on the attachment points on the Kursk is constant. Computers installed with comprehensive back-up systems controlled the entire lifting process.
5) Now that it has been raised, the Kursk is being towed to Murmansk hanging in serrated clamps. On arrival, the Giant/Kursk combination will be lifted by auxiliary pontoons in order to sail it into a dry dock.