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On August 12, 2000, a catastrophe occurred onboard nuclear submarine ‘Kursk’ (K-141) of Project “Antey”   (Oscar II) during exercises of the Northern Fleet. All submarine crew was lost as a result of this accident.

 SSN ‘Kursk’ has sank as a result of the torpedo ammunition explosion inside the compartment and was found on  13 August to the west of cape Teriberka, in 108 miles off the Kola Bay at the depth of 115 to116 m in the point  with co-ordinates 69°37'00'' N and 37°34'25'' E.

 Russian submarine experts will work alongside Scottish and Norwegian specialists on the vessel,  which has a crew  of around 80, a British naval source said.
 
 Earlier story Norwegian diving ship en route to Kursk nuclear submarine wreck .OSLO, Norway (AP) -  A  Norwegian-owned diving vessel was en route Monday toward the wreck of the Russian nuclear  submarine Kursk.  Salvage operations could start next week, its owners announced.

 From August 13 through 19 the sunken submarine was inspected during the rescue operation by manned submersible vehicles of the Northern Fleet and on August 20 - 21 by deep divers from Norwegian vessel "Seaway Eagle". More detailed survey of the submarine was continued at the end of September by means of deep-diving manned vehicles “Mir-1” and “Mir-2” from research vessel “Academik Mstislav Keldysh” and in October - November by unmanned submersible vehicles and divers of Norwegian company Halliburton AS from vessel “Regalia”.

Upon instructions of the President of Russia V.V.Putin the Governmental Commission chaired by the Deputy Chairman of the Russian Government I.I.Klebanov was established for investigation of causes of the submarine ‘Kursk’ sinking.

The Government of the Russian Federation assigned CDB ME “Rubin” the task of arrangement of “preparatory works for recovery of bodies of perished sailors from the nuclear submarine ‘Kursk’ and her salvage”. “Rubin” was entrusted this task as it is known as an enterprise with highly qualified engineering personnel who knew in details special features of submarine structure and who had necessary knowledge of modern salvaging methods and techniques. The enterprise was assigned to carry out negotiations (if required) about the salvage works with foreign companies.

The general management of the submarine salvage design was carried out by General Designer and Head of CDB ME “Rubin”, Academician of RAS, I.D.Spassky.

For co-ordination of works on the project and for operative solving of all technical and organisational issues raised in the process of work a Working Group of designers was established. I.L.Baranov, General Designer of the ‘Kursk’, headed the group. This group included also specialists from Krylov Research Institute, 1st Central Research Institute of the Russian Defence Ministry and 40th Research Institute of the Russian Defence Ministry.

In the process of the detail design development of the ‘Kursk’ salvage the about 10 variants of the sunken submarine salvage was reviewed.

 At the same time over 500 technical proposals were considered that were sent to the enterprise from other enterprises and individuals as well as from many foreign companies and firms.

Nevertheless, none of the reviewed variants provided the possibility of the submarine lifting in 2001. The overwhelming majority of proposals made by national and foreign companies and institutions, groups and individuals was not acceptable because the authors of proposals did not have required information about design features of the submarine, her actual status after the accident and conditions of the operation.

  Taking into account the fact that the period assigned for the operation was very short, there were no marine         technological means for the lifting from the depth over 100 meters of such a large size and displacement object     as submarine ‘Kursk’, the lifting could be performed only by means of existing equipment of foreign companies.

 Therefore the Russian side negotiated with several foreign companies and as a result Dutch company            Mammoet Transport Antilles N.V. was selected. The company management expressed the willingness and      confirmed the possibility to carry out the ‘Kursk’ salvage operation with involvement of a number of foreign   companies.

Destruction of the pressure hull in the first compartment and forward portion of the second compartment, loss of the overall strength of hull structures in the submarine forward part did not allow to lift the entire submarine. In this connection the decision was taken to cut out the destroyed compartment of the submarine.

This operation was executed using equipment of Dutch company Smit International (Mammoet’s partner) based on initial data provided by CDB ME “Rubin” and with their technical support.

 The general finally implemented plan of the submarine lifting and transportation was as  follows.

 Required lifting forces were created by hydraulic strandjacks (5) installed onboard the  lifting and transport barge (3). By means of these strandjacks the submarine was broken  off from the seabed and smoothly lifted to the surface in controllable manner.

 For the period of transportation the submarine was pulled by additional force to special  saddles (11) installed on the barge bottom. These saddle shapes repeated the submarine’s  superstructure lines. Special recess (10) was made in the barge bottom in order to locate  the submarine mast fairwater inside the barge hull. Hoisted masts of the submarine were  cut out prior to the lifting. The same hydraulic jacks that were used for the lifting created  the additional pulling force.

Lifting forces were transferred to the submarine hull (1) from hydraulic strandjacks (5) through strands (2) (a bundle of steel wires of special design). Grippers were fixed in holes (14) preliminary cut out between two frames in the upper part of the submarine pressure hull.

The calculation made by the enterprise designers determined that it was necessary to have 26 lifting points to apply forces required for the submarine breaking off from the seabed, lifting and transportation without loosing contact with the barge saddles (11).

Such a lifting method used for the first time in the ship salvage history could be implemented only due to high load carrying ability of the submarine pressure hull.

The scheme of SSN lifting after the separation from the bottom (a) and during the transportation (b)

For execution of all stages envisaged by the design it was necessary to create and use a whole complex of salvage equipment and crafts of both Mammoet and its contractors and the Northern Fleet of the Russian Navy.

This complex included barge “Giant 4” (Smit International) with the installed lifting system (Mammoet),  barge “Carrier” with equipment for the first compartment cutting out (Smit International), Diving Support  Vessel “Mayo” (DSND), tugboats: seagoing tugs contracted by Smit Maritime Contractors BV (‘Smit Wijs  Singapore’, ‘Atrek’ and ‘Havila Charmer’) and harbour tugs of the Northern Fleet; additional buoyancy  pontoons (Mammoet) specially constructed on PA “Sevmash” for the docking operation; floating dock PD-50  (Northern Fleet), crane ships “Paltus” and 7500 (Northern Fleet), rescue tug “Altay” (Northern Fleet), pontoons  SSP-80 and SSP-200 (Northern Fleet).

Beside these facilities the lifting operation was supported by escort, weather observation and radioactivity monitoring ships, aviation, auxiliary vessels and crafts of the Northern Fleet of the Russian Navy.