In the following text, Igor Spassky, head of the Rubin Marine Engineering Design Bureau, replies to questions from kursk.strana.ru readers.

        Q: Detailed calculations and experiments were carried out before the Kursk lifting operation was set in motion. Were all the results of such work made available to Mammoet-Smit (lift contractor specialists)? Why is it that they were not in the know about something? Why is it that they had overlooked something? Why is it that they are discovering something new during the operation? For example, before the operation was started, was it not known that the space between the two hulls contained structures that needed to be dismantled? Was it not known that the outer hull had a rubber coating that would be difficult to cut? Additional equipment had to be installed aboard the pontoons for towing in the Kursk – for that purpose, the Sevmash employees had to work round-the-clock (there were even doubts that the work would be completed on time). Why wasn’t all that taken into account beforehand?

        A: All the necessary and detailed technical engineering calculations and design work were carried out in the process of compiling the Kursk salvage operation, as a result of which the technical means and technology of hoisting the sunken sub were selected.

        Rubin and Mammoet have been working in close contact since May 18 of this year (the date the contract was signed) and all decisions are made jointly on the basis of initial data provided by Rubin and tests made by the Russian side of the technical decisions proposed by Mammoet.

        That is why all the structures that were dismantled in the space between the two hulls were known not only from Rubin blueprints, but also on the basis of an actual inspection by DSND company divers (UK) of the real conditions of the structures between the hulls on the Oryol submarine, similar to that of the Kursk.

        That the outer hull had a rubber coating was also known to the Mammoet company from initial information supplied by Rubin.

        More than that, the Krylov Research Institute tested the efficiency of an instrument proposed by the Dutch NCA company for cutting the outer hull covered by a rubber coating. The results of the tests were positive.

        The pontoons made by the Sevmash plant have been designed not for towing the Kursk, but to hoist the barge+Kursk system in the waters of the shiprepair yards in Roslyakovo in order to have the required draught when placing the submarine in dock.

        The pontoons were made according to Mammoet blueprints and no additional equipment was installed on them. The Sevmash employees worked round-the-clock for the sake of finishing the job on time.

        Q: Why was the equipment for slicing off the Kursk’s first compartment tested already in Kirkenes just before going out to sea and underwater tests were not carried out at all? Had the tests been carried out ahead of time, perhaps it would have been possible to avoid the regular malfunctions and breakdowns?

        A: The machinery for slicing off the sub’s first compartment was designed and made by the Dutch NCA company on the basis of an existing model that has been used already for many years for cutting metal structures on shore.

        Taking into account the very strong steel that Kursk is made of, as well as the specifics of working underwater at a depth of 100 meters in heavy and viscous seabed soil, the design of the cutter had to be upgraded, and this work was planned and carried out by that firm in Kirkenes. The results of the tests with the upgraded cutter are positive.

        Q: Can any unforeseen difficulties emerge in the decisive stages of the operation – during lifting, towing the submarine, and what kind of action will be undertaken in the event that it becomes known that the equipment is not coping with its tasks at these stages?

        A: There can be no unforeseen difficulties in the decisive stages of the operation. Such a complicated operation as bringing to the surface a submarine with two reactors and 22 cruise missiles on board from quite a sufficient depth in the harsh weather of the Barents Sea is being carried out for the first time.

        That is why we have taken all the necessary technical and organisational measures to ensure safety during the actual lifting of the sub, as well as during the towing phase and placing it into dry dock.

        Q: Why does the safety certificate for the operation contain a proviso that foresees the possibility of the submarine turning 180 degrees? How could this happen – at least theoretically?

        A: The situation with the submarine turning 180 degrees is, of course, theoretical, more than that – it’s fantastic, such a situation is practically impossible. However, the designers of the reactors have studied such an option in detail, and as a result, they have confirmed that even in this case, the reactors would suffer no damage.

        Q: Were other options of salvaging the submarine examined (towing it on the bottom of the sea to shallower water, pumping the water out of the compartments, towing it with the help of pontoons, etc.)? Why was this option given preference? Have such methods of raising sunken vessels been used in world practice?

        A: During the year since the Kursk went down, we have examined a great number of variants of lifting it, including those that have just been mentioned. As a result of analysing all the variants we examined, we chose the most reliable, the safest and most economical method that ensures the salvaging of the sub this year. Such a method of raising a submarine from the sea bottom has not yet been used in world practice.

        Q: Why has the operation been set for September, when the Barents Sea is ridden by storms, rather than July when the weather is more favourable?

        A: The deadline for the lifting operation – September – was not set, it was determined after a detailed study of the whole technological chain of the work that had to be done – designing, experimental, construction and sea-related operations.

        Q: How much time was required to complete the blueprinting part of the lifting operation? The international consortium that was initially supposed to carry out the operation refused to participate in it due to the unrealistic tight deadlines. How was it that these deadlines became so tight – did it take too long to plan the operation or was it that the international consortium was contacted too late?

        A: The international consortium refused to lift the sub in 2001 and proposed postponing the operation till 2002. That is why beginning with April, we began working with Mammoet on the actual lifting of the Kursk.

        This is what has been done to the present day – development of the lifting project, upgrading of the Giant-4 barge, manufacturing of the pontoons, completion of the cutting unit, testing of equipment at the Krylov Institute, cutting of technological holes in the submarine’s hull. All these jobs were done by specialists working practically round-the-clock in the course of 3.5 months.

        Q: Does the project take into account the complicated weather conditions in which the operation is to be carried out?

        A: The complicated weather conditions have been taken into account analytically in the calculated strength reserve coefficients of the structures and marine technical facilities participating in the operation.

        Q: Is there a possibility of leakages of oil products still remaining in the vessel while it is being lifted and towed? What measures are to be taken to prevent this?

        A: A small leakage of the onboard oil products is possible. Special oil collecting vessels will be on hand to prevent the spreading of the oil slick during the operation, beginning with the hoisting and ending with its being put into dry dock.

        Q: Are you proceeding according to the initial lifting schedule?

        A: On the whole, the initial schedule for preparing the lifting operation is being carried out in full, and in certain areas, I would say we are even ahead of schedule. Nonetheless, it must be admitted that at certain stages there were delays that were due to outside factors. That is why the procedure of performing this or that job was changed. In such cases, changes and supplements were introduced to the initial plans. Moreover, all decisions were adopted within the framework of the endorsed schedule.

        ends