Project 949A Antei nuclear-powered ballistic missile K-226 Orel will undergo modernization in 2013, a source in defense ministry told Izvestiya. It is planned to put a shaft line removed fr om perished SSN Kursk in 2001.
In addition, shaft line of the second propeller will be replaced as well. According to Izvestiya, it will be taken from a non-completed submarine of the same project.
An insider in defense industry told Izvestiya that "when Orel was laid down in 1989, both shafts driving the sub's propellers consisted of separate parts attached to each other by bolts and coupling joints. All parts must be solid, just like in Kursk, but shaft parts of Orel are hollow. Siliceous sand was put inside. According to designers, such shafts were supposed to be as robust as solid ones, and be lighter, more silent, cheaper, and easier in manufacturing". As for the source, "the hollow shafts needed light-weight screws. Unfortunately, designing of new screws terminated with the breakup of the Soviet Union, and in 1992 the sub was launched with new shaft lines but old heavy propellers. Problems started right after commissioning into the Navy. Shafts critically distorted at attaching points and began rubbing against the hull".
"As a result of that friction, when accelerating under water, the sub was making a specific sound clearly heard by Russian and foreign sonars. The shaft defect made Northern Fleet command lim it the submarine's operational zone. Although Orel did not leave the Barents Sea her detection was very easy. That is why, in 2001 it was decided to take solid shafts from Kursk which had been lifted and dismantled by that time", writes Izvestiya citing the insider.
According to the newspaper, "except for renewed propulsion, K-226 will receive a new data system, navigation aids, communication facilities, and sonars. The submarine's attack capability will be also improved, obsolete Granit antiship missiles will be replaced with new supersonic Onyx ones".