<p>The Russian Navy will refit, modernise and recommission two Sierra class (Project 945) titanium-hull nuclear-powered attack submarines by 2017.<br /><br /></p>.<p>The Zvezdochka shipyard said the Sierra class has a light and strong titanium pressure hull, enabling the vessels to dive to depths of up to 550 metres and enhancing their survivability, as well as having a low magnetic signature.<br /><br />A total of four Project 945 and 945A submarines were built in Russia.<br /><br />In addition to the Karp and the Kostroma, the Pskov and the Nizhny Novgorod were built in the early 1990s and are currently in service with the Northern Fleet.<br /><br />The K-239 Karp (Carp) was the first Project 945 (Barrakuda) submarine, which entered service with the Soviet Navy in 1984.<br /><br />The K-276 Kostroma was commissioned in 1986 and had to be repaired after a collision in February 1992 with the American submarine USS Baton Rouge (SSN-689) while on patrol off Kildin Island near Severomorsk.<br /><br />The US Navy said the collision occurred more than 22 km from shore, in international waters.<br />The shipyard signed a modernisation contract for the Karp and the Kostroma with the defence ministry in December 2012, a Zvezdochka official said.<br /><br />Karp has been sitting at the shipyard since 1994, he said, adding the submarine's titanium hull "is in a very good condition" but a significant part of its equipment is missing.<br /><br />The submarines' sonar and navigation systems will be replaced and their reactors refuelled, he said.<br /></p>
<p>The Russian Navy will refit, modernise and recommission two Sierra class (Project 945) titanium-hull nuclear-powered attack submarines by 2017.<br /><br /></p>.<p>The Zvezdochka shipyard said the Sierra class has a light and strong titanium pressure hull, enabling the vessels to dive to depths of up to 550 metres and enhancing their survivability, as well as having a low magnetic signature.<br /><br />A total of four Project 945 and 945A submarines were built in Russia.<br /><br />In addition to the Karp and the Kostroma, the Pskov and the Nizhny Novgorod were built in the early 1990s and are currently in service with the Northern Fleet.<br /><br />The K-239 Karp (Carp) was the first Project 945 (Barrakuda) submarine, which entered service with the Soviet Navy in 1984.<br /><br />The K-276 Kostroma was commissioned in 1986 and had to be repaired after a collision in February 1992 with the American submarine USS Baton Rouge (SSN-689) while on patrol off Kildin Island near Severomorsk.<br /><br />The US Navy said the collision occurred more than 22 km from shore, in international waters.<br />The shipyard signed a modernisation contract for the Karp and the Kostroma with the defence ministry in December 2012, a Zvezdochka official said.<br /><br />Karp has been sitting at the shipyard since 1994, he said, adding the submarine's titanium hull "is in a very good condition" but a significant part of its equipment is missing.<br /><br />The submarines' sonar and navigation systems will be replaced and their reactors refuelled, he said.<br /></p>