Brushes dust off 25-year old sub

Russian navy will repair and put into service the titanium-hull Sierra-class submarine “Karp” that for the last 15-years have been laid-up in Severodvinsk.Karp" will be one of the oldest nuclear powered submarines in service with the Northern fleet when she sails towards the Barents Sea in 2016. Originally commissioned in 1987, the submarine was only in service for ten years before being laid-up in 1997. “Karp” was recently moved from her laid-up location in Severodvinsk to the Zvezdochka yard where upgrades will start, reports a naval blog site. 
Upgrade work will take three years and includes the reactor, electronics and weapons, reports Izvestia.
The hull of the submarine is made in titanium, said to be the main reason why the submarine now will be upgraded and put into service again instead of being scraped. Titanium is very expensive; therefor it is cheaper to repair such submarines than to build new ones. Titanium resists deep-water pressure better than steel-hulls and do not attract magnetic mines.
A total of six Sierra-class submarines were built in the 80ies. Two of them are still in active duty, the “Nizhny Novgorod” and “Kostroma” both based in Vidyaevo on Russia’s Kola Peninsula. Two of the laid-up ones will be re-commissioned.
A senior official in the navy’s head command says to Izvestia that the decision to re-commission the Sierra-class submarines was taken in January. “It was not a spontaneous decision, we carefully considered and concluded that repair of the vessels were more cost-effective than scrapping them.”

The other Sierra-class submarine still in operation, the “Kostroma” is next in line for upgrade. Zvezdocka officials says “Kostroma” will be repaired after the “Karp” is ready, while the navy blog site says it is possible that this repair and upgrade will take place at Zvezdockha’s branch-yard Nerpa northwest of Murmansk.
“Kostroma” made headlines in 1992 when she collided with the American nuclear powered submarine “Baton Rouge” just outside the entrance to the Kola bay.
Repairs of the hulls will not be difficult, Zvezdockha argues, because unlike steel titanium does not corrode.