Russian Navy Yasen Class SSN Yasen class submarine (Russian: Проект 885 "Ясень", "ash tree"), also known as the Severodvinsk class, is a new Russian nuclear multipurpose attack submarine class. The submarine is based on the Akula-class submarine and the Alfa-class submarines and are projected to replace Russia's older Soviet-era class attack submarines both Akula class and Oscar class. Construction on the first submarine started on December 21, 1993. In April 2010 it was reported that the 7 May launch of the first boat had been postponed due to 'Technical Reasons'.On June 15 the first submarine was rolled out of its building hall. Plans call for the submarine to be in service by late 2010 or early 2011.