Complex sentence: In 2009, the boat "Serafim Sarovsky" was built, which was a continuation of the series of communications boats, the construction of which engaged the C3 JSC Severnaya Verf from 2001.
Split into simpler sentences: In 2009, the boat "Serafim Sarovsky" was built, as a continuation of the series of communications boats. Construction engaged the C3 JSC Severnaya Verf from 2001.