Complex sentence: The heavy lift vessels "Beluga Fraternity" and "Beluga Foresight" did commence a passage of the Northern Sea Route, however they were escorted by the Russian nuclear icebreaker "50 Years Since Victory".
Split into simpler sentences: The heavy lift vessels "Beluga Fraternity" and "Beluga Foresight" did commence a passage of the Northern Sea Route. But they were escorted by the Russian nuclear icebreaker "50 Years Since Victory".