Floating dock PD-16 with diesel submarine B-380 in it sank in Sevastopol, Russian Navy Base, Black sea, early in the morning Dec 15. Submarine was decommissioned in 2016, Naval dock PD-16 was also decommissioned. Later submarine surface in sank dock, see photos.
Russian (Soviet) Navy Tango-class diesel submarine B-380 (Gorgorvskiy Komsomolets), Project 641B known as the Som (Catfish), displacement 4600 tons, complement 76, sea endurance up to 90 days, commissioned in 1982, armament torpedoes and mines.
Navy PD-16 Floating Dock was commissioned in 1941, date of decommission unknown.