The organisation of the Bulgarian navy according to a CIA report dated 13 November 1952

An item reported that the Bulgarian Black Sea Fleet commanded by frigate captain Paraskevov had her headquarters at the harbour town Varna. It consisted of a surface ship division commanded by frigate captain Stefan Nikolov stationed at Varna and a submarine flotilla, the latter with her headquarters and command at Ochakov, USSR [=Ukraine].

Source
The report was published on www.archive.org, document number by CIA-RDP83-00415R012700120006-1