The Bulgarian tug Silistra according to a CIA report dated 8 September 1950

An item reported that the Bulgarian shipping company Bulgarian River Navigation (BRP) at Ruse possessed the tug Silistra with a tonnage of 1.500 ton, a crew numbering 13 men and 500hp horsepower. Tow capacity 4 barges upstream the river. In the past as seagoing tug used.

Source
The report was published on www.archive.org, document number CIA-RDP82-00039R000100080032-8