The Czechoslovakian CSPD motor tug Polona active on the Danube according to a CIA report dated 29 June 1955

An item dated 5 may 1955 reported the Czechoslovakian CSPD (Ceskoslovenska Plavda Dunajska) motor tug Polona on the Danube off Budapest, Hungary towing 6 empty barges downstream.

Source
The report was published on www.archive.org, document number CIA-RDP80-00810A007200560007-7