The Soviet SDGP tug Chasan active on the Danube according to a CIA report dated 10 June 1955

An item dealing with the Danube shipping movements reported that on 24 February 1955 was sighted on the position DKM 1820 the SDGP (Soviestkoye Dunasikoye Gosudarstvennoye Parokhodstvo) tug Chasan while towing loaded and empty tankers downstream.

Source
The report was published on www.archive.org, document number CIA-RDP80-00810A007000090002-6