Soviet shipyards started in 1934 with building inland paddle wheel steam tugs according to the CIA report called Soviet River Shipbuilding and vessel classification dated around 1955

For the report was the book Osnovy Teorii i Ustroystva Sudov Vnutrennego Planiya of A.P. Strakhov dated 1955 used. An item reported that in 1934 in the Soviet Union was started with the building of inland paddle wheel steam tugs similar to the (1.200 ihp) ones built between 1930-1934 although the hulls were now welded again in stead of riveted. In 1955 called the Leninets series.

Source

The report was published on www.archive.org, document number CIA-RDP80-00809A000700260105-5