Three stamps of Belarus have the same ship on a stamp, which is depict in the municipal arms of the town of Polotsk. https://en.wikipedia.org/wiki/Polotsk
The municipal arms of Polotsk (Vitebsk region) represents the image of a baroque shield on the blue ground of which there is a gold three-mast ship with unfolded silver sails floating on silver waves.
The 1985 stamp shows a portrait of Simeon of Polotsk (1629-1680) and in the background the coat of arms of the town. https://en.wikipedia.org/wiki/Symeon_of_Polotsk
The type of ship on the coat of arms looks if it is a cog, Polotsk was an important trading town with the Hanza towns in the Baltic.
Belarus 1992 2r sg 3 scott11. 1995 1800r sg 134, scott 137. 2017 N sg?, scott?