The F22 in the image is about 7 diagonal pixels long, that is √2⋅7 pixels length. The ship in the picture is 1727 pixels long, which equates to an actual length of almost exactly 3300m.
As a bonus this allows us to calculate the barrel-diameter: At 14 pixels width, this indicates a 27m diameter or a barrel-strength of a bit over 12m. Not sure if that is enough to contain the nuclear explosion that is mean to be fired inside it…
Die Putinistenpartei ist nicht demokratisch? Oh, nein! Anyways…