A blue flag, with a white horizontal band crossed by a red vertical band. The letters "M S Coy" are spread across the white band, with the "S" placed on the red band.
The Melbourne Steamship Company was formed in 1895 from a merger of three shipping companies.
According to articles in The Log (Nautical Assn. of Australia) the white and red bands were broad and the lettering was "MSCo" not "MSCoy" with the "o" not being enhanced although an illustration in Marine News 7/1970 shows it being enhanced. This publication shows an image in black and white and does not specify the lettering colour, showing it, like Sampson, in black. The Log is more specific giving the "M" and "Co" as blue and the "S" as white and portrayed as being slightly larger though it is noted that a company menu, and possibly an actual flag, are known to have shown all blue lettering.