The Hansa cog design on this stamp is a reconstruction of a Hansa cog of 1470 made by Busley and the drawing was made by von Svoboda an accumulation of ships in it book Historische Schiffe.
Mostly the cog was a one masted vessel but the later types were larger and carried two and three masts, the latter have a lateen mizzen sail. Length on the waterline 20m, width 7.20m.
The fore and main mast had a platform for archers.
Bulgaria 1977 1St sg 2597, scott2431. The photo shows a model of a Hansa cog around 1470.
Bulgaria 1984 3lev sgMS 3151, scott?
Isle of Man 1982 19½p sg217, scott 213.
Source: Navicula Enzyklopadie schiffe und Seefahrt.