What Was a Cog Ship?
The cog was the workhorse of the Hanseatic merchant fleet, and it was the ship that the League used to build its commercial dominance. The cog was a single-masted, square-rigged vessel with a high, blunt bow, a flat bottom, and a single deck. The cog was developed in the course of the thirteenth century, and it was a significant improvement over the older Viking-style vessels that had been used in the Baltic in the early Middle Ages.
The workhorse of the fleet
The cog’s high sides and flat bottom made it stable in heavy seas, and its single square sail made it easy to handle with a small crew. The cog was also capacious: a typical cog could carry 100 to 200 tons of cargo, and the largest cogs could carry up to 300 tons. The cog was, in effect, the first ship that could carry large cargoes across the open sea, and the cog was the foundation of the League’s commercial dominance.
The cog was developed in the shipyards of the Wendish towns, and it was used principally for the trade of the southern Baltic. The cog’s flat bottom made it ideal for the shallow waters of the Baltic, and its high sides made it suitable for the often stormy waters of the North Sea. The cog’s principal disadvantage was its dependence on wind: in calm weather the cog could not move, and in the narrow waters of the Baltic it sometimes had to be towed by rowboats.
Cog as warship
The cog was, in the first instance, a merchant ship, but it was also used as a warship. The League’s fleet of cogs was, in the late thirteenth and fourteenth centuries, the largest naval force in northern Europe, and the fleet was used to enforce the League’s embargoes, to suppress piracy, and to defend the League’s interests in the wars with Denmark and Burgundy. The cog’s high sides and flat bottom made it stable in battle, and its single square sail made it easy to handle in the confined waters of the Baltic.
The hulk takes over
The cog was gradually replaced, in the course of the fifteenth century, by the hulk, a larger and more versatile vessel that could carry more cargo and that could be used in the long-distance trade of the Atlantic. The cog, however, continued to be used for the coastal trade and the river trade, and the cog remained an important part of the Hanseatic merchant fleet until the late Middle Ages.