During the Middle Ages, trade in the Baltic Sea was spearheaded by the German Hanseatic League. The Hanseatic League used flat-bottomed cargo ships called cogs. They were between 18-26 meters long. The bottom part of the hull was carvel planked, but the high sides the planks shifted to clinker planking. The cog lacked a keel and could easily sail into shallow harbors or beaches. The cogs held a lot of cargo. A medium-sized ship could load 80 tons, the largest up to 150 tons.
The cogs only had one mast with a raw sail and were therefore dependent on the right winds. In bad weather, they had to find anchorage in sheltered coves and natural harbors. The old harbor site in Kuggviken is named after the cogs. On the southern shore there is an old, 20 meter long stone quay preserved. It has been possible to moor ships at the quay about 500-600 years ago. The quay testifies to lively connections with the outside world. Notes from the Stockholm customs register in 1533 mention nine skippers from Korpo in freight shipping between Stockholm and Reval (Tallinn), Narva and Riga.
The Korpo skippers used cargo ships that held 20-30 tons of cargo. These ships may have resembled a type of cargo ship used by Swedish merchants in Kalmar. The ships were smaller than the cogs and clinker-built with a keel. They also had one mast as well as the German-built cogs.
The common people used open, clinker-built boats or snipes. These ships had their origins in the type of vessels used by the Vikings. The ships were about 5-12 meters long, very seaworthy and used for rowing or sailing. These could take a load of 2-4 tons. In protected bays in the archipelago, small dugout boats of oak or pine logs were in everyday use for fishing and for everyday transport.
Church paintings from Korpo church
