Archaeological divers from Denmark’s Viking Ship Museum have discovered what may be the world’s largest medieval cog, a merchant vessel, off Copenhagen.

Built around 1410, the exceptionally well-preserved ship provides new insights into northern European shipbuilding and trade.

It was found half-buried in sand and silt at a depth of 13 meters in the Oresund strait between Denmark and Sweden.

Named Svaelget 2 after the channel where it was discovered, the ship’s preservation includes the starboard side and traces of rigging, rarely seen in cog wrecks, Diver Net has reported.

Its stern castle offers the first archaeological evidence of timber-built crew shelters previously known only from historical illustrations.